SOKE ASPECTS OP THE CHSMISTRX OP N-BSOMCIAMIDES PAST X AN INVESTIQATIQN OF THE HOMCCLTSIS OP THE bond m schb n*bromqamides PART XX QBSSR7ATI0NS W THE REACTIONS OP SOKE H»EHOHOAMIDES TO® OUPXNXO COMPOONBS Sf Frederick V. M illard A THESIS Submitted to the School fo r Advanced Graduate Studies of Michigan S tate U niversity of A griculture and Applied Science In p a rtia l fu lfillm e n t of the requirements fo r the degree of DOST® OF PHILOSOPHY Department of Chemistry 1958 ProQuest Number: 10008600 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete m anuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest ProQuest 10008600 Published by ProQuest LLC (2016). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code Microform Edition © ProQuest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106 - 1346 ACKNOWLEDGMENT The author wishes to express h is deepest appreciation to Dr, Robert D* Schuetz fo r Me valuable guidance and h is friendship throughout the course of IMS work, Appreciation is also sortended to the Michigan Chemical Company fo r th e ir generous fin an c ia l support* 11 iii vim jtrwiI*B iftBI. Candidate fo r the Degree of Doctor of Philosophy Major Subject* Minor Subjects! Organic Chemistry Physical and A nalytical Chemistry Biographical Data* Date of B irth! February 10, l#31j Johnson C ity , Hew fork Father* Frederick 1* M illard Mother i Roaaine S. M illard Education! Hew M ilford Consolidated School I936~19h9 Pennsylvania S tate U niversity 19H9~1953 B. S* Chemistry Michigan S tate U niversity 1953 Experiences Graduate A ssistant Michigan S tate U niversity, September lp53 to December 1955 Michigan Chemical Company Fellow, Michigan S tats U niversity, January 1956 to October 195? Professional A ffilia tio n s! American Chemical Society the Society of Sigma XI iv asm aspects of thb egaastax of n-bromomcddes FAST X JgJWiiiVSKiXAU&iJiUJn W AulSl wl HXmOGM-BROMIKB BOND OF SOME K-BROMOAHIDES PART IX OBSERVATIONS THE REACTIONS OF SOME m m g lsfin ic mmmrnrn %r Frederick W. H illard AN ABSWCT Submitted to the School fo r Advanced Graduate Studies of Michigan S ta te U niversity of A griculture and A ffiled Selene© In p a rtia l fu lfillm en t of the requirements fo r the degree' of DOCTOR OF PHILOSOPHY Department o f Chemistry Year Approved 1£58 ABSmfcCt fM f I Mm abtewgpt mm to ot&dy otwot&ufal e ffe c ts open ttio honclybi© cleavage o f the H*®r bond o f IJ^roiaofciaideo* A oarto* of S^rcraoaaida# having structure* o u ltab le fo r a otady of th e e ffe c t of aromatic m~ and p*enib® titatim war# lxxrwtdpbed with the objective o f wmwmt&m ^ o m ta of th e rm l honolyoi# o f the feB r bond* She baoie structure* eon* oddetred. novas il^brosto&ootiEKRlAld#^ H^3(x>5tobotoSAsidbds* I q and to- th e oy&theotii o f thee© the $r©jjareblon of fl.ro fNNe9ee%&bnfett£ dariw bivee wrejwHked* ^ one previously ie described # fine lnfbajte z8eosaroz®ssit# iiiAAdfe .Mi^ateUUMa^ iMlw or nosieiyeto 1m J .^a: w o o^roooaoo — -— •*--- — -— -— — fcjr-^j?.—ay — ■or w wttiLeMi tiwaWwi ra carrying 00% the In th e presence o f fre e lad fe el scavengers to tra p the radfoeXa- fbwod In the primary preeene* fh© etabl® o rp n ie fro© radical* ^piory^y^m ferl, and wiuyl laonoouort ouch an nothyX jsMStlnioryloto and aoiyXositrlJLo hops eog&oyed fo r th in purpose* $to- roB otiw n fth oXaftae w o f@wd to bo dependent upon the o le fin eom eniraiicm , and the reaction© wltsfet « s p r o data O a t eould n o t bo- in trep reiM e ith e r in tom e of a imimolaoular docso^ooltion of the IMromoa&dde o r of a fe to le c a la r process involving both the and the bydmayX. th e photoiniti& ted reaction o f H ^ m i^ ^ ^ ltro a o o ta n ilid o with iolaeiw* w o fMnd t© yioXd 9h% of beaa^i bromide and 91*5$ of vl p ^ tre m a ta x iiiid * * A fv m m m m fo tm tfeio reaction* m&- w m tew im i s jiropoeed t© Uko ihansftl re a c t!m of N^roraobenwuaide w ith tolatm e wore £mm& to give nearly ^ewMBitltetlve ySelde o f fcenssyX hraiaMe. mm. n th e 3eeQtaiti& o f the abaorm l reaction o i and -dmtdeo with d e f in e leapfrog to th e addition of brojuins to the double bond e*»d the regeneration o f th e parent awlfl# m e in v e rt looted* The reeetletie of W*l>isa«ift^i«o4 $$$$ H^BPOnOhmmBidO With CSyoXohflODOtlO ffflA iw fw w IPHfW xtnu&G w 3Ta*#J*a W alJMw$93£Mgp ## m t In additio n to obtaining high yield® of th e p r o a i m dM e 1^enylM aaoyX area m o isolated* fo r th e f l r a t time* eo a reeotloij product lao Bs an -effort to bovojuX eeeee» the of rem tioini the e ffe c t o f o le fin eiametsire, mimm&- podtarilgr* fre e ra d ic a l tnhibX iera, end fre e mdieaX ia ltlo te # two- otndiM* She re a c tiv ity of JM&roiae** > fc^—.-^^ JSt^ w taim ^ *T ‘*I~rfrrtoirtiM fi e^xxp» !*■OrAlfrtiliMrm iM tiK ioUtA j m wy^i-jQd fe Jinoreao© t M *nM frirt*«*> «1rt -m iO aM to 'm dO rw ik.-eirtkl ortuort — ■— — emmm©# w m ■mliraQitiiam m *W Au»l[tS •"*•?*^- AA d f 4k^: ^taw*ttwiOu&Jfc. A la rg e inereaae 1b th e vote o f th e reaction o f w ith a H y l a c e ta te m o ebearved m ehanglag rmmMm m lvm t fttm chlorob^ioeae to oitrom em aae. &mx&bm&mw9 j^^tarinitrobm o.«ne, and aoo^io^aoim tyroiiitrlX e were determlBed to have m rnmmmfal® of fe e t upcm the ra te of the vii of K^rora0 fe0 iawjild« oitb a lly ! aoot&t® in nitroaothoii* a t 36°. Wm troadwatiou of bo%h g|g<* aod toma*B tilb^e «ith B^ittsaoboims^o ««« dbmn&*& to yt«&& N^roaob«H®~ a& lO o00$ fO ararit to $spM 3^ ©stoly&e' tbo into i^y^**tS33Nm s> fbio liO O oo^ifioatiMlO M ft foond to © ootsr ^sadtisr m riU M * oo^itioH® iMpi tho bi^M lsiatlois x^asotloa ims w^wflSy #$0 0 * tlio INNriiMMMl o f assfMsybe&ao&o &&<£ ^jfl^^lnltrob^ntSOQo nos iflMioii to haire mo Offset tpO HtbO5 S O K IO Ifd .B B t3 U 3 ® l• * H m ® O f thO O 0 optf& eo& o of too horotofo^o soiss^wtos a3«soho3.^ ooototo tty!^ fbS E O O O tlO ll #f ^w ta^||g^00S5ti3lM 0‘ O & tb t ooo to ylold. o T 0y SON# OooofrfOod* Oootato la s& ttaiio*tfifflfi f??#fi00% l!t8 ! tfoot tbs oytyfr^ i# B ydjfogoo of t$$# olofia oabsimts 6w net tb# soaapeo of tbs b s^ iP O & iW iO hioh yooX aooo tbs b $s& 2 i& o -^-3 Sf.c a1 jk tb jt0 e. tO L v|lO fahlB tM aF a'h frtO ifcW H f^ cfr3 ^aE ifciifrO fttfS % .* @ 5 8 * S * P ^ I Apolar Is propoood for tbo otemsl feroM mtloxi & 0880tiO ii* v lil V TABLE OF CGBTMTS FART I AH IMVESTIOATION OF THE H0H0LYSI3 OF THE NITRO(OT-mOMBrE BONB OF SGMB N-BR0M0AMIDE3 Page IHTROIflJGTIOH 1 H IS T O R IC A L .....* .................. D iscussion . . . ......... .................... EXPERIHSNTAL. . ................. . . ........ . . . . . . . . . . . . . . . . . . . . ................... Reagents and A p p a ra tu s.... ................ A nalytical R e a g e n t s . ........... A nalytical Methods• ......... lodometric Analysis of N^broiaoacetanilides ....................... lodometric A nalysis of K^Bromobensamide and N-Brorao -phenylacet&mide ......... Determination of the Rate of Reaction of N-Bromoamides •with O lefin s.. ........... The Decomposition of H^Baromoamides in the Presence of o#« - ■ D ip h eiy l^» p ie^ l3 y d rasy l. The Reaction of H~Brorao^*«nitroacetanilide tilth a,a-Diphenyl-f? picrylhydrasyl in the Absence of Oxygen.. . . . . . . . . . . . . . . . . . . . . The Reaction of M^Bromobenzamid© with Tolnene. . . . . . . . . . . . . . . . . . . The Reaction of H~Bromo^~pheiylae©tamide with Toluene ......... The P h o to in itiated Reaction of B^Brorao^~nitroacetanil±de with T o l u e n e * Preparation of H-Bromoamides ....................... . . . ............... H-Broino~L~n±troac etanilid© ......... N-BroiriO*l4-*broinoacetanilide ........... N-*Bromo»li»chloroacetanilide. ......... N-Brom o^ii-trifluoromethylacetanilide ............. M»Bromoacetanllide.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H-Bromobensamide. . « . . . ......................... . . . • .......... . . . ............ H^Bromo*-i4HEiitrobensamid.e. ......... H*Bro*M^^h©^ylac©tamid© ......... Preparation of Amides. ......... p-Broiaoacetanilide ............. . . . . . .................. . . . . . ......... . 1. p*C hloroacetanilide. ......... a^^^enylaeetamide* ............. p-Hitrobensamide .............. ix 2 10 37 37 38 38 36 39 39 I4.0 U2 k3 Uk U£ k6 1*6 1*7 1*8 k9 k9 £0 £1 £1 £2 £2 £2 £3 £3 M L B Of CONTENTS * Continued Page Preparation o f a^a-D iphenyl-f ^ icry lh y d ra zy l . . . . ..........♦...............•. N^itrosodipheixylaidLrie ........... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ,l^Bipheiylhydrassine H ydrochloride ........... I,l-D iphenylhydra 2in e , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . •• a , *♦ . . . . . . . . . 51 51 51 55 55 Preparation o f p ^ ceti^ clo h en zo trifiu o rid e. , . . . . . . . . . *, * . , . . , , . , p*$it37©henaai Bromide. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . p ^ itrc^ enaotrihrc^ aid e.'.. . . . . . . . * . . . . . . . . . . . . . . . . . . . . . . . . . *. . p-NitrobenzotriflnoridQ. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . •. . . . . p*Ac©tamidobem soiriflu o r i d e , . • • • . . . . . . , * . . . . . . . . . . . . . . . . . . . . . 57 57 58 58 59 a ^ieryX hydrasyl . ,, * . . . . . . . . . . . . . . . . . . . , 56 PART XX oBsmtmfxoNS on *m reactions of some with m m m m compounds ima&OBUCTioN..,., , ......................................................... 6o HISTORICAL ................... 61 DISCUSSION...., **..................... ........ , .........................................?8 HXPBHMBNTaL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............. 118 Reagents and A p p a r a t u s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 Reactions of N^Bromoamides with Cyclohexene. . . . . . . . . . . . . . . . . . . . . 119 Reaction of H ^Broisio^-^itroacetanilide with Cyclohexene. . . . . . XL9 Reaction of N->Bromo*%fffint fftftfftff Wl< m± ©f iMMkfS^iStVl.'tym f& t to ito 1y $^S0$Jt§J& t* gt$ pNpiSBldVS |f#ll#|, 1sbs W $^ #» ^ to tffijftfflfr Ih0 Q U ipjrWEWKw^K# T JfwiW R ^ w rA w ^ > m iw w 3 1 l* * I JW w rjiiiIw S SW w P P a IW B * 4 2 S 3 JPiW lirV S P B ^ jAAfllhAfcA JEtfe ’ltak-^k. J5ft'U ffr-iBt \^/$ JFiMk\ ■ fW >J&M lh^ft'* 4 fca&:At4iMtfk wwWWJkS iftllftitfW ifefcAttfci A liHMMIMfJibAft'A «33FV n* wWp4W"vW® %Mb1te % m lPuL J&| tfcfA #&&$ K £m!wmr SS^gKaat, A}lsw 9* 6-tetrachloroacetanilide. The observed ca ta ly sis was inter** preted by Robertson and Waters as re su ltin g from the thermal decomposition of the p o sitiv e halogen compounds to y ield free halogen atoms and free organic ra d ic a ls, both of which could then a c t as hydrogen ab stracto rs and in itia te the autoxidation of te tr a lin . RRX RN* or x . ------ RN* ♦ + CxoHXa, HHH or XH ♦ CX0H1X* ":”'V I '"n"'r:'r'm C 10^X3 * CXOH10 - 0 * X* 0X$HXXOK)* ‘ "•■■■■■in nrvr*. CX0HXX* ♦ CXqHXX0*OH T heoretical Ju stific a tio n fo r the fe a s ib ility of hemolytic d isso ci­ atio n of the N-Br bond in N-bromoamides and -imides has been postulated by Waters (10, 11). *»*>-"« H H The dipolar character of most halogen bonds, e. q. C— HBr, favors h etero ly tic dissociatio n into a halide anion. However, i f the p o lar character o f the h alide bond i s reduced by introducing in to the molecule m oppositely d irected moment, such a s e x ists in an N^^romoamide doe to the p o larizatio n o f the carbonyl function, e .q . 0 R I * «»——»« n f p *> Br> th e o re tic a lly the charge d istrib u tio n of the ♦ halogen bond can be made so uniform th a t in mm^polar media the fo r hemolytic d isso ciatio n i s le ss than th a t fo r1 h etero ly tic d isso ciatio n . There can be no question th a t the in itia tio n of chains in the Bloomfield mechanism can be brought about by paths other than thermal hemolysis of th e N«*Br bond. Schmid and Xayrer (12) hare demonstrated th a t th e inclusion of c a ta ly tic amounts of benzoyl peroxide in ce rtain brom im tions with H^remesueel&tmide not only g reatly reduced the reactio n tim es, but i t also made possible the brominetcion of some compounds previously considered in e rt to M*broiaosuecinim ide, One such compound, toluene, which is not attacked by K~bromosuccinimide in the absenca of lig h t or a fre e rad ical producing c a ta ly s t, can be bromlnated to y ield 6k% of benzyl bromide when the reactio n is catalysed by benzoyl percod.de (13) , This fa ilu re o f N^bromosuociniraide to re act therm ally with toluene would seem to in d icate th a t, under the conditions of the reactio n , N^romosuccinimtde does not d isso ciate appreciably since the reactio n of a bromine atom with toluene to y ield hydrogen bromide and a benzyl ra d ic a l i i known to be a very fa c ile one (3JU). However, the fa ilu re Of N-bromosucciniiaide to re a c t with toluene is not general fo r a l l N«4>romoamides. For example, M-bromoacetamide reacts vigorously with 5 toluene in the dark a t 90°G * to give & nearly q u an titativ e y ield of bansyl bromide (4)* Bau*Boi (15) he* found th a t B^romosucetnimide w ill rap id ly brominate dipheryUaebhane end toiphenylnethane, without c a ta ly sis In refluxlng carbon tetrachloride* to y ield $1% of diphenyl** methyl bromide end 62$ of tripheiylm ethyl bromide respectively* la te re end Ford (16) have shown eonoluelvely th a t the: te rtia ry ra d ic a ls* "M ow to he prodnoed by the thermal decoiapositlo n o f te rtia ry ase^Offlpeus^e* h h » o (x )n * m { x ) m * ■■M && . (E end E* * alk yl* 2r r * ( x ) c . ♦ sa X * OB or 00^ % ) cataly se the hemolytic bromirmtions of K-brexaoimecInlmide % ab stractin g a bromine atom end generating a chain carrying smccinimidyl ra d ic a l. ♦ B E * (X )0 the decomposition o f *^ s o ^ a ^ e th y lb n ty ro n ltrile ) in the presence of B^bromosuec inimide in carbon tetrach lo rid e solution resulted in a vigorous reaction from which could be iso lated (±) -*a'-bromo-»a-methyl^ T m tyronitrile in 39% and m eeiniraide In 20$ yield s resp ectively. 0 CH3GH3 ♦. L *> GU^GEffi ~ GN + 6 He evidence fo r the form ation of any disuccirw ylftydm ai^ was obtained, in d icatin g th a t the fre e succinim idyl ra d ic a l must be a very strong hydrogen a b stra cto r In accord with the view th a t In a lly lic bromin&tion 1% Im th in ra d ic a l i&leh is th e effectiv e hydrogen a b stra c to r, and not atomic bromine, However, i t should be noted th a t disueeinoyl hydraaine i s as y e t unknown and repeated attem pts to prepare i t have been, im suecesafal (17), fh u s, i t may be th a t disuccinoylhydraaine is an inherently unstable molecule and incapable of is o la tio n , hence any argu­ ment based on a fa ilu re to is o la te i t would s e t be, on a very so lid basis* For th e reactions o f m* and ^ s u b s titu te d benaene derivatives the o ffse t of stru ctu re m re a c tiv ity is nearly always determined by a sin g le basin fa c to r | the po lar e ffe c t o f the su b stitu en t. the most widely known relatio n sh ip applied to co rrelate the e ffe c t of su b stitu en ts on ra te s o r e q u ilib ria .of reactions involving m* and p -su bstitu ted bmzm® deriv ativ es has bean ih© Hammett equation (7) log In th is kAo m cr/ ° <2 - , the sn b stlta sn t constant, is re la te d In sign and magnitude to th e a b ility of th e su b stitu en t to change the electron density a t the reactio n cen ter, and f* , the reaction constant, is a measure of the su sc e p tib ility of a given reaction to polar effects produced by su b stitu e n ts. the te rn , log kA o, represents the logarithm of the m tio o f the ra te or equilibrium constant of the su b stitu ted compound to the ra te or equilibrium constant of the unsubstituted compound. 7 1953, 111 d iffe re n t Substituent constants and 379 reactio n constants hud appeared in the lite ra tu re making th e HaMnett equation a p o t« etiftl expression e f i w (IS)* 1*2,000 rah© and equilibrium com iants The overwhelming m ajority of th is work baa been ©oaeerned with ntkn*9fftdlt$si3. reactio n s * However, I t ha# been &©mon»1a&i©d in recent year# th a t th e Hammett equation can be successfully a l l i e d to some reactions involving the formation or reaction s of fro© radicals* Forthermore, i t has hm n deraoa&ij^hed th a t although hemolytic r ©actions do not te w lv a ©barged interm ediates, polar effect® m y mmm* thelesa hare an inporfesmt influence m th e ir reactio n rates- (19)* The d isso eiatio n constants o f variously su b stitu ted hexarylethanes , determined by Marvel and hia ®0Hs»i!ksrs (20), could not be co rrelated by the Hammett equation aince i t m s found th a t gmbetituente with eith er p o sitiv e o r negative m $M m increased the degree o f dissociation* For several years th is fa ilu re of' the B arnett equation was regarded as evidence th a t a l l free ra d ic a l reactions were outside the scope o f the IwMMk JrtL _1>Lftl1rfJ*UL Haiissetw equation* The f i r s t successful app lication of the Hammett relatio n sh ip to a fre e ra d ic al process was th e study ©f the e ffe c t of su b stitu en ts on the ra te o f sons su b stitu ted bensoyl p erad d es reported by Swain, Stockmeyer, and Clark (21) in 1950* the ra te s of the unim olecular, spontaneous therm al d isso ciatio n of sixteen 'm and p-*substitut@d benaoyl peroxides into two su b stitu ted bensoate ra d ic als were found to f i t the Hammett equation closely* 8 In Hm fjt f fcff f# tvtm thflf ^p sw l^ nnnsiiwniiii hms y tg ^ lOTMH ttMtfv* ifffft$i$ im is^r Hm HUM*S% rydr'ege« to ab stra ctio n . ©Mgr «!«» foaau « w t «se »«a*i4t’rttcr of th e reoatien to Hama pels? effo o ts inereoeag uttfe t i e iaswMrtng e le e tm w ^ tf r tty o f Vm afeoteaattBg ra d ic a l, 1.®.* 0 9 from a consideration of th e foregoing data and observations, i t seemed th a t I t might be possible and of considerable in te re s t to synthesise a se rie s of su b stitu ted U*broiaoai5ides containing a phenyl rin g to carry the su b stitu e n t, and to determine the ra te of homolysis Of th e $*®r bond In. some non-polar medium. Furthermore, I t seemed very probable th a t th is data could be successfully treated by the H&ianett e q u a tio n * to the present tin e , m attem pts to measure the ra te of homeOysis o f th e H**Br bond in p o sitiv e bromine compounds have appeared in the lite r a tu r e * 10 m sm m xm £h* m m described in th is p a rt o f th e th e sis can fee divided in to tm parts* f i r s t , the synthesis of the N-feroBJoamides, and secondly, the attem pts made to measure th e ra te o f hemolysis of th e Jf*®r bond o f the H^romeamidea. the p rin cip al stru c tu ra l requirement in th e choice o f an N^romoamide, fo r the Investigation described h erein , m s th a t i t contain a bansssne ' rin g in th e molecule* th is m s a necessary p rereq u isite since I t m s the primary objective o f th is mrte to study the o ffse t of p -su bstituents on the ra te of hemolysis of th e IHBte bond fo r a serie s of N^romoami&es s ith th e expectation th a t the data Obtained could fee correlated by the ap p licatio n of the Hammett equation to such data. A search of the lite ra tu re revealed three basic stru ctu res th a t s a tis fy "this requirement* (1) K ^rom oacetanllide, (XX}W^3roiaobenaaiid.de, and (H I) H ^ro n o ^^ h ei^laeetaisid e. HBrCOGH3 O THBr CHgCOJEBBr Of the three stru c tu re s, i t m e decided to in vestigate the H^ferono* ac etan ilid e stru ctu re in itia lly since any polar effects produced fey a p^substituent should fee a t a mmimm in th is stru ctu re re la tiv e to the oth er bm* This wmM fee tru e since in the N**feromobenaamide stru ctu re 11 the polar e ffe c t of a m M tlia m t of n ecessity bo relayed th r o a t the carbonyl function re su ltin g la a "damping e ffe c t," and in H-bromon ^enylaootaiaido the su b stitu en t o ff not baa to bo transm itted not only through the carbonyl function, b u t through a methylene &r©up aa noil* . ■v Ihoyofoiron of tho th ree stim etu res, the M ^roiaoacotanilide is unique In th a t tho nitrogen atom carrying th® bromine Is d ire c tly bound to th® bonaen® rin g carrying th® aubotitneni. Son®, ju s tific a tio n fo r th is lino o f argument i s based on a consideration of ®“ S *t*£ U r values fo r a stru c tu ra lly I * " - *** V * m m aiM M m o t m awl p -au b atitu W bensoic acid® in aqueous solution a t 25° 1® by d efin itio n 1*GG, VhtXe th®' p value fo r the d isso ciatio n of m* and p^substituted phenylacetic a c id s, under sim ilar conditions, is 0 *k&9 (2k)* Another d esirab le featu re retained by the H-^bromoace ta a ilid e stru ctu re is th a t i t has m oarbewyi group d ire c tly bound to the nitrogen carrying th® bromine* As previously discussed, th is fa c ilita te s homolytic rupture of th e H-*#r bond because the moment Induced, due to th® p o larisatio n of mwmrniwi* the carbonyl, tends to oppose th® moment of the 3? <# Br bond Vhieh normally fSvor# a h etero ly tic cleavage* The synthesis of M-4>romoacetanilides presents several problems * The p rin cip al on® 1# th® extreme f a c ility vrith shich these compound# undergo an acid^catalysed rearrangement to nuclear bromineted acetan llid es (25). Other e x p lic a tin g featu res are th e ir se n sitiv ity to h eat, lig h t, and hydrolysis* The rm rvrn g m m tf know as the Orton rearrangement, has been the subject o f a considerable amount of research since i t #as f i r s t Observed by Bender in IBM (26). I t is su ffic ie n t fo r the purposes 12 o f the present discussion to not© th a t in hydraxylic solvents the rearrangement ha# been established to be on interm olecular process (25), sfctiXe in ap ro tic solvents, B ell (27) has found the rearrangement to be a one-stage intram olecular process showing general acid c a ta ly s is . B ell found i t possible to sto re solutions o f H ^rom oacetaiiilides in a v arie ty o f ap ro tic solvents in th e absence of lig h t, and a t ambient tem peratures, fo r .indefinite periods of tim e, th is observation, together' with the discovery by Blaak&ma (28) th a t the Orton rearrangement can be in itia te d by lig h t, suggesting a homolytic mechanism, encouraged the synthesis of these compounds fo r in vestig ation from the standpoint o f the present work. The procedure fo r the preparation of H*bromoacetanilide most frequently referred to in the lite ra tu re in th a t due to Slossen (2?), and involves the brondnation of a c etan ilid s by means of sodium hypebrom ite in. a very d ilu te aqueous boric aeid-sodlum tetrab o rate b u ffer. B oll (27) found th is procedure to be su itab le sad obtained samples of H^broiao&eetanilide containing 92*$?$ of the calculated amount of activ e bromine. However, in our hands, repeated attem pts to proper® H-bromoaeetabili& e by Slossen1s procedure fa ile d to y ield a product of g reater than ?1$ p u rity . The synthesis of H*foramoacetanilide and four p -su bstitu ted d eriv ativ es of sa tisfa c to ry p u rity m s achieved by the use of a procedure modeled a f te r a preparation o f N-^broKmcetanilide reported by Orton and Chattam y (30). th is method involved shaking suspension of the aeet& nilide in chloroform with a d ilu te aqueous solution of hypobromous 13 m M ecmtainlng $% of potassium bicarbonate * In general, the parent aa etan llld e s im m not appreciably soluble In chloroform while tfee K ^rojim cetanllidee are ^ a ite soluble In th is solvent, the procedure th erefo re yielded a chloroform solution of the desired N-»bromoacetanilides from idiloh th e prom ote could he iso lated by concentration of th e ir dhtoroform solutions a t room tempemtnrs and p re cip itatio n of the an ilin es with petroleum e th e r. I t was found th a t th e p u rity of th e N*fcro*aQ«* aeetan illd ea m e se n sitiv e to. th e p u rity of the chloroform and petroleum eth er employed in th e ir preparation* Chloroform freed o f l i e alcohol e ta h ills e r lay a thorough washing with m te r, and petroleum eth er, b .p . 30*60**, from which uneaturatee had 1mm removed by washing with concent to tte d su lfu ric seM* were found to be sa tisfa c to ry solvents. However, m m -after taking these precautions, occasionally during the concent ira iio n step the reactio n solution would rap id ly besom* f ille d with a so lid which proved to be nuclear broiainated aeehantlide. In .all. fiv e IT^romoacetaxiilides including one not previously described, (H ^oiK 5^^riiluorom © thylacetanilIde), were prepared by th is -general method# The preparation of H^romobeusamide mid M*bromo**a^henylaeetamide presented m d iffic u lty , and they warn prepared in good y ield and p u rity by known methods (1*1) • Table I l i s t s th e M^bromoamide® prepared, th e ir y ie ld s, p u ritie s , and m elting p o in ts, th e y ield s and p a ritie s in Table I represent the b e st obtained fo r those preparations th a t were repeated# Ih JJVJwbgi JL tssss&mssgsxs P eraoat Y ield K « n # e* H**<®roi^oetanilijd® 53 86*^8 9 9 .7 If^ r o r a o ^ ^ l.’feroac©tianiJULd© aa 1U 5-U ? 9 8 .0 K ^Broi^44^3?oim m cetam ilicie 13 126-123 9 8 .O N’* ^ w m ^ 4i^ iloroao et& siilid e 71 85-89 9 0 .5 73 n 3 -n it 9 7 .2 H^03^*^**-phaa5rlacetaifiici8 77 12ii-12U .5 9 9 .1 !$*^roBiob©iiiaaifli€is 75 *5 129-130 9 9 .9 H#®romo^U"^trobea5iamide 51 199-201 9 6 .5 M,^BroBioaiftl.d0 V ^ l I k-c^tohe3sae and. succtotoMe as the major produots resulting fseom the reaction of l^roisotocototoide and cyclohexene to WMely interpreted && mMmm® for a free radical chain mechanism. Indeed, Park and ©©^worker© (3k) have w ad the rati© of the- y ield o f 3teomoeyclohexen© to th a t of the -addition product, X,2*dfbr©mo©y©io* 'AaiM>^'idiA asa>k afea W namidQ employed as a broradnating agent. Vigors I I illu s tr a te s a p lo t of the log of the th io su lfate t i t e r rmmm t e e fo r t e d iffe re n t i n i ti a l concentrations of cyclohexene. AS to toe ease of the reaction with methyl methacrylate, toe reaction rate to pseud© first order with respect to the Ifteoisoate© tod dependent upon the cyclohexene concmtetion. A product analysis of this reaction resulted to toe isolation of p^trotoettoilld© to 78$ yield, ^ggg»l>2* dtor^yclohexane to 18$ yield, and Jteomocyoloheren© to 12$ yield, toe description of the experimental procedure and. a mtm complete dto* casston of toto reamtem will be taken up to toe second part of this toeato which to concerned with a more detailed study ©f toe,reaction ©f 19 0 0 0 4.0 2.0 Thiosulfate titer in ml 3 .0 .9 0.8 .6 4 10 Time, seconds x 10 F i g u r e I I . — C o n c e n t r a t i o n of N - b r o m o - 4 - n i t r o a c e t a n i l i d e v e r s u s time for the r e a c t i o n w i t h two d i f f e r e n t i n i t i a l c o n c e n t r a t i o n s of c y c l o h e x e n e in c h l o r o f o r m at 51.9°. C u r v e A, c y c l o h e x e n e i n i t i a l l y — .81 M. Curve B, c y c l o ­ h e x e n e i n i t i a l l y — 1. 3 0 M. 20 N^romoamidea with o lefiae re sta tin g in the addition o f bromine to the Wmfom m& SteCoy (35) to re Shewn th a t cyeaohoKens hydroj^rcoeiria, m m & ty present in c p k ^ » th a t has not been sp ecially p u rified , eaeerte a marked p o sitiv e eaiaXysle on the reaction of K^romosueolnljflide with eyolehe&ene. th is wee also found to be tru e fo r the reeotion of IC -^rojea^i-^troacetanilide with eycletescme, although not to such a marked decree* fig u re I I I shown a p lo t o f the. th io su lfate t i t e r against tin e fo r ■ the reactio n of B*bromcsuce inimide with two d iffe re n t cyclohexene samples in ohlorobieizjene solution a t ± 0*1°. ®ae i n i ti a l concentration of eyclohssxene and K^brc^irueeinlmicle m m 0*1U6 M and ®*pl H respectiv ely, The eyclQhecxene used to Obtain the data illu s tra te d by curve A m e obtained by d is tillin g a good commercial grade of cyclohexene through a packed coXumn and taking a middle fra c tio n fo r study, The cyclohexene used to obtain the data in curve b m e p u rified by m aking a sample of re d is tille d cyclohexene with M a<|uaous ferrous ajmaonium s u lfa te , drying in contact with anhydrous calcium s u lfa te , and fin a lly d ist i l l i ng i t froia mdinm w ire under a nitrogen atmosphere, This sample m s stored in contact with iro n wire and under a nitrogen atmosphere in a brown, glass fla s k , fig u re VT illu s tr a te s a p lo t o f the th io su lfate t i t e r versus itra© fo r the reactio n of N ^ror^^^nitro& cetanilide with 'the two d iffe re n t cyclohexene saaples described above, 'The i n i ti a l concentration of H ^ ro io o ^ ^ tro a cetan ilid © and cyeloheocene were 0*102 M and 0 ,p l M respectively* 21 5 hiosulfate titer in ml 4 2 1 10 Time, s econd s 12 x 10“ F i g u r e I I I . — C o n c e n t r a t i o n of N - b r o m o s u c c i n i m i d e versus time for the r e a c t i o n w i t h d i f f e r e n t samp l e s of c y c l o h e x e n e in c h l o r o b e n z e n e s o l u t i o n at 51.9°. Curve A, sp ecie n y purified cyclohexene. Curve B, r e d i s t i l l e d c y c l o h e x e n e . 22 8 7 in ml 6 Thiosulfote titer 5 4 2 1 0 Time, sec o n d s x 1 0 ” ’-'. F i g u r e I V . — C o n c e n t r a t i o n of N - b r o m o - 4 - n i t r o a c e t a n i l i d e v e r s u s time for the r e a c t i o n w i t h c y c l o h e x e n e in c hl o r o b e n z e n e at 51.9°. Cu rve A, s p e c i a l l y p u r i f i e d c y c l o h e x e n e . C u r v e B, r e d i s t i l l e d c y c l o h e x e n e . 23 A consideration of these d ata, together w ith the previously mentioned observation th a t the reaction of H*brorao**U*niiroaeetaailide w ith cyclohsxene y ield s a s m ll amount of 3^bromooytslohe5Kene, suggests th a t th is reM ilo n m u follow two eim ltaneoua ro u tes, on® leading to th e formation of a dibromide* and the other leading to l^roraocycloheseen© m& allowing hydroperoxide M tftlySfs. Solutions of ^ rc M H ^ ^ ^ tm o e ta n llid e ' in toluene m m found to he reasonably stab le to d iffu se lig h t, but exposure to lig h t from a strong Mazda bu31> resu lted in a rapid formation of bromine in the solution and p re c ip ita tio n of p^nitroac etamilld©. On continued irra d ia tio n the bromine d isap p eared as w ell as the sta rtin g M^bromoamide * Benzyl bromide (9U$) and p-*nitroae©tanilide (91>£$) were Iso lated from the reaction m ixture. % No evidence fo r hydrogen bromide evolution was detested during the main course of the reactio n but a sm all amount seemed to be present in the very l a t t e r stages of the reaction* A mechanism co nsisten t with these observations can be w ritten 1* p-dJOaJO^J^rGOeHs <**«■*-------+ Br* t« ^(No^jaA^GOGH^ ♦ m ar* **#*-*» pmjh** ♦ m m ** ♦ B®r i« Br* # PhGHa ** It. p-KBOftiOeHJIBrOOCH^ * HBr JU Br* jr**hboochs ♦ Br* 2Br* 6 . ?W3H,* ♦ jKW s ^ iW®*®008. — * ♦ p(BOa)CaH.t *HCOGH3 2U ?* mmm* % tr * w m e , ♦ Br­ ib e re la tiv e eonti^btttion of steps (6) and (?) to the formation of benzyl bromide mxmot be estim ated without ad d ition al data. However, judging from the a ffe re n t b u ild u p of bromine concentration daring the coarse of th e reaction Step (?) must be iraportant. the formation of hydrogen bromide, occurring only* a t th e end of the reactio n , is consistent with the. proposed mechanism in th a t hydrogen bromide should be released only a fte r th e disappearance of the K^romo4i^nitroae@ tanilide * Hnlike the N*bromoacetan ilid o s, l«*foramobenzamide and N-bromo*ta«* phenyiacetamide were found to undergo th e rm l decomposition in chloroform solution with the formation of bromine and small q u an tities of the parent amide* m carbon tetrach lo rid e solution bromine was the only Id e n tifiab le product o f the decomposition, the other iso latab le product being a red amorphous so lid which did s e t melt below - these observations suggest th a t the IMSr bond of these M^romoamidee does undergo a thermal hemolysis. However, lik e the H-bromoacet&nilides, N~bro^benzamide and N*«bromo-£i^ j^snylacetam ide react with olefin s in ajxrotic medium to y ield dibromidea. th is of. course prevents the use of a vinyl %P© in h ib ito r to remove the ra d ic als formed by the i n i ti a l hemolysis* AooimiingXy, i t m s decided to attem pt to adapt the procedure dweloped by la m and M dllish (3 f ) fo r the determination of the ra te of hemolysis of benzoyl p ^o xid e and aso-feis-isobutyronitril® * Their procedure employs the stab le free ra d ic a l a,e-diphenyl^ ^Icrylb y drazy l 2$ for the rad icals produced by the i n i ti a l d isso ciatio n . as & scavenger Ik© « #G*dipher5yl*f ^ieryljhydracyl ha© the advantage of being deeply colored so th a t th e ra te of i t s disappearance can be eonvlenily followed spec traphol^i^ t r ii^ lly * For Ike purpose of illu s tra tin g the method consider the following reactio n sequences B»#a £B&0* $fisQ* ♦ 2H- «ii»iH Tw rw>i|iW W W #0»' (slow) Products (fa s t) Inhere B3 20 2 represents benzoyl peroxide and H* re fe rs to a,a^-diphenyl-f <* piezylliydrasigrl* The ra te law fo r the disappearance of «, a^±phenyl-f ^icry lh y d razy l can be w ritten m m {BSfflpa) > > (H*> ** Sk^BSaP^) * constant Mmme the reaction becomes aero order in hydrassyl and a p lo t o f (H«) versus time should be lin e a r. M m and H ellish demonstrated th a t solutions of ©,a**diphenyl~fB ^ icry lh y d raay l obeyed B©er*e law and therefore a p lo t of absorbance, which 1® d ire c tly proportional to (H*), against time should be lin e a r, The slope of th is p lo t i s proportional to 22cx(Bi&202) and a knowledge of the bensoyl peroxide concentration would permit the evaluation of kx. 26 If* ea toe other hand* to# reaction were to proceed b y & blaoleeular presses such it» B*sPa * H* BsO* #■ H* ka a Product ♦ BaO* ■wwhmi-'iio Product toe m te law fo r toe disappearance of and to to dpph (slow ) (fa s t) would fee > > (H* ) i t becomes « «M *M e)£*'*> Hence toe reactio n * M C I*) &mpseudo f i r s t order in « *diphoiiyl*f ^ ery lfay d rasy l end & p in t of log {H*> or log absorbance ag ain st tin e Should fee lin e a r, to e Slope o f th is p lo t i s proportional to $&*($*#*) and a knowledge of to e benzoyl peroxide concentration would perm it toe calculation of ka. By to e use of th is procedure Been and H ellteh were able to obtain f i r s t order ra te constants fo r toe spontaneous thermal d issociation of benaoyi ptmmMm and aao^is^sofeutyT O niirile th a t were in good agreement w ith data* to theory toe method should fee applicable to toe d isso ciatio n o f an H«feromoamide.- toe p rin cip al difference feeing th a t toe proposed hemolysis y ield s two d iffe re n t rad icals ra th e r than two lik e radicals* to is does not complicate toe k in etics provided, to s t both radicals, re su ltin g from to e primary process re a c t rapidly with hydrazyl rad icals to form stab le products. 27 Solutions of a Ja'*dlphenyl"p -^ierylhydrazyl in chlorobenzene ware found to re a c t w ith the th ree types «r H*toromoamldea studied in the present work, the deep purple perraanganate-llke color o f the c^e-diphenyl- p -piorjrlhydrasyl m s observed to gradually feds and eventually become lig h t yellow then oKLorobenaene solutions of the hydra z»yl were warmed with the N-toromoamidee. A seen of the v isib le spec tram of & reaction mixture before and a fte r reaction Indicated th a t the products absorb appreciably below 600 m and therefore in te rfe re with the spectrophoto^ m etric estim ation of T5 *I £ O -P o • < 1) £ Q, O CO-H -P -P cc o I—I H .70 58 0 1 O Ti ne 3 4 5 in hours. F i r u r e V I I I . — R a t e of the r e a c t i o n of IT-bromo- o( p h e n v l a c e t a m i d e w i t h qL, - d i p h e n y l - ^ - p i c r y l h y d r a z y l in c h l o r o b e n z e n e at ,57.5°. at 700 mu 32 M o .5 0 2 4 6 8 Tim© in h o u rs . 10 12 Figure IX.— Rate of the reaction of N-bromobenzamide with jt, K - d i p h e n y l - >5 -picrylhydrazyl in chlorobenzene at 90°. o 86 Log (Log — =— ) at 700 mu 33 82 78 74 Tim e in hours. F i g u r e X . — R a t e of the r e a c t i o n of N - b r o m o - X - p h e n y l acetamide with ^ - d i p h e n y l - / - p i c r y l h y d r a z y l in c h l o r o b e n z e n e at 5 7 . 9 ° . 3b flp sr* F it shorn a p lo t of log XAq verm s time fo r the reaction of »4ireatt0^ in ol^Xorobommo a t p0° ± 0*1°. the i n i t i a l coco©en tra t ions cof c #a ’^ phe»yl«$ ^icrylhydrassyl and K4>rcnio-4i-«*xltro*» ae etan ilid e nere 1 4 x X® ■ M'and £*& x 10 K respectively. f£g$M f t H shews a p lo t' o f log l / l 0 versus tin e fo r the reaction o f K4>ro»ro^^h«icylaceta®ide trith a fc-»*diphenyl-f *picryll^draiByrl in ChXero* hmmmo a t 5? *9® ± 0 .1 °. The Xaltt&X concentrations o f fcy&mttyl and Here X.j> x li* 1* M and $*$ x ltf** & reap eetty sly . Figure XX ahem a p lo t o f log lA© ag ain st time fo r the reaction of a t an concentration of t* $ X .wS 10 HW ith w* ct,'«U«*nitroacetanilide was prepared by dissolving approximat ely 1 g* of the an ilid e in chlorobenzene th a t had been freed by a i r by bubbling a rapid stream of nitrogen through the solvent under reflux* The nitrogen used in th is experiment m s water pumped nitrogen, p u rified f i r s t by passage through Fleser* s solution (U9) to remove oxygen and then through a column of activated alumina to dry i t . F ifty m illilite r s of th is solution m s then tran sferre d , by means of & p ip e tte , to a nitrogen f ille d 100 ml. volumetric flask to which a sid e arm f itte d with a rubber stopple had been attached. The solution m s thermostated a t 90 ± 0.1° and a fte r eq u ilib ratio n , i t s concentration m s determined by the iodometric titr a tio n of an aliq u o t removed by in sertin g a hypodermic needle through th e rubber stopple. The solution m s found to be O.Ohl M in amide. A funnel, through which a rapid stream of nitrogen was passing, m s supported over th e mouth of the reaction flask and a quantity of o,c-Hiiphenyl*f -picrylhydrazyl su ffic ie n t to produce an absorbance in the range of the spectrophotometer m s rapidly added. A fter sw irling the flask in the bath to e ffect complete solution of the hydrazyl, samples were taken a t known time in te rv a ls, with a hypodermic needle inserted h3 1 the rubber stopple and th e ir absorbance a t 700 xau determined with a Beckmann model XSJ speetrophetojmster using 1.0002 cm. corex c e lls and a s l i t width of 0*01*2 mm. The data obtained is siumaarizad below* Time (sec.) Absorbance 0 0.632 2,1*70 0*632 6,120 0.6U5 10,590 0.653 Ik ,268 0.653 A fter rem itting in the constant temperature bath fo r two days the solution m e a deep brown in color and i t s absorbance a t 700 mx was too high to perm it measurement* On cooling the brown solution deposited a small quantity of a lig h t tan solid* This m aterial was iso lated and found to molt a t 207*209°* A fter recxystaiU isation from d ilu te aqueous ethanol* the m elting point increased to 210211° , and a mixed m elting point with an authentic sample of p ^ tro a e e ta n illd e showed no depression. .The Into a 100 ml* volumetric H ack were placed 1.0681 g. (0.00539 mole) of M^rojaobenzamide and 50 ml« of fresh ly d is tille d toluene* The flask m s immersed in a constant temperature bath held a t 50*0°, A fter US hours the reaction was complete as indicated by a negative te s t with moist starch*iodid© te s t paper. The color of bromine was apparent in the flas£ u n til near the end o f the reaction* A fter cooling the reaction Solution, a small q uantity of a co lo rless c ry sta llin e so lid separated Ijil faPom the so lu tio n . The so lid m s iso lated by f iltr a tio n , mushed on the f i l t e r with cold methanol, and observed to m elt a t 125-126°. A mixed m elting p o in t with on authentic sample of benssamide showed no depression. The f i l t r a t e m # q u an titativ ely tran sferred to a 100 ml. volumetric flask and d ilu ted to the mark with m ethanol.. two 25 ml# aliq u o ts were withdrawn from th is solution and added to two separate 25 ml, portions o f 0.1063 If mehhanolic s ilv e r n itra te , the re su ltin g solutions were then heated a t th e ir reflu x temperature fo r a h a lf hoar period. A fter allowing these solutions to cool, the excess s ilv e r ion was trac k -titra ted with 0.1162 % potassium thioeyunate to a fe rric th io eyanaie endpoint. O aieulations Showed th a t the reactio n yielded U.68 zneqs. Of benzyl bromide which represented a fX &$ y ield based on the ' o rig in a l amount of H^romobmmmicie. She experimental method p lo y e d was the same as th a t described above fo r .the reactio n of ^^rpmobmmM da with, toluene, She quantity of K^romo-u-phe^lacoimmide used was 1.0208 g* (O.OOl*?? mole) and, as in th e previous ease, the reaction was complete a fte r 1*8 hours. Cooling of the reaction mixture resu lted In the deposition of some colorless c ry sta llin e m aterial which was iso lated by f iltr a tio n , washed with cold methanol, and found to melt a t 156-15?°. A mixed m elting point of th is substance with an authentic sample of e*phenylaeetamide showed no depression. Analysis fo r benzyl bromide by the procedure described above indicated a y ield of b -52 megs, of benzyl bromide which represented 1*5 & 95% y ie ld baaed on the amount of N-bromo*<£-•phenylac etaaide o rig in ally used in the reaction* of m m fim m S t&io a 500 m l. flask wax*© pissed 16.1 g. (0.059 mole, 9$*3% purity) o f K ^roii»4i^nltroacets3^ and 1*5© »&* of toluene. The flask m s loosely stoppered and supported d irectly over a 100 watt lig h t bulb. A reflecto r of aluminum f o il m s arranged in such a manner as to focus the maximum amount of lig h t on the reaction fla sk . A fter several minutes of irra d ia tio n the ch aracteristic color of bromine appeared In the flask and in an hour the reaction mixture m s deep red in color and small c lu ste rs of a c ry sta llin e solid had separated from the solu tio n . At th is point there m s no evidence of hydrogen bromide evolution* A fter irra d ia tio n of the reaction mixture fo r two hours the bromine color had faded and a te s t with moist starch* iodide paper 'm & negative, indicating the disappearance of both free bromine and JJ^bromoamide. A sma l l amount of hydrogen bromide seemed to be present as evidenced by facing w ith moist a ir and an acidic te s t with wet litm us paper. The reaction mixture m s c h ille d and the lig h t tan Solid which had separated m s iso lated by f iltr a tio n , washed with carbon tetrach lo rid e, and a i r dried* This m aterial weighed 9.8 g. and melted a t 200*205°. ^ ^ c ry sta llisa tio n from 9%% ethanol yielded 8.1 g. o f pale tan needles which melted a t 209.5*210°. A mixed malting point with an authentic k6 ©f p ^ itrm c e ta n ilid © showed no depression, Assuming the 9.8 g. sample ■fee be ©asei&ially pure p-nltro& cQ tanilide, i t represents a 91 ,$% y iel$ b$©ed m the o rig in al amount of the h&loantlid© used in th© n a tio n # Forty m illilite r s of ben&yl alcoh ol m e added to th© f i ltr a te and the mixture m s fra c tio n a lly d is tille d under reduced pressure* A fter « forerun of toluene th ere m s obtained 9 $ g, (9k%) of bensyl bromide, b*p. at h m* A 3*1* flask equipped with a Herahberg s tir r e r and immersed in an lee bath, m s charged with 30 g* (0.163 mole) of p*nitroac© tanilide, 60 g, of potassium bicarbonate, 300 ml. of purified chloroform, and 1300 ml. of ice w ater. While the reaction mixture cooled to 0° an aqueous solution of hypobromous acid m s prepared by gradually adding 1*8 g. (13.3 m l., 0*30 mole) of bromine to an ice-cold aqueous suspension of 75 g* (0 .3h mole) of yellow mercuric oxide suspended in 600 ml. of w ater, the mixture was thoroughly shaken and a fte r filte rin g , the straw yellow solution of hypobromous acid m s added rapidly to th© rigorously s tirre d suspension of ac etan ilid e . The resu ltin g mixture was s tirre d fo r one hour while m aintaining i t s temperature below 2° , and then rapidly filte re d through a f r itte d glass funnel with the aid of a water a sp ira to r. The yellow chloroform layer m s separated, dried in contact with magnesium sulffcte, and stored in the re frig e ra to r. hi A fter twmv&l of tli# drying agent* th# f i l t r a t e was concentreted 3& a w la»# of ea, 200 ml. and the small amount o f so lid which had separated was removed by f iltr a tio n . Three hundred f i f t y m illilite r s of petroleum eth er were added to the f i l t r a t e and on- S h illin g pale yellow c ry sta ls of H ^ro ^4 ^ ^^tro acetan ilid © Separated* The product was. iso lated by f iltr a tio n , washed with cold petroleum eth er, and the excess solvent removed In vacuo. The y ield was 32 g. ( t 8g )f m.p* 1U5*1U7° . Cbattaway, e t a l . t (30) rep o rt a m elting point of 11*8° . lodometric an aly sis showed a p a rity of 91.0$. This preparation was repeated eig h t times with an average y ield of 82$ of a product ranging in p a rity from 95.5*98*0$. I t was found th a t a second, re e ry sta llic a tio n from chloroform and petroleum ether did not improve the p u rity . The product was observed to su ffer no lo ss in p u rity when stored in the re frig e ra to r fo r several months. Th# procedure employed, fo r the preparation of th is compound, was sim ilar to th at described fo r th© preparation of N ^ro m o -^n itro acetanilide, Into a SH liier flask f itte d with a Kershberg s tir r e r and. immersed in an Ice* salt b ath , were placed 10,7 g* (0 ,Oracle) of p-bromoacstanilid©, 26 g. of potassium bic&rbomtQ, and 500 nil* of water. An aqueous solution of hypobromous acid , prepared in the usual manner from 18 g. (0 .1 mol#) of bromine, 30 g. (0,138 mole) of yellow mercuric oxide, and 200 ml. of w ater, was added to the reaction m ixture. A fter s tirrin g fo r on© hour 200 ml. of p u rified chloroform was added and s tirrin g was continued fo r an ad d itio n al hour while m aintaining th# temperature of th# reaction U8 m ixture below 2°. A tta r separation and drying of the chloroform lay er In the usual manner, the ex tra ct mas concentrated to a volume of 30 ml* the addition of 150 slU of cold petroleum ether to the chloroform concentrate resu lted in the separation of pale yellow p lates which were co llected on a f i l t e r , washed with petroleum eth er, and dried Jm vacuo* The y ield of p ale yellow M,li*dibromoaceianilide was 12 ,1 g. (83$) , sup* 120 - 123° * lodometrie analysis in d icated a p u rity of 98*0$ . Chattaway and Orton (30) reported a m elting point of 11*6° fo r a sample which analysed to be nearly 100$ pure* N^Bromo^U^hlQroaeetanitlMe The procedure a llo y e d fo r the preparation of th is compound was e sse n tia lly the same as th a t described fo r the preparation of N-brorao**!*n itro aeetan H id e* The q u an tities of reagents employed were! 28 g. (0.165 mole) of p-G hloroaeetanilide suspended in a mixture of 2 1. of w ater, 100 g. of potassium bicarbonate, and 300 ml. of p u rified chloro­ form. The aqueous solution of hypobromous acid was prepared as previously described fro® 15*5 ml* (U8 g ., 0*3 mole) of bromine, 75 g* (0.3U mole) of yellow mercuric oxide, and 600 ml. of w ater. A fter s tirrin g fo r one hour the product was iso lated as previously described under the preparation of N-brom o-4|-nltroacetanilide. The resu ltin g pale yellow powder weighed 2p g. (?1$) and melted a t 85-89°. U-Ciiloroacetanilide is p l° (10). 90.5$* The reported m elting point of N**bromolodometric analysis showed a p u rity of k9 The procedure employed fo r the preparation of th is compound m s the same a s th a t described fo r the preparation of H-foromo-4;-n itro a e e ta n ilid e , the q u an titie s of reagent*' employed were* 5 g« (0 .021+6 mole) of p^acetaaidobensotrifluoride, 15 g. of potassium bicarbonate, 125 ml* of p u rified chloroform, and 300 ml, of w ater, The aqueous sola* tio n of hypobromous acid m s prepared as previously described from 2,6 ml* (8 g*, 0,05 mole) o f bromine, 13 g. (0.06 mole) of yellow mercuric oxide^ and 100 ml. of w ater, Hie reaction mixture was s tirre d fo r one hour and the product was iso lated as previously described. I t was a pale yellow powder which weighed 5 g. (13*%%) and melted a t 112*-lihG. lodometric an aly sis indicated a p u rity Of 91.18$. A 2*1. separatory funnel was charged with 5 g. (0,037 mole) of fin ely powdered a c e ta n ilid e , 6 g. of potassium bicarbonate (0,06 mole), 70 ml, of p u rified chloroform# and 1 l i t e r of ice w ater. An aqueous solution of hypobromous acid prepared from 8 g, (2.5 ml** 0.O5 mole) of bromine, Xk g* (0*065 mole) of yellow mercuric oxide and 500 ml. of ice water was added t© the mixture contained, in the separatory funnel. Approximately 200 g, ©f crushed ice was added and the reaction mixture was shaken in term itte n tly fo r 10 minutes* The yellow chloroform layer was separated, »iried in contact with ma$aesium su lfate and stored in the re frig e ra to r fo r several hours* A fter removal of the drying agent, the chloroform solution m s concentrated in vacuo to a volume o f ©a. 10 ml. Immediately, 100 ml. of So p u rifie d petroleum ether nee added and the mixture c h ille d in an ice hath# the pale yellow* c ry sta llin e so lid which separated was co llected on a f i l t e r with the a id of a w ater aspirator* washed with ad d itio n al petroleum ether* and dried i n vacuo. There was detained H.2 g. (53#) of K«-bromoacetanilide* m*p. 86*88°* The reported m elting point fo r th is m aterial is 06° (3$ ). lodom etric analysis showed the p u rity to he 91*1%+ W^BroKObenaamide The procedure used in th# synthesis o f th is compound was th a t described by Hawser and le a f row (hi)* The quantity, 12 g. (23*5 ml.* 0.U5 melej of bromine was s tirre d into a mixture o f H5 g« (1*12 moles) o f sodium hydroxide* 500 ml* of water* and 200 g. o f crushed ice contained in a separatory funnel* 4 52 g« (0*H15 mole) quantity of feenzamide was added and the mixture was shaken fo r 10 m inutes. Th© re su ltin g solution was added gradually* with stirrin g * in to a mixture o f U5 ml. of g la c ia l a c e tic acid* ISO ml- of water* and 50 g. of ice* The salmon colored so lid which formed was collected on a large Buchner funnel and washed with cold water u n til the wash water was co lo rless. A fter drying in a vacuum desiccator the crude IJ^romcfeenjsamide weighed 28 g, (9h*5#)* A sin g le re c ry sta lliz a tio n from chloroform and n*hexane yielded 63 g. (75 *5#) of a nearly co lo rless product m elting a t 126-128° * A second re c ty s ta llis a tio n from the same solvent mixture yielded colorless crystals* m .p., 129*130° . The reported m.p. of W-bromobensamide is 129*130° (H I). Iodomatric an aly sis indicated the product to b© 99.8# pure. 51 was repeated several times with e sse n tia lly the same y ield ana p a rity o f product. ■this confound was prepared by e sse n tia lly the same procedure as th a t described fo r the preparation of N-bromobenss&mide. the quantity, 15 $* (0.085 mole) of p~niti^bemsamid© mm placed in & separatory funnel and tre a te d with an ice-co ld , aqueous, sodium hypobromite solution prepared fmm Ib.U g* (0 .0? mole) of bromine, 9 g* (0.23 mole) of sodium hydroxide, and 150 ml. of water* A fter shaking fo r 10 minutes the heterogeneous reactio n mixture m s slowly added,, with- s tirrin g , to 50 ml. of crushed lee and water containing $ ml. of g la c ia l a c e tic acid which resu lted in the foaramtion of an orange so lid . This was Iso lated by f iltr a tio n and re o ry sta lllz sd from 1300 ml, of g lacial acetic acid to y ield 11 g, (51. 2$) o f H-bromo-U-^oitrobensamide as co lo rless needles, m.p, 19?-201°. The m.p. reported fo r th is compound is l? 8-202° ( h i) . Xodometrtc an aly sis showed the product to be 96.5$ pure. The procedure used m s identical to that previously described for the preparation of N*bromobenamaid©. From 11 g. ( 0*002 mole) of a*pheny!aeetamlde, 9 g. (0,23 mole) of Sodium hydroxide, and Ik .li g. ( 1**7 ml., 0 . 0? mole) of bromine, there m s obtained 10,2 g. (93%) of crude N-bromo-c-phenylacetaiaid©. A single recrystallisation from chloroform yielded 13,5 g. ( 77$) of pure N^romo-c^htsnylacetamid© in the form of colorless needles, m.p. 12U-125. 5° . 8*S value reported fo r th is substance i s 123-125° (1*0). XodowstaKLe emelysAi Shewed th e product to bo 98.9# pure. The preparation m s repeated several tin s# on a threefold la rg e r m ale with an average y ield o f 75# of a product sfoich analysed to an average p u rity of 99#* th is compound m s prepared according to the general procedure described by ?ogel (2*£}» fr m 67*5 g. (0*50 mole) of aeetan tlid e , 85 g. (26*5 ml*, 0*53 mole) o f bromine, and 375 »SU of g la c ia l ac etic acid as a reactio n media there m s obtained 82 g. (76*5#) of p*4>romoac@tanilid© a f te r a sin gle re e ry sta lliz a tio n from methanol* The m ite c ry sta llin e so lid melted a t 165°* The reported m. p . of p-bromoacetanilide is 165-167° (1*2) - A solution of 28 g* (0.22 mole) of p ^ h lo ro a n ilin e in 500 ml. of water containing 21 g. (0.22 mole) of concentrated hydrochloric acid m s treated with 27 g. (0.27 male) of acetic anhydride and 33 g. <0*38 mole) o f sodium a c e ta te . A fter thorough a g ita tio n , the mixture m s ch illed and th e S hite so lid which had separated from solution m s removed by f iltr a tio n , d ried , and ra c iy sta lliz e d from 95# ethanol. This procedure yielded 28 g. (76#) of p ^h lo ro acetan ilid e, as colo rless p lates which melted a t 175*177°. A m elting point of 17k° is reported fo r th is substance (50). A 500 ml* £l*ak f itte d w ith & mmhimXmX s tir r e r and & theraometer wee charged with lOO g. (0*85 mLs) of p h enylaectonitrile and 1U6 g. (1*1*5 wolee) o f m su lfu ric m id* An exothermic reactio n Immsdiwtbiy s e t in and th e temperature wee moderated a t TO0 by means of m in# hath u n til th e completion of th e reactio n , The viscous reactio n mixture wae poured in to §00 s&* of crushed loe and water and the re s u lt­ ing so lid was removed by f iltr a tio n and dissolved in 1*5 1. of b o ilin g w ater. The solution was made alk alin e w ith sodium bicarbonate, tre a te d with K orlte and f ilte re d while h o t. On cooling there was obtained 6k §• {55*50 of o^hei^laoetam ide as co lo rless p la te s , m.p. 156.5*157.5° (L iterature Valuei 157° (50)). A solu tion of 60 g . (0.32 mole) o f p-oltifobeamoyl chloride dissolved In 600 m l. o f ether was added dropwise to ISO g . (1.52 m ole.) o f cold, w e ll-s tirre d , concentrated ammonium hydroxide, the flooculent solid ’that formed was collected by filtr a tio n , m ated with cold eater, and recryatallised from a large volume o f eater, th is procedure yielded la .6 g. (7356) o f p-nitrobenaamide as pale yellow blades which melted a t 199° . The waitin g point recorded in the literatu re for th la m aterial is 5k ■IVujiiW gniTliiffi-^jB^i n The procedure followed m s th a t described by T #|g l (Itf). A solution a f 16,9 g, (0*10 mole) of diphenyl&inine dissolved in 150 37a , of 95% ethanol containing 1U„3 g* (0*11*5 mole) of hydrochloric aeid m s treated a t 5tt w ith a solution p e e r e d from 8 g , (O .ll mole) of sodium n itr ite and 12 n£U o f eater* The lig h t yellow so lid th a t separated from eolation m e co llected by f iltr a tio n , washed with cold w ater, and recrysiallissed from methanol, th e y ield of product was 15 g. (75%) of H ^trosodiphenyl* amine# yellow plates# mup. 68*69° , A s i t i n g point of 67*68° is reported fo r th is substance (k$)* the general procedure described by Fisher (i*l*) m s followed in th is preparation# A 300 ml, flask equipped with a mechanical s tir r e r , reflux condenser, and thermometer m s charged with 15 g« (0.076 mole) o f N*n±iro* aodiphenylamine, 25 g* (0.38 mole) of aine dust# and 100 ml, o f 95% ethanol* The flask was immersed in an ice bath and 31.5 g* (30 ml,# 0 .U9 mole) of g la c ia l ac etic aeid was added a t a moderate ra te to the s tirre d reaction mixture* A fter 30 minutes th e fa ilu re of a drop of the reaction mixture to produce a blue color m treatm ent with concentrated hydrochloric 55 acid Indicated the complete dimppeamnee o f the HmAbrosodiphflasrlemin© * An additional 100 ml, o f 95$ ethanol m s added and, a fter warming the reaction mixture on a steam bath for IS mlmtee i t m e filte r e d , the filtm b e m e ©onoantmted jty vacmo to a volume of jg,* 50 ml.* and an ice* cold ‘m ister* o f 50 m l, o f m ter and 100 ml, ©f hydrochloric aetd m e added to the ocmcentrat®, A fter being eat aside for some time %M g* ■ (?S$) o f l #l<*di^h^^lhydraslne hydrochloride m e obtained. Twelve grams (0*052* mole) of 1, l-^lpheiiylhydrazlne hydrochloride m e added to a solution of 20 g. (0,5 mole) of sodium hydroxide in 100 ml, o f w ater; A fter mrmlng the alk alin e solution fo r several minutes , ©a a steam hath a. purple o il separated from the reaction so lu tio n . The o il m e a ttra c te d from the alk alin e solution with two 100 ml, portions of beneene and the eosfeiaed ex tracts mere dried in contact with potassium hydroxide p a lle ts , A ftm removal of the solvent on a steam b ath , the residue' m s d is tille d in vao^o. The fra ctio n b o ilin g in the range 166-17O0 a t 6 mm. m s co llected as 1 ,l-diphex^^lhydmain©. I t m i#ied 5**6 g* and corresponds to a 95% y ie ld . The colorless o il so lid ifie d in the receiver as would be esspeotsd from i t s reported m elting point of 3 U .S 0 ( i t 5 ) The experimental procedure of Earn and Goldschmidt (1*7) m s followed to obtain th is confound. A solu tio n containing 9.6 g. (0,052 mole) of l #l^phenylhyxirazine dissolved in 35 ml, of chloroform m s rapidly 56 added to a second solution prepared from 7-U g« (0,03 mole) of p ic ry l ch lo rid e in 75 ml; of chloroform, A deep rod color m s produced iim ed isiely and 0 so lid separated from the reaction so lu tio n . A fter c h illin g in an ice b ath , the mixture m e filte re d and the crude l,l^ ip h « 3 iy lh ^ m « in e •hydrochloride m e mehed on the f i l t e r with cold chloroform . The y ield o f l,i^ p h e n y lh y d m sin e hydrochloride obtained m » U*3 f« (9M V The coBibined f i l t r a t e add mShlnga were concentrated under reduced pressure to a volume o f eg* 50 si* and then added to 100 ml. of hot 9 $% ethanol. On standing in the re frig e ra to r fo r several hours the solution deposited a quantity of deep red c ry sta ls Which were iso lated by £ iltra ~ tio n .and mahed with a sm all volume o f cold 9 $% ethanol* Concentration o f the mother liq u o r yielded a second quantity of product, th e to ta l y ie ld of product m s 8*7 g* (8h ,5$) of cjC ^iphesyl^f ^piciylhy&raaine which melted a t 168~1?2® with decomposition. th e reported value of the m elting point fo r th is cesgmrsaid is 172*173° (W)< the method of preparation fo r th is substance m s th a t described by Emm and Soldsohmidt (]*?)* 1 fla sk m s equipped with a mechanical s tir r e r and charged with 6 g* (0*015 mole) of t^■^dipheKyl^f ^ ie r y l* i^ydmeiae# 7® «* <0*V *“SU) ®* ***& peroacide, 5 g* of anhydrous sodium s u lfa te , and 90 ml. of chloroform. The reaction mixture m e s tirre d fo r an hoar a t room temperature and then f ilte re d . Th© deep purple 51 f i l t r a t e m s eom entrated under reduced pressure almost to dryness* A 100 b£L, volume of eth er m s added, and the re su ltin g mixture m s s e t Aside in the re frig e ra to r fo r several hours* the dark v io le t colored c ry sta ls Which separated sere removed by f iltr a tio n , mshed with cold ether and dried in r&erao * Concentration of the mother liip o r yielded a second qu antity of product Whidh ferou^it the to ta l y ield of crude to- U*1 g. (67$ ), R ecrystallizatio n o f th is M aterial from chloroform gar's 2.? g* of a dark purple c ry sta llin e so lid m elting a t 138-liiG0 • Hammond f t of c,c< ^ p h a» y i* ^ * p ic^ (36) rep o rt the m elting point to he lkO®« Into a $0® s a . three necked flask equipped with a mechanical s tir r e r , reflu x condenser and dropping fu m el m s placed 96 g* (0*? mole) of p*n±tr©tolu©ne . The reaction flask m s immersed in a p araffin hath held in th e temperature range 190*200°, and 260 g. (1.6 moles) of bromine m s added slowly from the d ra p in g funnel* A fter the bromine m s added the molten product me poured in to an evaporating dish and allowed to cry stal* lin e . A sing le reciystaX X im tion ©f th e crude product from 1 l i t e r of 1aw b o ilin g lig ro in gave 133 g* (6h*5%) of p*nitrobenm i bromide as color* le s s p la te s which melted a t 81*82° * p-JJitrobenzal bromide is reported to m elt a t 82° (8k)* $8 (k8) quantify, 133 g* (6,1*5 mole) o f p-oltrobanaal bromide was sh irred fo r k& hours a t roe®* temperature with a eolation of sodium The hyjxibrosaita |?repared by gradually s tirrin g 180 g, (1,17 woles) of broBdao into*** im mM eolation containing 180 g, (h.5 moles) of sodium feydroselde dissolved in IgGO ail* of w ater. The so lid th a t formed was removed by f iltr a tio n , washed with w ater, and re e iy sta lllse d from 800 ml. o f rasthanol. Thin procedure yielded 120 g. (71.5$) of p -n itro - bemotribroRdd© as p ile colored yellow p la te s. The m alting point of th e product was 86*87° in agreement with th a t reported fo r p«nitro^ bsnaotribrom tde (1*8), Into a 125 mi* G laisea fla sk act fo r vacuum d is tin c tio n were placed 85 g» (0.23 mole) of p-nitrobe&Botribromide and 50 g. (0,27 mole) of antimosy triflu o rid e . A mild exothermic reaction m s in itia te d by cautious .heating and a f te r th e subsidence of th is reactio n, the contents o f the flask was d is tille d in vymp*. Baring the d is tilla tio n a sudden carbonation of the crude reaction mixture occurred forcing some decomposed m aterial in to the restive?* The discolored, solid d is tilla te was extracted With a to ta l volume of 200 ml. o f eth er and the ex tract was washed with 6 n hydrochloric acid and then treated with 300 ml. of 6 M sodium hydroxide. The copious, grey so lid th a t separated was removed by f i l t r a ­ tio n , washed with e th e r, and the combined f i l t r a t e and washings were d ried in contact with magnesium s u lfa te . A fter removal of the ether on 59 a steam bath* the residue wm d is tille d fa vacuo to y ield 11+ g. (32#) o f a lig h t yellow o il which so lid ifie d la th® re ceiv er, m.p, 39^0°.# The reported m elting p oin t of p ^ itro fe ^ o trifln o rid e is 1*04*0.5° (U8). 4 mixture of 11+ g* (Q.Q73 mole) of p^nitrobem otrifluorid© , 65 g. (55 ml*, 0*65 mole) of concentrated hydrochloric a c id , and 35 ml* of 95# ethanol was trea te d with |2 g. (0*32 mole) of stannous chloride. The reactio n tem perature m e maintained in the range 6g~7^° by means of an ic e hath and regulation of th e ra te of addition of the atasmeus ch lo ride. A fter th e addition of the chloride was completed the yellow reaction so lu tio n was ch illed and- then poured into- an Ice cold solution containing 65 g* o f sodium hydroxide dissolved in 180 ml. of water* The re su ltin g mixture was thoroughly sn&meted with eth er and the ex tract: was dried in contact w ith magnesium su lfa te . The drying agent was removed by gravity f iltr a tio n and the eth er was then removed under diminished pressure. The residue of crude p**aminobensotrifXuoride was aoetylated d ire c tly with** out fa rth e r p u rific a tio n . Accordingly, 20 g* (0*1? mole) of acetic anhydride and 20 ml* of pyridine were added to the crude p*©jninobenzotrlfluoridQ and the reaction mixture was warmed on a steam bath fo r 30 minutes. A fter cooling the solution was poured, with s tirrin g , into 300 ml. of ice and w ater. The re su ltin g white so lid was collected on a f i l t e r , washed with w ater, and a ir d ried . The y ield of p^aoetam idobenzotrifluoride was 10 g. (67*5#) based on p^B ltroberisotrifluoride. The observed m elting p oin t of the product was I 50«*l5l ° , which is th e same as th a t reported in the lite ra tu re . 60 XHTROBUCtlOK The reaction of H-bromoimides and N^romoamdas with unsaturated compound® i&ich re su lts in the su b stitu tio n o f bromine fo r hydrogen is generally considered to proceed viff, a free rad ical chain mechanism, th is mechanism is discussed b rie fly in the f i r s t p a rt of th is th e sis and extensive reviews of the scop© of th is reaction are in the chemical lite ra tu re (51)* The reactio n leading to a lly lic bromin&tion can be considered the normal reactio n by v irtu e of the numerous demonstrations of the generality of the reaction appearing in the lite ra tu re . in a re la tiv e ly small number of eases However, a t the present* the reaction ha® been observed to take another course resu ltin g in the addition of bromine to the double bond of the unsaturated compound „ This abnormal reaction has been observed to occur both to the exclusion o f, and simultaneously w ith, the normal reactio n . The mechanism of the abnormal reaction i® unknown but is generally thought to proceed by an ionic path. However, a free rad ical mechanism has ce rtain ly not been experimentally excluded and indeed, ha® been postulated by a t le a s t on® in v estig ato r (52). I t m s with the aim of obtaining new experimental evidence which would be of help in interpret** ing the mechanism of the abnormal reactio n , th a t the present study m s undertaken. 61 HISTORICAL Inasmuch as the p reseat Investigation i s cone ©mad with the m echanistic aspects of the abnormal reaction of N*bromoimides and ^amides w ith tm aaturaied compounds leading to bromine ad d itio n, no attem pt has bees m de to review the normal o r a lly lio su b stitu tio n reactions except in cases where i t might hare a d ire c t bearing on the in terp re ta tio n of the: abnormal reaction* Farther# tim e the findings of the present .study suggest an ionic mechanism fo r the abnormal reaction# selected examples o f reactions idiieh illu s tr a te the f a c ility with which H«bromo compounds can enter in to ionic reactions hare te&m included. That the homolytle and h etero ly tic mode of fissio n of the bond in H'-bromoamid© and ~imid©s take place with comparable ease i s und@rstanda.bl® in view of the low bond energy Cc^> 33 k cal. per mole) and. sim ilar electronegativit±© s of nitrogen and bromine# 3*0 and 2.8 respectively (53). The f i r s t rep o rt of the addition reaction was th a t of bbhl and Jasehlnowski in 1921 who found th a t W^jromoacetamid© reacted with styrene to y ie ld styrene dibromide (5M * Ih© yield and reaction conditions were not given and the dibromide was the only product iso lated . In 1930 Fold!, seefciag to explore the scope of th is reaetio n, reported a study of the reaction of a v arie ty of N^bromoamidas and -^mOfonsmides with unsaturated compounds (55). Foldi found th a t the reaction of N-bromo-*HMR©thylbenaenesulfonainide with l^henylpropene gave a nearly q u an titativ e y ield o f the XU adduct. 62 CHs * QmU& + Br CH3 CH3 O^CH-CH^I^OjjPeHe ftswiwir, when cinnanQrl alcohol and a lly l bromide were treated with J^^4e®wratte>'*,i*W'i*iwa^tla3r3it>etogueieeeeNWKtXjDo®HajBid^diei th e eorresjwndlng dibromldes were tetain ed da 5©# and 80g y ield s reepeetlw ely. Poldl believed th a t the** reaction s followed th e ' general scheme a Uifii% m * t RCH m CHS -*»-*► RCHBrCHjjBr + MMOI A adthou# he did not iso la te any of the disulfonamlde product* By a n a l o g y to the known reactions o f JJ*bromo co^ound® with o lefin s i t seems most probable th a t the unisolated p ro te st was in re a lity benaeneaulfonamld©, The reactio n of $*bro®o«uXfonaraidea with o lefin s to y ield a 111 adduci HBHBrSOaRl ♦ RCH « CHa a* HCHBrCHakogS* was shown by Kharaech and P r ie s tly (56) to be q uite general and insensi­ tiv e to wide v ariatio n s in R,R* and Rn. The fa c t th a t in a l l cases the adducts obtained were those in which th e bromine atom occupied the same p o sitio n i t would have taken in the Ionic addition of hydrogen bromide to the' o le fin , is accepted as Strong evidence fo r an ionic mechanism* The authors suggest th a t the reaction i s unique to N^romosulfonamides since they ware unable to obtain the reaction with a v ariety o f K-bromoaJaides including H-bromobenssaadjde and N^rorao^-pherQrlaoetamide, So mention m s made of the course of the reaction with these bromin&ting agents other than th a t l t l ad tects were not obtained. 63 KttP* recen tly* ' 111 adduots have been iso lated from the reactions of and mmMm with o l e f i n . Park (3) has reported the > form ation of the 1*1 adduet in the reaction of cyelohexen© with IH&romo** trlchAor©acetasrfd© (60$), and IJ^roBK?trifluo3?oac0tainid« (38$). These adduetB were characterised only by th e ir elemental an aly sis. Bailey and Bello (S t) obtained a SJf yield of 3 ^rom o^i*sac0 iirljBdjdob n ty ro n itiile an- w ell as. a. 21$ y ield of' the corresponding dibrow&de on treatm ent of vinyl aeeto n itrile with N^romosuceinindde. Ziegler and his eo^ww&tars (1) isolated a 12$ yield of a H I adduet ae well as a 21$ y ield of 1 ,2^dib3ro)^oycloheQcane tmm the bromination of cycloheacene with Although there has been no d etailed mechanistic stu d ies, massy ®f » th e reactions which H^bromo coispotmda undergo are beet in terp reted as proceeding v ia a h etero ly tic fisso n of the N*Br bond# Brand© and ^hight (1?) suggest th a t the balano® between the two apparently competing reactions^^stddition and su b stitu tio n —depends upon several factors* the stru ctu re of the Hebrew compound, the stru ctu re of the o le fin , the solvent and escperimental conditions and c a ta ly sis. follow a re co n sisten t with th is generalisation. The © K aties th a t €k SstoM (58) has effected the m eleer brorainatioa of bsnaem* and beliiene mtth H^romosttc© by th e moo of F rted el Graft# ca ta ly sts omb m .lOmtekm ehloride . Hsane mod Zimmer (b) to w prepared perflm oroinated N^tnroaioeueciniside mod. H^3porao^lmtarimld0 mad Poand th a t they read ily broraimats toluene, miihonb c a ta ly s is , a t room tempenatar© to give aa^lnsively a nuclear brow im ted product. % comparison H ^rojK m ceiaim ide, in the absence of c a ta ly s ts , earn be ifoflmsced mith toluene mthoub change mod bensena' be# found 'lim ited mis me asoXvemt fo r the *fohi*&iegier reactio n . Park end M e coXX&bomtore 0 ) to re described the reaction o f the K^teosne deriv ativ es of raonochlero**, diehloro*, irichlo r© -, m d trifluoro** eeetamid© mith oyolotoeeme end toXaeae* fhay ftow l th a t the a b ility of in the allylic p o sitio n decreased in th e foUoming order* -CGlHja *0% > ^eCl^S > CC13 > > *GFB. S im ilarly , the a b ility ' to broadnete toluene in th e aide chain m « found to deereese in th e same order. I f I t In assumed th a t these data re fle c t the tendency of the N^roiaoacetamides to undergo heberolytie ra th e r them hemolytic cleavage of the IMBr bond, I t i s read ily seen th a t the Gbesrved order i s mot the .order predicted from electronic gstoU taftttaM * I t mould be -gqpstfta* th a t the tendency of the ti^rwm* m@tmAd** to donate p o sitiv e bromine msmM pamlleX the d isso ciatio n constants of the corresponding acetic acids mbich increase in the order •*CHa < <;HaCl < «€H01 g > *OCXa < *C&9* Park and h is collaborators attempted, to jmgfeiff the observed descrepwwsy by proposing th a t the 66 im M brom ination ©f toluene may proceed v ia a complex formation between th e H^remo compound and the toluene im betrate. However, in th i# laboratory Began (6) ia a sim ilar study observed the predicted order fo r tb s tendency of tb s N-bromo derivatives of monochXoro-*, diobloro^ sad triehloroaeetam lde toward aide chain foromtnation. Began*# d ata, -s&ich .is in contradiction with th a t of Park, was collected under oomo^mble experimental conditions except th a t shore*# Paa& worked a t m m te j^ m b u re , Began made his- observations a t itO° and 80® and is* the absence of n § n t* in addition Began made a complete m aterial analyseis fo r a l l th e bromine Introduced in to the reaction system a# an H***feromoamide or ^Imid©. fhe a b ility of th e solvent to a lte r the mod® o f fissio n of the N**Br bond Is strik in g ly i l l u s t r a t e by th e observation th a t while JMaromo-* succinimlde reacts with eyclohexen© in carbon tetrach lo rid e to- give a h i # y ield of the su b stitu tio n product, 3*4?roiaocyclohexene ( l ) j changing th e s o l v i t to water re s u lts in a 19% y ield Of the broinohydrin (59). B obsrte, Trumbull, Bennett, and Armstrong (60) found th a t the benzoyl peroxide catalyzed brom im tion of ncmboriylene With Kf*bromosucc±nimld© yielded m irily l^roM m cajtricyclene, they found th is to be the same product Obtained when norbonaylene was brominated with elemental bromine in pyridine and p rin c ip a lly because of th is observation they suggest an lonie mechanism, 66 ftwfowta *** la a Of tiui tava&mtlaa o f agarla* bat**® and wttqOMM «y*a«S»itM» with frfe ra n A o a itrfa ^ ftamd too fteWWWl I fiW iW m o tio n to - '""■*T w VKipM1 a w p n flw i f * * w * flo * IW llB R IP Ifw sp # Br * C 5 81.5* 4UF — -^D * NT i i * lr v& Hwfc S6fc^h6®S iN tiS iisS 4fftw& 4 to &;£ bsp&»tflwa iiBliBHBtjMtitt ffcwy 3$gi $& it^ tosp li m Siii ^vtPn 'PnKm^aitaigM a*Pf W PP* B^^ ,| pi 43a 1$®® s3^S^lSa p^$$kG & Ih^^BiSwlS #($!$& _ 1u-lJ^-^pBW W jtn^T^gXny~ Q,$**nm @T& W |P {£&) ^V'ata^ W8&® rT“»w^p” w fte? """wW tW 1feii oM •?- ftiii | hN)nSiiwS* CJtgO * CCQOCjfo —® - « . (%OBr • OMHyOyBb H w fcy Jp^NIRHffnniPM ilM dw M H ^P SP' Ik WB3P$J&isr &£ W P HW W W *ilttC MisfeMttBW *W *W PW 'w ’™ ww -w- w.m■■■-im i«■. eni»flwiCT)fewiFw^ew^|^ pom nddo w A lig h t eataljw JU i s a il b a n tin g a t ISO® la a iw olod W w , t a t la no earn trnt a M b a ttlta tio a prod u ct o b ta in o d . 67 ( 6 3 ) studied the bromimtlon o f vin yl Ccuvrsur and mmiaxrt&rilo with N^broi^micetelmide aad 1sol&ted products resultin g tm m addition tad substitution with a lly lte rearrangement * m% * m m ifffl 41 * 37 $% ♦ CH^BrCH-CHCU n% In a s tru c tu ra lly re la te d study Corey (6U) a tte s te d to brominete mstfoyi vinylaeotate with ft^romosuoeinimida end re alise d only addition* Since i t is knoen th a t methyl crotom te read ily undergoes Ziegler brosii* nation to giro a gcod y ield of r--bromoerotonate (1 ), Corey an ticip ated th a t bromlnation of the isomaric methyl vinylaoetate should also y ield methyl r^hroR«5crotonate because both reactions should have the same a lly lic ra d ic a l a s a common iatermcdia.tc si*H* 0 *»H' — GOoea3 Homeeor, only the addition product, methyl p, v*dib«>JKdmtgrrat« aas obtained, CHjWCBBHjjCOOCHg CH^rCHBrCHgCOOCHa 63 .1*? Corey suggests th at the polar effect of the cyano group on the n-fcydrogen invades rad ical attasfc a t th is position and thus in hibits the normal reaction. I t is significant th a t methyl vinylaoetate reacts much more Alority- than does methyl crotonat*. 66 1&e p a rtic ip a tio n o f &-4>ro]^aa(^inii8ido in addition reaction© has bom reported w ith ar$--unsaturated ketones of the benzalacetone type (6SJ* Stmihwlek, Fura^love, and Iftuaerof in m attem pt to prepare bromomethyl S tyryl ketone by the action of H^bromosuce inlraide on beasalacetone, obtained only bensalacetone dlbromid©* 0 0 gHaOHwCHOOCHg GaH8Oia*CHarCOCHa * )HH ft 1m5* 0 6l.5% I t mm found th a t th e hrdsdnation of bens&laeetone did not occur unless th e reaction mm ©atuiyasd with benaoyl perox&d©. On the hypothesis th a t psroxida can induce a decomposition of H*%romo«uecinimide resu ltin g in the form ation of elemental bromine which cemld then serve as the broidnating agent, the effect- of bensoyi peroxide m M-broEK>succinimtd© in carbon tetrac h lo rid e was studied* -I t was found th a t aassii amounts of bromine were formed b u t, th a t th e ra te Of bromine formation mm fa r to alow to account fo r the observed, reaction* accordingly, the authors concluded th a t the addition reaction involves d ire c t in teractio n between the Mbromo compound and the olefin* Intrigued by these finding® Bouthwick &%, ift. investigated the reactio n of K^romosuccinimide with several other c ,p -^ sa tu ra te d ketones with the expectation o f elucidating the mechanism* Bonsalaeetophenone was found to y ield ©f bensalacetophenone dibromide and 6$% of cuccinlmlde* $ ^herylbenmXacetophmone was found to re a c t with N^bromosuccinlm lde, in the absence of peroxide c a ta ly sis, to give 69 and soseln ljttid e. 0 O^OBWtlawJ^B * m 68^ o m ®m* m m pvodoet 1* obtained ehoa tb e bxtnBlsatloa la carried o a t «Lth a le a ea ta i tarnsiae. Atterajrte to broatiaate «,p*>diphenylb0»u»la0^ph«B6nis ' fa ile d and th e S-^rem m w elnlm iiie romoacetamide with various o lefin s in chloroform solution. 71 j&MJg x i m o to r s Q'B'umw m yhb m kc vtm m x * w o w a m x n m r a n some o lsfih s (5) "<"■'"■*1 ........... . PJbromid© Yield Percent' ' AsduUM Yield TmetnA Styrene 52 97 Cinnamic acid n 96 sth y l cinnam ta 39 77 tra n s ^ b i i*2a 6a. Benssalac etophenone 5? t o isfin 96 .. ...............— nilm.i 1M . *^dibroirasfoihencyl Braude and ^ t g h i (17) found th a t the course of the bromin&tion of csyelohsxsaae and allylbensena with H^nrt>mGeueclnlid.dQ could be d ra stic a lly a lte re d by the inclusion of alleyl ammonium s a lts in the reaction mixtures* Thus, in the presence of tetrðyl&iffit^^ bromide, the Ziegler bromi- nation of eyelohexene m s found to y ield predominately 1,2 ^dibromocyclohms&m* y m? m s, t&aSsl **• 7h% A lly l benzene m s found to give dibromophenylpropane as the main product ra th e r than ci«m »yl bromide* Jk stap le form ulation of the addition reaction f a ils to reveal the source of the hydrogen 'which replaces the bromine of the H^rojaosuccinlmide * t ,G )? * < ♦ a 0 HBr ’ ^ ir^ r ♦ 2 BH 0 In order to explain th is phenomenon Braude and m ig h t hare proposed a mechanism involving both ionic and fre e rad ical interm ediates, CD \ 0 m ^,Blr ** ■ Br Wr — (3) r * t - i ' (k) *■ — i 3 r \ Br D "4 K P 'v 0 donor r < 0 In support of Step (3 ), which p ictu res the two oppositly charged succiniraida ions undergoing an Electron tran sfer resu ltin g in the fo rm tio n of two 73 sacointmi dyl ra d ic a ls, i t was fdund th a t the unknown disaccinlm idyl m% be prepared by the reactio n of H^roiwsmiceiiiiniid© with s ilv e r succinlm ide, On th e strength of th is finding the author© propose th a t the an ticip ated disuseiniaddyl is unstable and Immediately d issociates in to two m M ln frtity l radicals* They fa rth e r suggest th a t although the ionic interm ediates of th e ir mechanism are w ritten as separate ions fo r c la r ity , the steps involving h etero ly sis may involve p a rtia l rath er than complete electron transfers, and th a t the- bromenium and succinimide ions remain in a mutual sphere of influence u n til complete satu ratio n of the doable bond has occurred* This is supported by the fa ilu re to- observe any mixed dihalide product when al^lammonium iodides were used as c a ta ly sts. One obvious shortcoming of Braude- and Maight1© mechanism Is i t s fa ilu re to elucidate the function c f ;,tho alltylMmuaiiim s a lt. Tiie authors envisage several ©.nsWsra to th is *4 -*nitroac: e tanH ide with cycljohexene in aprotic solvents m e unexpectedly found to y ie ld the addition product, t^m -4,2^ibrom ocycl0-‘ hexane, a s the major bromin&tion product* th e present stady m e an m te growth o f th is finding and m s undertaken fo r the purpose of obtaining experinisntal evidence which could be of .help in elucidating the mechanisms of the reactions of K^bromoauiidas with o le fin s . Obviously, such a stndy oan reasonably include only a re la tiv e ly few sp ecific examples from th e ssaltitade o f possible combimtions of N**bromoamides and- o le fin ic oo^Bpounds. Per reasons o f avs i 1ab.i l i ty and expediency1and, from th e o re tic a l considerations, the reactions of two o le fin s, cyclohex&ne and a lly l a c e ta te , with three H^romoamides, K ^3?oiso4i^itrm cetanllide, H ^roa^^^henylacetam ide and ^-bromobenaamide, were studied from the Standpoint of product form ation. Bromination of the two o lefin substrates with K-bromosucclnimide m e included fo r purposes of comparison• Ally! acetate was choaan for atudy as ona o f the unsaturated com­ pounds for two reasons* f ir s t , I t has been previously proposed that - o lefin s having electron attractin g groups adjacent to the a lly lic hydrogen do not readily undergo normal a lly lic bromination. Thao, the B«bremosuccInimide broadnations of methyl v iiy la ceta te and vin ylaceton itrile resu lt prim arily w it h u n r e a c tiv e in addition (6k,63), and the sim ilar breaiaatton o f a sulfone linkage adjacent to the double bond are completely to the a lly lic type o f reaction (85). These data indicate 60 th a t the n o m l m b etitu tto tt reactio n can be in h ib ited through po lar e ffe c ts «nd inasmuch as th e aeetoxy group of s l l y l acetate is electron withdrawing I t was expected th a t th is would favor the addition reaction a t the expense o f the su b stitu tio n reactio n . Secondly, the reaction o f a lly l ac etate with an N*br©mo compound had not been previously reported .and. the corresponding a lly lic bromide, a^ ro iaaally l acetate;, is unknown. liable 1X1 p resen ts a. summary of the re su lts of the H^rommmide brominetione of a lly l ac etate and eyclohexen®, I t i s evident th a t, w ith th e exception o f N ^ro^succinim ide, the H^romoamide® studied'. Show a marked tendency to undergo the addition ru c tio n # fu rth e r, the pro* ■ d ictio n th a t a lly l acetate Should not read ily undergo a lly lic bromin&tlon i s borne out by the fa ilu re of H^broaoaucciniziiide to give any appreciable y ie ld o f an a lly lic bromide m rm under peroxide c a ta ly s is . A very small y ield (ca.gg based cm th e assumption tfe&t i t m s c*-bromoallyl acetate) of a compound having chemical properties and an Infrared spectrum eon* s ls te n t with an a lly lic halide m s obtained. K© fu rth e r ch aracterisation of the m aterial was attem pted, the a b ility of H^romom^hmylaoetamide to convert cyelohexene into lm cetcc^^^ronKacyclohoxane in 6? *3% y ield is good evidence fo r th e fe a s ib ility of ionic fissio n of the IHSr bond. One of th e most in te re stin g fin d in g m s the iso la tio n of phenylbenaoylurea from the products of the reactions of N^romobensamide with eyclohexem© and a lly la c e ta te , fleldwis© the amounts of the urea d eriv ativ e iso lated were m a ll (see fab le H I ) . However, th is could in 81 • 0 CO d i—I © •H Q s> to Ph S; O o o s o K PQ l IS W EH 1—i '—* —* K M 9 CQ < Eh s 0 £ Ph 0 d d rH P , l>i • o tsl S £ •s 0 Si d 0 d © *H d £ *H *H < TO i 1 Ph O GO d o IH Ph •d. Si IH fH O K CQ CO Ph O CO CO 03 to O o- CO CO o 03 o co 2 £ 0 £ d as o d • 0 p •H © 0 rH d d o •H *H 0 0 £ O £ B •H Ph £ P -P P 0 0 Ph -H o o 0 £ P 1 0 rH 0 ^ d i P £ d o •H 0 o £ d • • 03 to 0• to to 03 03 • o 1— 1 03 i—1 i— I 03 •H p Ph • BO 0O EH p £ 0 > rH O CO m p £ 0 P O 0 0 id O ID o ID X! d d i—i « 0 £ d os S 06 0 1 PH ^ I I— I d t — I 0 0 1 rH • r— 1 CO ID 00 ,r— S pHr*s H Id Id o d o >H O (H CO • 03 rH + <13 < •H + s 0 »H d rH •H *H r="i 0 ^ X rH p O rH d 03 Ph 0 O i— I0 0 0 d 0 d d d '0 £ H £ d l>s*H O £ 0 ft 0 p o Qom * (3) Step (3) proposes a proton tra n sfe r reaction resu ltin g in the formation o f bsnsamid© and an electro n ically d eficien t nitrogen fragment id en tical to th a t proposed m m interm ediate in the Hofftoan, C urtiua, Lessen, and Schmidt reactions# Step (A) is raechanietically sim ilar to the rearrange* ment known to occur in these reactions (86) * 83 th e formation of N,M* ^heiylbenzoylurea by the subsequent reaction of phenyl isocyanate i» not c le a rly defined, fhe obvious reaction* com does not provide a sa tisfa c to ry answer in th a t i t is very slow* For eoasaple, W,1P -^pheiQrlbenasoylurea was prepared, fo r purposes of comparison, by refluxing a concentrated benzene solution of benzamide with phenyl isocyanate fo r 2h hours a fte r which only a 9*7% y ield of N,N**phenyl~ benzoyl urea was obtained and the bulk of the benzamide was recovered unchanged* Kuhn (03) obtained H,N*-phenylbenzoyluraa in a good y ield from the reactio n ju s t previously described. However, he found i t necessary to heat the reactants together in the absence of solvent a t 150°. Hoore and Cederholm (0?) rep o rt the reaction of phenyl isocyanate with N^broiaobenzaiaide to occur read ily to give a nearly q u an titativ e conversion to N*•(p~broraophenyl) *-benzoyl urea* 'This is supported by the work of S te ig litz and Barle (88) Who found th a t N^hlorobenz&mlde underwent a vigorous reaction with p^hlorephesyl isocyanate to y ield HKp^hlorophenyl)^!* -benzoylurea. they propose the follow ing mechanism* (i) '$ (2) f.ybO [ PhC QHKPh J ?hCOI3HJQOT?H-(l) 3 Bk ®m rmsnmM&mmt d e le te d in step (2) is sim ilar to the Orton rearrange­ ment ©f N -baloaoetanilides to nuclear halogenated aeetan ilid s* (25) shi©h baa bean shomi to proceed v ia an interm olacular process. I t therefor* seems possible th a t the formation of » ,» •^har^lfesnzoyl-* urea in the reactio n of N••feroiaobenaiandde with olefine a*y proceed by the following sequence* (1) 0OUB®r The interm ediate W^roiaophenylbenisoylurea could then undergo a subse­ quent reaction re su ltin g in m abatitution of hydrogen fo r bromine rath er than the rearrangement proposed by Stieglttfls and B arle. This diversion o f mechanism would have t© fee d ire c tly or in d irectly caneed fey the o lefin p re se n t. The important problem of the id e n tific a tio n of the source of the hydrogen found to replace the bromine of the N^bromoamide has not been adequately explained e ith e r fey the re su lts of the present invest!** gation or o f e a rlie r work. Therefore, a t the present time the mechanism of the formation of N,$f1*^jhenylfeenaoylurea is obscure, and of more sign ifican ce to the purpose of establishing a hemolytic or h eto ro ly tic path fo r the formation of diferomid© is the conclusion th a t phenyl iso** cyanats is a precursor to the urea formation* On th is premise step (1) 85 abSve, "Which seems the meet lo g ical route to the formation of isocyanate, Is only co n sistan t with a po lar mechanism fo r the formation of dibromide, In support o f the fe a s ib ility of step (1) Is T itherley1s observation (8^) th a t H,Nr •phenylbenzoylurea is obtained, rath er than the expected from the reaction of K^romobansamlde with sodiobensamid® in benzene so lu tio n . cm m t GONHNa ^HCONHCO a* th erefo re, I t la f e l t th a t the formation of N,N* -phcnylbenzoylurea as a minor product In the ad d itiv e brominations of a lly l acetate and eyclohexene w ith N-bromobenzamido gives Indication of an ionic mechanism as opposed to a fre e rad ical process* Most recen tly , Johnson and B ubliiz (90) in a prelim inary communi** catio n , have reported the iso la tio n of p ^romopropionyl Isocyanate BrGHgGH2GOMCO from the banzoyl peroxide catalyzed brominations of a lly l chlo rid e, a lly l bromide, and p-m ethallyl chloride with N^bromosuoclnimlde In chloroform. Neither the y ield of ft -toromopropionyl isocyanate dr the id e n tity of the other products o f the reaction sere reported* The suggestion is made however, th a t the reaction is of a free ra d ic al nature and perhaps a fre e rad ical analog of the Hoffmann hypohalite reaction of amides« The reactio n of N-bromoamides and «*imidea leading to the addition of bromine and regeneration of the parent amide or imide according to 86 th e follow ing general representation has bean observed fo r a reasonable number of cases.* ■ a mmtat * Br y>m ♦ 2 BGOMH, tn th is simple repa^ossntation no source fo r tb s hydrogen found to replace the bromine of the H4>romoamide is provided, th is obvious discrepancy has been doted by several in v estigators but m concrete inform ation re la te d to the Source of the hydrogen has been forthcoming, Braude and Haight (17) have proposed th a t the suceinimlde, iso lated in good y ield s from the ad d itive bromin&tion of cyclohexene and a lly l benaen© with H-bromosuecinimid® in the presence of alk y l ammonium s a lts . Is formed by the ab stractio n of hydrogen from an unidentified source by auecinimidyl ra d ic als rV a Q The formation of succiniraidyl ra d ic als by the electron tra n sfe r reaction pictured above, ra th e r than the simple m etathesis reaction leading to the form ation of dieuceinim idyl, was supported by* the finding th a t disuccinim idyl is unknown and a l l attem pts to prepare i t were unsuccessful ffe# extension of th is explanation to sim ilar bromirationa with N-feroraoacetaraide and M«bromobenraidde f a ils because the respective m etathesis *Se© th© H isto rical sectio n of f a r t 1 of th is th e sis. 87 product** H,N**&Saoe1ylhydraKine and N^H**dlbenzaylhydrazine, are well r known, sta b le compounds, In a study of the addition "of bromine to several unsaturated com* pounds using M^romoaeetamide a* the cole source of bromine, probet ($) m e ab le to Iso la te aeetamMa In nearly q u an titativ e y ie ld s. Again, the source of the hydrogen m e uneocplained* However, since Buckles (£2) bad e a rlie r proposed th a t these bromia&tionc with N*bromoacetamld® proceed vjt* a fre e ra d ic al chain mechanism, Frbbst proposed th a t the interm ediate acetamidyl rad icals abstracted hydrogen from excess o lefin and/or the products of the reaction* The solvent was elim inated as a p ossible hydrogen source by the use Of carbon tetrachloride* When tr i* phenylmethane m s included to provide a read ily ab straetable source of hydrogen, no Change in the reactio n m s noted and the bulk of the triphsnylmethane m s recovered unchanged, Ho products d ire c tly traceable to the rad icals presumed to be formed a* a re s u lt of the hydrogen ab stractio n stop have ever been found. It i s noteworthy th a t, without exception, considerable amounts of polymeric n o n -d istilla b le ta rs accompany the products of the abnormal brominetion. reactio n . Probst ($) has shown th a t the ta rs produced during the abnormal bromination of styrene with N*bromoaceiamide contain considerable amounts of bromine and nitrogen. In the present work i t m e found th a t the ta r re su ltin g from the bromination of a lly l acetate with H-bromo* bensamide contained 3h% of bromine. I t has been suggested th a t these ta rs have th e ir o rig in in reactions re su ltin g from the secondary rad icals produced by the proposed hydrogen ab stractio n step* 88 KOOKHSr ♦ V */ /CBrGS^ 4 BOTH* f )lB rc' ECOHH- * tCOKHBr H2 »**«**• EOOffiai * \B rd kr Z + ** BOOKS* ta rs HZ S Hydrogen donor in the experiments outlined in the f i r s t p a rt of th is discussion I t was shown th a t the reactio n of E-hroraohmssamid© with a lly l acetate was found to give moderate y ield s of 2,3 ^ihrojfKjpropylac e ta te and good yields Of bensamide. fbus, In a v ariety of solvents the y ield s of 2,3*dibromo* propyl ac etate ranged from 69*1 to 13% and the y ield s of benmraide from 38 .b to 90%* I f we consider the species known to be present In th is reaction* i . e . , aX lylacetats, N-^romoben^mide , 2,3Miibromopropyl ac etate, benswmide, and small amounts of H,H1-phenylbensoylurea, and we assume cafbon tetrac h lo rid e as the solvent, ’the most probable source of hydrogen from the standpoint of an ab stractio n by a bemsaraidyl rad ical would be the a lly lic hydrogen of a lly ! acetate* fh ls should be the case since th e re su ltin g a lly lie ra d ic al i t csapable of resonance CHa « Ci 4 hO0OC% sta b ilisa tio n * CHa*0H « CHOCOCHa th erefo re, to t e s t th is hypothesis, the a lly lic hydrogen o f a lly l acetate were replaced by deuterium fo r the purpose of die* tlnguishing i f the following reaction did Indeed play an important p art in the mechanism. ♦ GHa*CH-CD2OGGCH3“ -^ th e #3rnthesis of acetate m o achieved by the reduction of aoryly1 chloride with lithium aluminum deateride to y ield alcohol, followed by acety latio n to the acetate* ttw p m m X k | M I obtained tdtf 35*3$ CS^«CBOO01 *> CHjjwCHCDjOH 53*5$ #> CHj^CHGB^OCQOH^ 65*3$ tho only lltm M ttro t« r« P im to the lithium &wdmm hydride redaction of an a c ry lic acid d erivative to a lly l alcohol i s th a t of Benedict .and BsAML. (91) which rep o rts th e reduction of acry lic acid to a lly l alcohol i s 68*3$ conversion. The procedure Involves the usual acid workup and its fu rth e r complicated by reason of the mutual s o lu b ility of a lly l alcohol «*iri water# Since a lly l alcohol can undergo an acid catalysed oacotropic rearrangement (92) i t was desirable to m ln tu in a n eu tral or basic medium throughout the conversion of aery ly l chloride in to a #a *dideut®ro»* a lly l acetate In order to avoid th is rearrangement which would- re s u lt in the equal d istrib u tio n of deuterium between the a and Jr carbons CeC-OB^H C^C*GBsOHa 0 ■*** Q m CBj| OH I f th is were allowed to happen the significance of the eaqperiment would be considerably weakened due to the presence of an equal amount of 90 a lly llc hydrogen and deuterium in the system* $he isotope e ffe c t favors ing the hemolytic ab stractio n of hydrogen in preference to deubetriaw is o f considerable mAgnitudJ^ and i t could therefore be argued th a t i f a su ffic ie n t quantity of a lly lic hydrogen were av a ilab le, the amount of deuterium abstracted am id be so in sig n ific an t as to escape detection by spectroihtoaicetrie jaes&S* Accordingly' th e synthesis of a «c^dideutero*a l l r l acetate use carried out under conditions designed to prevent the occurrence of the acid catalysed oxotropic rearrangement* Several attem pts to reduce acry lic acid to a lly l alcohol with lithium aluminum hydride and incorporating is o la tio n techniques avoiding the usual acid, conditions, were unsuccessful. F in ally , i t m i found th a t a satisfac to ry y ield of a lly l alcohol could be obtained by reducing aery iy l chloride with lithium aluminum hydride and decomposing the reduction complex with a calculated amount of water and 2g f aqueous sodium hydroxide according to the procedure described by Amundsen and Nelson (9k)* ®hi& procedure resulted in the formation of a granular p re c ip ita te of lithium and aluminum s a lts from idiich the ether la y e r, containing the a lly l alcohol, could be read ily separated by f iltr a tio n , th e reduction of aery ly l chloride rath er than acry lic acid offered, a fa rth e r advantage in th a t the stoichiom etry fo r the redaction of an acid chloride require© le ss of the expensive lithium aluminum dmt&ridm m m i t does fo r the reduction of a cazbosylie acid . fhe isotope e ffe c t fo r hydrogen ab stractio n depends upon the stru ctu re containing the hydrogen and on the nature of the attaching radical* Howsaer, ty p ic a l values of kH/kl) range between 2.6<-9.9 (93)« ?1 A cstyletion of the alcohol m e effected a t room temperature with a c e tic anhydride in pyridine* This procedure has been successfully used to an ety laie a lly lic alcohols without isoiaerisaticm (95). K*£ffltero^en%amide m s prepared by the hydrolysis o f sodiobenzamide with deuterium oxide fo r the purpose of obtaining an infrared spectrum o f authentic deuterated m aterial* A comparison of the infrared spectra of deuterated and nondeuterated bensaraide served to estab lish th a t the deuterated compound could be read ily distinguished by the B*£> v ib ratio n abaorbtion a t 3 *9*4.3 microns (??)« ^ o ^ideute^p^a lly l acetate m s brominaied with S^romobemamida in r e f in in g carbon betraehlerM e and, a fte r p u rifica tio n by re e ry sta lli* cation from benzene, a y ield of pure benzamid© m s obtained* In a model experiment using the same re la tiv e amounts of nond^terated re* agents a ?8*8$ y ield of bsasamide was obtained. The in frared spectrum of the benzamide obtained from th e reaction with douterated acetate fa ile d to ind icate th e presence of any deuterium on nitrogen* The only d e fin ite conclusion th a t can be drawn from th is experiment is th a t the allyX ie hydrogen of a lly l acetate are not the source of the hydrogen found to replace the bromine of the sta rtin g N-bromobenzamide. B iH e th is finding does not disprove the rad ical hydrogen ab stractio n mechanism, i t can be c ite d as supporting evidence ag ain st th a t mechanism. Figures XX, XXX, and XX2X present the infrared. spectra o f the previously unebaraeterized> a >aMidgate3?o^a lly l alcohol, ■tt,«’^J^gS ^S S r SllyX a c e ta te , and H^^ u te y o ^ ^azajalde. A knowledge o f the etereooheiaicsal course o f a reaction can fee of great m X m in the of a meh&nism* Xhna the c la s s ic a l Cyclic bromonitua Interm ediate was f i r s t proposed by Roberts and Kimball (96) to explain the observed trana addition of bromine to maleic ami fyamtitt ac id s. I t therefore m i of in te re s t to in v estig ate the stereo* chemical conra© o f th e reaction of N^romobens&mide with an o le fin re su ltin g in the addition of bromine to the double bond. C learly th is 3E^Ss8t^ 44k.^l# Jti ik « M XifcpM fSf ® W & 23il@ fr B «^ k A l Mini *Th i—11 Wli *ii '■miiWl*Tf aMkTB wO E3t^3.033i 4flk«fe. f ^ t drin^'nT 'Wri A ' J ' ilk n 1! Artl^k jite/m T«i it. 1*1 .nk

* succinimide w ith olefins* fhe extension of Braudels mechanism to bromination with H^rasmbsgwmsdd© would p red ict the following path fo r the form ation of dibromide: By analogy with the accepted mechanism fo r the polar addition of bromine to o lefin s (97), th is mechanism Should be stereo specific ami lead to to m s addition* th erefo re, one obvious te s t ©f the mechanism is to determine the stereofeheisioal course of the reactio n , to th is end, 100 o ca o i— i CD in to o o aoitvMiwsjivHai JiMaoHaa FIGURE X I. — INFRARED SPECTRUM OF pC/^-DIDEUTERO-ALLYL ALCOHOL. 93 100 o o IEOWViI iLIIAISMVHiL iNaOHad o o CARBON TETRACHLORIDE H CQ — G> O M FIGURE X II.—INFRARED SPECTRUM OF K.ot-DIDEUTERO-ALLYL ACETATE. SOLUTION. 9k 95 ► — •, o CO o cc o :0 o Q CD CO *: o < K J o P PiI O v-j 1-H rr-T 6 O pEii' ! CO P-1 O W On co n a ix p PD o O r~ CM C) aoMVMiasftVHi JiKHDHSJ 96 * Sf the brominabion of the geometrical isomers of stilb en e with H-bromobensBamide m i undertaken. The choice of c ia - and tra n s-s tille n e fo r moo m the o le fin ic su b strate m a d ictated by several factors* The P ^ 9 isomers are re ad ily prepared and the diastereom erie dibroraides have v a stly d iffe re n t physical properties and are therefore ea sily separated aad id e n tifie d . F urther, since the basic problem of the present study was to d iffe re n tia te between a fre e rad ical or an ionic mechanism, the use of g^HtiiXben® offered a unique advantage in th a t Kharasch and h is co-workers (pfi) have shown th a t the isom erization of c i s - stilb en e to tran astilb en e i s sp e c ific a lly catalysed by bromine atoms. I t was found th a t the transform ation c ia -atilb o ae tran^:-stilben© did not occur in the presence of bromine and hydrogen bromide in the dark and in the absence of peroxid&e substances. The transform ation became exceedingly rapid in the presence of lig h t or paeoxtdic ca ta ly sts such as benzoyl peroxide. Furthermore, the lig h t and peroxide catalysed isom erizations could be completely in h ib ited by autioxidants such as catechol and th is phenols These fin d in g strongly indicate th a t bromine atoms are potent c a ta ly sts fo r the isom erization of #fs*stilfrsne and therefore the stilb en e stru ctu re can serve as a sen sitiv e detector of bromine atoms. Berthoud and Ureeh ( O CO CD 0 0 (A 1— 1 40 •rH X _AO - P CO 03 o 0 i-d (— 1 a) •f—i 5>h m -p X O CD L ri x 0 cx ♦ r— I I P o (X aD 0 co -p CO tx Xt > H 0 X o 03 0 to c; CQ X rH H XI QD o03 I -H cco C rtD *H Q rQ to• ao« CO LO 9 tO tQ CO rH o9 co LO CO £> X0 co LO rH 04 L CO 04 O sh 04 i— I 04 * 3 d i—I I—hI 0i—4i Eh u) CG s rrH 40 40 LO 00 QX a 04 04 •rH d I -h tO* 04 04 C O o C CQ 3 03 0 03 0 0 ct X ra 0 o > O O 0 CQ X CQ SX CD . 0 rj 05 £> 0 03 04 03 • O CD -P |X-H rX 0 IX i—1 X •H d 0 i—1 r j O X 0 rH ■ ■ L X 0 0 cc 0 t o O X X (T *' LA 0 r— I i—1 C" CO t> 04 X 04 SC !DC + CO •rH r) (X + 0 X 0 X -P ca ro f—1 + 'H o | CQ CQ I—* r-'-x + X CT X -P * CO C O CO CO CQ CQ 04 CQ m X 00 CD r—I I— 1 I— I rH CO CQ X=r uj PO -CO CQ CO co o O 0 JO 0 d H Q X C CQ 0 CD CO c-r‘ d XdQh 03 •rH , 0 trinitrobengQne and azoxybenzene have found considerable use as in h ib ito rs of free ra d ic a l chadn-reactions, and azoxybeazene, in p a rtic u la r, has been found to be a powerful in h ib ito r fo r reactio n s involving halogen atoms (100) * Further, i t was found th a t ¥-bromobenzamide was in e rt with respect to azoxybenzene and syra tri«* nitrobenzene * ■When solutions of cis*»atilbene in carbon tetrach lo rid e were treated with M-bromobenzamide in the presence of asoxybenfeen® and sym trin itro * benzene, no in h ib itio n of the isom erization occurred (see Table IV), This re s u lt was somewhat surprizing in th a t i t indicates th a t the N-bromobenzamid e catalysed isom erization of c fs-stilb en e does not proceed v ia a fre e radical-chain mechanism* Although the bromine catalyzed isom erization of cis^stilb en e is generally accepted to occur through an interm ediate containing an unpaired electron (101), other cie«*trans interconversions are presumed to proceed y ia polar mechanisms. F ries and K eister (82) have found th a t boron triflu o rid e is a powerful ca ta ly st fo r the isom erization of c is-stilb en e and they suggest the interconversion may proceed through the interm ediates FMJBfc*—CHPh I BF3 102 fh© pos tu la tio n of an anal© gous totarm ediate fo r the M^bromobensamide catalyzed Isom erization does not PhCH \ CHPh ^■wmwfr Br ♦ PhCH vmmmmCHPh ♦ / Br 9M s reasonable since th is stru ctu re is in reality* a raasonanee hatred of the cyclic bromonium interm ediate which is presumed to m aintain i t s s te ric id e n tity * Therefore, i f a bromine atom in terc onversion is elim inated, as the data suggests, a polar mechanism is indicated. However, a p recise form ulation of a polar mechanism remains obscure. In th a t i t was d e fin ite ly established th a t H^bromobenaamide promotes the isom erization of oi&^stilben© to i^^axiys^st Hb ene fa r fa ste r than i t a c ts as a brominating agent, the finding th a t msao«&#c »^dibromobibengyl is the product of the bromination of cis^stilb en e with N^bromobenzaraide cannot be c ite d as evidence fo r a fre e rad ical mechanism* On the other hand, i t does not preclude a ra d ic al mechanism* However, the observation th a t M^bromobengsamid© i s squally effectiv e in the presence of the fre e radical-ehain in h ib ito rs, assesybeazeae and sym^t r in itro b enzene» suggests th a t the isom erization occurs v ia a polar path rath er than a free rad ical chain mechanism * Of toe to o ls av ailab le to toe organic chemist fo r the elucidation of reaction mechanisms unquestionably a very valuable one is th a t of chemical k in e tic s. C ertainly in toe problem a t hand, a knowledge of to© ra te law would b® an invaluable aid in distinguishing between a free ra d ic a l c h a i n - r eaction and a polar mechanism* However, since i t was 103 not found possible to obtain a good m aterial balance fo r the emmg&mm o f the N^mmoamide lOmomal bmmination of o lefin s studied, a d etailed k in etio iw e e tig a tio n did not seem advisable,, The lack of a completely In e rt solvent and th e d is tin c t contrast in the so lu b ility ch a racteristics Of amides and th e ir H^bromo derivatives fu rth e r discouraged th© under­ taking o f a d etailed k in etic study. Without doubt, i t is fo r these same reasons th a t as y et no d etailed k in etic analysis of th e reaction of an N**br©moamide o r H*%romoimide with an unsaturuted compound appears in the chemical lite r a tu r e , I t mas f e l t however, th a t much could foe learned concerning the mechanism of the bromination of o lefin s with H-bromobenzamide by a study o f the e ffe c t of o le fin stru c tu re , solvent, c a ta ly sts, and Inhibitors upon the reaction ra te . This m s accomplished by maintaining a l l the reaction variables constant, except th® one under study, and measuring the time required fo r the disappearance of h a lf of the i n itia l N^bromobenzaBri.de concentration» In th is m y, the re la tiv e re a c tiv ity of H-bromobenzamide toward m ethallyl a c e ta te , a lly l a c e ta te , and aH y l cyanide m s determined. The method is probably b e st described by the us© of a specif ic example. For th is purpose, the determination of 'fee time required fo r reactio n of h a lf of fee W-bromobenssamide in fee presence of a n itro methane solution of m ethallyl acetate a t 3d ± 0.1° w ill be described in d e ta il, ©.©£ X» the i n i ti a l or 2era-tim e concentration of each reactan t m s 10h A stock solu tio n of m etballyl acetate was prepared by weighing 0*997 g* (0.0087^ mole) of m ethallyl acetate into a 50 ml* volumetric fla^k which was then therm )stated a t 38° and f ille d to th© mark with nitromethane which had been preheated to 38 0 . The s lig h t increase in volume o f the volum etric flask du© to th© elevated temperature was neglected. The m olarity of th is solution was therefore 0.175 M. A 0.07 H solution of N^bromobenaaaido was made up in a sim ilar manner. The H-bromobansjaraide used was carefu lly p u rified by repeated re c ry sia lliz a tio n from a mixture of chloroform aM n-hexane u n til iodometric an aly sis showed th© p u rity to be in excess of 99*9%* The exact m olarity of the K-bromobenzami&e stock solutions were always determined sh o rtly before th e ir use by the iodometrie titr a tio n of an aloquote with standard sodium th io s u lfa te . The reaction m s in itia te d by p ip ettin g a 10 ml* aliq u o t of the 0 ,1 7 5 M methaHyl acetate solution (thermostated a t 38°) into a 25 ml. portion of th© 0*07 M M-bromObenzamide solution contained in a lowa c tin ic 50 ml* volumetric flask immersed in the constant temperature bath held a t 38 ± 0 .1 °. The tim er was started when i t was estimated th a t h alf of the o lefin solution had been added. Samples were withdrawn a t d e fin ite time in te rv a ls by means of a 3*0 ml* p ip ette and immediately allowed to run into a mixture of 10 mi* of 10$ potassium iodide and 30 ml, of 1.0 $ acetic a c id . The lib e ra te d iodine was titr a te d with 0.030U1 N sodium th io su lfate solution to a starch end-point. For the reactions in which the N-bromobenz&mide disappeared rap id ly , the samples ware withdrawn and quenched in th© iodide mixture and the lib erated 105 Iodine was titr a te d a fte r completion of th© sampling operation • More often the reactions were ©low enough to permit immediate titr a tio n before i t m e necessary to remove the next aliquot* The i n i ti a l m olarity (Mo) of N~bromhbenzamide and m ethallyl acetate were calculated, by th© following relatio n ship ; ^ Of M*b^amoamide or o le fin goln. x Vol. (Ml*) ’) Thus, IS© fo r $~bromobenzamid© » m 0.05 M and M© fo r .m ethallyl acetate « A * m 0.05 M Mo The following data m e collected* Time (sec*) 0 T iter (ml*) 5*ltb (c a lc .) 50 6*85 205 b*H5 5*65 3.6o 3*00 700 2*b5 1,55 1*1*5 The time respired fo r the disappearance of h alf of the in itia l ll^bromobenzamide m e estimated graphically from a p lo t of the thioaulfat© t i t e r versus tim e. Figure XX? illu s tra te s th is procedure fo r th© specific example under consideration. The repro d ucib ility of the method m s checked fo r th© N-bromo^ benaam ide-allyl acetate system and found to be reasonably good* One com plicating fa cto r is the decrease in t i t e r observed fo r H-broraob©nzamide Thiosulfate titer in ml 106 Ta"«175 100 200 Tim e 400 300 in seconds. onds 600 F i g u r e X I V . — R a t e o f t he r e a c t i o n of N - b r o m o b e n z a m i d e w i t h m e t h a l l y l a c e t a t e in n i t r o m e t h a n e at 30°. 107 solutions in th® pars solven ts. A precursory investigatio n of the S ta b ility H^romobeazairdde solutions in n itro methane , fHrt^f.hyl a c e to n itrile , in ert* dp>^ dicmn© revealed th a t only nitromethan© m s re la tiv e ly Xn nitromethan©, and a t 38^, the solvent induced disappearance of H-aferoiaobenstoJRide ^ 3 in s i^ iifio a n t fo r the reactions requiring only hours fo r ©oinpletion, and even fo r th© reactions of longer duration the e ffe c t never m s observed to account fo r store than $% of the to ta l observed decrease in M-brcuritob©nzamlde cone ©ntration Table V contains the re su lts obtained by an id en tical procedure fo r the reaction of H^bro®obenaanid© with a lly l acetate and a lly l cyanide. BM f HA1F-1I7KS TO TH& W&OTKffi OF N^mMmmZAMIDB (MSB) m m THEM OMOTS m hitegkethane at 38 0. ■Olefin I n itia l O lefin Cone*, I n itia l HBB Cone., (aioleaA itar) (m olee/H ter) T1/ 8 (see.) M ethallyl ac etate 0.05 0.05 175 A lly ! acetate 0.©£ 0 .0$ U7$0 A lly! cyanide 0.05 0 .0$ 3I 870 In order to Observe th© e ffe c t of the solvent on the reactions of H^browiobenjsamide with matb&llyl ac etate, a lly la e e ta te , and allylcyanide Attempts were made to measure the h a lf olives a t 38° in ehlorobenzena and chloroform so lu tio n . In ehlorobenzene th© reactions with a lly l ac etate and a lly l cyanide were so slow th a t the determ ination of the h a lf -liv e s would be meaningless due to the re la tiv e ly larg e contribution 108 o f th# solvent re actio n . However, th# reactio n with m ethallyl acetate m e su ffic ie n tly rapid th a t the h a lf- life measured fo r i n itia l reactan t eoncontratione of 0*05 M contained a t most a $% solvent reaction contribution * 2m a manner Id e n tica l to th a t previously described, the i n i ti a l h a lf - lif e fo r the reaction of N-bromobeu^amide with m ethallyl acetate in chlorobensene a t 38° and a t zero-tim e reactant concentrations of 0,0$ M, was found to foe 141,000 seconds as compared to 175 seconds fo r the same reactio n in nltrometban© . the former value is not nearly as accurate as th® second because ©f the solveat reaction contribution* However, the Ul,0GQ seconds represents a mSMimm value and therefore adequately defines the larg e solvent dependency, fee d ie le c tric constants of n itro meth&n© and chlorobenaene a t 20° are 3? .5 and 5*?1 respectively. The h a lf - lif e fo r the reaction of H^bromobenssamide with a lly l ac etate in chlorobenzen© solution a t $7*k0 was found to be 16,700 seconds. The i n i ti a l concentrations of H-bromobenzamide and a lly l acetate were 0.039 Mand 0*766 M respectively* Althou^i th is observation is not comparable with th® other data from the standpoint of in itia l concentra­ tio n , i t does serve to emphasise the object in p oint, th a t the ra te s of reactio n s of N-bromobenaamijde w ith o lefins do exhibit a strong dependency upon the p o la rity o f the medium. VJhen chloroform was used as a solvent the re su lts obtained were not reproducible. Thus, th® h a lf-liv e s fo r id en tical reactions of m ethally a c e ta te with N-broraobenz&mide were found to vary as widely a s th# rat© o f th# same reaction on changing the soXveat from 109 nitobmethane to ehlorobenzene. I t sepsis very probable th a t th is e rra tic behavior mas a re s u lt of im purities In the chloroform. I t Is w ell known th a t th e p u rific a tio n and storage of chloroform from which the alcohol s ta b ilis e r has been removed, presents a d iffic u lt experimental ta sk . Further* a mitfcer of Investigators have encountered d iffic u lty in obtain­ ing chloroform which gives reproducible re su lts when serving as a reactio n media (102) * For th is reason the use of chloroform as a solvent m s discontinued. The e ffe c t of c a ta ly sts and in h ib ito rs upon reaction ra te affords one of th e b est methods of d iffe re n tia tio n between radical and non— ra d ic al reactions* Accordingly, i t was of in te re s t to investig ate the present reactio n from th is avenue of attack* As previously discussed, the choice of a su itab le m dical-chain in h ib ito r is made d iffic u lt by the a b ility of B-broiaoajoiides to oxidize most of the more commonly used in h ib ito rs. However, azoxybensena (100) and sya~trinitrobenaone (90) have found considerable use as in h ib ito rs of free radical-chain reactio n s, and in p a rtic u la r, have been shown to be effectiv e fo r reactions involv­ ing halogen atoms, Indeed, Sym trtnitrobenzane has been used to demonstrate the fre e ra d ic al nature of some reactions of H-bromosuccinim de by v irtu e of i t s a b ility to in h ib it these reactions (90) . Moreover, in the present work i t was found th at M^bromobenzamide is in e rt with respect to azoxybenzene and gym-trinitrobenzene, fhe reactio n of N-bromobenzamide with a lly l acetate in nitrometliane so lu tio n a t 38° was studied in the presence of c a ta ly tic amount® of &zoxybmzm@ and sym ^trinitrobengene. Three id en tical reactions were no conducted sijmiXt&neoiisly, as a control* The f i r s t contained no in h ib ito r and served The second* contained a 0*2 molar equivalent of azoxy- benzene, and the th ird a 0,2 molstr equivalent of gym*»trln itr obenzene, The ra te of these reactions m s followed by the usual iodometrie procedure* Table ?! presents the data obtained* MLB VI m m f o r ik h ib it o is oh thb b m c tio n o r 0*05 m h-^brcmobenzajccdb w ith 0 .0 5 n a i m l ACBmtB ih hitrokb tha.h e a t 38° Control Bun Time (sec*) T ite r (m l.) 0 120 890 1900 3615 1*930 7550 9.2itb 8.88 7.75 6.6b 5.02 b.60 3.02 0 *001 II Azoxybenzene Tine (sec*) T ite r (m l.) 0 102 885 3900 bo55 1*920 75b5 9.2bb 8.85 7.73 6.75 5.16 b.55 3.00 0.001 M gym«»Tri~ nitrobenzene Time (sec.) T ite r (m l.) 0 111 890 1910 3608 '1*925 7535 9.2bb 8,85 7.60 6.78 b.95 b.b8 2.95 a0 ,03205 H sodium thiosulf& te C alculated value Inspection o f th is data reveals th at the presence of azoxybenzene and ^Tfl-^trinitrobenzene in the reaction of H-*bromobenzaBiide with a lly l acetate produce© no measurable change in ra te of the reactio n . Within the p recision of the an a ly tical method, a l l the experimental points lis te d in Table ? ! describe a single lin e in a p lo t of t i t e r versus tim e. Thus, i t m s demonstrated th a t azoxybenzen© and s^rn-trinitrobenzene have Ill no e ffe c t upon th© reaction of N**bromobenzaad.de with a lly l acetate in nitrom ethane a t 38°, The study of the possible e ffe c t of free rad ical in itia to rs , such as benaoyl peroxide and aao -b is^iso b u ty ro n itrile, on the reaction ra te m s complicated by several factors* Peroxidic substances lib e ra te iodine from iodide solutions and therefore would in te rfe re with the iodometric a n a ly tic a l method used to follow the reactio n s. At the convenient temperature© fo r the study of the brorainatlon reactio n s, the common fre e rad ical in itia to rs do not Supply radicals a t a ra te consistent with the ra te of the bromination reaction* F in ally , i t has been shown th a t the fre e ra d ic als produced by the decomposition of polym erisation in itia to rs are capable of ab stractin g bromine from N*bromo compounds (16) | th is secondary reaction could therefore give fa lse evidence of c a ta ly sis * The ra te of the reaction of H-bromobenaaniid© with a lly ! acetate in nitromethane solution a t 38° m s found not to b© effected by the presence of c a ta ly tic amounts of aa c-h is-iso b u iy ro n itrile. Figure XV shows a p lo t of the data obtained. He data is av ailable concerning the rat© of the hoiaolytic d isso ci­ atio n of azo-b is^isob u ty ro nitrile in nitromethane. However, the rat© of d isso ciatio n has been shown to be in sen sitiv e to the nature of the solvent (103), and the unlmolecular d issociation constant in xylene a t 30 i s reported to b© 8,9 x 10 sec, * Obviously the amount of as©-b is -iao b u ty ro n itrile th at w ill undergo d isso ciatio n in 6 x 10* seconds a t 38° w ill be very sm all. N evertheless, 112 7 6 Thiosulfate titer in 5 4 3 o -L 0 Time, se c o n d s x 10~3. F i q u r e X V - — E f f e c t of n z o - b i s - i s o b u t y r o n i t r i l e on rate of r e a c t i o n of .042 M N-Bromobenznmi>le w i t h .036 a llyl a c e t a t e in n i t r o m e t h a n e at 30°. c o n t r o l run. 4- , .2 m o l a r e q u i v a l e n t of a zo-bi s - i s o b u t y r o n i tri le added. Q, 1 IJ i f 'thtt reactio n were to take place by a free radieal-ebain process, and I f the ©bains involved were re la tiv e ly long, a measurable acceleration Should be observed, ^Therefore, while the experiment is anything b at d e fin itiv e , i t dees have some significance and fa rth e r, i t is consistent With the re s u lts o f the in h ib ito r study* fhe unequivocal d iffe re n tia tio n between free rad ical and non** * ra d ic a l reactions can be a d iffic u lt experimental problem. Only through the use of the defining property of paramagnetism can an absolute answer be obtained* Frequently experimental d iffic u ltie s prevent the use of th is to o l and i t becomes necessary to make the assignment from a con­ sid era tio n of other c rite ria * The ehar&c te r is tie o most frequently cited fo r the d istin c tio n between ra d ic al and polar reactions are dependent upon the response of the reactio n in question to substituent e ffe c ts, solvent e ffe c ts, c a ta ly sts, in h ib ito rs, and diagnostic reactions* $0 one of these c r ite r ia is in i t s e lf su ffic ie n t fo r a clear-cu t assignment since exceptions to each individual e ffe c t are known. However, the complemen­ ta r y w h ic h agreement of several of these effects provides strong evidence upon the assignment can be made. £& general, electron releasing and electron a ttra c tin g substituents have the opposite e ffe c t upon polar reactions. On the other hand, ra d ic a l reaction s usually are re la tiv e ly insensitive to substituent #For an excellent discussion of th is topic see J . S. L effler, f,The Eeactive Interm ediates of Organic C hem istry/ Interscience P ublishers, 1ms.9 *« T. 193&, Clip* X II. ill* e ffe c ts , and show a random response to d iffe re n t types of substituents# Therefore, the larg e sub stitu en t effects found fo r the reaction of N"^bromobenzamide with m ethallyl ac etate, a lly ! ac etate, and a lly l cyanide are in d icativ e of a polar mechanism# This indication is fu rth er supported by the fa c t th a t th e observed order of re a c tiv ity QH^GHCHapCOCH^ > CHa«CHGH^OCOGH3 > CH^H GH^ i s the m m ad th a t q u a lita tiv e ly observed fo r th e bromination of the Same o lefin s with elemental bromine* Another im plication of th is experi­ ment is th a t, inasmuch as the observed order increases with the increasing n u cleo p h ilicity of the o lefin ic double bond, i t would seem lik e ly th a t the ra te determining step Is concerned with the donation of po sitiv e bromine to the double bond, analogous to the polar addition of bromine to most o le fin s . P olar reactions are normally in sen sitiv e to the presence of in h ib ito rs and the free rad icals produced in s itu by the thermal homolysis o f poly­ m erisation in itia to rs , whereas rad ical reactions usually show marked re tard atio n and acceleration effects* The demonstration th at the reaction of H~byonobenzara±de with a lly ! acetate is not affected by the presence of azosybenzene or s^B -trinitrobenzm e, in h ib ito rs which have been shown to be effectiv e fo r sim ilar reactions known to Involve halogen atoms, probably co n stitu te s the most important single piece of evidence support­ ing th e conclusion th a t the reaction does not proceed v ia free rad ical interm ediates * The demonstrated in a b ility of azo -b is-iso b u ty ro n itrile us to cataly se the reactio n is not p a rtic u la rly v alid evidence fo r the reasons previously discussed. $h© c r ite r ia o f solvent effect is frequently used as supporting evidence in the d iffe re n tia tio n of a rad ical process from a non**radieal one« P olar reaction s normally exhibit a strong s e n s it iv it y to the p o larity and solvating a b ility of the solvent while ra d ic al reactions are essea** t ia lly independent of solvent e ffe c ts. Many exceptions to th is generally aation are known but normally they are explainable in terms of affects such as dipole*dipole Intern t ions, ion-radicals and the lik e . The fa c t th a t the h a lf- life o f the reaction of N^bromobenaamide with m ethallyl acetate a t 30° increased by a fa c to r o f 23k on changing the solvent from nitrobenzene to chlorobenzane is good evidence fo r a polar mechanism. I t should, however, be m inted out th a t not a l l polar mechanisms show larg e solvent effect! SL*J&+* the ra te of a bimolecular process between oppositely charged iemss* or a reaction in which the charge is on one atom in th e reactan t but spread cu t over several in the tra n sitio n s ta te , w ill be weakly retarded by an increase in the ion«*Bolvat±ng power of the reactio n medium* However, the ra te of a process such as in which the tra n sitio n sta te must involve a separation of charge should be strongly accelerated by an increase in the ion*solvating power of the reaction medium (10^)* 116 Frequently the a b ility to in itia te addition polym erization of vinyl d eriv ativ es baa bean used aa a diagnostic reaction fo r the presence of a c tiv e fre e ra d ic als (105)# Other reactive systems are known which re a c t sp e c ific a lly with ionic Interm ediates such as carbanions and carbonium ions and therefore can be used to detect these interm ediates. Inasmuch as N^bromobenzamide has been shorn by* Probst (5) to react with styrene in carbon tetrach lo rid e to give a 53$ y ield of styrene dfbromide, i t was of in te re s t to see i f N•bromobenzamide could effect the polym erisation of styrene and fu rth e r, i f a polymer could b© obtained, i t would be of in te re s t to &m i f i t contained bromine or nitrogen or both. Accordingly a sample of styrene was p urified in the conventional manner and attem pts were made to in itia te i t s polym erisation with H'-toromobenzamide * Hie mixtures were heated in degassed sealed tubes a t 5?° fo r 18 hours* No polystyrene could b© Isolated under these conditions e ith e r in the presence or absence of N**bromobenzaiaid®. On the other hand, under the same experimental conditions benzoyl peroxide was found to read ily in itia te the polym erization of styrene# Once again no evidence for' fre e rad ical interm ediates was obtained • All of these observations, notably the fa ilu re of azoxybenzene and svm w K## -trinitrob enzene to in h ib it the reaction! the fa ilu re of azo-bis~ iso b u ty ro n itrile to show any accelerating effect! the large solvent and su b stitu en t a ffects found! and the iso latio n of N,N*-phenylbenzoylurea are consistent with a polar reaction# In lig h t of our present knowledge concerning the ad d itive bromination of o lefins with N-bromobenzaraide the most lo g ic a l route to the formation of a dibromide would seem to be the following* 117 comB* CONH y ■•( Bt CONH+ CBrCBr I t appears probable th a t step (1) be a t le a s t p a rtia lly ra te determining inasmuch as the ra te of the reaction was observed to increase with the increasing nueleop h llicity o£ the doable bond in the order* m ethally acetate > a lly l acetate > a lly l cyanide Assuming steps (1) and (&) to be v alid the mechanism fo r the formation of bensamide in good y ield from the subsequent reaction of the oppositely charged benzamide ions remains obscure * Obviously some ex terio r source of hydrogen is needed* the fa ilu re of the reaction of K-bromob erusamicle with a >€c«did@ut©roMallyl acetate to y ield IMettber©** benzaraide would m m to elim inate the a lly lic iydrogm as a p o ten tial hydrogen spur©©. This finding suggests th a t hydrogen procurement step does not proceed, via free rad ical interm ediates because, in carbon tetrac h lo rid e media, the a lly lie hydrogen should be the most readily absrfcractable hydrogen present. 118 Reagents and Apparatus The m elting points ware uncorreeted and. were determined using a r rtt* r‘r'~/ i ' ,'v mechanically s tirre d silico n e o il b ath. The Infrared spectra were determined with a Perk in-Elmer Model 21 Recording Infrared Spectrophotometer. M icroanalysis ware made by Microtech lab o rato ries, Skokie, I llin o is , The lithium aluminum deuteride m s obtained from Metal Hydrides, In c ,, Beverly, M assachusetts, and was 9$% pure. The deuterium oxide was the generous g if t o f Professor H art, The M-bromosuccinimide was obtained from Arapohoe Chemicals, In c ,, Boulder, Colorado, and m s recry stallized rapidly from hot water shortly before use. The m ethallyl acetate was kindly supplied by the food Machinery and Chemical Corporation, New York 17, N. X. The a lly l acetate m s Eastman Whit© lab el m aterial and m s re d is tille d using an e ffic ie n t colium Ju st p rio r to i t s use. The nitromethane m s a good commercial grade, fu rth er p u rified by drying in contact with anhydrous magnesium su lfate followed by d i s t il X la tio n through a glass hello# packed column. The dimethylformamide was treated with potassium hydroxide p e lle ts and d is tille d . The carbon tetrach lo rid e was p u rified by refluxing a C .P . grade with ±5% sodium hydroxide solution fo r 2k hours followed by a thorough washing with water. A fter a prelim inary drying in contact with anhydrous calcium chloride i t 119 was die tille d from phosphorous pentoxide. The chloroform, chlorobenzene, and. benzene w e p u rified as previously described in the f i r s t p art of th is thesis* A ll other reagents were eith er a good commercial grade or were prepared as described in d e ta il in the pages th a t follow* Reactions ©f N-Bromoamides with Cyclohexene Reaction of N-rBromo-it-nitroacetanilids with Cyclohexene Into a 500 ml. flask fitte d with a moisture protected reflux con-* denser and wrapped with aluminum fo il to exclude lig h t were placed 27.8 g. (0.107 mole) of N-bromo4j,-nitroac©tanilidQ, 300 ml. of chlorobenzene, and 25 ml. (20.3 g ., 0.25 mole) of cyclohexene. The reaction mixture was held a t 50° fo r 21* hour® a t which time a te s t with moist starch** iodide paper indicated completion of the reaction. The reaction mixture was ch illed in an ice bath and the so lid th a t had separated from solution was collected by suction f iltr a tio n . A fter drying, the lig h t tan solid melted a t 209-210° . A mixed melting point of the product with an authentic sample of p -n itro acetan ilid e showed no depression. The y ield was 17.5 g. (95 S%)* The chlorobenzene f iltr a te was concentrated, in vacuo, to a volume o f ca. 25 ml. and th e residue d is tille d using a small Vigreux column. Three fra ctio n s were collected# 1, b.p. 25*70° a t 8 mm., 5*2 g .j 2, go b.p* 70— 78° a t 8 mm., 0*5 g*j 3* b.p* 78— 80 a t 7 mm*, 6*0 g ., n^ 1.5U81* The d is tilla tio n had to be interrupted due to decomposition of the d is tilla n d accompanied by the evolution of hydrogen bromide. The residue 120 1aas a bladk glassy m aterial weighing 6 g. chlorobenzene. The f i r s t fractio n was larg ely She second fractio n reacted rapidly with s ilv e r n itra te to give s ilv e r bromide, and rapidly became discolored on standing* The th ird fra ctio n gave a s lig h t reaction with silv e r n itra te but showed no d isco lo ratio n on being s e t aside* Authentic samples of 3-broraoeycle>~ hexene were observed to discolor or darken rapidly on standing a t room tem perature. The physical properties observed for authentic samples of tra n s - l, 2-dibromocyclohexane and 3‘■bromocyclohexene were respectively: b .p . 86° a t 8 aim., 1 .5516} b .p . 75- 79° a t 8 nan., n!° 1.5270. Assuming fra c tio n 2 to be 3-broraocyclohexene i t represents a 3% y ie ld , and assuming fractio n 3 to be larg ely tra n s it . 2~dibromocyclohexane» i t represents a 21.6$ yield* In another experiment employing chloroform as a reaction solvent rath er than chlorobenzene, 70 g* (0.262 mole) of N-bromo-4i-nitroacetanilide were reacted with 110 g* (1*35 moles) of cyclohexene. iso la tio n of the products by a procedure analogous to th a t described above resulted in a 78$ y ield of p-nitroacetam lLide, a 38$ y ield of tran s-1, 2-dibromocyclohexane, id en tified by i t s in frared spectrum, and a 12$ y ield of 3-bromoeyclohexane • Reaction of ^^BromoHi^henTlacetamide with Cyclohexene in G lacial Acetic Acid ........... .............. . Into a 500 ml. flask equipped with a mechanical s tir r e r were placed 35 g* (0 .16U mole) of N-brorao-U-95° a t 6 mm., 7*9 g*, n^0 1.510?* Decomposition forced th® discontinuation of the d is tilla tio n and a black glassy residue weighing 8 .U g* remained in the d is tilla tio n flask* Infrared spectra of fractions 2 and 3 were sim ilar and consistent with th© spectrum of authentic 2,3^ibromopropyl acetate. Fractions 2 and 3 were combined and re d is tille d to yield 11.2 g. (57 *k%) of pure 2,3^dibromopropylacetate, b*p* 9U*95° a t 6 mm* Anal* GalcM. fo r CsHsBr20g* Br, 61.U7* Found* Br, 61.66, 127 b) In N, N-Dimethylforrnamide # 111 th® apparatus Just previously described, 3k .1 g. (0.17 mole) of N^romobenzamide, 22.8 g. (0.23 mole) of a lly l acetate, and 250 ml. of N,H~dimethylforraamid© were s tirre d a t 57® fo r 30 minutes. A te s t with moist atareh-io&id© paper indicated the reaction to be couplets. Wien c h illin g the reaction mixture fa ile d to induce any cry sta llizatio n , the solvent was removed under reduced pressure, the resu ltin g viscous, o ily residue, weight 1*6 g*, deposited a small amount of cry stallin e solid on cooling. The solid was isolated by f iltr a tio n , and when dry, weighed 5*5 g* 9 M.p. lZ2~12k° * treatment of th is m aterial with boiling water yielded a small amount of crude N *^henylbenzoylurea Which a fte r re c ry sta lliz a tio n from 95% ethanol, melted a t 200-201°. On cooling, the aqueous ex tract deposited 5*1 g* of benzamide, m.p. 125*126°. The f i l t r a t e was d is tille d in vacuo and a fte r a small low-boiling forerun, there was obtained a single fraction* b.p. 85-87° a t k mm., so 10.3 g ., Up 1.5030. A fter th is fraction was collected the d is tilla tio n temperature rose rapidly to 130° and the d is tilla te so lid ified in the receiv er. Decomposition of the distilXand with the ©volution of hydrogen bromide occurred a t th is temperature and the d is tilla tio n was discon­ tinued. EecrystaXliz&tion of the solid d is tilla te from water revealed i t to be benzamlde, m.p. 125*126°, identified by a mixed melting point with authentic m aterial. The residue from th© d is tilla tio n so lid ified to a dark mass exhibiting some c ry sta llin ity . ethanol, treated with Iforite and filte re d . m s obtained 1.1 g. (5M%) of I t was dissolved in hot 95% On cooling the f i l t r a t e there -pheiylbenzoylurea, as fin e crystalline 128 needles, m.p. 20X’*^02° • Th© mother liquor was evaporated to dryness, extracted with bo ilin g water, and filte re d . Th© f i l t r a t e on cooling deposited 3*U g. of a lig h t tan cry sta llin e m aterial, m.p. 112*120°. R ecrystallizaiion of th is from water yielded nearly colorless cry stals of benmmide, sup. 126**127°, 2.8 g. The to ta l iso latio n of benzamide iMas therefore 7*9 g. 0&,k%) + The liq u id product m s identified fey mans of i t s infrared spectrum to be 2,3*dibromopropylacatate. The yield m s 10.3 g. (U6.7$). c) In nitromethane. In a 1 l i t e r flask ©quipped as described above sere placed 5b g. (0*27 mole) of H~bromobenzamide, 36 g. (0.36 mole) of a lly l acetate, and UOO ml. of nitromethane. The reaction mixture m s stirre d a t ambient temperature fo r 2b hours. A spontaneous 10° ris e of the reaction temperature was noted during the f i r s t hour, and a fte r 2.5 hours had elapsed the homogeneous solution began to deposit a while cry stallin e so lid . A fter 2b hours a te s t with moist starch-iodide paper indicated the presence of unreacted M*bromobenzamide. A b rie f warming of the reaction mixture on the steam bath sufficed to conflate the reaction. The reaction mixture m s se t aside in the refrig erato r overnight a fte r which the cry sta llin e deposit m s isolated by f iltr a tio n . Th© colorless p lates were washed on the f i l t e r with cold nitromethane and a ir d ried . The dry product weighed 20.0 g. and melted a t 126*127° ♦ A mixed melting point with authentic benzamide showed no depression. Th® f i l t r a t e and combined washings were concentrated in vacuo to a volume of ca. 50 ml. C hilling induced the deposition of a second quantity 129 of cry sta ls sim ilar in appearance to the I n it i a l product. These were Isolated as before to y ield 9.3 g. of pore benzamide* m.p. 129-126°. This brought th© to ta l iso latio n of benzaurf.de to 29.3 g. (90%). The solvent m s removed from th© combined f i l t r a t e and washings and the re su ltin g orange o il m s d is tille d in vacuo. The yield of 2,3-dibromopropyl acetate* id en tified by i t s infrared spectrum* m s 8 g. (23%), 0 so b .p . 70*79 a t 2 mm., xs^ 1.5110. As before* the d is tilla tio n had to be interrupted due to th© decomposition of the d istilla n d . Th© black* glassy residue weighed 15.1 g. The residue m s analyzed for bromine according to th© method of Umhoefer (72). An accurately weighed sample m s digested with sodium and isopropanol and the liberated bromide ion m s determined volum etrieally by th© Volhard method (73). This determin­ atio n revealed th© residue to contain 3h% o f bromine by weight, Bromination of A llyl Acetate with N-Bromosuccinimide A 500 mBL« flask m s charged with 50 g. (0.28 mol©) of N-bromosuccinimide freshly recry stallized from water* 30 g. (0.30 mole) of a lly l acetate* 0.35 g* of benzoyl peroxide* and 70 ml, of carbon tetrachloride. The mixture m s heated gently a t i t s reflux temperature on a steam bath* and a fte r bO minutes the reaction m s complete as indicated by a to s t with moist starch-iodid© paper. At 1th is time* th© flask was removed from the ©team bath* 70 ml, of carbon tetrachloride was added* and th© mixture wa« ch illed in an ice bath. This resulted in the separation of a lig h t orange* p la stic mass which became rig id on further cooling. The clear carbon tetrachloride layer m s removed by decantation and the viscous residue was extracted with additional hot carbon tetrachloride • 130 Th© combined carbon tetrachloride extracts were concentrated tinder reduced pressure and th© resulting orange oU was fractionated in vacuo employing a small Vigreux column f itte d with a vacuum fraction c u tte r. Four fractio n s were ©oUecteds 1, b .p . 60-65° a t 6 ram., 0.8 g.j 2, b .p . j* ■o SO _ 65-70 a t 6 mm., 2.6 g*, n^ 1.1*9501 3, b .p . 70*103 a t 6 mm., 1.1* g.j 1*, b .p . 105*108° a t 6 ram*, n^® 1*5083. The d is tilla tio n was discontinued due to decomposition of the d lstilla n d accompanied by the evolution of hydrogen bromide. & black resinous residue weighing 13 g. was obtained. Fraction 2 gave a copious p recip itate of silv er bromide on treatment with methanolic silv e r n itra te -#111© fraction 3 gave only a slig h t tu rb id ity . The infrared spectra of fractions 2 and i* were recorded. Th© spectra of fra c tio n h was in good agreement with the spectra of authentic 2,3dibroraopropyl acetate. The spectra of fraction 2 gave evidence of unsaturation and was quite sim ilar to the spectrum of a lly l acetate. Samples of fractio n s 2 and i* were put through a Perk in-Elmer Model 151* Vapor Fractometer a t 1?5°* Fraction I* was found to be essentially pure, and had an appearance time of 21* minutes identical to th at of authentic 2,3 -dibromopropylac e ta te . Fraction 2 gave a complex pattern suggesting th a t decomposition was occurring under th© conditions lo o sed by the instrument. Fraction 2 m s observed to darken on standing, and th is behavior as well as i t s lower boiling point, infrared spectrum, and re a c tiv ity to methanolic silv e r n itra te are suggestive of an a lly lic halide# Ho fu rth er work was done to characterise fraction 2 although i t appears probable th a t i t is th© unknown ct-bromoallyl acetate. 131 80 1*5083, represents a 10.2$ yield e£ 2,3^ibramoprapyl acetate (Literature values: b.p* 100*101° a t 5 mm. V. Q Fraction 1*, b.p* 105*108 a t 6 ram., s®° USMli (?1*))* Many attempts to induce cry sta llizatio n of the p lastic* lik e product obtained from the reaction were unsuccessful. Finally i t was dissolved * in a large volume of hot 9%% ethanol and the solution was se t aside in the re frig e ra to r fo r several weeks. This procedure yielded 8*6 g. (30$) of c ry sta llin e mtccinimide, m.p. 122*1214° , identified by a mixed melting point with authentic material* Ho further attempt was made to iso la te product from the mother liq u o r. Preparation of a ,a*Bi&eutero-allyl Acetate A crrlyl Chloride The procedure of Steeple* Gross, and Mariella was followed (75) • A mixture of 175 g* (2.1*h moles) of acrylic acid, 690 g. \h*9 moles) of reagent grade benzoyl chloride, and 0.5. g. of hydroquinone was distilled, as rapidly as possible using a 30 cm insulated Vigraux column u n til the d is tilla tio n head temperature reached . The d is tilla te m s then re d is tille d employing a 100 cm. vacuum jacketed column equipped with a to ta l reflu x , p a r tia l take-off d is tilla tio n head. The fraction boiling a t ?2*?li° m s collected as pure acrylyl chloride. The yield m s 187 g. (81*.5$)« a,q-Dideutero - a lly l Alcohol CHa-CH-GDgOH A 1 l i t e r three-necked round-bottomed flask m s provided with a 132 moisture protected reflux: condenser, a Trubore s tir r e r , and a dropping funnel. The system was thoroughly flushed with a stream of dry nitrogen, and 300 ml. of ether was d is tille d from lithium aluminum hydride d irec tly in to the reaction fla sk . Six grams (0.11* mole) of lithium aluminum deuteride m s quickly added and the resulting slu rry was heated a t i t s reflux temperature fo r one hour to effect maximum dissolution of the deuteride. The reaction flask was immersed in an ice bath and a solution of 20 g. (0.22 mole) of acrylyl chloride in 100 ml. of ether was added dropwlse to th® s tirre d deuteride slu rry . Following the addition, of the acid chloride, which m i completed in 30 minutes, the reaction mix­ tu re was allowed to s t i r a t room temperature fo r 2 hours. The flask m s again immersed In an ice bath and 7 ml. of water, 7 ml, of 15$ sodium hydroxide, and 7 ml. of water were added dropwlse and in th a t order. The reaction mixture was s tirre d a t room temperature fo r an additional 5 hours and then filte re d through a fritte d glass funnel. The white granular solid was washed on the f i l t e r with three 50 ml. portions of ether and the combined f i l t r a t e and washings were dried in contact with sodium su lfa te . The ether extract was then concen­ tra te d using a glass helice packed column to a volume of ca. 60 ml. and again dried in contact with fresh sodium su lfate. A fter removal of the drying agent, 30 ml. of n-butyl ether (b.p* 11*0-11*1°) was added to the ether solution to a c t as a chaser, and the mixture was fractio n ally d is tille d employing a 30 cm. jacketed glass helice packed column equipped with a to ta l reflu x , p a rtia l take-off d is tilla tio n head. were collected a f te r removal of the ethers Three fractions 1, b.p . U5-80°, 0 .5S g.; 133 2, b*p* 80*95 s 1*17 g.j 3, b .p . 95-98°, 5*90 g. (L iterature b.p, a lly l aleohol, 96*97° (50)}* Fractions 2 and. 3 represent a crude yield of 53.5#* ^.j.^l^ i^ y u t|e ro^!yiyli Acetate ch^ ch*cb8*ogoch3 A solution of 7 g* (0,116 mole) of a , a~dideuter*allyl alcohol (fraction© 2 and 3 in the previous synthesis) in 15 ml, of pyridine was c h ille d to 0° in an ice bath* The quantity 12 g, (0*12 sole) of acetic anhydride was added and the solution was set aside a t room temperature fo r 20 hours* The solution was then poured into a precooled mixture of 10 ml* of concentrated hydrochloric acid and 50 ml. of water contained in a small separatory funnel. A fter thorough mixing, the solution was extracted with four 20 ml, portions of n*pentane and the combined extracts were dried in contact with sodium su lfa te . The drying agent was then removed by f iltr a tio n through a small plug of glass wool, and 25 ad. of n*butyl ether was added to th© ether extract to ac t as a chaser. The solution was then fractio n ally d is tille d using a 30 cm. glass helice packed column* The fraction boiling a t 95**(101)*10U° was collected as a , a*dideutero-allyl acetate. Th® yield was 7.8 g. (65-3$). The reported b oiling point of a lly l acetate is 102-10h° (50). Preparation of N*Deutero~b©iizamida Sodium benzamide The procedure used to obtain th is s a lt was sim ilar to th a t described by T iterly (76)* Approximately k g* of sodium amide (Matheson, Coleman, 13U and B ell, 90% pure) was placed in a 200 ml. flask containing 100 ml. of freshly* d is tille d benzene • A 12 g. (0*1 mole) quantity of bensamide was added and the mixture was heated a t i t s reflux temperature for 2 hours using a moisture protected condenser* The voluminous, white p re c ip ita te th a t had formed during the reflux period was collected on a f r itte d glass funnel with the aid of a water aspirator and washed with hot benzene to remove any unreacted benzamide* the resulting white powder was dried in vacuo and stored in a desiccator * The yield was 11 g* {11%)* N*Deutero*b enzasnide A mixture of 0*90 g* {Q*G063 mole) of sodium bensaraide and 3 ml# of 9 9 deuterium oxide was warmed u n til a clear solution was obtained. The solution was protected from atmospheric moisture and allowed to c ry s ta llis e Slowly, The resu ltin g cry stallin e product was isolated by suction f iltr a tio n and dried in a vacuum desiccator* The yield, of crude H-^deutero^b©nsamide, m.p* 123**12U°, was 0*50 g. (65*5$). The crude product was treated with 35 ml* of hot benzene, filte re d while hot, and concent tra te d to a volume of ea* 25 ml. 0n cooling the product in itia lly deposited as a fin e , gel«*Like suspension. This on being set aside over­ nig h t, reformed in to small, colorless cry sta ls. bsnzamldewas O.38 g. (SO#)* m.p. 127°. The yield of N*dsutero- The Infrared spectrum of a saturated chloroform solution of the product showed an absorbtion band a t 3.9-U.3 microns. This band is absent in the infrared spectrum of undsn berated benzamide and has been assigned to vibration of the N-B bond (77)* 135 E©action of HHBromobenzamide with a #a-D±deutero«>*llyl Acetate A $0 b£L» flask was charged with 2*5 g* (0*0125 mole) of N-bromobenzamide, 25 ml, of carbon tetrachloride, and 2,5 g, (0,025 mole) of a,e-d±deub©ro-allyl acetate, The reaction mixture was heated a t i t s reflu x temperature under a moisture protected condenser for 90 minutesj a t which time a t e s t with moist starch-riodide paper indicated completion of the reaction* The reaction mixture was se t aside overnight In the re frig e ra to r and the cry stallin e deposit th at formed was isolated byf iltr a tio n , The crude benss&mide weighed, 0,89 g*, m,p» 115°-120°. I t m s dissolved in UO ml. of hot benzene* treated with Horite* and f ilte r e d . On cooling the f i l t r a t e there m s obtained 0 , 6 g, (39,8%) of pure cry stals of benmmide* m,p. 12? * The infrared spectrum of a saturated chloroform solution m s identical with the spectrum of u&deuterm ted benzamide, and showed, no absorbance in the U.2 micron region ch aracteristic of the $J-B bond* Preparation of c is - and trans-Stllbens Acid The procedure followed in the synthesis of th is material m s th at of Buckles and Bremer (?S), A mixture of U2.U g. (0,U0 mole) of freshly d is tille d banaaldehyde, 5b*6 g. (0*U0 mole) of phenylacetic acid, U0 ml. of. triethylam ine, and 80 of acetic anhydride m s heated a t i t s reflux temperature for 5 hours* The mixture was then subjected to steam d i s t i l ­ la tio n u n til the d i s t il l a t e m s no longer cloudy. After cooling, the 136 so lid In the residue was dissolved in 1 l i t e r of hot $0% ethanol, treated with Borit©, and filtered * red with 6 If hydrochloric acid* The f i l t r a t e was acidified to congo The resulting solid was recry stallised from aqueous ethanol to yield 50 g* ($6%) of a-phenylcinnamic acid, irup* 165-167° (L iterature value* 1?2-173° (78))* cis«©tilbene The procedure of Buckle© and Mheeler was followed in the preparation of th is M aterial (79)* A mixture of 26 g* (0*12 mole) of a*phenylcinnamic acid , 160 ml* of p ra c tic a l grad© quinoline, and 2.5 g* of copper chromite was heated in an o il bath fo r 75 minutes. After cooling, the solution was poured into 550 ml* of 10# hydrochloric acid and extracted with three 50 nil. portions of ether* The combined ether extracts were washed with 10# sodium bicarbonate and dried in contact with sodium su lfate. After removal of the ether, the dark brown o il was dissolved in a minimum volume of n-hesane, ch illed to 0°, and filtered * The n-hemn© was removed on a steam bath and the residue was d is tille d under diminished pressure using a small Yigreux column. Three fractio n s were collected? 1, b.p* $5“HU° a t 12 mm*, 2*5 g .| a ao o 2, b.p* llL-120 a t 12 mm*, 3*5 g«, Ujj 1.6212$ 3, b*p* 120-121 a t 12 so m . , 7.0 g ., n_ 1.6226. Fraction 1 was colored and m s discarded. Fractions 2 and 3 were colorless, refractiv e o ils representing a 50g y ield of c ls -stilb e n a . ©tilben© arcs The reported (79) physical constants of c is Jfc© b*p* 133^136° a t 10 rasul 1*6212-1*6218. 137 tran s -6 t i lb ene The method employed to obtain th is compound m a th a t described by $hriner and Berger in Organic Synthesis (80). From 100 g. (0.1*8 mole) of benzoin, treated with a sine amalgam prepared from. 200 g. (3*06 g. atom) of sine dust and 50 g. (0.18 mole) of mercuric chloride, there was obtained 5? g* of crude product* R ecrystallization of th is from 600 ml. of 95% ethanol yielded 1*5 g* (53%) of colorless plates of trans^stilben© melting a t 122*123°. Broraimtions of c js and trans-Stilbene Bromination of c >ene with Hemental Bromine Into a 100 ml. flask equipped with a mechanical s tir r e r and a dropping funnel were placed 3 g# (0.012 mole) of cis^s tilb ene and 20 ml* of carbon d isu lfid e . The flask m s wrapped with aluminum f o il to exclude lig h t and immersed in an ice bath. A solution of 3.7 g* 0.G2I* mole) of bromine in 10 ml. of carbon d isu lfid e m s added dropwlse to the s tirre d reaction mixture. A fter completion of the bromine addition, s tirrin g m s continued fo r an hour, the reaction mixture m s filte re d and the f i l t r a t e m s washed immediately with 3% sodium b is u lfite to destroy unreacted bromine. The carbon d isu lfid e lay er m s evaporated to dryness under a stream of a i r , and the resu ltin g whit© solid m s recrystallized from 25 ml. of 9$% ethanol. The y ield of dl-c,a* -dibromobibenzyl, m.p. 111°, m s lw5 g. Concentration of the mother liquor yielded an additional 0.3 g. of product bringing the to ta l yield of d l-g , a 1-dibromobibenzyl to 1*.8 g. (85$). 138 The ©olid iso lated by the i n i ti a l f iltr a tio n was r ©crystallized from dioxane to y ield 0*3? g« (6*6%) of flieso-c .a 1-dlbroraobibenzvl melting a t 23U-2360. the reported melting points of raesp- and dl-g.c*-dibroiaobihenzyl are 237° and 109 .5-111° respectively (81)* Bromination of trans^Stilhene with Elemental Bromine the experiment was carried out by the same procedure and on the same scale as th a t described above for the bromination of c ia -stilb en e. there was obtained 3*6 g. (63.8$) ©f laesc-a *a1-dfbromobibenzyl» m,p. 236-237°, end 0*?5 g* (13 *2$) of dl*«, a *-dtbromob ib enzyl, m*p. 109-111° * Bromination of cis-S tilbene with N-Bromobenzamide Into a 300 olU fla s k , wrapped with aluminum f o il to exclude lig h t, and equipped with a mechanical s tir r e r and a moisture protected condenser were placed 9*it g* (O.0ii7 mole) of N-bromobenzamide, 7*0 g. (0.039 mole) of c is-stilb e n e , and 100 ml. of carbon tetrachloride* A fter heating the reaction mixture a t i t s reflux temperature for four hours a te s t with moist starch-iodide paper indicated the reaction to be complete. After c h illin g , the reaction mixture was f ilte re d on a suction f i l t e r and the white c ry sta llin e solid thus obtained weighed 9*75 g* a fte r drying. Evaporation of the f i l t r a t e yielded 7*3 g. of an orange semic ry sta llin e mass which a f te r several re cry stallisa tio n s from 95$ ethanol yielded 2*6 g. of trans- 31ilbene. No d l-c .c 1-dibremobibenzyl could be isolated from th is m aterial. 139 The i n i ti a l quantity pi so lid (9*75 g .) was thoroughly extracted with 60 ml* of b o ilin g water. The water Insoluble fractio n weighed 6.Sh g . and melted with decomposition a t 206*230°. R ecry stallisatio n of th is m aterial from dioxane yielded U*2 g* (53*8^) of meso-c.e* -dibr oraobibenzyl m elting a t 231**236°. On cooling, the aqueous ex tract deposited 2*3 g. of benzamide (m.p. 128° ) | concentration ©f the mother liq uo r yielded a second quantity weighing 0.8 g. (m.p* 123*126°) * The to ta l recovery of benssamide was therefore 3.1 g. (5fa*550* Bromination of tran s-StUbene with $— Bromobenzamide According to the procedure described above for the bromination of c is - stilbene with W-bromobanzamide, 7 g. (0.039 mole) of tran s-stilbene dissolved in 100 ml. of carbon tetrachloride was treated with 10 g. (0.05 mole) of N-bromobenzamide, The reaction was complete in 3*5 hours. As before, the quantity of white crystals th a t deposited on cooling, H .6 g*, m.p, 125*lbO°, was separated into two fractions by extraction with boiling water* The water insoluble fractio n , 7*4 m.p. 200-230°, was recry stallized from dioxane to y ield 5.2 g. (61$) of meso-a.a*dibromobiboixsyl, m.p* 237*238°. From the aqueous f i l t r a t e there m s obtained 3.3b g. (55*2$) of benzamide, m.p. 120-126.5°. Attempted Bromination of c ts -Stilbene with K-Bromobenzamide a t 38o A 300 ml. three-necked, flask was f itte d with a mechanical s ti r r e r , covered with aluminum f o il to exclude lig h t, and immersed in a water bath held a t 38°. The flask was charged with 5 g* (0.025 mole) of N-bromobenzaraide, 3 g. (0.017 mole) of cis-S tilbene, and 100 ml* of iho carbon tetrach lo rid e * the mixture was stirre d for 2k hours and then ch illed in an ice bath and f ilte re d . The resu ltin g white solid was washed on the f i l t e r with cold carbon tetrachloride and dried ha vacuo. The m aterial weighed h.96 g ., melted a t 120-130° with decomposition to a red m elt, and was found, to lib e ra te iodine from potassium iodide solu­ tion* An accurately weighed sample m s analysed iodometrically for H-bromob enssamide and found to be 99*0% pure H-toromobenzamide. The recovery of unchanged N-hromobensamid© was therefore equal to It.9 g# <9S«* Evaporation of the carbon tetrachloride f i l t r a t e to dryness and r© crystallization of the residue from 9S% ethanol yielded 2.31 g. (T9•&%) of tra n s-s t u b one, m.p* 123-121*°. A control experiment was carried out by thsrmoat&tting a solution of so 1 g. of c is -stilb en ea Up 1*6193, in 10 ml. of carbon tetrachloride contained in a brown glass flask a t 38° for 2k hours. A fter removal of the solvent under reduced pressure there was obtained 0.77 g. (17%) of as se unchanged c is -stilb en e, 1.6193' (Literature values -1.6193 (79)). The recovered c is - stilb en e m s found to be soluble in a l l proportions in cold n-hexane. This property i s ch aracteristic of cis-stilb en e which is very soluble in n-hex&ne whereas tran s-stilbene is quite insoluble in cold n-hexane (79). 110- N-Bromobenz&mid© Catalyzed Isomerization of e is-Stilbene The I~Bromobenzamide Catalyzed Isomerization of cis-Stilbene A $Q ml* flask equipped with a moisture protected reflux condenser and covered with aluminum f o il to exclude lig h t was charged with a mixture of 3 g* (0*01? mole) of o ^ stilbene* 0*5 g* (0*0025 mole) of H-bromob enzamide, and 25 ml, of carbon tetrachloride, The mixture was heated gently a t i t s reflux temperature for 2 hours and then chilled in an ice bath, The c ry sta llin e deposit th a t resulted was collected on a f i l t e r , weight 2,k g ,, m,p* 121-123°« Concentration of the mother liquor yielded a second quantity th a t m s combined with th a t f i r s t obtained and the combined m aterial m s treated with hot 95# ethanol, A small amount of the sample m s insoluble in the hot ethanol, and separation of th is by f i l t r a t i o n yielded an estimated 200-300 mg* of crude jneso-a^a* -dibromobibenzyl, m.p, 230-235° * A single re cry stalliz atio n from a large volume of benzene yielded prisms of pure mesons ,c f~dlbromdbibenzyl, m.p. 235-236 . The ethanol f i l t r a t e m s set aside a t room temperature for several hours and the m aterial dried. w h ic h precipitated was removed by f iltr a tio n and The y ield of pure tran s-stilbene m s 1*95 g.* m.p. 123-12U0 . The volume of the mother liquor was 115 ml. According to the data of P rice and Melster (82) the so lu b ility of tran s-stilbene in 95# ethanol a t 25° is O.Oil* g* per 5 ml. This facto r m s applied to correct fo r the lo s s of trans-stilb© ne in the aether liquor. The to ta l recovery of tran s- stilb en e was thus found to be 2,9& g* or 98.5# of the theoretical amount. In another experiment, 3 g. (0.017 raole) of c is-stilb en e, 0.268 g* (O.OOllh mole) of H-bromobenzaraide , and 15 ml. of carbon tetrachloride ua iff®**© placed in a small glass-stoppered flask and se t aside for 5 days a t room temperature and in absolute darkness* The contents of the flask were te ste d with moist starch-iodid© paper and found to contain unchanged N^bromobenzamide. Crystals of tran s-atlibene could be readily d is tin ­ guished in th© mixture by v irtu e of th e ir density being le ss than th a t of carbon tetrachloride and therefore flo atin g on the surface whereas, the more dens© &*bromobenzamide cry stal remained on th© bottom of th© flask* The mixture was evaporated to dryness and th© cry sta llin e reside© was re c ry sta llise d from 95$ ethanol* There was obtained 2*35 g. (78*1$) of trances t i lb ene * m.p. 123*’12.U° * Th© Isomerization of cis-atilben© with N-Bromobenzamide In the Presence 'ihMbitOrS^ a t 36tf...................................................... .. ..... — Of ' c- “ -nv.-T T . , lllr - n l. , lm . - u i . n . . lr A mixture of 0*62 g* (G.QG3U mole) of cia-stllb en e, 0*1 g. (0.0005 mole) of M-bromobenzamide, 0*2 g» of azosybenzene, and 10 ml* of carbon tetrach lo rid e was placed in a 25 ml* volumetric flask th a t was covered with black tap© to completely exclude lig h t- Th© mixture was placed in a constant temperature bath a t 38° for 2U hours* A fter cooling, the solid present was removed by f iltr a tio n m d found to be unchanged N-broraobenzalaxde. Th® f i l t r a t e was evaporated to dryness and the cry stallin e residue was r© crystallized from 10 blU of 9S% ethanol- There was obtained 0.5U g* (87*1$) of tran a-stilb en e, m.p. 121-122°. In a second experiment, 1,3,5- t r i n itr obenzene m s used instead of azoxybanzene• From 1*0 g* (0.0055 mole) of e is -stilb en e, 0*1 g. (0.0005 mole) of M-bromobenzamide, 0*2 g. of 1 ,3 ,5 -tr initrbbenz ene, and 10 ml. of carbon tetrach lo rid e there was obtained 0*905 g* (90*5$) of tran sstilben®, m.p. 121-122°. Ui3 Attempted In itia tio n of Styrene Polymerization with N*Bromobenzamide A mixture of 1 g* of freshly prepared N-bromobenzamide and an 11.6 gm sample of freshly d is tille d styren© was placed in a Pyrex ampoule, frozen in a dry iee-isopropanol bath, and evacuated to less than 1 mm. The vacuum was broken and the mixture m s allowed to warm to room temperature, refrozen, and a fte r evacuation the ampoule was sealed* As a control, a sample of styrene was treated in an identical manner except th a t the inclusion of N-foromrbenzamide was omitted* The ampoules were covered with aluminum f o i l to exclude lig h t and placed In a constant temperature bath a t £8 for 18 hours* After the heating period, the contents of the ampoules were poured into an excess of methanol. In both cases only a very small amount of insoluble material was produced indicating th a t no extensive polymerization had occurred. Preparation of 3-Bromocyclohexene A flask m s charged with 82 g. (1.0 mole) of cyelohexene, 36.6 g* (0*2 mole) of H^bromosuccinimide, and l£G ml. of carbon tetrachloride. After being heated a t i t s reflux temperature fo r h hours th© reaction mixture gave a negative te s t with moist starch-iod5.de paper indicating completion of the reaction. A fter cooling the reaction mixture, the precipitated succin sid e m s removed by f iltr a tio n , 16.5 g. (83-52), m.p. 121t-125°• Ike solvent was removed from the f i l t r a t e on a steam bath* D istilla tio n of the residue in vacuo yielded 2U.ii g. (76.7%) of 3-bromacyclohaxene, b.p. i$*50° a t 6 ram, (L iterature b .p ., 69**?2° a t 13 mm. (3h)). llll* Preparation of tran s-1 . 2-Bibromocyclohexane The procedure used to obtain th is m aterial was th a t of Snyder and Brooke as described in Organic Synthesis (71), From 61.5 g. (0.75 mole) of cyclohexene and 105 g* (0.65 mole) of bromine there m s obtained 180 g* (83. 2$) of trane-1 .2-dibr oraocvclohexane. b .p . 79~8l° a t 7 ram* This y ield represents the amount obtained a fte r p u rificatio n of the crude product by treatment with 20% alcoholic potassium hydroxide. Preparation of 2.,3 -DfbromopropyL Acetate A solution of 13 g. (0.13 mole) of a lly l acetate dissolved in 50 ml# of carbon tetrachloride m s treated -with 21 g. (0.13 mole) of bromine dissolved in 50 ail. of carbon tetrach lo rid e. After the disappear­ ance of the bromine color the solvent m s removed on a steam bath and the viscous residue m s d is tlle d using a small Vigreux column under reduced There m s obtained 26.8 g. {19 *2%)f of 2,3-dibromopropyl S$© acetate# b*p. 82-86° a t k 1mu, n^ 1 .5109. The reported (?U) physical pressure. constants of 2, 3-dibromopropyl acetate are* b .p . 100-101° a t 5 ram., so rip X.506U. Preparation of -Phenylbenzoylurea Ten grams (0.082 mole) of benzaraide m s dissolved in 300 ml. of boiling benzene and the solution m s dried by allowing benzene to d i s t i l l from the solution u n til the d is tilla te m s no longer cloudy. The quantity 10 g. (O.O84 mole) of phenyl isocyanate m s added to the 1U S benzamide solution and th is mixture was heated a t it® reflux temperature fo r 2k hour®* On cooling, the solution deposited a quantity of colorless c ry sta ls which were collected on a f i l t e r and washed with cold benzene, » .p . X23-12S . the bulk of the crude product appeared to be unchanged benzamide, and on th is assumption i t was extracted with boiling water to remove the benaaraide. The insoluble fraction was racry stallized from 95% ethanol to y ield colorless needles, m.p* 202*203°* R ecrystallization of these from benzene yielded 1.9 g* (9*7$) of N,N* -phenylbenzoylurea as co lo rless p la te le ts , m.p* 2 0 ^ 2 0 5 , (lite ra tu re m.p., 20U° (83))* Evidently the reaction was very slow a t the temperature imposed by the use of a low b oiling solvent* However, inasmuch as the quantity of product obtained was su ffic ie n t for th# intended use no effo rt was made to improve th# y ie ld . Preparation of A llyl Cyanide This compound was obtained by th© method described by Supniewski and Salzberg in Organic Synthesis (8U)« From 121 g. (1.0 mole) of a lly l bromide and 97 g* (1.1 moles) of dry, commercial cuprous cyanide there was obtained 33*5 g* (50%) of a lly l cyanide, b .p . 116*117°* 1U6 LITEEATDRS CITED (1 K. Z iegler, A. Spath, E, Sehaaf, W. Schumann, and E. Winkelmann. Aim., ^ 1 , 80 (19U2). (2 A. Wohl, B ar., £2, 51 (1919). <3 J . 13« Park, H. J. 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