3-^RXI.THMAPHrHISES ? m i - PABff ii - mmumffisM srntra % Icon OAporin A THESIS Submitted to the School of graduate Studloe of Michigan State tfai*iv«l% of Agriculture and Applied Science in partial fulfillment of the requirement® for the degree of bootgb or v m o s m m Department of Chemistry 19S6 ProQuest Number: 10008653 All rights reserved INFO RM ATIO N TO A LL USERS The quality o f this reproduction is dependent upon the quality o f the copy subm itted. In the unlikely event that the author did not send a com plete 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 P roQ uest 10008653 Published by ProQ uest LLC (2016). Copyright of the Dissertation is held by the Author. All rights reserved. This w ork is protected against unauthorized copying under Title 17, United States Code M icroform Edition © ProQ uest LLC. ProQ uest LLC. 789 East E isenhow er Parkway P.O. Box 1346 Ann Arbor, Ml 4 8 1 0 6 - 1346 ACKNOWLiiMWiM the anther idshes to eapreee his sincere thanks to Br. Bobert B# Schueis for his wise counsel end valued friendship throughout the course of this Investigation* He it alee indebted to hie fiance, Laura., for her eld In completing the final drift of this thesis * **#»**»**» ii TOA Leon Ciporin candidate for the degree of Doctor of Philosophy Final examination, April 2?, 1956, 1*30 P. H., Boom 128* Chemistry Conference Boom Dissertation! J^Aiylthieuaphthenast Part 1 - Synthesis$ Part 12 ~ Ultraviolet Spectra Outline of Studies Major SubJest« Organic Chemistry N&mer Subjects« Physical and Biologloal Chemistry Biographical Items Bom* March 15, 1928* Bern Xork City Undergraduate Studies* B« A #, Hew Tork University, 191*9 Graduate Studies, K # S*f Michigan State University, 1952 Additional Graduate Study, Michigan State University* 1953-2956 Saperlaaoet Graduate Assistant, Michigan State University, i&wL9$i, m > i m I M s r , United States Air force, 2951*1952 Bseearch Associate, Northwestern University, 1955-1956 Professional Affiliations* African Chemical Society The Society of Sigma 21 ill P&ffi X «• OTflMXS m $ xx - m m t m m m u m Wy fa m iA Im imArn &*9Cn» ^apwJJt m m m & m to tlm SfrltfHriX ot WwSisbI* St^d^ss ol HicMion $ia%# $»Xir»r*l% ©f Ajpio^tair* *sd ^ppli*-tl«lA.twaawlstlWl*»*«m«««o3iyllc Acids.. .... 35 itO .... SUMMARY pas ; i y - vitRAYxem 1$ 19 W 62 spsctra maanmzm, .... ................. 63 s i a m . , , ....... 65 discussion........ 79 sternumxl 93 SDJfflMY..,,, ......... .................... SEPiBSHCS®.,.......... 106 10? vii v m cr f m m page I Known Arylthiazmphfcheoea.«*»*.*.************,***.******* II 3-S ..... ........... ••»»»«*« III 3*AryltfclAnSphtl&neS,*'»••*»«»*.******••*»*«•••»****•*»* IV o^Aroyl^p*ohloroph«iyl Metb/1 S f VI VII VXXX XX I u l T l d e 9 21 2li a 26 S^j5lor©^3*»r^2^tklaai^htfe©aecarbc>3syXIc J>ei4s....... 31 Bffsst of Substituents m Biphenyl A b s o r p t i o n * * , , 73 UltravioletAbaoiptlon of 3-A*^XtManapbtl3©ne».** .... Ultraviolet 89 Absorption of Thlanaphihene#*******«*•*,*.«*9$ iXimv&oisi Absolution of 3~Pfaen^lthianaphthene********* 96 UltravioletAbsorption of 3~(1 ^aphtbyl) -thianaphthens* 91 .II Ultraviolet Absolution of 3,31^ItManapbthane........ 98 XU Ultraviolet Absorption of S-*Chloro-3"-piienyl*-2^thianaphtbenecarboxylic XIII Ultraviolet Absorption of £~Qh!oro-*3-(21thianyl) 2-tbIamph«ion©earbo3!7liG AeidM ( «.4 0 .M..*.... 1G® 1®2 XIV Ultraviolet Absorption of 5^hXoro-3**( o-cajboarohenyX)2-tManapbthen©oarbtMcylic lOlt vili BASS? 1 SCHTHSSIS 1 TIQ H Although thtanaphtfcene Ims boon k m m ainoe 1893 (7), little of lie chmdMtvy has boon ayotomatieally studied* the early m r k in thianaphtbane *tM^CH«GH-GOOIE (ClJ^ GBCH-COOH -l- " ’7 > KH- The reduction of 3-hydroxytldanaphthen© (9) vlth sin© dust and acetic acid form* thianaphthene, Tlie hydroxythianaphiheiiB is prepared from anthranilic add* 5 COOK “SQHaCOOH ^ OK OH the acid reduction of ©^thlocyanoacaiephenone produces thia* n&phthena (10) * The a » t M 1 involve# dlasottzation of ©^amiaoaceto* phenone folletmd by treatment with potassium thiocyanate. CODE Here roceuily, thianaphthene has become available by the vapor phase catalytic deh^drogenailon of a mixture of styrene (11) or ethyl* hmemmm (13) and hydrogen sulfide, or of o~ethylthiophsnol alone (12). The Isolation of tl&anaphtbsne t v m natural source* was first reported by Bos* (lit) in 1902, He successfully separated thianaphthene from the naphthalene fraction of coal distillates by formation of its plcrate. ^eisagerber (IS) developed a more efficient method which involved treating crude naphthalene with sulfuric acid followed by cleavage of the resulting sulfonic acids* Final purification was accomplished by preparing the sodio-dsriratlve from solutions of the crude material with sodamlde * AXl^l#thylthianaphthene has been prepared by dehydration of phenyl aoetonyl sulfide (1?)* 3~&©thylth±anaphth9ne , as m l 1 as the 3<*ethyl homoleg, has been prepared in low yield by the action of a Griguard reagent on the keto form of 3~hyire;xyihi&naphihsne (18,19) * 7 K (Ops OH - * The preparation of J^noalkylthianaphthanee by direct alkylaiion of thianaphiliene d t b alfeyl halidea has mot boom reported* The 3«*ethyl R~propyl, end n«butylt!4a>)EmiphthonKis boro boom obtained by acylation of tblsn^htbone followed by a Olemmenson reduction of the respective kebome* (20,21)* fhie letter method hoc Id mot bo applicable to tfae preparation of 2<*al^ItManaphthenee since electropbillc substitution occur* primarily at the >peetii«m (2U)* A amber of tMaaaphthene hemolegs have been synthesised through a aeries of sulfonlum salts (18,19). ICMs dll bo treated in greater detail later* OHj (QH,)a304 Yyr ~l CHa ■SCHa ® °4 . ♦I OH. \ — OCH, J 8 A recent synthesis of thianaphthene hosnologs involves the addition of a 2 ,2«Kiim©bh0ayethyl phenyl sulfide to phosphoric acid at high temperature and low pressure whereupon the resultant thianaphthene iwsedlately distills from the reaction mixture (22,23)* Ketbylthiamphihente with the alfeyl group in the 5,6, and 7 position have been obtained by this method* A*ylthiai*aphtbeiiea For convenience, previously prepared arylthiafiaphtfaeneB with raferancee to the original literature have been listed in fable I, Those compounds have been synthesised by more varied methods then those previously described for the alkyltidanaphthenes. 2*Fhenylthianaphthene has beau prepared by cyoliaing 2-*pbenyl~5~ thienyl-bulyrlc acid with a dehydrating agent, followed by reduction apd hydrogenation of the Intermediate eyelle ketone (25) * ts/wm n Gaertner (26) has prepared 2~pbenylihianaphthem in low yield by the free radical arylatlon of tiiianaphthene using R-nitrosoacetanllide as a source of phenyl free radicals. m 9 tmm t Substituent Reference 2*>Pfasnyl 3^FbsnyX*5^«®tbyl 3^hsn^*6~l^roay 25,26 JI^J* f i wHj gF» wOJtyf 3*Pfesi^l*2-tbloph«nyl '3^(cH^aa^bli0nyl)~5H^hyl~2^ajrb©*y 3-(p^!f*2«*phsnox3r«6^etiQrl ii-Pbanyl 18 2? 28 28 19 28 25 30 2~\t*-*fhianspbthyl) 31,16 2ml%*~Thian*phtbvl} $1 32 32 32 3* 3~y>*-Rwa0**3*-eoujaaringrl) Jf 3**(3* Al3^1^2f^indol^l) 2^ta«*l^j43a)*>by^oKy 242 *-Quinolinyl) 2*12#~ and 3 •••ethyl- derivatives ore formed (37). A reaction utilising & bemoisotbiaaole as m intermediate has been need to prepare 2~(2 ’^uinoXinyl) ~3~hydro:xythiasaphth3~hydro:syfchl&mphth$m© (Jl*) , Finally, 2~{ 2*-quinelinyl) -thianaphthene is formed by tbs addition of 2wthianapbtbex^yllithium to quinoline, followed by oxidation with nitrobenaene (3S>)* IS m m m m Preparation of 3#3*-Bltfeianaphtheiie A general method, of considerable utility, for the preparation of synmetrieaX biaryls involves the condensation of tec molecules of an aryl halide, in the presence of a metallic agent, with the eMmt* nation of the halogen ae a metal halide* f ArX ♦ K '— -^ Ar ~ Ar ♦ MXa the extensive investigations of Frits bllaann (S8) showed that copper H a particularly effective metal in this type of condensation! and as a result biaryl formation with the elimination of copper halide has become widely known as the $XXma*m reaction. An excellent review of the Bllmarm reaction has been made by Fatxte ($9) * An alternative method of preparing symmetrical biaryls from aryl halides was introduced by Xrimsmkqy and turner (60), their synthesis of such compounds involves the intramolecular coupling of an arylmagnesium halide in tbs presence of metallle salts such as cupric chloride, nickel braids, or silver bromide * 8 toMgt + s m At ~ Ar * MgXa + 2M the sequences of reactions followed in this work in attempts to synthesise 3,3f*blthianaphthsne are shown in Figure 1, The 3-halothianaphthenes used in this Investigation were prepared by procedures previously described In the literature. The synthesis 16 17 of 3^wwiothlai»phtt»aa m s aeo^lishad by the direct brominatton of tMaaftphfcbeae An chloroform m a solvent, following the method of aarasskovicss end Hodeet 0*6)* MonobromAnailon occurred preferentially at the 3-position to give a seventy percent yield of 3-br©raothifc~ napbthone, the Method of Qaertner (hi) nee need in the preparation of 3-iodothionaphthane, Thlanaphthsn® dissolved In b s m a m m s iodinated in the presence of mercuric oxide, After passing the reaction mixture through a column of alumina end activated charcoal, the decolorised solution yielded >*iodothi^^|Mhene in a thirty-four percent yield based m the original tldaimphthene* The TJllmaan reaetlea see attempted with both 3-bromothAai^phthene and 3~ledotht«mphtiiena employing the following general procedure * The aryl halide m & planed in an eight centimeter Pyrex test tube and heated to about 10 ® by means of an oil bath. At this point, while stirring the aryl halide with a thermometer, three to five tines the required $uantiiy of copper bvosae m s added portionwise while the tempemture m s gradually raised to 25Cf to 280°. The reaction temperature m e maintained at tide level for tme hoars after the ad­ dition of the copper brenae had been completed. The resulting solid mass m s entreated vtih hot chloroform. Prior to Its m e in these experiments, commercial copper brense was treated according to a procedure developed by Kleiderer and Adams ($0) • These authors claim superior results when the copper feron&e is activated in the following manner, A small amount of iodine 18 1* allowed to reaei with copper broaae i&mrmxpon cupric iodide forms on the surface of the metel. % e » dissolving the cupric iodide in dilute acid, copper feronse having a greatly increased surface area is O b ta in e d , ill attends to effect the coupling of 3~bromotfaianaphihen© in this moaner failed, end the recovery of aryl halide was essentially quantitative* However, 3,3 •"bitMaaas&thene was Obtained la rather peer yields of from fear to seventeen percent by coupling 3-iodotbianephbheiie in 1dm preetnce of copper brexme at a reaction temperature of 2®)°. ft* low reactivity of the J^nomothlanaphtheiie as compared with the corresponding 3*led© compound Is la accord with the observation that aryl bromides and chlorides undergo the HUmann reaction satis* facterily only when activated by electroxi withdrawing groups la the ortho or para positions* 1 high melting crystalline substance was isolated as a byproduct during the fonaaiion of 3 ^--bithiamphihen© frost 3~iod©th±anapbth«me. Although no structural studies were made on this substance, elementary analysis Indicates that it is probably a polymer of ihiamphthene. at*ixKk>pf has Observed similar polymer formation i&en luxlothiopheiies are subjected to- the W b m m reaction* Treatment of 3<*bromcthianaphthene with an equiiaolar quantity of cupric chloride resisted only in an eighty-five percent recovery of the starting material* the residue was an uncrystalliaable dark colored amorphous material, ^hen nickel bromide was employed as the 19 coupling agent, the J^bremetManaphthene coaid not be recovered and the product was & mnorystallla© intractable material* m s reaction might have succeeded with silver bromide as the metallic salt. It has been reported to be a particularly effective coupling agent (81,82), Preparation of 3-Arylihtattaphthenes by Reaction of 3*Thianaphthylmagnesium Bromide with Cyclic Ketones the synthetic scheme of reaction steps followed in these prepara­ tions is outlined in Figure XX, where cyclohexanone is used as an illustration, Ketones utilised other than cyelohoscaaono, sere t<-tetralone, g-iaethylcyclohesasone and S^hydroxythiaiwiphthene, the laet pressed to exist in its bate form* the method of preparing the l^ycloalfesnylthianaphthenes is essentially that of 3&®uskovicis and Hodest (h6), the 3-tiiianaphthylmagnesium bromide was allowed to intersect with the appropriate cyclic ketone in ether as a solvent, Ifter decomposing the Grlgnard complex and working up the reaction mixture in the usual manner, the 3-cycloalkenylthionaphthsae m s isolated by low pressure distillation, The intermediate tertiary alcohol, which undoubtedly was the primary product of the reaction, underwent dehydration during the vacuum distillation, The formation of an olefin from a tertiary alcohol by slow distillation is a general phenomenon (63), The ketones used in this investigation and the corresponding l-cycloalkenylthiamphthenes synthesised from them are listed in Table XX, Mention should be made of the unsuccessful reaction of 3-thianaphthylmagnaalum bromide with 3~hydroxyth±anaphihene. The tautomsrlsm of 3-^^roxythlanaphthene has been known for some years. I Distill \ Dow P 21 IA8U II II (J Kotono Boaetod Hold B.p.( °C 35jS oC -fotroleno 22X /s OH, 3-Hydroxythlauaphthane (ttte f«n) Ho product lUo-150 2 205*210 3 160-170 2 22 Auwsrs anl Thieea (61*) concludQd from a semi-quantitative analysis that 3-t\ydr€>xythianaphth«i5e exists mainly In the kite tom under ordinary conditions. Xrollpfeiffer and his co-workers (18,19) were able to prepare 3-aethyl- and 3-othylthiamphthene la lew yields by the interaction of the appropriate Orignard reagent with the kete form of 3-hydrcxythianaphthane, the failure of 3~tMa»aphthy2magnesiuiii bromide to react in a similar manner in the present investigation cam probably be ascribed to its reaction with the end form of 3-hydroxythianaphthene. m support of this tentative explanation of the failure of the Grignard reagent of 3«bro»othlanaphthene to react with 3-feydroxytMamphthene is the fact that the only products isolated from such reactions were thl&naphthene and a brown fdymsrlo material similar in appearance to thioindigo* The 3-cycloalkanyltfalanaphtlicn*s m m converted to their corres­ ponding 3~arylthlanaphth©ras by dehydrogenation, which was accomplished by heating the former compounds with sulfur at a temperature of 23 approximately 250°* flms* compounds, which have not boon previously deseribsd in tbs literature, are 11ated in fable HI, the sulfur dehydrogenation of 3-(21~methyl~l •-cyelohexenyl)-thianapbthsns resulted only in producing a very dark amorphous solid from i&ioh no crystalline produet could be isolated, J&lraination of a methyl group in tbs course of a sulfur debydrogenation is a fairly common phenomenon (65)« Ibis nay partially account for the decompo­ sition of the compound during the dehydrogenation procedure. Preparation of £-Cbl©r©~3~Aryl~2-TMauaphthenecarbQxyliG Acids the sequence of reaction steps employed In the preparation of these substituted thianaphthonecarbo^ylic acids is outlined in Figure IF, the synthesis of the necessary intermediates, p-ehloro~ bemenearulfonyl chloride, p- •CM ps t** CM f^l (H U> \ £3 9 vO CM i 2 CO VO 9 CM Ct v\ Bft a o 3 o iH 1 * •HI 2 «o Cm n n m m ? Krollpfeiffer’s frqpognd Mechanism foi* the Bing Gloeure of an o**.iroyl^iMhlorophenyl Methyl Sulfide CX^ > \ — W S-B Cl ,i--- 0-R 01 H-COOH * so. CH» 01 ^ * ' ' T Q ^ s p08. 01 7* ' ^ i C T C o a * * CH#0H 33 G 1£3c^”R s c% It was apparent from the above ©bservationa that the ortho thiomethyl group was necessary for the occurrence of ketonie cleavage. To corroborate this, benaophenom was treated with ehleroaeetie acid using the sane eagperiaiental procedure as previously described, the bemophenone was recovered from the reaction mixture unchanged* the following mechaaiam Is offered as a tentative explanation to account t m the formation of a d d products due to the ketonie cleavage phenomenon observed with ©-aroyl-p^clilorophenyl methyl sulfides. 01Q S ^ - 8 S4HrCO0S OH* CM* 01 s~c b 3~c q g e $»CHgCO0S Ctk an* s ^ h 3-cooh 0% Several factors favor this integration. First, the principal cases in which ketonie cleavage occurred were accompanied by failure of the A ring closure reaction* This 'would strongly suggest that the inter­ mediate m ^ o r d m salt uas present at the time eater was added to the reaction mixture. Secondly, a strongly positive sulfonium group ortho to the aroyl group mould enhance the positive character of the keionlc carbon* the fallure to Isolate the other fnagwnt resulting from this ketonlo cleavage reaction can very probably be ascribed to the high solubility of sulfonium salts is aqueous media* An attempt ms made to dehalogen&te 5~chloro~3-pheuyl~2-tbia- naphtheneoarboxyllo sold through catalytic hydrogenolyeis of the earbon-halogen bond by adaptation of a method used by Blanchette and Broun (6?) to dehalogenate 2 ,5~dtehloro-3-thienylearlroxylic acid. The failure of this dehalogenation reaction m e not entirely unempeeted since it is v t H known that a chlorine atom, In the majority of cases, Is considerably less labile when substituted in beneene than when in a position adjacent to the negative heteroatom * 3-(3*,hf-I>ihydro-l ♦-naphthyD-thianaphthene In tbs same manner as previously described, the Grlgnard reagent was formed from 16 g* (0*076 mole) of 3-br«®othianaphthene and 1.88 g, (0 ,07? mole) of magnesium turnings in b© ml. of dry ether. The quantity, 10*7 g* (0,<>7ti mole) of oC-tetralone dissolved in 5© ml* of dry benzene was added dropsies to the cooled solution, after which the hi mixture was heated at its reflux temperature for 19 hours to complete the reaction, ^heu the reaction mixture had cooled, the Grignard complex sag decomposed with 100 ml, of a 10% solution of sulfuric a d d containing an equal volume of crushed ice. The organic layer was asperated, washed with saturated sodium carbonate solution and then with water. After drying the solution over anhydrous sodium sulfate, the ether was removed by evaporation on a steam bath, Vacuum distillation of the crude product gave $ g, (0,019 molej 26%) of a viscous orange oil boiling at 205-210° ( 3 «m*) * ^he boiling point reported for this compound is 165° (1 ms,) (ii6), 3*11 1-Naphthyl)-tliiaaaphtfesne A uniform mixture containing k g, (0,015 mole) of 3-(3tf^’-dihydre~l*-naphthyl)-tfaiaiaaphthene and 0,6 g, (0,032 mole) of pondered sulfur was kept at a temperature of 2b©~260° by means of an oil bath until the evolved gas failed to darken a lead acetate solution. The crude dehydrogenation product was purified by sublimation at 2h0° (10 mm,) to yield 1,5 g, (0.0058 molej 3®S) of a sublimate, which after recrystallising twice from 9$% ethanol melted at 90-92°, Analysis of this material for carbon and hydrogen gave the following resultst Oalc*d for Founds C, 82,8| H, b,9 83,(Jj H, h«? tih ?4fetbyloyelohexanol OH fill* compound was prepared according to a procedure developed by Ugnade and Hightingal© (S3) * A 100 mg, quantity of metallic sodium was added to 59 g« (0,5 ml*) of o~ereool which was thou warmed until tfeo metal had dissolved, The solution was then transferred to a glass hydrogenation bomb linr and 2,5 g, of Haney nickel wore added, the hydrogenation was carried out immediately in a Farr High Pressure Hydrogenation apparatus at an initial hydrogen pressure of 2700 p.s,i, 0 and a maximum temperature of 120 » V4ien the initial pressure had dropped 1000 p,e,i., the reaction use considered complete and the besto was opened. After transferring the hydrogenation mixture to a suitable container, the bomb and liner were rinsed with 100 ml, of bensene, The combined washing* and reaction solution was filtered to remove spent catalyst and then washed twice with 25 ml* quantities of 105 sodium hydroxide solutionf once with 25 ml, of saturated sodium bicarbonate solution and finally with 50 sal, of water. After drying the bensene solution over potassium hydroxide, the solvent was removed by evaporation on a steam bath, distillation of the crude product gave 36 g, (0,J2 mole* 61$) of a product boiling at 160*4.65°, the reported boiling point for this compound is 165-166° (53>. 1*5 this eowpmwfci was prepared by ploying the procedure of Carlin (5?)* In & one liter flask, equipped with stirrer, condenser and dropping funnel, was placed an oxidising solution containing §5 g, (0.21 mole) of sodium dieferomate and 52 g, (0,50 mole* 29 ml.) of concfmtrated sulfuric aeid in 300 ml. of water. To this eolation, 2fa g, (0,21 mole) of 2*methylcyelohexai*ol dissolved in Uc ml. of glacial acetic acid was added, with stirring, at a rate soffioient to maintain the reaction temperature between 50 and 55°. Stirring was continued for an additional hour and a half after the addition of the alcohol was complete. The reaction mixture was then transferred to a separatory funnel and extracted with three 100 ml. quantities of ether. The combined ether extracts were washed with three 100 ml. portions $% sodium hydroxide solution. After evaporating the ether on a steam bath, the crude ketone was added to a solution of 23 g. ($.21 mole) of amnicarbftslde hydrochloride, 25 g, of sodium acetate, ICO ml. of water and $ ml, of 10$ aqueous sodium hydroxide contained in a one liter bottle . The bottle was mechanically shaken for 21 hours and the precipitated ©emiearbasone was recovered by filtration* The ©rude material melted at 156-188°. The reported melting point for this seaicaibasono is 193~19b° ( 5 W . After decomposing the semicarbftsone with 800 ml. of 12$ sulfuric acid solu­ tion, the solution was extracted with ether and the ether extract was 1*6 dried ©war anhydrous sodium sulfate, The ether was renewed on a «te*» bath m l the residue distilled yielding XI* g. (0.13 mole* 62$) of a produet boiling at X5S-161*. The reported boiling point ©f this eyoli© ketone la 166° ($?)* >•(2 ^Methyl-*! *-cyelohexsnyl)-thianapbthen® fit© dpigaard reagent was formed as previously described from 36 g, (©,076 nolo) ©f 3~bro»otfcianaphthene and 1,9 g. (0,077 mol©) ©f magnesium turnings In 1*0 ml, ©f dry ether. f© tbo cooXod solution, were added 9*5 g. {©,085 mole) of 2~ro®thylcyclohexanone dissolved la $© ml, of dry bemene at a rat© sufficient to maintain a ©onstaBfc reflux ©f ether, The reaction mixture was kept at Its reflux temper­ ature for 0 boars after tbs addition of ketone was complete. Tbs Mtgnard complex was thsn deoomposed with XOO ml. of 10$ agusoos sulfuric sold and 1stM» organic Xaysr separated, Xt was washed with saturated sodium carbonate solution, thsn with water, and dried over anhydrous sodium sulfate, Following renewal of the other on a ste«» hath, the residue was fractionally distilled to yield 3,8 g. (0,0X6 moXei £1$) of ©rude product boiling at 160-170° (2 »»,), Attempted synthesis of 3-(©-T©XyX)^thlan»phtbene hi Following the exjmwsdaeiitaX procedure previously described for the sulfur deiydrogenation of similar compounds, on intimate mixture of J*8 g* (0*016 mole) of erode 3*»(2’-raethyl-l*-cyclohexenyl)-tbia*naphtheae end Ijb g* {0*0^1* mole) of powdered sulfur was bested at a temperature of 2§&*a60° until the evolution of hydrogen sulfide bed ceased* The reaction mass was extracted with bensene, filtered, washed with £0 ml* of 10$ sgueeu* sodium sulfite and dried over anhydrous sodium sulfate* After removing the benzene on a steam bath, tbs residue use subjected to sublimation at 130° (3 mm*) but only decomposition m s observed to occur and no sublimate mould be obtained* 3-%dro35yiihiai5a.phthene this compound m s prepared by tbs method of Hutchison and Smiles (55), tbs quantity * 51 g* (0*390 mole) of ethylaeetoaeetate m e added to >© g* (0*195 mole) of o-mercaptobenzoic sold In 250 ml* of concentrated sulfuric aeid at a rate sufficient to maintain the re~ action temperature between 50 and 55°. *4»n the evolution of carbon dioxide ceased, the reaction mixture m s poured onto crushed ice, and the resulting precipitate collected by filtration and then steam distilled to yield k g* (0*027 molej Xb$) of a crude product melting at 67-69°, The reported melting point of 3-hydroxythiaoaphthene is 71° (56) * The low yield of product resulted from the air oxidation of the 3-djjdro;«ythianaphthenQ t© thioindlgo during the steam distillation* The yield could very probably bo improved by using a nitrogen atmosphere the operation. Attempted Preparation of 3,3**Bithianaphihene from 3-Hydroxy- and >» arowoiJi^aaa^ii^iietio The Gv&tfMrd reagent was prepared aa previously described fnam the interaction of 2.5 g* (0*012 mole) of 3-bro«othia»aphth@a© and Q*k g» (0,016 mole) of magnesium t umb le In 30 ml, of etber as a solvent. To the Qrignard reagent, at room temperature, was added 2 g. (D#013 mole) of l^bydroxgrihlaiiaphthene diesolved In IS ml, of dry bsrasne *&ioh resulted in no observable reaction* The reaction mixture wag then refluaeed at Its boiling point for an eighteen h o w period and then treated with 2$ ml* of ten percent aqueous sulfuric acid, and the organic layer was separated* After washing with saturated sodium carbonate solution and then with eater, the organic layer was dried over anhydrous sodium sulfate* The ether was removed on a steam bath and vacuum distillation of the residue yielded only thiamaphihem and unreaoted 3-bremothian&phtfc©m, The red-brown colored residue remain* ing after the distillation appeared to bo polymeric and could not be further purified. Preparation of 5-Chloro-3*aryl-2-tl5lanaphth©no* earboxylie Acids p ^laoi^bmasei^sulfonyl chloride QX h9 To g. (3 mclej 19$ ml.) of cblorosulfonic acid kept at a temperature of *5 to -10° and stirred, were added dropwise 113 g. (1 molej 10J ml,) ©f chlorobenzene over a period of three hours. Stirring was oontinued at the same temperature for an additional three hours to eomplete the reaction, after haing aet aside overnight, at room temperature, the reaction mixture was poured onto lee and resulted in the precipitation of the p-chlorobenzenaeulfonyl chloride * this was recovered by filtration and after drying neighed 190 g, (0,90 melef 90$), It had a melting point of h2~bh0 * The reported m.p. ie 53° (39) . p-Chlorothiophenol 01 A mixture of 312 g, (1.1*7 mole) of crude p~chlorobenzenesulfonyl chloride, 1§0O g, of ice and 807 g, (8 .22 mole| lihO ml.) of ooncentrated eulfurie acid was cooled to o and stirred while 392 g. (6.00 mole) of gin© duet were added over a period of one hour. To insure completeness of reaction, stirring was continued at 0° for an additional tee hours and then the reaction mixture was set aside overnight at r o m temperature. Steam distillation of the reaction mixture gave 100 g. (0.69 molej 1*730 of a solid, after separation from the dis­ tillate, which melted at 52*93°. The reported a,p. is 53° (1*0). 50 p~CKlorophenyl Methyl Sulfide SOB* A 100 g. (0,69 mole) quantity of p~chlorothiophenoX m e dissolved 1® 350 ml. of ben percent aqueous sodium hydroxide, To this solution, while being stirred, ware added dropwise over a one half hour period, 1?T £• (X.)i0 mole) of dimethyl sulfate* During the course of the re* action an additional 150 ml. of 105 aqueous sodiusa hydroxide was added to the reaction mixture to maintain its alkalinity. The resultant oily product m s extracted with ether and dried over anhydrous sodium sulfate* The ether m e removed on a steam hath and the residue fractionally distilled to yield 9k*7 g, <0*60 mole; $7%) of a product boiling at 107® ( U «m.)| njf 1.5997. tt* imported te.p, 1* 170° (760 ran.) (Id). tor further characterisation, the selfone m s prepared by oxidis­ ing 0,5 g, of the p-chlorophenyl methyl sulfide dissolved in 1 ml, of glacial acetic acid with 0.7 g, of potassium permanganate contained in 25 ml. of water. The excess oxidising agent m e destroyed by adding dropwise saturated aqueous sodium bisulfite solution until the per­ manganate odor m s discharged. Ice m s then added and the resulting precipitate m s filtered and recryst&lliaed once from methanol. It melted at 97,5*96°. The reported m*p. for this derivative is 96° (1*2), o*Bensoyl*p*chlorophenyl Hethyl Sulfide 51 In a 300 &L, three necked flask supported in an Ida bath and fitted with a stirrer* reflux condenser and dropping funnel, were placed 39*8 g* (0*30 mole) of anhydrous aluminum ohloride and 1*1*9 g* (0*30 mole) of benaoyl chloride* after starting the stirrer* 10 g, (*063 mole) of p^chlorophenyl methyl sulfide were added dropwise over a period of a half hour* Following the addition of the sulfide, stirring was continued* at room temperature f for ten hours at which time the reaetioa mixture had taken on a deep red color* After being eft aside overnight at room temperature* the reaction mixture was cautiously poured into a slurry of 250 ml* of dilute hydrochloric acid* containing an equal volume of crushed ice* and extracted with ether* The ether extract* after washing with three 70 ml* portions of 10% sodium hydroxide solution* was dried over anhydrous sodium sulfate* After removing the ether on a steam bath the residue was fractionally distilled and gave 9*6 g* (,(2lt melef 3®0 of a fluorescent green oil boiling at 156*160° (3 mm*) which solidified on being set aside at room temperature* It was reerystalli&ed from llgroin as a white solid and melted at 101*103°« Analysis of the compound for carbon and hydrogen gave the following results* Qale'd for 0*48*103011 C* 61*.0j H* it*2 Found* 0* oii.lj H* lul The semlearbasone of this ketone melted at 83-85° after recrystalIllation from methanol* In two additional preparations of this compound using the same molar ratios of reactants* the yields were 9*25 and 21,95 using reaction periods of seven and seventeen hours respectively. 52 5-Chloro~3~phenyl~2~thiatfipbthenecarb^ Acid A mixture of 8,6 g, (0,033 meld) of o**bei»ioyl-p**chldropl»iiyl methyl sulfide and 1? g. (0,16 male) of ehlaracetie acid m i heated m a steam bath for eight hour* and then at 130° for an additional thirteen how*. After allowing the reaction mixture to cool to room temperature, eater m e added until precipitation of the product m e complete* It weighed 1,5 g. (0,0052 mole) after filtration and drying which corresponded to a 16$ yield of the crude tbisnaphthemeearboxylie acid. The product melted at 263-265° with decomposition, after a single reorystallisation from bensens. Analysis of this compound for carbon and hydrogen gave the following results* Cale'd for CieH*0*SClt C, 62,kj H, 3,1 Found* 0, 62,2; H, 3,1* The neutralisation equivalent was found to be 28? g, as oompared with a calculated value of 288 g, The filtrate obtained after removal of the crude thlanaphthene* carbexylie acid was evaporated and a 0,95 g. (0,0078 mole) quantity of bensoie acid m e isolated. It melted at 121-122° and showed no depression in its melting point when mixed with an authentic sample of benzoic acid. In a subsequent experiment, !i»3 g» (0,016 mole) of o-besasoyl-pohlorophenyl methyl sulfide end ?,h g, (0.076 mole) of chloroacotic aeid yielded 1.8 g, (0,015 mole) of bensoic acid as a byproduct after a reaction period of four and a third days at 130°. 53 Attempted Preparation ©f -tMenapht&enecarboxyliG acid Prom the 5-Chloro Derivative By C&talylio Bydrogenolysi* A mixture of 1*2 g* (0,001*2 mole) of 5-chloro-3~phenyl-2~ tbl^naphtheiiaea^xyllc acid, 2,U g. of a charcoal supported palladium catalyst, ISO ml* of methanol, 10 ml. of water, and 2 ml. of concentrated sulfuric acid were placed in a Farr loir Pressure Hydrogenation Apparatus, hydrogenation was carried out for four hours at room temperature and an initial pressure of 25 p.®,i* The catalyst was 1m t w m & by filtration and the filtrate concentrated on a steam hath until precipitation of the product occurred. After filtering and drying* the precipitate melted at 263*265° and was Indistinguishable from th» original starting material* o^*Baphthoyl Chloride A mixture of 25 g* (0,15 mole) of ^-naphthoic acid and 30 g, (0,15 mole) of phosphorous pentachloride was heated ©a a steam bath until the evolution of hydrogen chloride ceased. The resulting clear solution was submitted to fractional distillation. After removing phosphorous oxychloridc below $0° (IB mm.), 25*0 g, (0.13 mole; 87%) of &C~n&phth©yl chloride which boiled at 187*191° (18 mm.) was collected. Its reported b,p* is 168° (10 mm.) (1*3), o~(l~!?aphthe>yl)~p*ehloropfc«-myl Methyl Sulfide 51* the experimental procedure employed m u the same as that used in the preparation of ^bemoyl -p-cl&oropbenyX methyl sulfide* The quantities of material used i® the synthesis were 18,3 g. (0*11 solo) of o^naphthoyl chloride, 1$,9 g, (0*098 sole) of anhydrous aluminum cbiorlde and 6,? g* (0,0|*2 solo) of p-ofclorophenyl methyl sulfide* distillation of the crude ©-(1-naphthoyl) -p-chlorophenyl methyl sulfide yielded 0*5 g, (G,G016 molef 1*5) of a produet boiling at 185*190° (3 «»«)* A single ro©ryataXlisation from ligroln gave a whit© crystal­ line solid which melted at 115~1170* Analysis of this compound for carbon and hydrogen gave the following results* Calc'd for C^H^OaSl* found* C# 68,5i C, 69*lf H# k.% 3*9 Attempted Preparation of 5-^hloro-3*(l1-naplithyl)-2-thianaphbhene-* carboaeyllc Acid A mixture of 0,30 g* (0*001 mole) of ©~(l-naphtbeyl)-p-chlorophenyl methyl sulfide and 1*0 g« (0,01 mole) of ehloroaeetio acid m s heated on the steam bath for 11 houra* After allotting the reaetlon mixture to cool to room temperature, water mas added to it until the precipitation of i!*e produet m m complete, the latter m m reeovered by filtration and after drying it weighed 0m2k g, (0*0006 mole) * It mas identified, after repurlficatioa, as msaeted starting material by its melting point and mixed melting point with an authentic sample of the original compound. The recovered starting material from the above process on extraction with a 105 solution of sodium hydroxide yielded approximately 0 mg* (0*0003 mole) of wLrnaphthote acid which melted at 160-161° and showed no depression in its melting 55 P«i»* idwrn adawKI uitfe an authentic sample of <<~n»phtboio reid. So oi*w products mere isolated from the reaction mixture ^ -Jfaphthoyl chloride f M e material m m prepared in the seas manner as it* o^-lsomer using the sane molar quantities of reactants as sere used in the preparation of the ^-iaemer. Bistillatioa of the wide product yielded 21*6 g* (0*11 melef 16%) of pore (^naphthoyl chloride helling at 176° (11 mm,) which solidified to a white solid which melted at Ii0^b2a, the reported physical constants for this compound arei b.p, 30h-306° (?60 ramjj m*p, h3° Galc'd for round* Q, 52.9J K, 2*b 0, 52,7f Hf 2*9 The neutralisation equivalent of this compound was found to be 292 g, as eos^ared with its calculated value of 29b grams* o~(2~Carfeoxyben*©yl)-p-chlorophenyl Methyl Sulfide A mixture of 10 g* (0,062 mole) of p-chlerephenyl methyl sulfide and 1$*6 g, (0,031 mole) of phthsllio anhydride was treated with 10*5 g, (0,065 mole) of anhydrous aluminum chloride. The latter was added in small portions. Following the complete addition of the aluminum chloride catalyst, the reaction mixture was maintained at a temperature 60 of 80° for four hours by immersion of the reaction flask in an oil hath* After allowing the reaction mixture to cool to rocm temperature the Friedel and Crafte complex was decomposed with water and the excess p-ehlorophenyl methyl eulfide was removed by steam distillation. The residual solid was collected by filtration and extracted with hot chloroform in which the unreacted phthallic anhydride was insoluble* After removing the chloroform m a steam bath, the solid residue was washed three times, on a filter, with small quantities of petroleum ether, and dried* It weighed 1*2 g. (*\00h mole) which corresponded to a 1|$ yield of the desired product which melted at 183-185°. A single recrystalliaation from aqueous acetic acid raised the melting o point to 181*~186 „ Analysis of this a d d product for carbon and hydrogen gave the following results* Galo'd for Cm ntx%S£l* C, $8J$ H, 3*6 Found* C, 58*h; 8, 3.8 The neutralisation equivalent of this a d d was determined to be 302 g, shile the calculated value is 30? grams. Several previous attempts to prepare e-(2-carboxybensoyl) -p~ chlorophenyl methyl sulfide using carbon disulfide or a-tetrachloroethane as a Friedel-Crafts solvent failed to yield any of the desired product* 5-Ghlor©-3-(21-carboxyphenyl) -2-thianaphtheneearboayllc Acid -coca 61 A mixture of 0*h g. (0*0013 mole) of o~(2-carboxybensoyl) -pchlorephenyl methyl sulfide and 1*0 g* (0*01 mole) of obloroacetic acid wet heated on a steam bath for 1? hours* Vtam tho reaction mixture had cooled to room temperature, eater was added to it until the precipitation of the product was complete* The precipitated dibasic acid mas filtered and recrystallised from bensene to yield 0*25 g# (0*0008 mole| 615) of pure product which melted at 282~28h° with decomposition* This scnperamd crystallised with one**third of a mole of bensene as advent of cryet&llis ation and all attempts to remove the bensene failed. Analysis of the compound for carbon and hydrogen gave the following results i Calc *d for C ^ H # 43S1 * 1/3 (G*fg«)s 0, 60*3| H, 3*1 Foundi 0, 60,2) B, 3,3 The neutralisation equivalent of the product was determined to be 17? g, as compared with a calculated value of 179 grams* Attempted Formation of Bensoic Acid from Bemophenone A mixture of 10*5 g, (0*057 mole) of bensopfcenone and i|2 g* (O.hS mole) of chloroacetic acid was heated on a steam bath for two days* After cooling the reaction mixture to room temperature it was treated with water and the resulting precipitate, after recovery by filtration, was found to be starting material of which there was a total recovery. 62 m s m t 1* The tTHsHmn synthesis of 3,31-bithian&phthans ms carried oat with 3~iedofcManaphthsi*e in the presence of copper browse, The aitempted coupling of >^thiampJjthylaagjieeiiffii bromide with eapric chloride or nickel bromide failed to yield 3,3*-bithianaphthene. 2, Tho syntheses of S-sriae^lthiajnaphtbene and 3-(l‘-naphthyl)thianttphthono wore iracceesfal* Tho properties of the products are ■HB iJ* to Hil mr rfw rw l~C a>l 8* * jWp 3« fine e*-ai^l-^ehl€a»^hoBgrl methyl eralfidoo wore prepared* The yields were correlated with the amount of eterle hindrance in­ volved in formation of the predaeta* The properties of these collides are reported* h« ftag elomire of three of the five o-areyl^-chlorophenyl methyl sulfides was successfully carried oat to yield the corres­ ponding §-chlw<>*3-a3?yl-2-thian^dithenecarboxylic acids* The proper­ ties of these thianaphthene derivatives are reported* A mechanism has been proposed to account for a kctonie cleavage reaction Observed with three of the o-aroyl-p-chlorophenyl methyl sulfides. M * SPBCTltt 63 IHfROBUGTIOH The initial investigation el Hie effect of restricted rotation in biphenyl compounds on the ultraviolet absorption spectra of such substances vac wade twenty years age by Pickett and eo~workers (68). Since then several other investigators (69~lk) have determined the absorption spectra of biaronatic compounds exhibiting restricted rotation and similar studies have now been extended to biarematie type compounds containing heterocyclic nuclei (75,76). The theoretical considerations Involved in investigations of this kind nay be briefly described using biphenyl as an example. In the ground state. Indicated by structure b, the rotation around Hie pivot a, b. o. bond is hindered slightly due to Hie mutual repulsion of the hydrogen atoms in the ortho positions with respect to the pivot bond. However, if the hindering barrier is not high, some molecules of biphenyl are nearly eoplanar as a result of thermal motion. For these molecules, ionic structures such as a and £ make significant contributions to Hie excited states of the molecule which are important in absorption. Such excited states give full extension to the conjugated system and should lead to intense absorption at relatively long wavelengths of 6h light, These ionic structures require that the two phenyl rings be approximately eoplanar. Thus, biphenyl derivatives without hindered rotation, particularly those unaubotituted in the positions ortho to the pivot bond, should exhibit an intense absorption characteristic of the entire aromatic ring system. Those biphenyl derivatives with highly hindered rotation, notably those substituted in the ortho positions with respect to the pivot bond, would have more or less difficulty, depending on the substituents, in assuming a eoplanar structure, and consequently, should exhibit absorption approximately equivalent to that of the single ring structure. The purpose of the present investigation herein described was to determine the extent to which rotation was restricted around the pivot bond in 3,3 f^ithianaphihene and certain 3^arylthi^naphthenes by an examination of their ultraviolet absorption spectra. Results of this study should, it is anticipated, facilitate the selection of compounds of this type amenable to optical resolution which would permit further study in the general problem of restricted rotation and structure in the bithianaphthene*, arylthianaphthenee, and their derivatives. (6 m m m Pioksit, WLter, and Franca (68), in the 3»ar 1936, made the original Investigation el the effect of restrieted rotation on the ultraviolet absorption spectra of biphenyl and Its derivatives. Their Investigation involved the determination of the spectra of the fallotting compounds. Cl Cl Cl Cl 01 01 ci C1 ci la, lb. CHa o CH? 0Ha Ila, Hb, o Cl XZXa ci mb. o IVa IVb. The spectrum of each biphenyl derivative vas compared to the analogously substituted bensene compound, The k ,h'-diclilor©biphenyl 66 ( H I a) and It,h1^iaethylbiphepyl (IF a) shoved greatly enhanced absorption intensities at longer wavelength* of light than the corresponding cblorobeneene (IZX h)and toluene (IF b). However, ®*b§6$2* ,h*,6,-hexam©thylbiphenyl (II a) and 2,h,6,2* Jk* ,6-he**chlorobiphenyl gave abeorption spectra almost Identical with their respective single ring analogs, 2 ,6-trlchlorobensene <1 b) and mesitylene (11 b) * these observations sere interpreted to support the very reasonable contention that la and H a could not achieve coplanarity due to the sterie hindrance to free rotation supplied by the four ortho substltusntsf end as a result the important ionic structures of the latter tm compounds could not contribute to their absorption of light. Following publication of these results, other investigators employed the sane technique with considerable success. The following year, Pestsmer and Mayer-Fitsch (69) studied several singly substituted biphenyls. In general, their results showed that biphenyl with a single ortho substituent had absorption spectra of reduced intensity compared to unsubstituted, meta-substituted, or para-substituted biphenyls. Calvin (70), in 1939, discussed the theoretical aspects of the offset of conjugated resonance forms on the absorption spectra of biphenyls, he predicted that certain non-resolvable tetra-ortho- srbbstituted biphenyls should show a spectrum characteristic of the entire conjugated molecule, since such molecules could approach a degree of coplanarity. On the other hand, certain resolvable biphenyls should have spectra similar to the uncoupled parts of the biphenyl molecule due to loss of free rotation about the pivot bond. 67 Calvin*a predictions were confirmed by 0*Shaughnessy and Hodebush (Tl) in m axtensive study covering some twenty cosapounds in which the wan©«* effect® of conjugation, coplanarity, and restricted rotation were thoroughly investigated. For example, they determined the spectra (Figaro FI) of 3,3*-4imetboaybiphenyl (V a) and of 5,5*-di~ KSQthoJsy-2,21-dimeihylbiphenyl (V b). GHa CB* 01 7 a temtmaiien of these absorption curves shoes that tbere Is a maximum or peak for 3,31-dlmethoaeybiphenyl (? a) at 260 mu corresponding to biphenyl absorption and a smaller peak at 300 mu corresponding to aidsole absorption. In the spectrum of V b, the anisole absorption is practically unaffected whereas the biphenyl absorption has been enormously decreased, this decrease was explained as due to the in* ability of the molecule to assume a eoplanar configuration as a conse­ quence of the sterie hindrance presented by the ortho methyl groups* Another series of compounds studied by 0*Shaughnessy and Hodebush were the biphenyl homologs listed below* GHa GH3 68 rr-r trrtr*' '* ’ ’* ;ir: irr a:.i 263 iLe: 303 69 CH« CHS CH* vxxx OH* 08* OH* IX 08* CHj - c®» OS, CB* CHa X 08* 08* XI The absorption spectra of these compounds are graphed in Figure V H # The strong afesorpiion of biphenyl (VI) occur® at 2kd mu, This absorp­ tion is enhanced in h ,h#-dii»eti^lblphQiityX (IX) due to the interaction of the para-ZBSthyl groups with the conjugated system, The spectrum of 3,31**4iasthylbipl^nyl (VXXX) is similar to that of biphenyl since meta-»substittients cannot Interact with the conjugated system. There is a decrease in absorption intensity for 2,2* dinethylblphenyl (VII) due to the sterle hindrance of the tm ortho-methyl groups around the pivot bend, Although absorption is also decreased in the epeotrun of 2,2* #h ^ 9^tetraisethyibiphen3rl (X), interaction of the para-methyl groups with idie conjugated system counteracts the steric hindrance of the srtfeo-methyl groups to a degree. Finally, t,V ,U,k%, 6,6* hexa- srothylblpbenyl (XI), with four ortho-methyl substituents, shows the smallest absorption intensity of tMs series of compounds, The relationship between restricted rotation and absorption spectra was extended to aryl substituted aromatic compounds by Jones (76), This author reports that 9-phenylanthracene (XIX), 9,10-di-(o<, -naphthyl)anthracene (XXV), and 9,9* dianthyrl (XV) hare spectra which are almost 70 FIGV jRD VII Ultraviolet Absorption of IX lUToBtit.uted Iiphenyl iphenyl VII. 2,2*-Dimethyl 15 VIII. 3 f3 f-Dimethyl t ~r 4 , 4 1-Dimethyl VIII o * V 10 VII XI 240 260 280 Wav e 1 eng th , m 300 320 71 identical with that of anthracene . Molecular models show that «n aryl substituent at the 9* or lO^o&r^oaa atoms in anthracene interferes *ith tbs ©rU^hydrogens at tbe X~ and positions of the anthracene nucleus. This results in sterlet hindrance to free rotation nx mi xiv XV t? about the pivot bond. Tbs s m s author showed that Q -phsnylnaphthalens (XVI) h M a m n latsnss absorption spectrum than naphthalene or bensena (figure I S D . XVI FIGTIKG VIII Itrsviolet Spectr ( 3 -H ie n y ln a p lit h a le n e oo V a p T ith a le n e ♦ Tenscne 230 250 290 V/a?e 1 en&t ■i , ra 510 330 73 Xn this there la no stsric hlsdsmksd to notation around thf pivot bond* m U a a s o n and ftodebush (?2), in 19bl, publiahed the results of their study of the offoot of substi tuent groups on biphenyl absorption, A partial list of their data is recorded in Table VI, and some interesting observations were made from these data. The 2 ,2*-substituted biphenyls show a decreased absorption at longer wavelengths of light than do tho corresponding 3, 3#~ or h^**aAbstitwtad biphenyls. This is in accord with tiw* principle of sterle Inhibition to resonance between the brns rings* Xfc is also notable that h,ii*-diliydroxyblphenyl has a greater intensity of absorption than the corresponding 3,3f- isoner. This illustrates the fast that para-hydroxy groups have the Ability to extend the resonating system by formation of polar excited states as indicated Above. TABLE VI m?mv or s u b s titu te s cm b xfh e kil absqrftxoh Biphenyl Compound 2,2*~dimeth0xy ii^-dlmetfaoxy 2,2*"dibydr©gy 3#3f•dihydroxy h ,tf«difeydroay 2 #2f~dioarboxy 3,3»-.diearboxy h ftf-diehlero A m i w» 277 263 285 255 265 26C 2l»3 260 6,000 21,700 6,000 12,000 22,ItOO 2,200 20,000 21,700 the effect of amino and nitre groups on biphenyl absorption was investigated, In 19k%$ by Sherwood and Galvin (?3)# Their results confirmed and extended tbs previous work of Kodabush. Nothing more m & published concerning biphenyl absorption for several years until Pickett and her co-workcra (7h) reinitiated re­ search in this important field* They examined the absorption spectra of a series of ultra- and smlnobitolyls* A comparison of the absorption curves (Figure U ) of &,6»-dinitro-2,2*-bitolyl (X?IX) and S ^ ’-dinitro2#2,*bibolyX (Wtlll) was In accord with the already established theory » the latter GHa CH3 m 9 N0a CHa NG* OH* H0a mi having the more intense absorption idth a shift to longer wavelengths * Further, these authors also recorded the absorption curves of four diaainobitolyl compounds (2XX-IXXX), gh 3 gh 3 M O U R E IX Ultraviolet Spectra 20 5 , 5 ’-Dini tro-2, 2 '- M t o lyl 15 10 01*9 6 16 f-Uinitro-2,2 "bitolyl 220 240 260 2 SO Vav e 1 ength, m \ 300 76 The di«iti»o~3,3•-bitolyl (XI) was found to have the greatest absorption intensity since rotation is practically unhindered« Correspondingly, d^-diamine-S #2»~bitolyl (XXX) had the smallest absorption because the four ortho^substituents prevented rotation around the pivot bond* the h ,M-di*idJa©~2,2*-bitolyl (XXX) shoved a greater absorpbioa thaa $ ,$»^iaatno~2,2*-bitolyl (XXIX) due to the extension of the conjugated system by a shift of an electron pair from the nitrogen in the p&ra-position, similarly to that previously discussed in the case of h ,h^ilydroxybiphenyl # As recently as 19SS» dean and Herd (76) investigated restricted rotation and absorption spectra in the sulfur heterocyclic blthienyl series. The ultraviolet absorption curves of four of these compounds are recorded in Figure X* The 3,31«-dinitr©~5,51-diacetyl-2, 2•-hithienyl (XXTC) has a high intensity XXIXI XOT XXVI absorption due to conjugation between the tm thiophene rings. Thus, steric hindrance does not occur to any appreciable extent. An analogous explasiation can be made to account for the similar although reduced absorption spectra of the 3 f3* ,£ ,5*-tetranitro-2 ,2•-bithienyl compound P IG U K E X 77 Ultraviolet Baectra 48 44 XXIII, 2 ’>5,5« -T et r am e ttiy1 3 , 3 ’-bi thienyl-1> 4 ’dicarboxyl!c Acid 7',4,4 ’-Tetranitro5,5 ’-dimethyl-3 7,*hithienyl 40 XXVI 3 , 3 1,5,5'-Tetranitro8,7*-hithienyl 36 7 , 3 ’-Ainitro- 5,5’diacetyl-3,2’-bithienyl 32 28 2.0 XXV 16 XXI 12 XXIII 230 250 270 Wav e1 ength, m ^ 310 33 78 {3&?)# f e m w , 2,21*b,ix*-tetranitro-$,5>1-dl»ethyl-3,31-bitbienyl (XXI7) and 2,2 *,5,£»-tstr«»ethyl~3,3 *~bithienyl~h,k1-dieerboaylAc acid •how very negligible absorption due to the four ©rtho-eubetituenia restricting rotation around the pivot bend and thus preventing ••planarity of the twe heterocyclic rings, dean and Herd also con­ clude that none of the E^-bithienyle examined by than gave indioatione of sufficient reetrlction of rotation about the pivot bond to permit their resolution into enaniloi&erphie ieoswre. 79 m m m m The 3**arylthianaphlhones for ^deb ultraviolet absorption curves m m determined la this Investigation are listed In Table VIII, together with the wavelengths and extinction coefficients of their absorption maxima* The iMividual curves for each of the arylthianaphthena® are shown in the figures XX to XVII, la general, the spectra of these compounds are In accord with the theory previously discussed in the historical part of this thesis* Before proceeding with the detailed discussion of these absorption spectra, it is necessary to assess the effect of the chlorine and carboxyl groups in the three similar 5wjhloro-3-aryl-2-thiamphthenecarboxylic acids on the ultraviolet absorption curves of these com* pounds* This information Is needed in order to make an interpretive comparison of the absorption spectra of the 5-chloro-3^ryl-f^thianaphthenecaibo3qrlic acids with the absorption spectra of the 3«^ylthia?naphthenes containing no functional group or halogen substituent. Vi%h regard to the chlorine substituent, it has previously been sheen (71) that chlorine exhibits only negligible resonance inter­ action with the aromatic ring in chlorobensene. This is justified, on 80 FIGURE XI Ultraviolet Spectrum of llii anaphth en e O* -5 260 280 28 24 20 16 Ol * *3 12 18 240 Wavelength, m>\ 300 320 340 FIGURE XII Ultraviolet Snectrum of 3 - Uh en y 1th i th en e 3.3 x y r 5 k Q KiO" wi' 10 220 240 300 260 Wavelength, hla ^ 320 340 32 P IG U K S X I I I 70 r ritraviolet Spectrum of 3 - ( 1 T-ITaphthyl)- tlii anaphthene 1.08 x 10-5 II 60 50 40 01 * 3 r* » i 220 240 860 880 V/avelencth, n H. 300 520 340 33 FIGURE XIV Ultraviolet Spectrum of 3 ,3 1-£ithiana,phthene 1.24 x 10“5 M 23 24 20 e * to" 16 12 '8 i 220 i 240 i 260 i 230 Wavelength * i 500 i 320 i 340 84 FIGURE XV Ultraviolet Spectrum of 5-Chloro-3-phenyl-2-thianaphthenecar'boxylic Acid 4*98 x 10“^ M 14 12 10 8 mi 6 0 220 240 260 280 Wavelength, 300 320 340 85 3PIGUKE XVI 5-G!aloro-3-(2,-thienyl)-2-thianaphthenecar'boxylic Acid 9*8 x 10"*6 M 12 e *10 10 220 240 260 280 Wave length, m / ^ 300 320 340 86 I W J R U XVII Ultraviolet Spectrum of 5-Chloro-3- (o-corlDoxyphenyl)-2-thic.np.phthenecarboxylic Acid 4.5 x 10“5 H 8 e * io 6 4 0 200 040 260 200 Wavelength* ma^ 500 300 340 67 theoretical grounds, by the comparatively snail contribution, duo to resonance, of the halogen to the excited state of the aromatic ring, Padhye and Deeai (79) have compared the absorption spectrum of £^hlerethla>naphthene dlfa that of thianaphthene . Their results show that the absorption speetra of these compounds are quite similar and that, therefore, chlorine must interact with the tkUnaphthene nucleus only to a minor degree causing a small shift of the absorption wmadm to slightly longer wavelengths while the absorption intensities remain nearly identical. On the other hand, the carboxyl function due to double bond character in its structure can interact with the aromatic ring and extend the resonance of the aromatic structure. This would be expected to have a very considerable effect on the absorption spectrum of such a molecule, OtShaughnesay and Bodebuah (71) have confirmed this in the case of biphenyl derivatives having carboxyl groups substituted ortho and para to the pivot bond. The presence of the carboxyl function shifted the characteristic absorption maximum of the biphenyl ring system to longer wavelengths and very considerably enhanced its absorption Intensity, The same effect would be expected to be operative in a 2-thia~ naphtbeneoarboxylie acid. The absorption spectra of several 2-thianaphthyl ketones have been recorded (80) and the shift to longer wavelengths accompanied by more intense absorption is observed. It is quite reasonable to assume that the carbonyl functions of the ketone and earboxylie acid will affect absorption spectra in a similar manner. 86 f e aid is the discussion of tho absorption spectra determined In the ©curse of tbs present investigation, tbs curves of the compounds studied have been graphed together In Figure XTOI . The extinction coefficients have been converted to logarithms to facilitate inclusion of ell the absorption curves on the same scale. the absorption curve (Figure X ? m c# Figure XX) for thianaphthene has the fine structure which Is characteristic of «n unsubstituted aromatic compound. % e n the conjugated system is extended by substi~ tutlon of a phenyl group In the Imposition of the thianaphthene nucleus, there is m Increase in absorption intensity and a smoothing out of its fine structure (Figure XFItt d, Figure HI) . The same phenomenon Is observed in the spectrum of biphenyl as compared to bensens (68). However, >*{I1-napbtbyl) -thianaphthene (Figure XVIH e, Figure XIH) has a considerably loser absorption intensity than 3-phenylthlanaphthexie (Figure fflllX d, Figure XXX), If eteric hindrance sere not operative, and thus were net preventing coplanarity of the naphthyl and thlanaphthyl part® of the mol©cula, the naphthyl group would be expected to extend the total resonating system by a larger factor then a phesyl group and, as a result, enhance the absorption intensity to a greater degree«, The reduction in absorption Intensity can be attributed to the hindrance to free rotation about the pivot bond imposed by the hydrogen atom* in the and Oppositions, thus inhibiting coplanarity of the naphthyl and thianaphifcyl group with a resulting loss in resonance. B9 t m u vxx VLTBMXCtM ABSORPTION OF 3-ARH,T3fOANAJ»H?KE»SS .a A max. m II I S' S COOH Cnr^) Vsv^*s'-^cecfi 227 28.it 856 18.5 888 87.8 833 81.8 897 88.lt 885 76.5 895 10.9 839 lit.6 858 7.1 236 13.1 29lt 7.0 836 7.7 286 3.3 0008 COQH 90 FIGTJKE Trill 4.0 cl 3.5 — f O -| £ b r-j« 240 a. b# 300 080 Wavelength* X 5 - C h l o r o - 3 - 340 ( 8 1- tlii enyl)-2-thic naphtlienecar■ boxylie Acid ___ ______ 3 , 3 1-31th i d naph ih one Thianap'ithene d. 3-Kienylt:iisnrpht:iene ........ , ,.. f. 3- (11-Faplithyl)-thir naplithene — .__ ___ 5-Cnloro-3-phenyl-2-tlLiansphthenecar'boxyli c Aci d --------- - 5-Chloro-3-(o - carboxyahenyl)-O-thianrphthenecarboxyl!c Acid 91 ef thd absorption spectra of 5*chlox*o**3«»(2*-thlexiyX)• 2«thlJmapht>i«ia«^^3^1i0 acid (Figure OTII a, Figure OT) and 5^hler©~3^l»Byl-2-t^^ acid (Figaro O T H f, Figaro IP) reveal a vary close similarity* The iseeleetronlo relation­ ship bebessn bensene and thlaphene wold predict such a similarity In the spectra of these compounds. Both absorption curves show a reduced intensity compared to these compounds sfcieh apt not substituted in the 2-position with respect to the pivot bond, This undoubtedly la a result of the otorio inhibition to free rotation supplied by the carboxyl group ubieh prevent* ooplaaarlty of the thtezyl or phenyl group uith the thianaphthyl group thereby reducing the reeonance of the eyatws* A* previously noted, the carboxyl group tend* to enhance absorption d m to its interaction xdlih the aroasatic ring* That the opposite occurs is a further indication that the carboxyl group is sterlcally isMhlttng full resonance in these structures* %%*n a second carboxyl group la placed adjacent to the pivot bond, at in 5-chloro->(OHsarbox^phenyX)-2^ihiamphtherocarboaylic acid (Figure aePIXZ g, Figure WXX), the absorption madmm almost disappears* Thus, resonance through the pivot bond appears to bo virtually non* sidetent due to the lack of copXanarlty of the thianaphthyl and phanyl groups* each coplanarity being prevented by stevie hindrance of the %m carboxyl gronps. fim absorption spectrum of 3,3*•blthianaphthene (Figaro XFIXX b, figure t£F) is someefeat more difficult to fully explain* Although there is an increase in the absorption intensity as compared to that 92 Of thlanaphthene , the fine structure of the thianaphthene spectrum has been retained, Therefore, the spectrum of 3,3*~bithianaphthene may be interpreted to show an absorption curve approximately equivalent to twice the concentration of thianaphthene, Such a situation would preclude any very appreciable resonance through the pivot bond. This would strongly suggest that W e hydrogen atoms at the k- and I*1poeitione are capable of Imposing eterlo hindrance to free rotation about the pivot bond, resulting in non~coplanarity of the two this*naphthyl groups with the attendant loes in resonance. Thie i* an analogous situation to that found for l,l*-biimphthyl by other author* (83) and to 3*(l*-naphthyl)-thianaphthene, discussed previously* lb conclusion* it can be stated, with a very reasonable degree of certainty, that 5^chloro*3*(o*-caiboxyphenyl)-2*thianaphthen«carboxyliQ acid and very probably 3,3 •*bithianaphthene exist in a nop-coplanar structure and the former should therefore be capable of optical resolu­ tion. However, it is not to be inferred that evidence for non* coplanarity Is sufficient by itself for predicting the possibility of resolution in compounds where optical activity is due to restricted rotation. 93 Exmmmzi The ultraviolet abeorptioB spectra m m determined smployixig a Bookman Model W Spectrophotometer equipped with equally matched, oao centtoetcr^ fused quartz cells. The solvent used in every ease was Eastman Kodak C*P, grade cycloheaoam iMoh was further purified by passage through a coltmai of ©ilica gel, The matching of the quarts cells use frequently checked by comparing readings taken with cyelehe&acts alum in the cells. The solutions were prepared by the volume dilution method and mfc were all of the order of 10 M, The procedure used in preparing the solutions m m as follows, A sample of t x KT* moles was accurately weighed out on m analytical balance and dissolved In ICO ml, of cyelohesssm® measured in a calibrated volumetric flask, A 5 ml* aliquot of this solution was then diluted to 100 ml, in a calibrated volumetric flask, An aliquot of the latter solution was transferred to a quarts cell, Optical density readings m m from 2SO~3iiO m at every J m takes over a range of wavelengths and at every 2 mu in the regions of abrupt change in absorption. The values for the optical density readings m m converted to volar extinction coefficients by means of the equation, 8___ 0 m -gj— «hsr« « 1* Ms® notar extinction coefficient, S ia the optical density, C is tbs ooneentretien of the light absorbing species in melon per liter,* and 1 is the length in centimeters of the light path in the 9h absorbing solution, ?4iu*s fur tb» logarithms of tbs nolar #xtinotlon oo#fflol#»t» m then tabulated. The eo*w«airati©»a and readings far th» individual compounds ara listed la Tablaa r a i 1to X W . 95 TASLE WTM h TKXAHAPRTKaifi 3.7 * 10"* M mxelength, mi 220 222 22b 226 228 230 232 23b 2bO 2bS 250 255 260 265 270 275 280 285 290 295 300 305 310 315 320 330 3bO 5 0.672 0.809 0.950 1.05 1.05 0.960 0.750 0.538 0.198 0056 0.17b 0.198 0.198 0.160 0.105 0.055 0.058 0.065 0.080 o.obo 0.050 0.007 0.006 0.006 0.005 0.00b 0.00b 8 X 10"* 18.1 21.8 25.6 28.3 28.3 25.9 20.3 lb.5 5.bO b.21 b.70 5.38 5.38 b.86 2.83 l.b8 1.56 1.75 2.16 1.08 1.35 0.19 0.16 0.16 0.1b 0.11 0.11 log 8 b.26 b.3b b.bl b.b5 b.b5 b.bl b.31 b.16 3.73 3.62 3.67 3.73 3.73 3.69 3.b5 3.17 3.19 3.2b 3.33 3.03 3.13 2.28 2.20 2.20 2.15 2.0b 2.0b 96 TABLE 1A * 10"* M tknlmgUi, n B 8 * 10** 220 m 22b 226 228 230 238 23b 2b0 2b5 2S0 255 260 265 270 275 280 285 290 295 300 305 310 ns 320 330 3b0 0,7b0 0.718 0.706 0.721 0.761 0.795 0.800 0,775 0.567 0.b33 OjkJU 0,b6? 0.b22 0.387 0.328 QAJ1 0.561 0.689 0.782 0.850 0.8b0 0.800 0.700 0.515 0.bl9 0 ,07b 0,008 19.5 18.9 18.6 19.0 20.0 20.9 21 a 20.b lb .9 U.b 11.5 12.2 11.1 10.2 6.6 11.3 lb .8 18.1 20.6 22 .b 22.1 21.1 16.it 13.6 11.0 1.9 0,21 log « b.29 b.28 b.27 It.28 b.30 b.32 b.32 lt.31 b.17 b.06 b.06 b.09 b,05 b.oi 3.93 b.05 bjL7 b.26 b.31 b.35 b.3b b.32 b.26 b.13 b.Ob 3.28 2.32 97 TABL8 1 3-(1 »-*AJ>HrHTI.)-THIMIAmEaN ft 226 222 225 228 230 235 2b0 21*5 250 255 260 265 270 275 280 285 290 295 300 305 310 325 320 325 330 3I4O 8 e x 1 K. 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