THE SYNTHESIS AND CHARACTERIZATION OF NITRAMINOTETRAZOLES By James A, Garrison A THESIS Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of DOCTOR OP PHILOSOPHY Department of Chemistry 195U ProQuest Number: 10008310 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 manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest ProQuest 10008310 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 Acm M LEum m The author wishes to express his appreciation to Boater Robert M. Herbst for M s valuable assist** sues sad helpful guidance throu#out the eourse of this work* Part t of this thesis was serried out under N, S, llavy Research Contract N123S-6T279, task Order No. 2. Part II was supported by a Parke-Davis Fellowship. This financial assistance is gratefully acknowledged. i g irw - j g i nffpFW t M M P » ! rw M i tir il w TABLE Off CONTENTS Page INTRODUCTION..................*................. 1 PART I SYNTHESIS AND CHARACTERIZATION OF $-NHRAMINOTSTRAZOLE...... D i s c u s s i o n . ..... Eaqoerimental, .... ........... Preparation of 5*Anri.notetraaole Preparation of 9-Aminotetrazole Nitrate..... ......... Preparation of 5**Nitranlnotetrazole..... From 9-Aminotetrazole ..... From N-Nitro-N1*aminoguanidine ..... Preparation of Salts of 9~Nitrarainotetrazole .... Untraviolet Absorption Spectra.. ......... Potentiometric Titrations .... 3 3 8 8 9 9 9 11 12 Ik Ik PART II SYNTHESIS AND CHARACTERIZATION OF ALKYL.^NITRAMINOYErRAZOLES. 19 Discussion....... 19 Eaperimental, ...... k3 Preparation of Alkyl 5*Aminotetrazoles ........... k3 Preparation of Alkyl fJ-AmLnotatrazole Nitrates......... k3 Preparation of 1-Methyl-9-nitrsminotetrazole......... k3 k9 Preparation of l-Ethyl-5-nitraminotetrazole........... Preparation of 5-MetlylnitrsiainotetrazolG ........... k6 From 5-Methylaminotetrazole Nitrate...... k6 From Meihylnitrocyanamide..............a........*....... k6 Preparation of 9-Ethylnitraminotetrazole........... k8 Reduction of ^-Metliylnitraminotetraaole............ k8 Preparation of Potassium Salts of Alkyl Nitroninotetrazoles k9 Preparation of 2-Amiaopyridine Salts of Alkyl^-Nitraminotetrazoles...... h9 Potentiometric Titrations ......... 91 Ultraviolet Absorption Spectra ................ 91 Infrared Absorption Spectra ..... 91 SUMMARY.............. 93 LITERATURE CITED....................... 9k APPENDICES.................................. 99 LIST OF TABLES TABLE I. II. IH. IV. V, Page Salts of 5-8itraminotstraaole -with Organic Bases ...... 13 Apparent Dissociation Constants of Alkyl 5-NitrarainQtetrbz oles......................... ...............2? Alkyl 5-Aminotetrazole Nitrates............... Wi Salts of Alkyl ^-Nitraminotetrazoles with 2-Aminapyrldine 50 Wave Lengths of Maximum and Minimum Ultraviolet Absorp­ tion of Alkyl 5-Nitraminotetrazoles and Their Potassium Salta....... 52 LIST Cg FIGURES Figure Page 1. Ultraviolet Absorption Spectrum of 5-Nitraminotetrazole. ...... Prepared from 5-Aminotetrazole 15 2. Ultraviolet Absorption Spectrum of 5-rJItraminotetr&zole. Prepared from N-nitro-N1-aminoguanidine ...... 16 3. Potentiometric Titration of 5-Nitraminotetrazole. ................... 17 Prepared from 5-Aminotetrazole li. Fotentiometric Titration of 5-Nitraroinotetrazole. Prepared from H-nitro-M*-aminoguanidine .... 18 5* Fotentiometric Titration of l^etbyl-5*-nitraroinotetrazole. 28 6. Potentioroetric Titration of 5-Metbylnitrarainotetrazole..,. 29 7. Ultraviolet Absorption Spectrum of l-Methyl-5-nitraminotetrazole ............. 32 8. Ultraviolet Absorption Spectrum of 1-Ethyl-5-nitramInotetrazol© .... 33 9. Ultraviolet Absorption Spectrum of 5-Methylnitrarainotetra3i* zole .................... ............ ...... 10. Ultraviolet Absorption Spectrum of 5-Ethylnitraminotetrazole .... .................... ......... ..... . 35 11. Ultraviolet Absorption Spectrum of Dipotassium 5-nitramino 36 tetrazole .............. ...... 12. Infrared Absorption Spectrum of 5-Nitraminotetrazole...... 37 13. Infrared Absorption Spectrum of l-Methyl-5-nItraminotetrassole .... ...................... ...... 38 li*. Infrared Absorption Spectrum of l-Ethyl-5-nitraminotetrazole ......... *....... 39 15. Infrared Absorption Spectrum of 5-Methylnitraminotetrasole 1*0 16. Infrared Absorption Spectrum of 5-Etbylnitraminotetrazole. 1*1 17. Combined Infrared Absorption Spectra of 5-Hitrsnlnotetrazole Derivatives ..... 1*2 1 INTRODUCTION It has long been known that the nitric acid salts of certain amidic derivatives such as urea and guanidine can be dehydrated with the formation of nltrourea and nitroguanidine, respectively* In both instances the fundamental reaction appears to involve conversion of a substituted ammonium nitrate into a similarly substituted nitraraine. The structural analogy which can be observed between S-aminotetrazole (I) and guanidine (II) suggested the possibility that the nitric acid salt of the former might be converted by dehydration Into a nitrosraino tetrazole. I II The first part of this thesis presents a study of the preparation of the nitric acid salt of £-aminotetrazole and its conversion into 5-nitrarainQtetrazole. Although 5-nltraainotetrazole had already been prepared by the treatment of N-nitro-N aninoguanidine with nitrous acid and cyclization of the resulting guanyl azid© (l), it was necessary to reconcile the recorded properties (l) of the nitraminotetrazole with those observed in this laboratory. 2 Tatraaol© derivatives in which the hydrogen attached to the ring nitrogens has not been replaced generally behave as acidic substances (2,3). 5-Nitraminotetrazole (HI) H-N C-NBNOg II in is no exception and, in fact, behaves as a dibasic acid due to the presence of a second dissociable hydrogen in the nitramino group. It had been suggested without sufficient supporting evidence that the hydrogen of the nitramino group was responsible for the first dissoci­ ation ( k ,$). In order to establish which of the two hydrogens of 5-nitraminotetrazole was most easily dissociated, the preparation of nitraminotetrazoles in which one or the other hydrogen was replaced by a simple alkyl group was undertaken. Since 1-alkyl-5>-sninotetrazoles (6) and ^-alkylaminotetrazoles (7) could be prepared by unequivocal syntheses, the nitration of compounds of these types by dehydration of their nitric acid salts was studied. The structures of the resulting compounds were supported by independent synthesis and by comparison of their physical properties including absorption spectra. The results of these studies are described in the second part of this thesis. PART I THE SYNTHESIS AND CHARACTERIZATIOH OP $-HXTR/OTOTETRAZOLE 3 DISCOSSIOH The similarity' between 5-®ninotetrazole and guanidine in certain structural features suggested that nitrarainotetrazola might be prepared from 5-aminotetrazole much as nitroguanidine can be prepared from guanidine. Since it was first described by Thiele (7), 5*arainotetrazole has generally been looked upon as an acidic substance. Although the amino group can be acylated (8) and under suitable conditions di&zotized (7), its salts with mineral acids are extensively hydrolyzed in aqueous solution. S-Araimotetrazole nitrate {9) can be prepared by crystallization of £-aminotetrazole from warm, moderately concentrated nitric acid. Presumably the amino group is involved in salt formation, although participation of the ring nitrogens cannot be excluded. Care must be taken in preparation of the nitrate since prolonged heating may result in considerable decomposition. The crude nitric acid salt rosy be recrystallized from water, presumably because the crude salt was not washed free of excess nitric acid. Dehydration of the nitrate with sulfuric acid at room temperature led to the formation of a nitraazinotetrazole * The reaction was quenched by addition of ice and water. After removal of most of the sulfate with barium carbonate, the product was extracted from the aqueous solution with etliyl ether. Crude nitrazninotetrazole was obtained by evaporation of the ether at room temperature. On crystallization from k dioxane-benzene mixture a solvated product resulted. The loss in weight upon drying indicated that the crystalline material was either a trihydrate or a complex of two moles of nitraminoteirazole with one mole of dloxane and two moles of water. Elemental analysis of the solvated material supported the hydrated-dioxanate form. The presence of water in the solvated material was also established qualitatively by interaction with calcium carbide in anhydrous ether, tinder these conditions a gas was evolved, probably acetylene, that gave a colorless precipitate when passed into an alcoholic silver nitrate solution. The anhydrous nitraminotetrazole did not cause gas evolution with calcium carbide under the same conditions. The water in the solvated product was estimated quantitatively by the Karl Fischer technique. Analogy with the guanidine series suggested that 5-nitramlnotetra~ sole (X) or 1-nitro-5-aminotetrazole (II) might be formedj however, 2-n!tro**5-®®inotetrazola (IH) could not be excluded. H-N--- C*NHNOa l II HO3-N--- C-8Ba I H=C*KHa II v I so* i ii I - v ni Lieber, et al, (l) have described a compound prepared by the inter­ action of H-nitro-H *-aminoguanidine (IV) and nitrous acid followed by eyeH z ation of the resulting guanyl aside (V) to which they assigned the structure of 5-nitraminotetrazole (l). Assignment of structure was based on the reduction of the nitro compound to 5 HN=C— HHNO* HN=C— RHHO- mm* | | s3 IV v HN _! ^ C-8HR0, | | I 5**tetrazolylhydrazine (VIXI) which Thiele had prepared by redaction of diazotized 5-sminotetrazole (VI) (10) and by decomposition of $~szo~ tetrazole (VII) (11), H-& C-NHN02 Zn + HC1 \ N/ f H-N I C-N2+ Cl* II ZnCl» " V * hci H-N--- C-NHNHa I * V * vin VI H-M--- C-N«N-C---- H-H V1, v* I J I dil. HaSO. VII The nitraminotetrazole prepared fro m 5-aninotetrazole differed in certain respects from the compound prepared from nitroaminoguanidine. The former crystallized as a hydrated-dioxanate -which lost its solvent of crystallization in three or four days at room temperature or in 8-10 hours at 60-70°C.j drying at higher temperature may be dangerous, (Although drying at 100°C, had been successful on several occasions, one sample of about 100 mg, exploded violently in the oven while being 6 dried at 100°C. completely pulverizing the glass vial containing the sample although the mouth of the vial was not stoppered.) Furthermore, the compound was not sensitive to shoek even when struck very sharply with a hammer on an anvil. The product from nitroaminoguanidine was said to crystallize as an anhydrous solid which was sensitive to shock (1). In order to resolve these differences the preparation of 5-nitrarainotetrazole according to Lieber, et al. (l) was repeated. The product so prepared also crystallized as a hydrated-dioxanate and failed to exhibit sensitivity to shock. The previously reported shock-sensitivity may have been due to a trace of the azide as contaminant. The identity of the two products was confirmed by the preparation of several salts with organic bases. Lieber, et al. (12) had described an extensive series of such salts of 5-nitraminotQtrazole. The salts with pyridine, diethylsniline, 2-arainopyridine, and ethylene diamine were found to be easily prepared. Salts prepared from the nitraminotetrazoles obtained by both procedures were identical as shorn by the data recorded in Table I. In other respects, including ultraviolet absorption spectrum and potentiometrie titration, the nitraminotetrazoles prepared by both methods were also identical. The ultraviolet absorption spectrum showed a maximum absorption at 277*276 my. and a minimum absorption at 237 mp for the solvated and anhydrous nitraminotetrazoles prepeared by both methods. On potentiometrie titration £-nitraminotetrazole behaves as a di­ basic acid. The first dissociation has been described as that of a 7 completely dissociated strong acid (h ) while the second dissociation has a pK value of 6.2. Although the results of the potentiometrie titrations of solvated and anhydrous products prepared by both methods were identical, our data do not support the conclusion that the first dissociation is that of a completely dissociated strong acid. Its behavior is more comparable to that of a moderately strong dibasic acid such as oxalic acid. Our results indicate that pK^ is 2.55, while our values for pKa, 6.05 and 6.0I4 for the two preparations, are in good agreement with the value observed by Lieber, et al. (ii). 8 EXPERIMENTAL* Preparation of ^-Aminotetrazole A large scale adaptation of the preparation of $-®ninotetrazole (2) has been developed. All operations should be carried out in a good hood. Powdered dicyendiamide (326 gra.) and 528 gm. of powdered sodium aside were suspended in 800 ml. of water in a 5 1.-resin flask. The top of the flask was secured and fitted with an efficient reflux condenser, a stirrer, and a dropptng-funnel, The flask was warmed to 50°C. in a water bath after which 680 ml. of concentrated hydrochloric acid was added with stirring, through the dropping-funnel at such a rate that the hydrazoic acid liberated refluxed very slowly. Addition of the acid required about an hour during which period the water bath was allowed to warm to 65-70°C. where it was maintained for six hours. The stirrer was stopped and crystallization of the product began soon after addition of the hydrochloric acid was complete. The reaction mixture was allowed to stand at room temperature overnight and then thoroughly chilled in an ice bath before the product was filtered by suction and washed with ice water. The crude product was recrystallized from 1500 ml. of boiling water from which it separated as the mono­ hydrate. After drying at 110°C, anhydrous 5-aminotetrazole was obtained. Held 610 gm., (90JS) m.p. 206°C, with decomposition in a capillary (7). * Carbon, hydrogen, and nitrogen analyses by Micro-Tech Laboratories, Skokie, Illinois, 9 Preparation of 5-Aminotetragole Nitrate Ten grant of 5-aminotetrazole vere nixed with a solution of 16 gn. of concentrated nitric acid (sp. gr. 1.U19) in 15 ml. of water. The mixture was warmed until homogeneous and then cooled immediately. (It is best to heat r&pidly to attain complete solution of the 5-amino* tetrazole and to cool rapidly since prolonged heating causes decompo­ sition and decreased yield.) The product crystallised immediately as colorless needles. It was recrystallized from water, field 15 gm. (97%) m.p. 178-179°C. with decomposition. Analysis. Calculated for C H ^ ^ i Pound* C, 8.11* H, 2.72} H, 56.78. C, 8.i48i H, 2.91} N, 56.82. Preparation of 5-Ritraminotetragole Finely divided 5-aminotetrazole nitrate (lli.8 gm., 0.1 mole) was added in small portions with stirring to 20 ml. of cold concentrated sulfuric acid. The mixture should be cooled in an ice-water bath during the addition of the nitrate. After complete addition of the salt, the milky suspension was allowed to stand at room temperature until it became homogeneous. The cold sulfuric acid solution was diluted with 250 ml. of water and ice after which slightly less than the amount of barium carbonate required to neutralize the sulfuric acid was added. The mixture was digested on & steam bath until carbon dioxide evolution ceased. The barium sulfate was removed by centrifugation and was washed twice by resuspension in hot water. The combined aqueous solutions were 10 evaporated to about 100 ml. under reduced pressure. The concentrate was shaken with five 100 ml. portions of ether. After evaporating the combined ethereal extracts almost to dryness in a current of air, the residue was treated with 250 ml. of benzene which caused the product to separate as colorless plates. When the crude product was recrystal­ lised by dissolving in a small volume of l,li«dioxans and adding a large excess of benzene, there was obtained 10.7 gm. ($1$) of solvated 5-nitraminotetrazole which decomposed with a reddish flash at about 135°G. on the melting point block. In a capillary the product decomposed with gas evolution variously at 160-170°C. The aqueous concentrate was further evaporated to about 10 ml. and extracted with three 50 ml. portions of ether. The ethereal extracts were treated as just described to give 0.8 gn. of solvated product of the same decomposition characteristics. The total yield of solvated product was 11.5 gsi. (58$). The presence of water in the solvated product was demonstrated qualitatively by the evolution of acetylene when calcium carbide was added to a solution of the material in dry ether. The gas evolved gave a colorless precipitate when passed into alcoholic silver nitrate solution. Anhydrous 5~nltraminotetra2ole did not cause gas evolution under these conditions. Water was also estimated quantitatively with the Karl Fischer reagent. Analysis. Calculated for 2GHgHg0.g*C^H©0.g«2H 20i c, 18.8j H, ii.2) H, k3.7) H*0, 9.1*. Found* C, 19.U, 19.5) H, l*.2, U.3) H, U3.1, h 3 .3 } HjjO, 10.3. 11 Anhydrous 5-nitraminotetrazole was obtained by drying the hydrated dioxanate at 70°C. for 2k hours. Analysis. Calculated for 2CH^60a*C4H803*2H^)i C4HaOa*211^0, 32.3. Found* 29.6* When air-dried at room temperature for six days the weight loss was 30*5$. Analysis of anhydrous 5-nitraminoietrazolQ. Calculated for GH;jNaOa* C, 9.2) H, 1.6) H, 6k*6, Found* C, 9.6, 9.6) H, 1.7, 1.6) H, 6U.7, 61*.5. Preparation of 5-Nitraminotetrazole from N-Kitro-N1-aminoguanidine A quantity of 5-nitraminotetrazole was prepared from N-nitro-N’sminoguanidine following the procedure of Lieber, at al. (l). The product was isolated as described by these authors and was found to be solvated. Analysis of the hydrated dioxanate dried at 70°C. for 2k hours. Calculated for 2CHgK603*C4)S[803*2KaO* C4H 60a*21130, 32.3. Found* 29.1. The yield of 5-nitraminotetrazole was improved substantially by the following modified procedure* To a cold solution of 9 ,k gm. of sodium nitrite and 13.7 0®. of N-nitro-N1-aminoguanidine in $0 ml. of water there was added with coiling (below 15°C.) and stirring a cold mixture of 11.8 ml. of concentrated hydrochloric acid and 50 ml. of water. The mixture was allowed to come to room temperature and was filtered and evaporated to dryness in a current of air. The residue was extracted with three 100 ml. portions of ether. Evaporation of 12 the ether left ft residue of crude nitroguanyl azide that was taken up in 100 ml, of 95$ ethanol and treated with an aqueous-alcoholic solu­ tion of sodium acetate until precipitation of the sodium salt of 5-nitraroinotetrazole was complete. the sodium salt was filtered and air-dried. Tield 13 @n. (75/0} explodes at 21o-220°C. on the melting point block. A solution of 8,7 g. of sodium nitraminotetrazole in 30 ml. of water was treated with 25 ml. of 18$ hydrochloric acid. The solution was extracted with five 100 ml. portions of ether from which 8.0 g. of solvated 5-nitrsninotetrszole was isolated by concentration and pre­ cipitation with benzene. Concentration of the aqueous solution to 10 ml. and extraction with three 100 ml. portions of ether, followed by evaporation of the ether and precipitation with benzene gave 2 g. of the product. The combined fractions were recrystallized from a 1,i*-dioxane-benzene mixture as before to give 9.5 g. of solvated product (86$ from the sodium salt) showing the same decomposition characteris­ tics previously described. Preparation of Salta of 5-Kitraminotetrazole Salts with pyridine , diethyl&niline, 2-aminopyridine, and ethylene diamine were prepared from 5-nitraminotetrazole prepared by both pro­ cedures. The salts were prepared by dissolving 0,7 g. of solvated 5-nitrsrainotetrazole in ether and treating with an ethereal solution of the appropriate amine. The salt, which precipitated immediately, was filtered and recrystallized from an appropriate solvent. 13 A list of the salts prepared, the solvents used in recrystalli­ zation, melting points, and analyses are given in Table I. TABLE I SALTS OP 5-OTUIMIN0TOTAZ0LE WITH ORGANIC BASES Amine M.P.* M.P.b N*a Formula Calc*d Found pyridine® 131*132 131*132 C6H7N70 L6.18 U6.70 li6,70 N-Diethyl anilined 12L-125 12ii-125 Cll®17®7® 35,11 35.W 35.68 2-Aminopyridine® 181-182 181*182 C6HeJls0 U9.99 1*9.88 50.17 Ethylene diamine* 239 CsH10liaO 58.93 58.87 59.00 239 A, Salts of the 5-Kitrafflinotetraaole prepared from 5~Aminotetrazole. All compounds decompose at the melting point. Temperatures corrected. b. Salts of the 5-lfitraminotetraaole prepared from N-nitro-N *-sminogusnidine (12). A H compounds decompose at the melting point. Temperatures corrected. c. Recrystallized from acetone. d. Recrystallized from ethyl acetate. e. Recrystallized from ltl isopropyl alcohol-ethyl alcohol. f. Recrystallized from isopropyl alcohol-water mixture. Ik Ultr aviolet Absorption Spectra of 5’ *Nitrarrdnotetraaole The ultraviolet absorption spectra of samples of 5-nitraminotetrazole prepared from 5-aminotetrazole and from N-nitro-N *-aminoguanidine were determined. Both anhydrous and solvated materials were examined. All spectra mere observed in aqueous solutions of 1 x 10“4 to 1 x IQ**6 molarity using a Beckman Model D-U Spectrophotometer. The results are given in Appendix I, and are represented graphically in Figi'r^s 1-2. Bo significant differences were apparent. Potentiometrie Titrations of jj-Nitramlnotetrazole Samples of anhydrous 5-nitrsminotetrazole and of the solvated material prepared by both methods, from 5-aminotetrazole and from N-nitro-N1-eminogusnidine, were titrated potentiometrieally using a Beckman Model <3 pH Meter. All titrations were carried out at 2$°C. ! G.02°C. in an initial volume of 200 ml. Complete agreement was found for all compounds. Data and results are given in Appendix H, and are represented graphically in Figures 3~k, 15 1.3 1.2 1.1 Extinction Coefficient x 10' 1.0 0.8 0.7 0.6 0.5 0.3 0.2 0.1 220 2U0 260 Wave Length 280 300 320 in Mu Figure 1. Ultraviolet Absorption Spectrum of 5-Nitraminotetrazole (Anhydrous) Prepared from 5-Aminotetrazole. 16 1.3 1.2 1.1 1.0 0.8 0.7 0.6 Extinction Coefficient x 10"' 0.9 0.3 0.2 0.1 0 220 2l|0 260 Wave Length 280 300 320 in Mju. Figure 2. Ultraviolet Absorption Spectrum of 5-Nitroaminotetrazole (Anhydrous) Prepared from i\l-nitro-N*-Aminoguanidine. M 3 CM CM CM CM CM M3 r-i iH rH CM i —I CO CM CM 0\ 03 Figure 3. Potentiometrie Titration Curve of 5-Nitraminotetrazole (Anhydrous) Prepared from 5-Aminotetrazole. 17 CO CM 18 CM O C\ CO CM VO CM -CM Ct CM CM o CM o CO ■o I —1 O 0 X O) 0 ss Pd y CM rH O M CO vO -ct o CM o o\ CO CM ft part 11 THE SIMTHESIS AMD CHARACTERIZATION OF SOME ALKTL 5*NimMXNOTETRAZO£ES 19 DISCUSSION In Fart 1 5-nitraminotetrazole was characterized as a dibasic acid with pK values of 2,5 and 6,1, Since the two hydrogen atoms in the structure do not necessarily occupy equivalent positions, it became of interest to determine whether the hydrogen attached to the tetrazole nucleus or the hydrogen of the nitramino group was responsible for the relatively strongly acidic character of the compound, Lieber, et al, (U ,5) had assigned the stronger acid function to the hydrogen of the nitramino group. This conclusion was based on comparison of ultraviolet absorption spectra 5-nitraminotetrazole, and several of its salts, with the ultraviolet absorption spectra of N-nitro-N ‘-aminoguanidine and nitramide. Since corresponding data for other tetrazole derivatives were not cited and the differences in absorption maxima were quite large, it was thought that further work was needed to definitely establish which hydrogen was responsible for the first dissociation constant. It has been shown that all tetrazole derivatives in which the hydrogen attached to the ring nitrogens has not been replaced by a substituent group may behave as acidic substances. An analogy has been developed between 5-substituted tetrazole derivatives, R-CN4H, and carbosylic acids, R-COOH, and it has been shown in a rather extensive series of compounds that the nature of the group R affects the acidic dissociation constant of the 5-substituted tetrazoles in much the same way as it affects the dissociation constant of the carboaylic acids 20 (2,3,13). Baur (IjU) has shown that 5-aminotetrazole behaves as a weak acid (pK“f>,93). The basicity of the amino group is largely masked by the acidic function of the tetrazole ring. Acetylation of the amino group in 5-aoinotatrazole causes a marked increase in the acidic dissociation of the tetrazole group (pK°4i,53 (15))* It would hardly be eapected that the electron-with-drawing effect of the acetyl group would be sufficient to endow the amldic hydrogen with such a strongly acidic character. If the introduction of a nitro group in place of one of the amino hydrogens of 5-eminotetrazole is considered as comparable to an aoylatlon with a strongly electron-withdrawing group, it could be anticipated that the effect upon the acidic dissociation of the tetra­ zole ring would be markedly greater than that produced by the acetyl group, In this event the nuclear hydrogen of the 5-nitraminotetrazole would become responsible for the relatively strong acidic dissociation of the compound. The stability of the tetrazole anion would be enhanced by resonance of the following type (Type 1). H-N C~NHHOa II It would be observed that (-)N--- C-NHKOa II N----C-NHH03 II II -HHNQ Type 1. 21 the resonance Inherent in the nitro group would serve to increase the number of forms contributing to the resonance hybrid. Dissociation and resonance of Type 1 assumes that the strongly acidic dissociation of 5-nitraminotetrazole involves the hydrogen of the tetrazole nucleus rather than the nitramino hydrogen. On the other hand, the possibility that 5-nitraminotetrazole may exist in several tautomeric forms cannot be neglected. It should be noted that both H-H C-H-* I li — Q H-N----C-NHNOa I (B) (a ) H-H C"tfN0j) (C) II H-N- C-HHO* (b) hydrogens occupy equivalent positions in tautomer (C) mad that they would be indistinguishable in this instance. Assuming for the moment that the hydrogen of the nitramino group is the first to dissociate, the resulting tetrazole anion would be stabilized, not only by the resonance possibilities inherent in the ring system, but also by conjugation of the resonance of the ring structure with that of the nitro group (Type 2), As before, the resonance possibilities inherent in the nitro group would increase the number of forms contributing to the hybrid, 22 (-) H-K C-N-l V Type 2 In order to determine which type of resonance predominated, two series of monoalkyl nltraminotetrazoles were prepared and their physical properties studied. The first series included l-reethyl~5-nitraminotetrazole (I) and l-ethyl-5-nitraminotetrazole (IX) in both of which dissociation and resonance of Type 1 can not exist, but dissociation and resonance of Type 2 is possible. The second series consisted of S-methylnitrsBninotetrazole (III) and 5-ethylnltraminotetrazole (I?) in both of which dissociation find resonance of Type 2 is blocked while dissociation and resonance of Type 1 is unhindered. CHa-H C-KHNOa C3Hb -NII ' L> (II) (I) C#e H-H- 'a (in) (w) 23 Quantities of l-methyl-5-*aminotetrazole, l-ethyl-5-eminotetrazole, 5~raetbylaminotetrazQle, and 5-ethylaminotetrazole were prepared accord­ ing to the methods of Garbrecht and Herbst (3,6). The corresponding alkyl 5-nitrarainotetrazolea were prepared by dehydration of the appro­ priate alkyl 5-arainotetrazole nitrates by adaptations of the procedure described in Part I. No attempt was made to find the optimum conditions for the preparation and Isolation of the alkyl nitraminotetrazoles. The nitration of the S-alkyiaminotetrazoles could have taken place on the tetrazole ring in positions 1- or 2* with the formation of a l-n±tro-alkylaminotetrazole (V) or a 2-nitro«5-alkylaminotetrazole (VI), Therefore, it was necessary to prove the structure of the product OoM 1 C-NH-a N=C-NH-R ii i (V) I (VI) a * CK3 , c gHg formed by direct nitration of at least one 5-slkylaminotetrazole. Two courses were available* first, synthesis of a 5-slkylnitraminotetra- zole by an independent method$ second, reduction of a f?-alkylnitramInotetrazole and characterization of the reduction product. The independent synthesis was carried out as follows* Potassium methylnitramine (VIl), prepared according to Franchimont (16), was treated with cyanogen bromide to form methylnitrocyanamide (VIII). After interaction of methylnitrocyanamide and hydrazoic acid, 2k 5-mQthylnltararolnotetrazole (ill) was isolated. This was shown to be identical with the product formed by direct nitration of 5-wethylaraino* tetrasole by comparison of melting points, mixed melting point, (YII) (vm) (in) Infrared absorption spectra and characterization as a salt with 2-axndnopyridin©, Reduction of 5»nitran)inotetrazole has been shown to lead to the formation of £~tetrazolyl hydrazine (l), The analogous reduction of £-methylnitraminotetrazole would be expected to lead to N-iaethyl-N(5-tetrazolyl) -hydrazine (IX), Subsequent condensation of the hydrazine with benzaldehyde should result in an acidic iydrazone (X), A similar series of reactions with the corresponding l-rutro-5-methylaminotetrazol® should give a neutral or basic product (Xl), Similarly, a neutral product would be anticipated upon the analogous treatment of 2-nitro- ^-methylaminotetrazole (Yl), The product actually obtained upon re* ductlon of the nitro S-methyleminotetrazole was J^methylarainotetr&zole probably formed by hydrogenolysis of the intermediate hydrazine (IX), Therefore, the reduction of the nitro 5-raethylaninotetrazole did not help to establish the position of nitration. H VB H VH (in) (ix)I {CgHgCHO /CH3 H-N -N--- C-N - i i _ N-CHG6Hb (X) OgH-N C-HH-CHB • v * H2 HgN-N C-SH-CH3 v (V) C6H6CH0 G6HeCS2M-K K C-HH-CH* J in) The structure of the corresponding 5-ethylnitraminotetra.zole obtained by nitration of Si-ethylaminotetraaole was assumed to be correct­ ly assigned by analog in the method of preparation and because of the similarity of its properties. Although the structure of 1-methyl- and l-ethyl-5-nltrsminotetrazole (I,H) was not supported by am independent synthesis, it seemed reason­ able to assume that nitration of 1-methyl- and l-ethyl-5-aminotetrazole 26 would follow a course analogous to that established for other 5-aniao* tetrazoles. This assumption finds support in the properties of the compounds as evidenced particularly by their dissociation constants and ultraviolet absorption spectra. The l-alkyl-5~nitrazninotetrazole8 are moderately strong monobasic acids (pK » 2,7*2,8). If nitration is assumed to take place on one of the ring nitrogens, a 1-alkyl-2(or W-nitro-S-iminotetr&zolin© (lHa,b) would result. Resonance R-N I C I xna R-N--- G *m I I xnb stabilisation of the tetrazole anion would probably be very minor in such a structure as compared with the resonance stabilization of the 5-nitrssnino compounds (Type 2). The apparent dissociation constants for the alkyl nltraminotetrazoles were determined and the results are presented in Table II. A typical titration curve for each series is presented in Figure® 5*6* The l-alkyl-5-nitraminotetrazoles were found to have a pK value of about 2.7, while the 5~alkylnitraminotetrazoles have a pE value of about 2 ,9 • The results demonstrate that resonance of either Type 1 or Type 2 could explain the relatively strong acidic dissociation of 5-nitraminotetrazole. Since the hydrogen, both of the tetrazole nucleus and of the nitramino group, is dissociated with equal ease it became necessary 27 TABLE II APPARENT DISSOCIATION CONSTANTS OP ALKIL 5-NITRAMINOT1TRA20LES Compound pKl Apparent K x 109 ^-Ritraainotetrazole 2.55 (».) 2.8 («) l-Methyl-5-nitraminotetrazole 2.72 1 .9 l-Ethyl-5~nitramlnotetrazole 2 .7 k 1.8 5~HetlQrlnitramlnotetrazolQ 2.86 1.3 5-Etliylnitrajainotetrazole 2,86 1J* (a.) The values for the second apparent dissociation are pK * 6.0i*, t • 9 .1 x 10-7; to NO C o -P & o w ,o "d CD u CO CM CM t—I 0) ?c •M CM uotssT'JisiiBj;,! ^uao.iej u\ rH —d’ rH O 3 •r~» C •H rH i —©I O 40 +f3r © +3 O 5 su CM H CN rH O o O in Cm' rH W S3 o Sh O •H Va.ve lumbers CK CO x; to G © s? % XA VO +> ■ad 1A I iH rH <>•4 ■+3 '©H "T «H o G +3 o © tx CO G O •H +3 04 G O w X) "G © CM ■LA u 'a CM o CO aoT?:?xuis'oea;J C_.) o cm -cj o ■c"S 3 cm CO CM rH C\ o in Cm' O i —I o o •H 0\ c! 'ave r,umbers •rH -P tco a M3 o cm cv o VcO CM rH iioxssxuE xiej t %u0oa‘8c; Uu o i —i •O A} 0 a -H i —CD OI CM IS) CO JH p CD P O •S JH o oE •oH in i —I a Numbers On -rl C! -CD3 p ■d iH P CD t t-A ■P O u CD Wave > 03 p o CD (X 'O a o •H P o, u o m X •o CD O CM '-A o o CM o rH uoiPspusirejr q.uaoaaj U 10 M 'a U1 rH O 3 •r~) r"\ I— I CD rH O £3 u -P CD -P Os 0 C 1 U m a o H ( h wumbers o •H CT\ -cH -P •H G rH & i u\ O a 0 ave h-i CD C. P o 0 C l, c/ j « o -rH P C l, Sh O CO £> x> 0 c3 C'J M vO iH -=} 0 W) -H IO' O X) M3 tjoTssTiiisue.IT, auooj:e;i o CM .1 Figure 2.7 Infrared Absorption Spectra of Sitraminotetraaoles A, f^Hltreminoietr&zole. B, l-^iethyl**S<^iitraHiinotetraaol©, C , l*Etl^l-*^nitr«ainoteia*azole # B, ^-Ketbylnitraminotetrazol®. E. 5-BtiQrlnitra»iiioteta*aaole, WAVE 2000 NUMBERS IS00 CM-1 IN 1000 900 100 80 60 40 20 80 60 40 20 80 60 40 20 80 60 40 20 80 60 40 20 0 WAVELENGTH IN MICRONS figure 17 . 800 700 h3 EXPERIMENTAL Preparation of Alkyl 5-Aminot.etrazoles l«Methyl-5-aminotetrazole and l-ethyl-5-aminotetrazole ware prepared from the appropriate alkyl cyanamides and hydrazoic acid as described by Garbrecht and Herbst (6). 5-M®thyleminotetrazole and 5-ethylaninotetrasole ■were prepared by debenzylation of 5—benzylmethylamino— or $*4)6Myl* ethylaninotetrazole according to Oarbrecht and Hsrbst (3). Preparation of Alkyl 5-Amtnotetrazole Nitrates One molar portion of the appropriate l-alkyl-5-sminotetrazole, or 5-alkylaminotetrazole, was added with cooling to 1.5 molar portions of concentrated nitric acid (sp. gr. 1 .ip.9). The mixture was warmed care­ fully to prevent overheating until all of the tetrazole had dissolved. The nitric acid salt, which separated on cooling, was filtered and washed with ethyl ether. The salt was used without recrystalliz ation. Melting points and analyses are given in Table HI. Preparation of l*»MethvI-5-nitraminotetrazole (a) Five grams of l-methyl-5-arainotetrazole nitrate were dissolved with cooling in 7,0 ml. of cold concentrated sulfuric acid. The mixture was allowed to warm to 20°C. and was poured slowly into 150 ml. of ice cold ethyl ether. The ether was removed by decantation and the sulfuric acid further extracted with one 150 ml. and two 50 ml. portions of ether. The combined ether extracts were dried over sodium sulfate and 1*1* TABLE i n A i m g-AMXKOrETRAZOLE MITRATES R-N C-HB-R* . HN03 H V R R* M.P. °c. Molecular Formula Analysis Calculated. C H N C Found H 8 ch 3 S 158-160 CJjHgNgOg lk.6 3.7 51.8 15.2 3.6 51.9 Cj^[6 H 125-7 CaHgK603 20*5 U.6 1*7.7 20.7 U.5 U7.6 8 CHa 70-72 CaHeN603 U*.8 3.7 51.8 lU.6 3.6 51.9 H CaHe 68-70 c 3h 6i«6o 3 20.5 U.6 1*7.7 20.8 U.8 1*7.2 hS evaporated to dryness at room temperature. The l«methyl-5~nitraminotetrazole i&ich remained was recrystallized by dissolving in a email volume of ethyl acetate and then adding a Tour to five Told volume oT petroleum ether, field OJk g. (9%), m.p. 129-130°C. (b) To 8 ml, of cold concentrated sulfuric acid was added 6.9 g. (0.023 mole) of l-methyl-5-*aminotetrazole nitrate. The mixture was allowed to warm slowly to 20°C. and then poured over 50 g. of ice. After 90% of the sulfuric acid had been neutralized by addition of the calculated amount of potassium hydroxide, the aqueous solution was extracted with ether in a liquid-liquid continuous extractor for three days. The ether solution was then separated, dried over sodium sulfate, and evaporated to about 100 ml. on a steam bath. The remaining ether was removed under a current of air at room temperature. The solid residue was recrystallized as described above and was identical with the l-roethyl-5-nitraminotetrazole prepared above. Held 1.9 g. (31#), m.p. 129*130°C. Analysis. Calculated for C*H4H60a* G, 16.67$ H, 2,80j N, 58.33. Found* C, 16.81j H, 2.67$ K, 58.08. Preparation of l-Ethyl-5~nitraminotetragole Five grams of l-ethyl-5-srainQtetrazGle nitrate was dissolved in 10 ml. of cold concentrated sulfuric acid in such a manner that the temperature did not rise above 10°C. The mixture was allowed to warm slowly to 20°c. and was poured into 150 ml. of ice cold ether. The sulfuric acid was further extracted with two 150 ml. and four 50 ml. b6 portions of other. The combined, extracts were evaporated to dryness at roan temperature. The crude residue was recrystallized from benzene. Held 1.15 g. (26/0, m.p. 102-103°G. Analysis. Calculated for G3HeK603* C, 22.77# H, 3.82] M, 53.13. Founds C, 23.121 H, 3.7bj 8, 52.95. Preparation of 5^etba,,lnitraminotetrazole (aJ 5*Methyl®rainotetrazole nitrate (6.5 g., 0.0b mole) was added slowly with cooling and stirring to 5.5 ml. of cold concentrated sulfuric acid. The mixture was allowed to stand in an ice bath for 10-15 minutes and then poured over 30 g. of ice. (On one occasion the product crystal­ lized from the aqueous solution] however, this could not be repeated.) The aqueous solution was extracted with two 150 ml. and three 50 ml. portions of ether. The combined ethereal extracts were dried over sodium sulfate and evaporated to dryness st room temperature. The residue, after recrystallization by dissolving in ethyl acetate and add­ ing a three fold volume of petroleum ether, gave 2.0 g. (35#) of 5-methylnitraminotetr&zole, m.p. H2-H3°G, Analysis, Calculated for C ^ 4Ne0 3s C , 16.67$ H, 2.80] H, 58.33. Found* C, 16.71] H, 2.95] 8, 58.03. (b) Forty grams of N ,N‘-dinitrodimethyloxamide (16) was treated with 160 ml. of concentrated ammonia solution (sp. gr. 0.899). The mix­ ture warmed spontaneously to about bO°C. After cooling to roam temperature, the mixture was made slightly acid to Congo red with 10# 1*7 sulfuric sold. The colorless precipitate of oxamide was removed by filtration and the filtrate extracted with three 100 ml. portions of ether * An equivalent amount of potassium hydroxide dissolved in 100 ml* of methanol was added to the ether extracts. Upon evaporation of the solution to small volume , potassium metbylnitremine separated as a colorless powder. Xield 18 g. m.p. 220°C. (16). One tenth mole (11.1* g.) of potassium methylnitramine suspended in 50 ml. of methanol was treated with 0.1 mole (10.6 g.) of cyanogen bromide in 100 ml. of ether. The solution was filtered to remove the potassium bromide and tbs filtrate evaporated to a small volume. At this point the mixture separated into two layers. The upper layvr was insoluble in.water and was assumed to be methylnitrocyanamide. Due to the possibility of decomposition, no effort was made to purify the product. Four grams of crude methylnitrocyananide were dissolved in 25 ml. of a 13% solution of hydrazoic acid in benzene and allowed to stand for two days. Next an additional 25 ml. of hydrazoic acid solution was added and the mixture refluxed for two hours. After cooling and evaporating to small volume, 100 ml. of petroleum ether was added. The mixture separated into two layers. The upper, petroleum ether, layer was removed by decantation and the lower layer dissolved in ethyl acetate. The ethyl acetate solution was diluted with a four fold volume of petroleum ether. Upon standing, a quantity of long, colorless needles, m.p. 113-llh°C., separated which were identical with the 1+8 5-iaethylnitraminotetrazole described above as shown by mixed melting point, infrared absorption spectra, and identity of the salts with 2-aninopyridlne. Preparation of 5-Sthvlnitraralnotetrazole 5~Etliylaminotetrazole nitrate (2.0 g.) was dissolved in 2.0 ml. of cold concentrated sulfuric acid. The cold mixture was then poured over 20 g, of ice. The aqueous solution was extracted with two 100 ml. portions of ether. The combined ethereal extracts were dried over sodium sulfate and evaporated to dryness in a current of air. The residue was taken up In ethyl acetate and a large volume of petroleum ether was added, 5-Sthylnitraminotetrazole separated as colorleas plates. Yield 0.7 g. {2$%) m.p. 88-89°C. Analysis. Calculated for CgHgH,^* Found* 0 , 22.72; H, 3.99; C, 22.77; H, 3.82; H, 53.13. 53.23. Reduction of 5^ethyInitraminotetraaole A sample of 5-siethylnitraminotetrazole (1.U1+ g., 0.01 mole) dis* solved in 50 ml. of absolute ethanol was reduced under hydrogen at 50 p ,3 .1, using palladium oxide catalyst (The American Platinum Works). When three molar equivalents of hydrogen had been absorbed, the re­ duction was stopped and the catalyst was removed by filtration. To the alcoholic solution was added 1.06 g. of banzaldehyde and the solu­ tion was evaporated to dryness. The product was recrystallized from l,ll-dioxane. Elemental analysis and melting point characteristics indicated that the product was ^-raethylaminotetrazola. Yield 0.5 g. U9 (.5®%) f m .p• 185-187°C . (The product resolidified on further heating and remelted at 22li~225°C.) Analysis. Calculated for C^(6N8j C, 2l*.2j H, 5.09 i N, 70.7. Foundi C, 2k.l*j H, 5.07j H, 70.1*. Preparation of Potassium Salts of Alkyl Nitrarainotetrazoles The potassium salts of the alljyl niiraminotetrazoles were prepared by dissolving the tetrazole in ether and adding metbanolic potassium hydroxide until precipitation was complete. The salt was removed by filtration and recrystallized from ethyl acetate, fields were essential­ ly quantitative. The potassium salts decompose explosively at, or near, their melting points which are as follows i l-methyl-5-nitraminotetraaole, 170-171°C.| l-ethyl-5-nitraminotetrazole, 205-206°C.j 5-methylnitraminotetrazole, 191-192°C,j 5-ethylnitrsminotetrazole, 17i4-175°C. Due to the explosive character of these salts, it has not been possible to obtain reliable nitrogen analyses. However, ultraviolet absorption spectra of the salts in water were identical with those of the respective tetrazoles In water or in an equivalent a&ount of dilute aqueous potassium hydroxide solution. Preparation of 2-Aminopyridine Salts of Alkyl Nitraminotetrazoles Salts with 2-aminopyridine were prepared by treating an ethereal solution of the appropriate tetrazole with an equivalent amount of 2-aminopyridine dissolved in ether. The products were recrystallized from 1*1 isopropyl alcohol-ethyl alcohol. The yields were quantitative. Melting points and analyses are listed in T able IF. $0 TABLE IV SALTS OF ALKIL 5-HITRAMINOTETRAZOLES WITH 2-AMINOPIRIDINE Tetrazole Analysis Calculated Found C H H C I' M.P. °C. Molecular Formula l-Hethyl-5nitramino- 177-8 MwKeOa 35.3 1*.2 h i .0 35.5 hJh J*6.8 l-Ethyl-5nitramino- 131-2 CaHia^e°a 38.1 h ,8 UU.I4 38.2 h . l h h.2 5~Methyl« nitramino- 165-7 C 35.3 h ,2 h i .0 35.1 h .2 hhl 5-Ethylnltramino- 139-kO CeHxaNftOa ^ 60 9 38.1 M N 38.5 5.1 Uul 51 Potentlometric Titrations Samples of l-methyl~5-nitrsnino~, l*»ethy1-5-nitramino-, 5-methylnitramino-, and 5-ethylnitraiaInotetrazole ware titrated potentiometrically using a Beckman Model G pH Meter. All titrations were carried out at 25°C.*0.02°C« The initial concentration was about 0,01 molar. The data obtained are given in Appendix n. Typical titration curve are shown in Figures 5-6. The results are summarized in Table II. Ultraviolet Absorption Spectra The ultraviolet absorption spectra of l-alkyl-5-nitrsminotetrazoles, 5-alkylnitraminotetrazoles, and their potassium salts, and the dipotassium salt of 5-nitraminotetrazole were determined using a Beckman Model D-U Spectrophotometer. The results are given in Appendix I and are represented graphically in Figures 7-11. A summary of the location of absorption maxima and minima is given in Table V, Infrared Absorption Spectra The infrared absorption spectra of the following compounds were determined using a Perkin-Elroer Recording Infrared Spectrophotometer Model 211 5-nitraminotetrazole (Figure 12), l-methyl-5-nitraminotatrazole (Figure 13), 1-ethyl-5-nitraminotetrazole (Figure lU), 5-methylnitraminotetrazole (Figure 15), and 5-ethylnitraminotetrazole (Figure 16). For comparative purposes the infrared absorption spectra are shown together in Figure 17. 52 TABLE V WAVE LENGTHS OP MAXIMUM AND MINIMUM ULTRAVIOLET ABSORPTION OP ALKXL ^•NITRAMINOTETRAZQLES AND THEIR POTASSIUM SALTS Compound Ultraviolet Absorption tfajdLmum " Minimum 5>~Nitr«minotetrazole 2T7 237 1-Methyl-^-nitraminotatrazole 277 237 l~Etliyl~f>-nItrarninotetrazole 277 237 S^ethylnitraminotetrazole 2L6 — S-Et^ladtraminoteirazole 2ii6 ****** Potassium £-»Nitraminotetrazole 277 237 (5) Potassium l*Methyl» 5-uitr«minotetrazole 277 237 Potassium 1-EtHyl5-nitraminotetrazole 277 237 Potassium 5-Methylnitraminotetrazole 2L6 Potassium 5-Et^lnitramino-tetrazole 2h6 Dipotassium 5-Nitraminotetrazole 270 230 S3 SUMMABX It has been shown that 5-nltrsniinotetrazole may be prepared by nitration of 5-arainotstrezole. The apparent dissociation constants and the ultraviolet absorption spectra of 5-nitraminotetrazole, so prepared, were determined and found to be identical 'with the corresponding properties of the nitraminotetrazole prepared by cyclization nitroguanyl azide. Salts with four organic bases were prepared from 5-nitraminotetrazole synthesized by both procedures and were found to be identical. Two 1-alky1~5-nitraminotetrazoles and two 5-alkyl-nitraminotetrazoles were prepared by nitration of the appropriate alkyl 5~aniinotetra­ zoles and their apparent dissociation constants were determined. The compounds in both series were found to be moderately strong acids. The structure of 5-methylnitraminotetrazole was supported by in­ dependent synthesis and comparison of physical properties, inoluding absorption spectra. The ultraviolet absorption spectra of the alkyl-5-nitraminotetrazoles were determined. The l-alkyl-5-nitraminotetrazoles were found to have maximum and minimum absorption at 277-78 mp and 237 rap, re­ spectively. Since 5-nitraminotetrazole has the same maximum and minimum, It was concluded that the first dissociation of 5-nitrsroinotetrazole involved the hydrogen of the nitramino group. The 5-alkylnitraminotetrazoles exhibited a maximum absorption at 2h6 mji. The alkyl 5-nitraminotetrazoles ware further characterized by their infrared absorption spectra and by their salts with 2-aminopyridine, $h LITERATURE CITED 1. Lieber, Sherman, Henry, and Cohen, J. Am. Chem. Soc., 73, 2327 (1951). 2. Mihina and Herbst, J. Org. Chan., 15, 1082 (1950). 3. Oarbrecht and Herbst, J, Org. Chem., 18, 1022 L. Lieber, Patinkin, and Tao, J. Am. (1953). Chem. Soc., J l , 1792 (195l). 5. Lieber, Sherman, and Patinkin, J. Am. Chem. Soc., 2329 (1951). 6. Garbrecht and Herbst, J. Org. Chem., 18, 101L (1953). 7. Thiele, Ann., 270, 1 (1892). 8. Thiele and Ingle, Ann., 2§2, 233 (1895). 9. StollS, Ber., 62, 1118 (1929). 10. Thiele and Marais, Ann., 273. lUi (1893). 11. Thiele, Ann., ^0^, 57 (1898). 12. Lieber, Herrick, and Sherman, J. Am. Chem. Soc., 7 h , 268L (1952). 13. Herbst, Garbrecht, and Garrison, Unpublished Results. Hi. Baur, Z. physik. Chem., 2£, 1*09 (1897). 15. Herbst and Garbrecht, J. Org. Chem., 18, 1283 (1953). 16. Unbgrove and Franchimont, Rec. trav. chim., 15, 195 (1895). APPENDIX I ULTRAVIOLET ABSORPTION DATA 55 ULTRAVIOLET ABSORPTION SPECTRUM 5*WITRAMINOTETRAZOLE (ANHYDROUS) PRSPARED PROM ^-AMINOTETRAZOLS (0,0130 g,/l, in water) /Vin ra^i 226 22k 228 232 23i* 236 237 238 235 21*0 21*1* 2l*8 252 256 260 261* 268 Optical Density .1*35 .333 .235 .165 .11*3 .133 ,132 .131* .138 .11*5 .198 .291* .1*32 .591* .768 .950 1,10 € x 10~4 .1*31* .332 .233 .163 .11*3 .132 .131 .133 .138 .11*1* .197 .293 .1*39 .593 .777 .51*6 1.095 /\in rap Optical Density 272 271* 1.21 1.26 276 282 1.28 1.29 1.29 1.27 1.21* 281* 268 1.20 1.12 277 278 280 292 296 300 3P5 310 320 330 31*0 .997 .855 .719 .553 .389 .11*1* £ x 1O*4 1.215 1.21*5 1.275 1.285 1.285 1.255 1.21*5 1.205 1.115 .996 .856 .717 .550 .388 .11*3 .036 .036 .006 .007 56 ULTRAVIOLET ABSORPTION SPECTRUM 5-NITRAMINOTETRAZOLE (A M m O U S ) PREPARED FROM MITRO-N *-AMINOQUANIDINE (0.0098 g./'l. in water) f \ i n rnp Optical Density 220 226 230 23U 236 .31*5 .221* .156 .111* .101* 23? .102 238 2i*0 2itU 2l*8 .103 .111 .150 .223 252 256 .326 .151 £ x 10~4 .1*51 276 .296 277 .206 .11*9 .139 .135 278 .136 .11*6 .198 .295 .1*31 .596 .778 .955 260 261* 266 .782 1.037 270 272 27U 275 .885 .922 .950 .962 1.176 1.222 1.262 1.282 .588 .722 )\in nji Optical Density .970 .975 .975 .970 279 280 .962 282 286 290 .950 .880 .791* 291* .700 300 .5U8 .1*19 .298 .261* .111 .058 .028 .007 305 310 315 320 325 330 3hO Cx IQ*4 1.288 1.292 1.292 1.288 1.282 1.262 1.169 1.051* .925 .731* .555 .391* .250 .11*7 .075 .037 .008 57 ULTRAVIOLET ABSORFTIOH SPECTRUM 5-NITRAMINOTETRAZOLE (SOLVATED) PREPARED FROM 5-AMINOTETRAZOLE (o,Ollo g,/L, In water) /\in mp 220 226 230 23k 238 239 2i*0 2l*2 2l*6 250 253 255 257 259 260 263 265 267 270 272 Optical Density *181* .119 .O83 ,062 .059 .062 .066 .077 .118 ,181* .21*1* ,288 .336 .383 ,1*08 .1*75 .520 .561 .612 .637 £ x 10-* .308 .197 .139 ,101* .097 .105 ,110 ,129 .197 .308 .1*07 .1*80 ,561 .61*3 .679 .795 .870 ,91*0 1.021* 1.067 /\in mji Optical Density £ x 10“4 271* 276 277 278 279 280 282 286 290 291* 298 305 320 .653 .667 .670 *670 .667 .665 .653 .612 .553 .1*98 .1*20 .289 .075 1.096 1,118 1.121 1,121 1.118 1.113 1,091 1.021* .927 .812 .696 .1*82 .101 58 ULTRAVIOLET ABSORPTION SPECTRUM 1^4ETHIL-5-N3TRAMIHOTETRAZOLE (0.01035 g,/l. in water) Ain mji 820 224 228 232 236 240 242 248 250 254 258 262 266 270 272 274 Optical Density .396 .324 €x 10** ,680 5.51 4.51 3.63 3.16 2.99 3A7 3.59 4.23 4.61 5.49 6.43 7.42 8.40 9.16 9.47 .694 9.66 .261 .227 .215 .228 .258 .304 *331 .394 .462 .533 .603 .658 A in oji Optical Density .700 .700 6 x 10~s 279 280 .700 282 .683 9.75 9.75 9.77 9.77 9.75 9,69 9.51 275 276 277 278 .702 .702 .696 284 .665 9.26 288 .612 292 296 .541 300 .386 8.52 7.53 6.43 5.38 305 .302 4.21 310 320 .229 .108 3.19 1.50 .462 59 ULTRAVIOLET /iBSGRPTIGN SPECTRUM l-ETHYL-5-NITRAMINOTETRiiZOLE (0.011*60 g./l. in water) )lin up 220 22l* 228 232 23l* 235 236 237 238 21*0 210* 21*8 252 2^6 260 Optical Density ,1*21 ,356 .311* .259 ,253 .251 ,21*8 .251 .252 ,26b .308 ,361 .1*1*1 .528 .625 £ x 10”3 1**56 3.85 3,39 2.80 2.71* 2.72 2,68 2.72 2.73 2.86 3.29 3.91 li.77 5.71 6.76 ^\in up 261* 268 27U 275 276 277 278 279 280 281* 268 295 300 310 320 Optical Density .718 .802 .898 .900 .910 .915 .910 .908 .905 .868 .802 .633 .508 .298 .139 *3 £ x 10 7.77 8.68 9.72 9.71* 9.85 9.90 9.85 9.83 9.79 9.39 8.68 6.85 5.50 3.23 1.50 60 ULTRAVIOLET AB3QRPTI0H SPECTRUM 5-METHYLNlTRAI'lINCTErRAZOLE (0*01630 g . / l . in vater) h i n mj2 220 22l* 226 232 236 21*0 21*2 21*1* 2i*3 21*6 21*7 21*8 230 231* Optical Density .338 .332 .378 .1*23 .1*72 .311 .323 .330 .332 .332 .329 .323 .311* .1*78 €x •>■3 10 in mji Optical Density e x io 2.99 3.11 3.31* 3.76 1*.17 1*.32 i*.62 i*.69 238 .1*32 3.82 262 266 .382 1*.70 1**70 1*.68 i*.6i* 292 303 .332 .281* .21*3 .213 .163 «lli2 .118 .096 .073 .031* 3.38 2.91* 2.31 2.17 1**31* 1*.23 310 320 *038 .016 270 271* 278 281* 288 296 300 1.88 1.1*1* 1.26 l.Oi* 0.83 0.67 0 .1*8 0.31* 0 .11* 61 ULTRAVIOLET ABSORPTION SPECTRUM ^-STHXLNITRAMINOTETRAZOLE (0,01838 g./L. In water) ^ i n rap. 220 224 226 232 236 238 242 243 244 245 246 247 248 250 Optical Density .324 .344 .403 .472 .548 .572 .617 .621 .625 ,628 .632 .628 .618 .604 € i 10-3 ^yin raji 2.5U 254 258 2.70 3.16 3.70 4.30 4.48 4.84 4.8? 4.90 4.92 4.95 4.92 4.85 4.73 Optical Density 272 .553 .486 .413 .346 .283 .253 276 .211 280 286 290 295 .174 .131 .105 262 266 270 300 310 320 .078 .056 .023 .007 6 x 10*3 4.34 3.81 3.24 2.71 2.22 1.98 1.65 1.36 1.03 0.82 0.61 0.44 0.18 0,05 62 ULTRAVIOLET ABSORPTION SPECTRUM POTASSIUM l-METHIL-5^irilAMIIfarETRAZOLE (0*01732 g./l, in water) h in rap 220 22JU 226 232 23b 23$ 236 237 238 2i*0 2kk 2l*8 2$2 2$6 260 26k Optical Density .1*98 .386 .300 .21*6 .236 .232 .230 .232 .231* .21*1 .276 .329 .393 .1*68 .51*6 .622 €% io~3 5.21* i*,06 3.16 2.56 2.1*8 2.1*1* 2.1*2 2.1*1* 2.1*6 2.51* 2.90 3.1*6 1*.13 1*.92 5.71* 6.51* ^in mp 268 272 275 276 277 278 279 280 281* 288 292 296 300 305 310 320 Optical Density .688 .71*2 .765 .768 .770 .768 .768 .765 .728 .670 .592 .508 .1*21* .330 .21*9 .118 <5 x 10"* 7.21* 7.81 8.05 8*08 8.10 8.08 8.08 8.05 7.66 7.05 6.23 5.31* U 3.U7 2.62 1.2lt 63 ULTRAVIOLET ABSORPTION SPECTRUM POTASSIUM l-ETm ^*H2TRAMIHCTEm ZOLE (0.02189 g.A. Xin rapt 220 22k 228 232 23k 235 236 23? 238 2kO 2hk 2U8 252 256 260 26U water) Optical Density 6 x lo-8 ^in niji sn M2 5.31 k.ik •362 •301 .287 ,28k .280 .28^ .28k .292 .329 .388 ,k6o .5k5 3.25 2,70 268 272 275 276 277 2?8 279 280 28k 288 292 296 .632 .722 2.57 2.55 2.51 2.55 2.55 2.62 2.95 3*k8 k.12 k.89 5.67 6.k7 300 305 310 320 Optical Density .798 .858 .881 .883 .885 .885 .882 .880 .8kl .778 .688 .592 .k92 .386 .290 .136 f x 10"* 7.15 7.69 7.90 7.91 7.93 7.93 7.91 7.89 7.5k 6.97 6.17 5.31 k.kl 3.k6 2.60 1.22 61* TORAVIOLET ABSORPTION SPECTRUM POTASSIUM 54IETHILMITRAMIN0TM*RAZ0LE (0.01708 g.A. in water) in tji 220 22k 228 232 236 2l*0 2i*2 2l|it 21*5 21*6 21*7 21*8 Optical Density ,21*1* •273 .325 .386 .1*30 .1*?6 .1*85 .1*93 .1*95 .1$6 .1*95 .1*91 S x 10*® ^in rap 2.60 2.91 250 252* 260 265 270 275 280 290 3 .h i It.12 1*.6? 5.08 5.17 5.26 5.28 5.29 5.28 5.22* 300 310 320 Optical Density .2*82 .1*52 .385 .325 .267 .222 .181* .121* .071* .037 .018 € x 10' 5.11* 1*.82 U.11 3.1*7 2.85 2.37 1.96 1.32 0.79 0.1*0 0,19 65 ultraviolet absorption spectrum potassium 5-STEXLNITRAMINarETRAZOLE (0.02069 g.A* ^ ^ in mp 220 221* 228 232 236 2i*0 2l*2 2bh 21*5 2i*6 2h7 2i*8 Optical Density .251 .292 .353 .1*23 .1*81* .52? .538 .51*2 .51*2 .51*2 .538 .532 6 x io*a 2.36 2Jh 3.31 3.9? 1*.55 1*,95 5.06 5.09 5.09 5.09 5.06 5.oo water) in mp. 250 251* 260 265 270 275 280 290 300 310 320 Optical Density 6x10-* .520 .1*75 .386 .311 .21*1* .192 .151 .097 .051* .026 .012 lt.89 U-U6 3.63 2,92 2.30 1,80 1.1*2 0,91 0.51 0.2l* 0.11 66 ULTRAVIOLET ABSORPTION SPECTRUM I-METHIL-S-NTI'RAMINOTETRAZOLE (0.00645 g.A. with an equivalent of 0,001 N &0H.) 230 234 235 236 237 2kO 250 260 270 .240 .156 .147 .146 .146 .148 .158 .223 .323 .419 6 x io*a 5.36 3.49 3.28 3.26 3.26 3.31 3.53 4.98 7.21 9.36 s- 220 Optical Density £ ^in mjk 275 276 277 278 279 280 Optical Density .440 .442 .444 .444 .442 290 .367 300 .250 .150 .077 310 320 £ x 10 9.83 9.88 9.92 9.82 9.88 9.83 8.20 5.59 3.35 1.72 67 ULTRAVIOLET ABSORPTION SPECTRUM l*ETm-5-NITRAMNOTET&AZOLE (0.00733 g.A. with an equivalent of 0,001 N KOH in water) ^ in rap 220 230 23li 235 236 237 21*0 2#0 260 270 Optical Density .226 .11*9 .11*2 .no. .iia M .155 ,221 .323 .1*21 ^xio-3 /^in rap i*.88 3.21 3.06 3.01* 3.01* 3.11 3,31* 1*.77 6.97 9.08 275 276 277 278 279 280 290 300 310 320 Optical Density e x io"a .1*1*6 .1*50 .1*51 .1*51 .1*1*9 .1*1*7 .370 .252 .11*8 .072 9.62 9.71 9.73 9.73 9.69 9.61* 7.98 5.1*1* 3.19 1.55 68 0LTRA7I0LKC ABSORPTION SP3CTRUM 5^^HIIKITRAMIN0TETRA20LE (0.00597 g.A. with an equivalent of 0,001 N KOH in water) Optical Density 6 x 10~® ^in inp Optical Density 6 x 10’* 220 .132 3*19 250 .218 5.26 230 .163 3.93 260 .169 bM 2I4.G .216 5.21 270 .118 2.85 .227 5*W 290 &09 in Bp l.llO 2U6 >227 5.U8 310 .023 0.56 zkj M l 320 .015 0.36 69 d/TEAVIOLET ABSORPTION SPECTEDK ^*STHILNITRAMINOTETRAZOLE (0.00710 g./l. with an equivalent of 0.001 H KOH in water) ^ in asp Optical Density 6x10-* ^ in TSfx Optical Density ^ x 10“3 220 .121* 2.76 250 .230 5.12 2J0 .16b 3M 260 .168 3.7b 240 .229 5.10 270 .10b 2.32 2b5 Jko 5.3b 290 .038 0.87 2h6 .2bi 5.37 310 .010 0.22 2h7 .m 5.37 320 .oob 0.09 70 ULTRAVIOLET ABSQRPTIGH SPECTRUM 5-4TITRAMIN0TETRAZ0LE (0,0205 g. A . in 0,1 H KOH) } \ in mp 220 ' 22k 228 229 230 232 233 2& 238 2U2 2k6 250 25ii 258 262 Optical Density £ x 10 Jyin .598 .1*77 .1*22 ,1*20 .1*16 ,ia8 ,1*20 .1*35 .1*8? .563 .61*2 .725 .790 .81*0 .890 3.79 3.03 2.68 2.66 2,61* 2.65 2,66 2,76 3.09 3.57 M7 k.60 5.01 5.33 5.6U 266 268 270 271 272 273 21h 278 282 286 290 29U 300 310 320 Optical Density .938 .950 .955 .960 .960 .960 .955 .930 ,875 .800 .723 .637 .508 .301* .138 £ x 10~3 5.95 6.02 6.05 6.09 6.09 6.09 6.05 5.90 5.55 5.07 1*.58 li.ol* 3.22 1.93 0.88 AFPEHDIX II P0T2KTICMETRIC TITEATION DATA 71 POTENTIOMETRIG DURATION 5-NIKiAMINOTEXRAZOLE (ANHXDROUS) PREPARED PROM 5-AMXNCTETRAZOLE Sample 'weight* 0.2075 g. in 200 ml. water Potassium Hydroxide t 0.10li3 N. pH Base Added Ml, pH Base Added Ml, 2.23 2.32 2.li6 0.00 2,20 5.1*8 6.15 6.80 7.30 8.02 8.50 9.30 9.97 5.70 5.82 5.92 6.02 6.0? 6.15 6.23 6,29 6.37 6.U3 6.63 6.91 7.16 7.31 7.55 8.15 8.35 9.00 9.35 9.72 10.06 10,25 10.53 10.73 10.86 19.27 20.20 21.10 22.00 2 .k 9 2.52 2.56 2.61 2.63 2 JO 2.76 2M 1 1 .k2 3.09 3.29 3JU3 3.53 3.75 3.8? U.G7 lt.22 it.JU7 ii.59 It.82 12.55 13,1*2 13.88 li.12 Hi,50 Hi .6? Hi ,82 H*.98 15.18 15.37 15.68 16.00 17.00 18.02 h .9 9 5.29 5.51 22.60 23.18 23.87 2lt.30 2M5 25.32 26.63 28.00 28.72 29.00 29.32 29.68 29.72 29.88 29.98 30.10 30.30 30.50 30.95 31.50 32.05 72 r a s m c w m i c TITRATION 5-NlTRAMINOrstraz ole (anhydrous ) PREPARED FROM N-HITRO-N»-AMIHOGU/JODIHE Sample weight* 0.2167 g. in 200 ml. of water Potassium Hydroadde* pi 2.22 2.33 2J8 2.1*5 2.1*8 2.50 2.5X 2.55 2.59 2.63 2.68 2.75 2.85 2,93 3.09 3.16 3.29 3.1*3 3.51 3.63 3.71 3.82 3.90 i*.02 li.12 i*.28 1*.37 li.51 1*.66 U.78 1*.99 5.12 5.22 5.33 0 ,10i*3 N Base Added Ml. 0.00 1.08 2.00 6,05 6.50 6.92 7.1*3 7.99 8.50 9,10 9.6? 10.00 11.10 12.50 13.08 13.50 11**06 lit.61 11*.80 15.02 15,15 15.30 15.35 15.1*8 15.58 15.70 15.80 15.95 16.18 16.32 16.87 17.28 17.00 18.12 pH Base Added Ml* 5.1*8 5.61 5.71* 5.85 5.90 5.91* 19.00 19.97 21.00 22.00 22.52 23.00 23.70 21*.10 2i*,50 21*.98 25.52 26.00 27.10 29.00 29.60 30.61* 30.98 31.12 31.30 31.1*8 31.50 31.60 31.70 31.78 31.95 32.10 32.30 32.90 33.78 31*.98 36.22 6.02 6,06 6.10 6.13 6.21 6.27 6.1*1 6.72 7.02 7.22 7.1*3 7,59 7.88 7.99 8.55 9.05 9.39 9.62 9.92 10.08 10.27 10.56 10.80 10.98 11.12 73 POTENTIQMETRIC TITRATION 5*HITRAMINOTlTRAZOLE (SOLVATED) PREPARED PROM 5-AMXNGTEIRAZOLE Sample x-?©ightt 0.2610 g. in 200 ml. of water Potassium Hydroxide* 0,101*3 N pH 2.1*2 2.1*8 2.69 2.72 2.76 2,a 2.82 3.23 3.51 3.71 l*,ll* 1*.53 1**83 5.08 5.1*3 5.85 5.90 Base Added HI. pH 0.00 5.95 1.76 5.93 6.1*3 7.08 7.68 8.06 11,18 12.18 12.58 13.13 13-113 13.78 lit.16 15.16 17.18 17.66 6.00 6,08 6.15 6.20 6,i*o 6.72 6,98 7*22 7.65 8,12 8,86 9.82 10.22 10.52 10,73 Base Added HI. 17.98 18.1*8 19.00 19.58 19.93 21.1*8 23.53 21*.68 25.1*3 26.08 26.38 26.50 26.73 26.98 27.33 27.78 PCTEMTIOMETRIC TITRATION ^-SITRAMIIiOTETEAZONE (SOLVATED) PREPARED FROM N-NITRQ-N1W JIINOGUjkNIDIN3 Sample weight* 0,2106 g, in 200 ml, of water Potassium Hydroxide* 0 .1014-3 M pH 2.52 2,65 2.72 2.76 2,79 2.85 2.95 3.27 3.1*2 3.90 k .l9 1*,5S U.78 k .9 $ 5.21 Base Added Ml. 0.00 2.37 3.93 L.U5 ii.97 5.97 6,71 8.77 9.37 10,27 10,55 10,83 11,00 11.20 11.6,5 pH 5.70 6.02 6.08 6.12 6,22 6.56 7,06 7.31 7.95 9.77 10.27 10.53 Base Added Ml. 13.05 11*,73 15,13 15,1*5 15.95 17.97 19.70 20.35 21,05 21.1*5 21.72 21.95 75 POTE8TICMETRIC TITRATION l-^ETHYL-5**NITRAMIN0TErRA20LE Sanple weight* 0.1012 g. in 100 ml, of water Potassium Hydroxidet 0.0830 M Ml. Base Added 0.00 1.00 2.00 3.00 3.50 3.60 3.72 3.80 3.90 I+.OQ It.10 1+.20 1+.30 k.ko k.$Q It,60 pH Ml. Base Added pH 2,38 2.1+3 2.51 2,58 2.62 2.63 2.61+ 2.6? 2.67 2,68 2.70 2.71 2.72 2.73 2.75 2.76 It*70 It.80 1+.90 5.00 6.00 7.00 8.00 8.25 8.29 8.33 8,37 8 *1+2 8.1+5 8.1+9 8.53 8.75 2.78 2.78 2.80 2,81 2.98 3.22 3.91+ It.82 5.1+3 5.93 6.35 6.78 7.33 8.58 9.18 10.08 76 POTENTICMETEIC TITRATION 1-ETHXL-5-HITRAMIN0TETRA20LE Sample weight* 0.1166 g. In 100 ml, of water Potaasl'un Hydroxide* 0,0830 N Ml. Base Added 0.00 1,00 2.00 3,00 3.50 3,60 3.70 3,80 3.90 Loo k .10 It,30 iUO it,50 It,60 it.70 it.80 ii.90 PH 2.39 2.1*5 2,52 2.60 2.63 2.65 2,66 2.67 2.68 2.70 2.71 2,73 2,73 2.75 2.75 2,76 2,78 2,79 Ml. Base Added 5.00 5.50 6.00 7,00 8.00 8.15 8.30 8Jt2 8.55 8.62 8.67 8.72 8,76 8.80 8.83 8.88 8.92 9.00 pH 2.79 2.88 2.95 3.16 3.56 3*66 3.79 3.96 U.20 it.52 lt.83 5.$2 6,13 6.79 7.28 9.13 9.U5 9.88 77 POTENTICHETRIC TITRATION 5*^™«LNITRAMINC3TETRAZOLE Sstaple weight* 0.0970 g. in 100 ml. of water Potassium Hydroxides 0.0830 N HI, Base Added 0,00 1,00 2,00 3.00 3.50 3.60 3.70 3.80 3.90 l.oo 1.10 1.20 1.30 l.l0 1.50 3.00 pH 2 JO 2.57 2.6? 2.76 2.82 2.83 2,81 2.85 2.86 2.87 2.89 2.90 2.92 2.91 2,96 3.03 Ml, Base Added 6.00 6.50 7.00 7.50 7.75 7.81 7,92 7.95 8.00 8.03 8.07 8,11 8.15 8.19 8.31 pH 3.23 3.39 3,61 3.99 1.16 1,82 5.2 5.88 6.18 6.15 6.78 7,16 8.27 9.05 9.85 78 POTENTICKETRIC TITRATION 5-STHItN3TRAMINOTETRAZOLE Sample •weight* 0,0990 g. in 100 nil, of water Potassium Hydroxide: 0,0830 N HI. Base Added 0,00 1.00 2.00 3.00 3.30 3.40 3.50 3.60 3.70 3.80 3.90 4.00 4.10 4.20 4.30 pH 2.49 2.57 2.67 2.77 2,81 2.82 2.83 2.83 2.85 2.86 2.88 2.89 2.91 2.93 2.94 HI. Base Added 4.50 5.00 6.01 6.75 7.00 7.25 7.29 7.33 7.37 7.43 7.46 7.50 7.53 7.57 8.00 pH 2.98 3.08 3.33 3.75 4.o4 5.12 5.63 6.03 6.32 6.78 7.25 8.72 9.20 9.53 10.40 rag s m m a x a m n op % 4mm A. Gsrrlfton m m m um Stfottltted to tfeo S M of Grsduoto Stadio# of Ktehlgon ttoto Collage of Agriculture a»liietetrasol*. It woo found that 5*oltra*sinot8tr«oX« prepared by both procedures wart identical in all respects. Tetr*#ole derivatives la which the hydrogen attached to the ring nitrogens has not been replaced generally behave as aoidic substance* (2,3). ^Hitrawlnetetrasole (HI) is m exception sal, In foot, H-U--- C-Hi-itO* i i ■ v * in behaves as a dibasic sold doa to the presence of a second dissociable i^rdrogen in the nitraraino group. Xt had boon suggested without sufficient supporting evidence that the hydrogen of the nitrasino group v w most easily dissociated as a proton (it). In order to establish which of the two hydrogens of ^nltrasinotetrasole was most easily dissociated, the preparation of nitraninotatrstolas in which one or the other hydrogen was replaced by a simple alkyl group was undertaken, Sima l-elkyl-^-aniaotetroaoles (5) and S-elkyleniiiotetresolaa (3) could be propared by unequivocal syntheses, the nitration of compounds of these typos by dehydration of their nitric acid salts was studied, the structures of the resulting coapeujsde were supported by independent synthesis and by comparison of their physical properties including absorption spectra. -2 Janes Garrison The apparent dissociation constants of l-alkyl-5-nitr«»ii»tetrasolss and the S-elkylnitraoinotetrasolea were determined. It was found that both aeries of compound* were moderately strong aside and that althar hydrogen could have bean respoDBlble for the first dissooiAtion of S-nitrsainQtetrasole. The ultraviolet absorption spsotr* of both series of alkyl ^-nitresinotatrasolee ware determined. It was found that both the l-alkyl-£<&trcwlnotetresoles end their potassium salts exhibited a isexlmun absorption at 277*275 ap, end e minimum Absorption at 236-7 ®p. ^-Hitrneinotetrasole was found to possess mudiiram and minimus absorptioa at the sens wave lengths. On the other hand, 5-alkyInitraminotstrasolA* and their potassium salts exhibited maximum absorption at 2k6aji. frm this it was concluded thet the first diaeocletion of ^-nitrA»inotetr«Bolo involved the hydrogen of the nitramino @r*oup. The alkyl S-nitrfiiainotetrttoles were characterised by their infrared absorption speetrs end by preparation of salts with 2-salnopyridiae. Jm