1.2.4- Triazole, 4-amino-3,5-diphenyl

DIPHENYL-5-AMINO-1,2,3-TRIAZOLE (lff-l,2,3-Triazole, 5-amino-l,4-diphenyl-) and... 

Fig. 4.6. Dependence of on time for 3,5-diphenyl-4-amino-triazole synthesis at 130 °C.

Amination at an azole ring nitrogen is known for Af-unsubstituted azoles. Thus 4,5-diphenyl-1,2,3-triazole with hydroxylamine-O-sulfonic acid gives approximately equal amounts of the 1- (104) and 2-amino derivatives (105) (74AHC(16)33). Pyrazole affords (106) and indazole gives comparable amounts of the 1- and 2-amino derivatives. 

Triazole, 5-amino-1,4-diphenyl-photo-Dimroth rearrangement, 5, 697... 

A. 1,4-Diphenyl-5-amino-l,2,3-triazole. A 500-ml. three-necked flask is equipped with a sealed stirrer, a thermometer well, and a dropping funnel which is protected by a drying tube and has a pressure-equalizing side arm. A mixture of 35.7 g. (0.3 mole) of phenyl azide (Note 1) and 38.6 g. (0.33 mole) of phenylacetonitrile (Note 2) is placed in the flask. The flask is immersed in an ice-water mixture contained in a 1-gal. Thermos flask. After the reaction mixture has cooled to about 2°, a solution of 24.3 g. (0.45 mole) of sodium methoxide (Note 3) in 150 ml. of absolute ethanol is added dropwise during the course of 2 hours. The reaction mixture is then stirred at 2-5° in the ice-water bath for a period of 48 hours (Note 4). After the cooling bath has been removed and the flask allowed to warm spontaneously to room temperature, the mixture is filtered by suction on a sintered glass funnel, and the col-... 

B. 4-Phenyl-5-anilino-l,2,3-triazole. Six grams (0.025 mole) of 1,4-diphenyl-5-amino-l,2,3-triazole is dissolved in 20 g. of dry pyridine (distilled from solid sodium hydroxide) and heated under reflux for 24 hours (Note 6). The reaction mixture (Note 7) is poured into 11. of ice water. The product separates as a slightly yellowish milky oil which is converted to white needle-like crystals by stirring the mixture and scratching the beaker with a glass rod. The product is collected by suction filtration, washed with water, suction-dried, and recrystallized from aqueous ethanol (Note 8). The yield is 5.5-5.6 g. (92-93%) of fine white needle-like crystals, m.p. 167-169° (Note 9), soluble in hot water and ether, but difficultly soluble in benzene. 

The reactivity and regioselectivity of the cycloaddition of l-(A-phenacylidene)amino-1,2,3-triazoles with diphenyl nitrilimine (see Section 4.01.7.4) are examined on the basis of CNDO/2 calculations. The cycloaddition regioselectivity is HOMOjdipoie) controlled. The predominant orbital interaction shown in Figure 1 rationalizes the regioselective formation of 277-1,2,3-triazoles... 

A number of 5,5-dialkyldihydro-4.ff-l,2,3-triazole-4-ones and 5-amino-4,4-diphenyl-4//-1,2,3-triazoles have been studied by N NMR spectroscopy. Their N chemical shifts (corrected to the external standard of ammonia) are listed in Figure 11 <93CB103>. The N NMR spectra of triazole and benzotriazole boron derivatives have been reported <89IC4022>. 4-(l-Azido-l-methylethyl)-lH-1,2,3-triazole shows N chemical shifts (D20/pyridine, MeN02 external standard) 3 — 284.6 (Na), - 161.5 (Ny), d - 135.8 (N/9), d-9lA,d- 79.2, and d - 60.4 ppm <89CB9l 1>. 

A similar sequence of reactions occurs with diphenyl cyanocarbonimidate (127). Sequential reaction of (127) with aniline and hydrazine gave 3-amino-5-phenylaminotriazole (Scheme 23) <82JHC1205, 87JHC275). With amino acids as the first nucleophile, more complex triazoles can be formed <93T165>. 

A number of general methods for the synthesis of meso-ionic 1,2,4-triazol-3-ones are available. Sodium ethoxide-catalyzed cyclization of 1-benzoyl-l,4-diphenylsemicarbazide (201, R = R = R = Ph, X = O) yielded anhydro-3-hydroxy-1,4,5-triphenyl-1,2,4-triazolium hydroxide (200, R = R = R = Ph). A general route to meso-ionic 1,2,4-triazol-3-ones (200) is exemplified by the formation of the 1,4,5-triphenyl derivative (200, R = R = R = Ph) from A-amino-MA -diphenylbenzamidine (202, R = R = R = Ph) and phosgene. In contrast with this ready meso-ionic compound formation, the corresponding reaction of the iV-methylbenzamidine (202, R = Me, R = R = Ph) did not yield the meso-ionic 1,2,4-triazol-3-one (200, R = Me, R = R = Ph). The product was in fact 3,4-diphenyl-2-methyl-l,2,4-triazol-5-onium chloride (203), which on heating gave 3,4-diphenyl-1,2,4-triazol-5-one (204, R = Ph). The formation of the A-methyl derivative (200, R = Me, R = R = Ph, yield 79%) by heating the 7V-thiobenzoyl semicarbazide (201, R = Me, R = R = Ph, X = S) with potassium carbonate in methyl cyanide has been reported. Another synthesis of A-methyl derivatives (200, R = Me) involves methylation of 3-methyl-4-phenyl-l,2,4-triazol-5-one (204,... 

Kohlensaure-arylamid-hydrazide cyclisieren mit Bromcyan unter analogen Versuchsbedingun-gen wie Carbonsaure-hydrazideohneIsolierung von Zwischenprodukten zu 2-Amino-5-ary 1-amino-1,3,4-oxadiazolen276. Die Reaktion laBt sich nicht auf Kohlensaure-anilid-(l-phe-nyl-hydrazid) ubertragen, da hier 3-Amino-l,4-diphenyl-5-oxo-4,5-dihydro-1,2,4-triazol ent-... 

Boiling the 1,3,5-trisubstituted verdazyls (134) for five hours in acetone afforded 1,3-disubstituted 5-amino-1,2,4-triazoles (135, 136) (78KGS1137) and tetrahydro-1,2,4,5-tetrazines (137) (64M457,72CB549) at higher temperatures, besides the triazoles (135,136), 1,3-diphenyl-1,2,4-triazole (138) and aniline were obtained (72CB549). 

Vilsmeier reaction, 4, 1051 Furo[3,2-6]pyrroles MO calculations, 6, 979 synthesis, 4, 1069 6, 1009 Furo[3,4-a]pyrrolo[2,1,5-cd]indolizine nomenclature, 1, 22 Furopyrylium salts, 4, 993-995 Furoquinolines biosynthesis, 4, 992 occurrence, 4, 988 pharmacology, 4, 992 reactions, 4, 988 synthesis, 4, 989 Furo[3,2-c]quinolines, 4, 991 Furo[3,4-fe]quinoxaline, 1,3-diphenyl-synthesis, 4, 993 Furoquinoxalines, 4, 992 Furo[2,3-6]quinoxalines synthesis, 4, 992 Furosemide toxicity, 1, 136 Furospinulosin UV spectra, 4, 587 Furospongin-I mass spectrometry, 4, 583 Furo[3,4-d][l,2,3]triazole, 2,6-dihydro-synthesis, 6, 996 Furo[3,4 -d][ 1,2,3]triazoles synthesis, 6, 996 Furoxan, 4-amino-3-aryl-tautomerism, 6, 404 Furoxan, 4-amino-3-methyl-synthesis, 4, 414 Furoxan, 4-aryl-3-methyl-rearrangement, 6, 408 Furoxan, 3-aryl-4-nitro-synthesis, 6, 414 Furoxan, 4-benzoyl-3-methyl-oxime... 

Treatment of 4-amino-l,5-diphenyl-l,2,3-triazole with phenacyl bromide is reported to give the derivative (191) (80KGS1695). 

Besides ring-chain tautomerism (Section 4.11.4.1.2(0) and the Dimroth rearrangement (Section 4.11.4.1.2(iii)) cleavage reactions of some amino-, azido and diazo-methyltriazoles have been reported. Thus, 5-azido-l,4-diphenyl-l,2,3-triazole (121) proved to be unusually labile above 50 °C. Nitrogen is evolved with the formation of a conjugated nitrile (122) (64JA2025, 70JOC2215). Similarly the diazomethyltriazole (123) decomposes to (124). Both reactions can be explained in terms of concerted processes. 

Treatment of 3-amino-5-hydrazino-l,2,4-triazole with benzil produced 2-amino-6,7-diphenyl-[l,2,4]triazolo[5,l-c][l,2,4]triazine via either direct formation involving cycliz-ation on the triazole N-1 or attack at N-4 of the triazole to yield the [3,4-c] compound which rearranged to the [5,1-c] isomer (76JCS(P1)1492). Ring closure of 3,4-diamino-1,2,4-triazines with carboxylic acids is also a route to various [l,2,4]triazolo[5,l-c][l,2,4]triazines (64CB2173). 

---