4.5- Diphenyl-1.2.3-triazole. amination

Diphenyl- -triazole is aminated by reaction with hydroxylamine-0-sulfonic acid. The I - and 2-aminotriazoles are formed in approximately equal amounts. Intramolecular amination of 1- and 2-aryltriazoles is achieved by generating a nitrene intermediate in the ortho position of the aryl substituent for example, in the thermolysis (Scheme 42) of the azide (17). ... 

Under similar conditions, 5-phenyltetrazole is converted to a complex mixture containing amine 164 (42%), 3,5-diphenyl triazole, and different phenyl-substituted triazines and tetrazines (62LA146). Electrophilic amination of 1,2,4-triazole by HOSA [80JCR(M)514] or by DNPH (89S269) leads to l-amino- and 4-aminotriazole with the great dominance of the first. This is the only method to synthesize unsubstituted 1-amino-s-triazole. It is known as the nitrene amination of 1,2,4-triazoles [Eq. (46)] [74AHC (17)213]. 

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. 

Halogeno-l-methyl-l,2,3-triazoles undergo substitution reactions with amines, but the 4-halogeno analogs do not. 5-Chloro-l,4-diphenyl-l,2,3-triazole with sodium cyanide in DMSO gives the cyano derivative (63JCS2032). 1-Substituted 3-chloro- and 5-chloro-l,2,4-triazoles both react with amines. 

Oxidation of heterocyclic amino derivatives yields various reaction products depending on the structure of the amine. 4-Benzylamino-3-methyl-4//-1,2,4-triazole is oxidized with DCT in chloroform to give the azomethine derivative 110 (69ZC325). l-Amino-4,5-diphenyl-l,2,3-triazole under the action of CBT forms diphenylacetylene 2-aminobenzotriazole yields cis, cw-l,4-dicyanobuta-l,3-diene and 1-aminobenzotriazole yields a mixture of chlorobenzene and o-dichlorobenzene. Oxidation of 1-aminobenzotriazole in the presence of tetraphenylcyclopentadienone leads to 1,2,3,4-tetraphenylnaphthalene via benzyne intermediate [68JCS(CC)1305 69JCS(C)1474] (Scheme 101). 

The synthesis of meso-ionic 1,3,4-thiadiazole-imines described by Grashey et al. (see Vol. 3, p. 698) has been independently described by a Russian group of workers. The conversion of meso-ionic 4,5-diphenyl-l,3,4-thiadiazole-2-thiones into meso-ionic l,2,4-triazole-3-thiones under the influence of amines has also been further exemplified. ... 

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