SYNTHESIS OF 3H-1,3,4-BENZOTRIAZEPINES FROM 5-ARYLTETRAZOLES AND N-ARYLBENZIMIDOYL CHLORIDES

Heating of 5-phenyltetrazole with N-phenylbenzimidoyl chloride in the absence of solvent or in toluene, dioxane, benzonitrile, pyridine or N ,N-dimethylformamide results in the formation of 3,4,5-triphenyl-1,2,4 -triazole 1. Thermolysis of 1-imidoyl- and 2-imidoyl-5-phenyltetrazole s (obtained from the same reagents under phase-transfer conditions) in dioxane, toluene and benzonitrile leads to 2,5-diphenyl-3H-1,3,4-benz otriazepine 2. In pyridine and N,N-dimethylformamide a mixture of tria zole 1 and triazepine 2 in the ratio approximately 1:1.5 is obtained u nder the same conditions. Heating of imidoyltetrazoles, obtained from 5-aryltetrazoles and N-arylbenzimidoyl chlorides, in m-xylene results in formation of the corresponding 3H-1,3,4-benzotriazepines.