1,2,3-Triazoles. Part 3. 4-Aminotriazole-5-carbaldehydes from 4-aminotriazoles

Abstract

4-Amino-3-methyl-(and 3-benzyl-) 1,2,3-triazoles were converted by dimethylformamide and phosphoryl chloride into 4-dimethylaminomethyleneamino-5-carbaldehydes (2b and c), which were hydrolysed by dilute acid to the corresponding 4-amino-aldehydes (1a and b). 4-Amino-1-methyl-1,2,3-triazole gave only 4-dimethylamino-methyleneamino-1-methyl-1,2,3-triazole. Dichloromethyl methyl ether with tin(IV) chloride effected only 4-N-formylation of 4-aminotriazoles, but in the presence of dimethylformamide these reagents converted 4-amino-3-benzyl-1,2,3-triazole into the 4-dimethylaminomethyleneamino-derivative. Several 4-N-acetyl derivatives of the starting materials are reported. ¹H N.m.r. spectra are discussed.