Cyclization of 5-diazoimidazole-4-thioamide
Cyclization of 5-diazoimidazole-4-thioamide and -4-methylthioamide gives derivatives of a new heterocyclic system — imidazo[4,5-e]-2,3,4-thiadiazine — which are readily recyclized to 2-azapurines. 4-Methylthioimidazo[4,5-d]-1,2,3-triazine was synthesized, and its reactions with amines and hydrazines were studied.