2-Acylamino-3-chloroacrylonitriles,Promising Reagents for Heterocyclization

2-Acylamino-3-chloroacrylonitriles prepared by treating available N-(1,2,2-trichloroethyl)amides of carboxylic acids with sodium cyanide readily undergo cyclization in the presence of excess hydrazine hydrate. The cyclization products, 5-amino-4-acylaminopyrazoles, were applied to the synthesis of new imidazo[4,5-c]pyrazole and pyrazolo[1,5-a]pyrimidine derivatives.