Transformation of the condensation products of 2-acylamino-3,3-dichloroacrylonitriles with imidazole into pyrazolo[1,5-a]pyrimidine derivatives

Successive treatment of accessible 2-acylamino-3,3-dichloroacrylonitriles with imidazole and hydrazine hydrate led to the formation of 4-acylamino-3(5)-amino-5(3)-(1 H -imidazol-1-yl)pyrazoles, and condensation of the latter with acetylacetone afforded 3-acylamino-2-(1 H -imidazol-1-yl)-5,7-dimethylpyrazolo [1,5- a ]pyrimidines whose structure was reliably determined by X-ray analysis.