Heterocyclic compounds. I. Reactions of o-amino-carboxamide with β-diketones: Synthesis of imidazo[1,5-a]pyrimidine and pyrazolo[1,5-a]pyrimidine derivatives

Treatment of 5-aminoimidazole-4-carboxamide hydrochloride (1) and 5-aminopyrazole-4-carboxamide hemisulfate (2) with β-diketones furnished 2,4-disubstituted imidazo[1,5-a]pyrimidine-8-carboxamide (7) and 5,7-disubstituted pyrazolo[1,5-a]pyrimidine-3-carboxamide (8) respectively. The ¹H nmr and ¹³C nmr spectra of these compounds and the X-ray crystallography of compound 7a are discussed.