Reactions of α‐ketohydrazidoyl halides with some heterocyclic amines. Facile synthesis of arylazo derivatives of fused heterocycles with a bridgehead nitrogen atom

Abstract

Abstract Arylazo derivatives of imidazo[2,1‐ b ]thiazoles, imidazo[1,2‐ b ]pyrazoles, imidazo[1,2‐ b ]‐ s ‐triazoles, imidazo[1,2‐ a ]pyrimidines, and imidazo[1,2‐ a ]pyridines were obtained in good yields from α‐keto hydrazidoyl halides and 2‐aminothiazole, 5‐aminopyrazole, 5‐aminotriazole, 2‐aminopyrimidine, and 2‐aminopyridine, respectively ( cf . Tables I and II). The structures of the products were assigned and confirmed on the basis of their elemental analyses, spectra, and alternate synthesis wherever possible.