Facile synthesis of 5-bromotropono[c]-fused pyrazoles and isoxazole

A facile synthesis of a series of new 5-bromotropono[c]pyrazole derivatives (3 and 10–15) as well as 5-bromotropono[ c ]isoxazole (17) is described, involving a condensation reaction of 3-acetyl-5-bromotropolone (1) with hydrazine monohydrate (2), arylhydrazine hydrochlorides (4–9), and hydroxylamine hydrochloride (16), respectively. All the synthesized compounds were obtained in good yields of 56%–77% and their structures were characterized by spectral data and HRMS.