Solution phase synthesis of imidazo[1,2-b]pyrazol-2-one, an interesting 5,5-fused heterocyclic ring system

Published in: Journal, Volume : 45, Issue : 3, Pages : 619-621

DOI : 10.1016/j.tetlet.2003.10.177

Author : Blass, Benjamin E.; Srivastava, Anil; Coburn, Keith R.; Faulkner, Amy L.; Janusz, John J.; Ridgeway, James M.; Seibel, William L.

Abstract : The solution phase synthesis of a series of imidazo[1,2-b]pyrazol-2-ones, e.g., I, a fused 5,5-ring system, is described. The heterocyclization of α-hydrazino acids with α-cyano ketones gave 5-aminopyrazoles, e.g., II, which underwent an intramol. cyclodehydration to give the corresponding imidazo[1,2-b]pyrazol-2-ones.