Solid-phase approach towards the synthesis of functionalized imidazo[1,2-b]pyrazol-2-ones

Published in: Journal, Volume : 45, Issue : 6, Pages : 1275-1277

DOI : 10.1016/j.tetlet.2003.11.135

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

Abstract : The solid-phase synthesis of a series of imidazo[1,2-b]pyrazol-2-ones, an interesting 5,5-fused ring system, based on diverse set of hydrazine acids and malonitriles is described. The method involves formation of 5-aminopyrazoles on solid support and subsequent cyclizative cleavage off the resin. Compounds were obtained in acceptable to excellent yields and are suitable for biol. evaluation without further purification Example compounds thus prepared included 1,8-dihydro-3-[[4-(trifluoromethoxy)phenyl]methyl]-6H-imidazo[1,2-b]thieno[3,4-d]pyrazol-2(3H)-one (I) and 6-(1,1-dimethylethyl)-3-[[4-(trifluoromethoxy)phenyl]methyl]-1H-imidazo[1,2-b]pyrazol-2(3H)-one (II).