Tetsuji Saito

Pyrazolo[1,5-a]pyrimidines, triazolo[1,5-a]pyrimidines and their tricyclic derivatives as corticotropin-releasing factor 1 (CRF1) receptor antagonists

To identify structurally novel CRF1 receptor antagonists, a series of bicyclic core antagonists, pyrazolo[1,5-a]pyrimidines, triazolo[1,5-a]pyrimidines, imidazo[1,2-a]pyrimidines and pyrazolo[1,5-a][1,3,5]triazines were designed, synthesized and evaluated as CRF1 receptor antagonists. Compounds 2-27 showed binding affinity (IC(50)=4.2-418 nM) and antagonist activity (EC(50)=4.0-889 nM). Compound 5 was found to show oral efficacy in an Elevated Plus Maze test in rats. Further chemical modification of them led us to discovery of the tricyclic core antagonists pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidines. The discovery process of these compounds is presented, as is the study of the structure-activity relationship.

6,7-Dihydro-5H-cyclopenta[d]pyrazolo[1,5-a]pyrimidines and their derivatives as novel corticotropin-releasing factor 1 receptor antagonists.

To identify an orally active corticotropin-releasing factor 1 receptor antagonist, a series of 6,7-dihydro-5H-cyclopenta[d]pyrazolo[1,5-a]pyrimidines and their derivatives were designed, synthesized and evaluated. An in vitro study followed by in vivo and pharmacokinetic studies of these heterotricyclic compounds led us to the discovery of an orally active CRF1 receptor antagonist. The results of a structure-activity relationship study are presented.

Pyrrolo[1,2-b]pyridazines, pyrrolo[2,1-f]triazin-4(3H)-ones, and related compounds as novel corticotropin-releasing factor 1 (CRF1) receptor antagonists

To identify structurally novel corticotropin-releasing factor 1 (CRF(1)) receptor antagonists, a series of bicyclic core analogs pyrrolo[1,2-b]pyridazines and pyrrolo[2,1-f]triazin-4(3H)-ones, which were designed based on a monocyclic core antagonist, was synthesized and evaluated. Among the compounds tested, 2-difluoromethoxy-4-methylpyridin-5-yl analog 27 was found to show efficacy in a dose-dependent manner in an elevated plus maze test in rats. The discovery process and structure-activity relationship is presented.