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 (IC50= 4.2–418nM) and antagonist activity (EC50= 4.0–889nM). Compound 5 was found to show ...