Synthesis of 3-phenylpyrazolo[4,3-b]pyridines via a convenient synthesis of 4-amino-3-arylpyrazoles and SAR of corticotropin-Releasing factor receptor type-1 antagonists

3-Phenylpyrazolo[4,3-b]pyridines were synthesized via a cyclization of 4-amino-3-phenylpyrazoles 11–13 with ethyl acetoacetate. These compounds were found to be potent CRF1 antagonists. The 2-alkylpyrazolo[4,3-b]pyridines were more polar but less active than the corresponding 1-alkyl-isomers.