Synthesis and biological activity of fluoro-substituted pyrrolo[2,3-d]pyrimidines: The development of potential positron emission tomography imaging agents for the corticotropin-releasing hormone type 1 receptor

A series of fluoro-substituted 4-(dialkylamino)pyrrolo[2,3-d]pyrimidines was synthesized and their binding affinity for corticotropin-releasing hormone type 1 receptor (CRHR1) was investigated. Compounds 11a and 11b possessed very high CRHR1 affinity (Ki=3.5, 0.91 nM, respectively). They are promising candidates for the development of 18F-containing nonpeptide PET radioligands for CRHR1.