Synthesis and Structure-Activity Relationships for the Anti-Mycobacterial Activity of 3-Phenyl- N -(Pyridin-2-ylmethyl)Pyrazolo[1,5- a ]Pyrimidin-7-Amines.

Pyrazolo[1,5- a ]pyrimidines have been reported as potent inhibitors of mycobacterial ATP synthase for the treatment of Mycobacterium tuberculosis ( M.tb ). In this work, we report the design and synthesis of approximately 70 novel 3,5-diphenyl- N -(pyridin-2-ylmethyl)pyrazolo[1,5- a ]pyrimidin-7-amines and their comprehensive structure-activity relationship studies. The most effective pyrazolo[1,5- a ]pyrimidin-7-amine analogues contained a 3-(4-fluoro)phenyl group, together with a variety of 5-alkyl, 5-aryl and 5-heteroaryl substituents. A range of substituted 7-(2-pyridylmethylamine) derivatives were also active. Some of these compounds exhibited potent in vitro M.tb growth inhibition, low hERG liability and good mouse/human liver microsomal stabilities, highlighting their potential as inhibitors of M.tb .