Potent and selective pyrazolo[1,5-a]pyrimidine based inhibitors of B-RafV600E kinase with favorable physicochemical and pharmacokinetic properties

Herein we describe a novel series of ATP competitive B-Raf inhibitors based on the pyrazolo[1,5-a]pyrimidine scaffold. These inhibitors exhibit both excellent cellular potency and striking B-Raf selectivity. Optimization led to the identification of compound 17, a potent, selective and orally available agent with improved physicochemical and pharmacokinetic properties.