Synthesis of 5,7-diarylpyrazolo[1,5- a ]pyrimidines via KOH mediated tandem reaction of 1 H -pyrazol-3-amines and chalcones

An efficient and facile protocol has been developed for the synthesis of pyrazolo[1,5-a]pyrimidines through the tandem reaction of 3-aminopyrazoles and chalcones in the presence of catalytic amounts of KOH. The reported method offers access to 5,7-diarylpyrazolo[1,5-a]pyrimidines in good to excellent yields. A gram-scale reaction has been performed to demonstrate the potency of optimized procedure for the scale-up processes.