Rational synthesis of pyrazolopyrimidines via cyclocondensation of ynones obtained from the Sonogashira reaction.

Pyrazolopyrimidines combine the structural and electronic properties of both pyrazole and pyrimidine, imparting unique characteristics that make them valuable in medicinal chemistry and drug discovery. We successfully developed an atom economic protocol for the synthesis of a series of pyrazolo-fused pyrimidines by employing various ynones and 3-aminopyrazole using K2CO3 as a base in ethanol. The reactions proceeded under milder conditions, furnishing the desired products in moderate to excellent yields.