Divergent synthesis of 3-formylpyrazolo[1,5-a]pyrimidines and methylene-bridged bis(pyrazolo[1,5-a]pyrimidines) using DMSO as a single carbon synthon

Abstract

A divergent approach has been explored for synthesizing 3-formylpyrazolo[1,5-a]pyrimidines and methylene-bridged bis(pyrazolo[1,5-a]pyrimidines) using DMSO as a C1 synthon. A library of 3-formylpyrazolo[1,5-a]pyrimidines and methylene-bridged bis(pyrazolo[1,5-a]pyrimidines) has been synthesized using CuOAc and AcOH, respectively. The reaction progressed through a radical pathway. The usefulness of 3-formylpyrazolo[1,5-a]pyrimidines in synthesizing a zaleplon derivative has been demonstrated.