Novel one pot synthesis of polysubstituted pyrazolo[1,5-a]- and imidazo[1,2-a]pyrimidines

We have described a convenient regioselective one-pot approach to pyrazolo1,5-a]- and imidazo1,2-a]pyrimidine derivatives from α,β-unsaturated imines generated in situ and amino heterocycles. Reaction is general with respect to all three components, namely (i) nitrile, (ii) aldehyde, and (iii) amino heterocycle reagents. Good yields (52-77%), convenient isolation of the targeted molecules are the distinct characteristics of the developed protocol.