In(OTf) ₃ ‐HBF ₄ Assisted Multicomponent Approach for One‐Pot Synthesis of Pyrazolopyridinone Fused Imidazopyridines

Abstract

Abstract An efficient methodolgy has been developed towards the one‐pot synthesis of pyrazolopyridinone fused imidazopyridines from 4‐formyl‐1 H ‐pyrazole‐3‐carboxylates, pyridin‐2‐amines and tert ‐butyl isonitrile as the starting materials. The transformation has been accomplished by using In(OTf) 3 assisted Groebke‐Blackburn‐Bienayme (GBB) multicomponent approach to yield the N ‐fused imidazo[1,2‐ a ]pyridine scaffolds which were further served in‐situ HBF 4 mediated dealkylation and tandem intramolecular condensation. The current protocol paves the way for the synthesis of biologically interesting molecular frameworks and has advantages in terms of low catalyst loading with appreciable atom economy and easy‐to‐perform reaction conditions with straightforward purification procedure. Importantly, this efficient catalytic system offers a lot of future scope for variety of organic transformations in other MCRs.