In(OTf)3‐HBF4 Assisted Multicomponent Approach for One‐Pot Synthesis of Pyrazolopyridinone Fused Imidazopyridines. Issue 15 (26th September 2016)

• Record Type: Journal Article
• Authors: Devi, Nisha; Singh, Dharmender; Sunkaria, Ramesh K.; Malakar, Chandi C.; Mehra, Saloni; Rawal, Ravindra K.; Singh, Virender
• Is Part Of: ChemistrySelect. Volume 1:Issue 15(2016)
• Page Start: 4696
• Page End: 4703
• Publication Date: 2016-09-26
• Subjects: Catalysis -- Imidazopyridine -- Indium Triflate -- Lewis acid -- Multicomponent Reaction -- Pyrazole fused; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.201601133
• Languages: English
• ISSNs: 2365-6549

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 HBF4 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. Abstract : An efficient one‐pot multicomponent approach for the synthesis of pyrazolopyridinone fused imidazopyridines was developed where three C−N and one C−C bond are formed. The tetracyclic frameworks were obtained in 89–99 % yield and no column chromatographic purification was required.