Lee K, Kim YA, Jung C, Sim J, Rajasekar S, Kwak JH, Viji M, Jung JK. Microwave-Mediated, Catalyst-Free Synthesis of 1,2,4-Triazolo[1,5-
a]pyridines from Enaminonitriles.
Molecules 2024;
29:894. [PMID:
38398645 PMCID:
PMC10892893 DOI:
10.3390/molecules29040894]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Revised: 02/02/2024] [Accepted: 02/13/2024] [Indexed: 02/25/2024] Open
Abstract
A catalyst-free, additive-free, and eco-friendly method for synthesizing 1,2,4-triazolo[1,5-a]pyridines under microwave conditions has been established. This tandem reaction involves the use of enaminonitriles and benzohydrazides, a transamidation mechanism followed by nucleophilic addition with nitrile, and subsequent condensation to yield the target compound in a short reaction time. The methodology demonstrates a broad substrate scope and good functional group tolerance, resulting in the formation of products in good-to-excellent yields. Furthermore, the scale-up reaction and late-stage functionalization of triazolo pyridine further demonstrate its synthetic utility. A plausible reaction pathway, based on our findings, has been proposed.
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