Pavithra E, Kannadasan S, Shanmugam P. Synthesis of 5-aryl-3,3′-bis-indolyl and bis-7-aza-indolyl methanone derivatives from 5-bromo-7-azaindoles
via sequential methylenation using microwave irradiation, CAN oxidation, and Suzuki coupling reactions.
RSC Adv 2022;
12:30712-30721. [PMID:
36349162 PMCID:
PMC9607884 DOI:
10.1039/d2ra05849a]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 10/18/2022] [Indexed: 11/05/2022] Open
Abstract
A catalyst-free and green chemical method has been developed for the methylenation of indole and N-methyl-7-aza indoles with aqueous formaldehyde afforded respective N,N′-dimethyl-3,3′-bis-7-azaindolylmethanes under microwave irradiation in excellent yield. Subsequent oxidation of the products thus obtained, using one electron chemical oxidant CAN afforded N,N′-dimethyl-3,3′-bis-7-azaindolylmethanone derivatives in excellent yield. This resulted in methanone derivatives with halogen substitution at the aryl ring which when subjected to Suzuki coupling with aryl boronic acids furnished highly functionalized fluorescent biaryl derivatives. Plausible mechanisms, characterization including XRD, and evaluation of photophysical properties of the Suzuki coupled products are described.
A catalyst-free methylenation of 7-aza indoles under MW irradiation and CAN oxidation of methylenated products to the respective ketones are achieved. Plausible mechanisms of the reactions and photophysical properties of the products are described.![]()
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