Koyioni M, Kourtellaris A, Koutentis PA. Synthesis of Canthin-4-ones and Isocanthin-4-ones via B Ring Construction.
J Org Chem 2024;
89:6444-6455. [PMID:
38657206 PMCID:
PMC11077480 DOI:
10.1021/acs.joc.4c00440]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 04/11/2024] [Accepted: 04/16/2024] [Indexed: 04/26/2024]
Abstract
Canthin-4-one is synthesized via a six-step procedure starting from commercially available 3-amino-4-bromopyridine in 26% overall yield. 3-Amino-4-bromopyridine is initially converted to 8-bromo-1,5-naphthyridin-4(1H)-one. O-Methylation, intermolecular Pd-catalyzed C-C coupling, and demethylation afford the key intermediate, 8-(2-chlorophenyl)-1,5-naphthyridin-4(1H)-one, for which intramolecular C-N coupling completes the synthesis of the canthin-4-one skeleton. Ten canthin-4-one analogues were prepared in addition to the parent compound. With minor modifications, the synthesis also applies to the synthesis of two series of isocanthin-4-ones.
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