Gao W, Liu J, Jiang Y, Li Y. First synthesis of 2-(benzofuran-2-yl)-6,7-methylene dioxyquinoline-3-carboxylic acid derivatives.
Beilstein J Org Chem 2011;
7:210-7. [PMID:
21445378 PMCID:
PMC3062989 DOI:
10.3762/bjoc.7.28]
[Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Accepted: 01/20/2011] [Indexed: 11/23/2022] Open
Abstract
A facile and inexpensive synthesis of a series of novel methylenedioxy-bearing 2-(benzofuran-2-yl)-quinoline-3-carboxylic acid derivatives 3a-h via the one-pot reaction of ethyl 2-chloromethyl-6,7-methylenedioxyquinoline-3-carboxylate (5) with various substituted salicylaldehydes 6a-g as well as 2-hydroxy-1-naphthaldehyde (6h) is described. Substrate 5 was synthesized by the Friedländer condensation reaction of 2-amino-4,5-methylenedioxybenzaldehyde (4) with ethyl 4-chloro-3-oxobutanoate using KHSO(4) as catalyst under ultrasound irradiation conditions. The targeted compounds 3a-h were obtained in good yields of 52-82% and their structures were established based on spectral data and elemental analyses.
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