Synlett 2002(12): 2095-2097
DOI: 10.1055/s-2002-35569
LETTER
© Georg Thieme Verlag Stuttgart · New York

A Convenient Preparation of 4-Carboxamide Derivatives of Pyridazino[4,5-b]indoles and Pyridazino[4,5-b]benzo[b]furans

José C. González-Gómez*, Eugenio Uriarte
Departamento de Química Orgánica, Facultad de Farmacia, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
Fax: +34(981)594912; e-Mail: jcgg1971@yahoo.es;
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Publication History

Received 22 August 2002
Publication Date:
20 November 2002 (online)

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Abstract

Diels-Alder reaction of indole or 3-coumaranone with 3,6-dicarbomethoxy-1,2,4,5-tetrazine followed by MgCl2-mediated C-4 regioselective amidation of the tricyclic diester and subsequent Krapcho dealkoxycarbonylation, provided a convenient route to 4-carboxamide derivatives of pyridazino[4,5-b]indoles and pyridazino[4,5-b]benzo[b]furans. 1,4-Biscarboxamide derivatives were also obtained by full amidation of diester intermediates with an excess of the amine.