Synthesis 2001(13): 1941-1948
DOI: 10.1055/s-2001-17696
PAPER
© Georg Thieme Verlag Stuttgart · New York

Synthesis of [1]Benzopyrano[4,3-b]pyrrol-4(1H)-ones from 4-Chloro-3-formylcoumarin

Angel Alberola, Luis Calvo, Alfonso González-Ortega*, Alfonso P. Encabo, M. Carmen Sañudo
Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Valladolid, 47005, Spain
Fax: +34(98)3423013; e-Mail: algon@qo.uva.es;
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Publikationsverlauf

Received 22 May 2001
Publikationsdatum:
10. August 2004 (online)

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Abstract

2-Functionalized [1]benzopyrano[4,3-b]pyrrol-4(1H)-ones were obtained by the Fischer-Fink reaction starting from 4-chloro-3-formylcoumarin and different α-amino derivatives (e.g. glycinonitriles, ethyl glycinates and α-amino ketones). In general limitations to the synthetic method arise when α-amino derivatives with very reactive functions were used (e.g. carboxaldehyde groups or their acetal derivatives) leading to Knorr type reactions, or when they contain relatively inactive methylenes (e.g. carboxamide groups) which failed to complete the cyclization process.

1

Deceased 26 March 2001.

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X-ray crystal structure analysis of 8e: formula C15H13NO4, M = 271.26, colorless crystal 0.47 0.19 × 0.12 mm, a = 7.2581(11), b = 16.127(2), c = 11.4669(18)Å, α = 90°, β = 106.422(3)º, γ = 90º, V = 1287.5(3)Å3,Z = 2, monoclinic, space group P2(1)/c. Crystallographic data (excluding structure factors) for the structure in this paper has been deposited at the Cambridge Crystallographic Data Center as supplementary publication no. CCDC 166556. Copies of the data can be obtained free of charge on application to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK, (fax: +44 1223 336033 or e-mail: deposit@ccdc.cam.ac.uk).