Synthesis 2010(2): 239-248  
DOI: 10.1055/s-0029-1217128
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

Synthesis of 5-Amino-1,10b-dihydro-2H-chromeno[3,4-c]pyridine-2,4(3H)-diones from Coumarins and Cyanoacetamides under Basic Conditions

Ornelio Rosati*a, Massimo Curini*a, Maria Carla Marcotullio*a, Gildas Oball-Monda, Caroline Pelucchini*a, Antonio Procopio*b
a Dipartimento di Chimica e Tecnologia del Farmaco, Università degli Studi di Perugia, Via del Liceo, 1, 06123 Perugia (PG), Italy
b Dipartimento Farmaco-Biologico, Università degli Studi della Magna Græcia Complesso Ninì Barbieri, 88021 Roccelletta di Borgia (CZ), Italy
Fax: +39(075)5855116; e-Mail: ornros@unipg.it;
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Publikationsverlauf

Received 28 May 2009
Publikationsdatum:
20. November 2009 (online)

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Abstract

The reaction of various coumarins with cyanoacetamide derivatives under basic conditions (sodium ethoxide, piperidine or 2,2,6,6-tetramethylpiperidine), proceeds via an interesting process which involves skeletal rearrangement of the coumarin, a Michael addition and two cyclizations to afford 5-amino-1,10b-dihydro-2H-chromeno[3,4-c]pyridine-2,4(3H)-diones. The same reaction in the presence of N,N¢-ethane-1,2-diylbis(2-cyanoacetamide) gives the corresponding mono and bis 5-amino-1,10b-dihydro-2H-chromeno[3,4-c]pyridine-2,4(3H)-diones.

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Supplementary crystallographic data for compounds 10a (CCDC 723518) and 14 (CCDC 723519) can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif

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Due to the presence of a stereogenic centre on each of the polycyclic units in 15b, 16b and 17b (C-14b and C-14b′), these compounds exist as diastereoisomeric mixtures. The minor structural differences in these sets of diastereoisomers affects the chemical shifts of several of the carbon atoms. These are listed in the ¹³C NMR spectral data as a double peak with a 0.05-0.10 ppm difference in shift, thereby increasing the number of signals overall.