E. Stoyanov, I. C. Ivanov, D. Heber
Jan 21, 2000
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0
Influential Citations
55
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Journal
Molecules
Abstract
Pharmaceutical Institute, Christian-Albrechts University of Kiel, Gutenbergstr. 76, D-24118 Kiel,GermanyTel.: (+49-431) 880-1118, Fax: (+49-431) 880-1352, E-mail: dheber@pharmazie.uni-kiel.de*Author to whom correspondence should be addressed.Received: 7 December 1999 / Accepted: 31 December 1999 / Published: 21 January 2000Abstract: Reaction of 4-hydroxy-6-methyl-2-pyrone (1a) as well as 4-hydroxy-6-methyl-2(1H)-pyridones (1b-d) with arylmethylene malononitriles or arylmethylene methyl cyano-acetates (2a-h) leads to the formation of the very stable 5,6-fused bicyclic 2-amino-4H-pyran derivatives 3a-3af.Keywords: pyrano[4,3-b]pyran, pyrano[3,2-c]pyridine, arylmethylene malononitrile, aryl-methylene cyanoacetate, Michael addition.IntroductionWiener et al. first published [1] that 4-hydroxycoumarin cyclized through Michael addition to ben-zylidene malononitrile in pyridine as solvent to give a derivative of 2-aminopyrano[3,2-c]benzopyran(A) (Figure 1). Later, Junek and Aigner [2] found a second case of this heterocyclization via additionof 4-hydroxy-6-methyl-2-pyrone (1a, “triacetic acid lactone”, Scheme 1) to tetracyanoethylene, thuspreparing a substituted 2-amino-4H,5H-pyrano[4,3-b]pyran (B). Many years thereafter, Shaker [3] re-