Synthesis of novel tricyclic 2H,7H-furo[3′,4′:6,7]cyclohepta-[1,2-b]pyran system
作者:M. Yu. Arsenyeva、V. G. Arsenyev
DOI:10.1007/s10593-009-0199-5
日期:2008.11
The reaction of 8-hydroxy-1,3-dimethyl-4H-cyclohepta[c]furan-4-one with the ethoxymethylene derivatives of malononitrile or ethyl cyanoacetate in the presence of KOH gave noncyclic cyanovinyl derivatives as their potassium salts rather than the expected alpha-pyrone derivatives. They are smoothly cyclized to the target alpha-pyrones by refluxing with acid. The corresponding 3-benzamido-2H-pyran-2-ones can be obtained in a single vessel from the 2-aryl-4-ethoxymethylene-4H-1,3-oxazol-5-ones using the same scheme.
Synthesis of derivatives of the new condensed system 4H,7H-furo[3′,4′:6,7]cyclohepta[1,2-b]pyran
作者:M. Yu. Arsen’eva、V. G. Arsen’ev
DOI:10.1007/s10593-008-0037-1
日期:2008.2
8-Hydroxy-1,3-dimethyl-4H-cyclohepta[c]furan-4-one reacts with arylidenemalononitriles and, like 1,3-oxo enols, forms the corresponding condensed 2-amino-4H-pyrans. The analogous reaction with 3-(dicyanomethylene)indolin-2-ones give spirocyclic 2-amino-4H-pyrans. The 4-aminopyrimidine ring is formed on the basis of the enamino nitrile fragment of the new pyrans by successive reaction with triethoxymethane and then with aqueous ammonia.
Olekhnovich; Boroshko; Borodkin, Russian Journal of Organic Chemistry, 1997, vol. 33, # 2, p. 234 - 242