Collect. Czech. Chem. Commun. 1981, 46, 748-758

Stable 2H-pyran derivatives accessible by cyclocondensation of p-substituted benzoylacetonitriles

Josef Kuthan, Jaroslav Paleček and Jiří Valihrach

Department of Organic Chemistry, Prague Institute of Chemical Technology, 166 28 Prague 6


The 2H-pyrans IIa-f can be prepared by thermal cyclocondensation of the ketonitriles Ia-f. The alternative structure III of the compounds obtained has been excluded unambiguously on the basis of spectral data. The compounds VII to XI have been isolated as byproducts of the said cyclocondensation of the compound Ia in acetic acid with catalysis of ammonium acetate. Probable course of the reaction investigated is discussed.