Process for the preparation of cyclic enamides

摘要

Special cyclic enamides are prepared by splitting off alcohols catalytically from the corresponding alkoxylated cyclic amides, in the presence of at least one tetraalkylammonium and/or alkali metal salt of tetrafluoroboric acid and/or of hexafluorophosphoric acid as the catalyst, at a temperature of from about 120 DEG to 250 DEG C., distilling off the detached alcohol and isolating the formed enamide in known manner. Particularly preferred starting compounds are those cyclic amides which have been obtained by anodic alkoxylation of corresponding cyclic N-compounds in an alcohol in the presence of supporting electrolytes which are identical with the catalysts subsequently used for splitting off the alcohol, and by distilling off the alcohol from the reaction batch. The enamides are valuable starting products and intermediates for various syntheses, for example, syntheses of prostaglandins and of other pharmaceuticals.