The photochemistry of vinylogous amides and imides

The photochemical reactions of a series of vinylogous amides and imides were investigated. Of the cases investigated the intra molecular cycloaddition of vinylogous amides failed. Of the four vinylogous imides studied, two yielded the expected photo ene products. Irradiation of N-acetyl-3-(N-2-(2-methylcyclohexenylethyl))■ amino-5,5-dimethyl-2-cyclohexene-l-one and N-acetyl-3-(N-2(2,6,6- trimethylcyclohexenylethyl))amino-5,5-dimethyl-2-cyclohexene-l-one with pryex filtered light gave mixtures of acyl migration and photoene products. Irradiation of N-acetyl-3-(N-2-(2,6,6-trimethylcyclohexenylethyl))amino-5-isopropyl-2-cyclohexene-l-one yielded a single crystalline product which proved to be the result of an acyl migration reaction. In an effort to facilitate the photo ene reaction, N-formyl-3-(N-2-(2,6,6-trimethylcyclohexenylethyl))amino-5-isopropyl2-cyclohexene-l-one was prepared and irradiated. Prolonged irradiation resulted in no change in the starting material.