Photochemical Reaction of Isocoumarin and Related Compounds

Abstract

The effect of irradiation with ultraviolet ray for methanol solution of 2-carboxystyrenes and 3, 4-dihydroisocoumarins were examined. Irradiation of 2-carboxystyrene and its β-(4'-methoxyphenyl), β-methyl, β, β-dimethyl, and β-cyclohexylidenemethyl derivatives gave the corresponding cyclized compounds. Some of these reactions were reversible since styrene derivatives were obtained from 3, 4-dihydroisocoumarins in the same manner. In the case of ring closed reactions of β-alkyl substituted 2-carboxystyrenes, such as β-methyl, β, β-dimethyl, and β-cyclohexylidenemethyl derivatives, the rearranged products were obtained. These products agreed with each of an authentic sample which was synthesized by another, method.