Abstract
Irradiation of 2-bromo-N-ethyl-4'-hydroxybenzanilide (Ia) in aqueous sodium hydroxide gave 2'-ethylspiro [cyclohexa-2, 5-diene-1, 1'-isoindoline]-3', 4-dione (II), N-ethyl-4'-hydroxybiphenyl-2-carboxamide (III), and 4'-hydroxybenzanilide (IV). When the above photolysis was run in the presence of sodium borohydride, 2'-ethyl-4-hydroxyspiro-[cyclohexa-2, 5-diene-1, 1'-isoindolin]-3'-one (V) was obtained in good yield. This dienol (V) was oxidized with manganese dioxide to give the spiro-dienone (II). On the other hand, irradiation of 2-chloro-N-ethyl-4'-hydroxybenzanilide (Ib) in aqueous sodium hydroxide gave almost the starting material. However, when the photolysis of Ib was run in the presence of sodium borohydride or sodium sulfite, the biphenyl (III) was obtained in good yield. The reaction processes of these reactions were discussed.
