Electron transfer photooxygenation of 8-methoxypsoralen

Abstract

9,10-Dicyanoanthracene (DCA) and chloranil sensitized electron transfer photooxygenation of 8-methoxypscralen in MeOH–MeCN (7 : 3, v/v) gave the furan ring oxidized product 4′-oxo-5′,8-dimethoxypsoralen {2,9-dimethoxy-7H-furo[3,2-g][1]benzopyran-3,7(2H)-dione} in 38 and 74% yield, respectively, while in HOAC–MeCN (2 : 8, v/v), similar photooxygenation gave 4′-oxo-5′-acetoxy-8-methoxypsoralen {2-acetoxy-9-methoxy-7H-furo[3,2-g][1]benzopyran-3,7(2H)-dione} as product in 30 and 73% yield, respectively.