Singlet oxygen reactions of 1, 3-isoquinolinediones 1a-1e could be sensitized by the anionic sensitizer Rose Bengal (RB) in methanol or by tetraphenylporphin (TPP) in the presence of pyridine as a base and a cosolvent in benzene. The products are the corresponding 1, 3, 4- isoquinolinetriones 2a-2e and methyl 1-hydroxy-3-oxoisoindole-1-carboxylates 3b-3e in methanol and the triketones 2a-2e and the 3-hydroxy-3-alkyl (aryl) ...
