7-(4-methoxy-benzylamino)-2-(4-methoxy-phenyl)-2-methyl-6-oxo-5,6-dihydro-[1,3]dithiino[5,4-b]pyrrole-4-carboxylic acid methyl ester
2-(4-methoxy-phenyl)-2-methyl-6,7-dioxo-5,6,7,7a-tetrahydro-[1,3]dithiino[5,4-b]pyrrole-4-carboxylic acid methyl ester