1-methyl-3-(4-methylphenyl)pyrrole-2,5-dione

(3E)-3-(methoxymethylidene)-1-methylpyrrolidine-2,5-dione

3-(3-methoxyphenyl)-1-methylpyrrole-2,5-dione

dimethyl (3S,3aS,6aR)-5-methyl-4,6-dioxo-3-phenylhexahydro-1H-furo[3,4-c]pyrrole-1,1-dicarboxylate

dimethyl (1R,3aR,6aS)-5-methyl-4,6-dioxo-1-phenyl-3a,6a-dihydro-1H-furo[3,4-c]pyrrole-3,3-dicarboxylate