ethyl 4-diethylaminomethyl-3-(ethoxycarbonylmethyl)-5-methylpyrrole-2-carboxylate

diethyl 4,4'-bis(2-hydroxyethyl)-3,3'-dimethylpyrromethane-5,5'-dicarboxylate

3,3'-dimethyl-4,4'-bis-(2-acetoxyethyl)pyrromethane-5,5'-dicarboxylic acid