benzyl 5-((5-(tert-butoxycarbonyl)-4-ethyl-3-methyl-1H-pyrrol-2-yl)methyl)-3-(2-methoxy-2-oxoethyl)-4-methyl-1H-pyrrole-2-carboxylate

3-Ethyl-5-(4-methoxycarbonylmethyl-3-methyl-1H-pyrrol-2-ylmethyl)-4-methyl-1H-pyrrole-2-carboxylic acid tert-butyl ester

t-butyl 3,3'-dimethyl-4-ethyl-4'-(methoxycarbonylmethyl)-5'-formyldipyrrylmethane-5-carboxylate

t-butyl 3,3'-dimethyl-4-ethyl-4'-(2-methoxycarbonylethyl)-5'-formyldipyrrylmethane-5-carboxylate

t-butyl 3,3'-dimethyl-4-ethyl-4'-(methoxycarbonylmethyl)-5'-carboxy-dipyrrylmethane-5-carboxylate