(2RS)-4-Ethyl-5'-formyl-2,5-dihydro-3,3'-dimethyl-5-oxo-2,2'dipyrrylmethan-4'-propionsaeure 、
(RS)-5'-Carboxy-3-ethyl-2,5-dihydro-3',4-dimethyl-5-oxo-2,2'-dipyrrylmethan-4'-propionsaeure 生成 (4RS)-3,18-Diethyl-1,4,5,15,16,19,22,24-octahydro-2,7,13,17-tetramethyl-1,19-dioxo-21H-bilin-8,12-dipropionsaeure-hydrochlorid