3'-ethyl-4,4'-dimethyl-5-t-butoxycarbonyl-3-<2-(2,4,5-trichlorophenoxycarbonyl)ethyl>dipyrromethane-5'-carboxylic acid 、
t-butyl 3-ethyl-5'-formyl-3'-(2-methoxycarbonylethyl)-4,4'-dimethyldipyrromethane-5-carboxylate 在
对甲苯磺酸 作用下,
以
甲醇 、
二氯甲烷 为溶剂,
反应 0.5h,
以73%的产率得到di-t-butyl 3,7-diethyl-6-(2-methoxycarbonylethyl)-1,4,5,8-tetramethyl 2-<2-(2,4,5-trichlorophenoxycarbonyl)ethyl>-b-bilene-1',8'-dicarboxylate hydrochloride