5-carboxymethyl-5'sulphonato-1,1'-di-(3,3-diethoxypropyl)-3,3,3',3'-tetramethyl-indocarbocyanine ethyl ester 在
硫酸 作用下,
以
氯仿 为溶剂,
以76%的产率得到6,7,9,10-tetrahydro-2-carboxymethyl-14-sulphonato-16,16,18,18-tetramethyl-7aH,8aH-bisindolinium[3,2-a;3',2'-a]pyrano[3,2-c;5,6-c']dipyridin-5-ium