N-(5-(phenylamino)penta-2,5-dienylidene)aniline monohydrochloride → 4-[2-[6-anilino-1,3,5-hexatrienyl]-3-methyl-5-sulfo-3-(4-sulfobutyl)-3H-1-indoliumyl]-1-butanesulfonate

Participants

Reaction Steps

300 mg (0.55 mmol) of 2,3-dimethyl-5-sulfo-1,3-di(4-sulfobutyl)-3H-indolium and 190 mg (0.66 mmol) of N-[5-(phenylamino)-2,4-pentadienylidene]aniline monohydrochloride were heated in 6 mL acetic anhydride-acetic acid (1:1, v/v) mixture for 30 min at 110° C. After cooling the product was precipitated with ethyl acetate, filtered off and washed with ether to give 240 mg (56%) of 4-[2-[6-anilino-1,3,5-hexatrienyl]-3-methyl-5-sulfo-3-(4-sulfobutyl)-3H-1-indoliumyl]-1-butanesulfonate. λmax (abs) 505 nm (methanol). This product was used for following step without additional purification.

Provenance & Evidence