Water → (2S-trans)-18-Carboxy-20-(carboxymethyl)-13-ethyl-2,3-dihydro-3,7,12,17-tetramethyl-8-vinyl-21H,23H-porphine-2-propionic acid; (17S,18S)-18-(2-Carboxyethyl)-20-(carboxymethyl)-12-ethenyl-7-ethyl-3,8,13,17-tetramethyl-17,18,22,23-tetrahydroporphyrin-2-carboxylic acid

Participants

Reaction Steps

The procedure of Smith and Bushell (M. J. Bushell, Ph.D. Thesis, Univ. of Liverpool, U.K., 1978) was used. The starting material, 1 gm of methyl pheophorbide-a, was dissolved in dry tetrahydrofuran (THF). To this was added sodium methoxide prepared by dissolving 200 mg sodium in 40 ml methanol, and the reaction was allowed to stir at room temperature for 1 hr. The mixture was poured into water and extracted with dichloromethane. The organic layer was washed with water, dried over anhydrous sodium sulfate and evaporated. The residue was dissolved in chloroform and treated with dichloromethane and ether, and the solid obtained was chromatographed on Alumina (Grade III) and eluted with toluene/dichloromethane 1/1. The major band, chlorin-e6 tetramethyl ester was recrystallized from dichloromethane/methanol to obtain 700 mg or 67% yield of the compound of formula ##STR7## By re-utilizing the remaining starting material, an overall yield of 88.7% was obtained, and the structure was confirmed by NMR spectroscopy.

Provenance & Evidence