Lithium hydroxide, monohydrate → HCID 69624759, compound

Participants

Reaction Steps

First, 1.72 g (1.94 mmol) of 2-[N-(carbobenzyloxy)amino]-3-[2-(2,3,4,6-tetra-O-benzyl-α-D-mannopyranosyl)indole-3-yl]propionic acid ethyl ester [compound (XI) wherein R1 to R4 are benzyl, R6 is ethyl and Ar is phenyl) was dissolved in 1,2-dimethoxyethane (60 ml)-water (30 ml). Then, 0.24 g (5.82 mmol) of lithium hydroxide monohydrate was added to the mixture and stirred at room temperature for about 16 hours. After the reaction was terminated, 0.5N citric acid (30 ml) was added to the reacted mixture which was then subjected to extraction with dichloromethane. The extracted solution was washed with water and then dried on anhydrous sodium sulfate. After removal of solvent, the residue was fractionated by columun chromatography on silica gel [silica gel: Merck Rieselgel 60 (230-400 mesh ASTM); elution solvent: n-hexane, ethyl acetate and methanol (3:6:0.6)] to elute compound (XII-1) and then compound (XII-2) which were further purified by preparative thin layer chromatography [preparative thin layer plate: Merck Kieselgel 60 F254 (1 mm thick); development solvent: n-hexane, ethyl acetate and methanol (3:6:0.5)] to give 0.66 g (yield 40%) of (2R*)-2-[N-(carbobenzyloxy)amino]-3-[2-(2,3,4,6-tetra-O-benzyl-α-D-mannopyranosyl)indole-3-yl]propionic acid [compound (XII-1) wherein R1 to R4 are benzyl and Ar is phenyl] and 0.29 g (yield 17%) of (2S*)-2-[N-(carbobenzyloxy) amino]-3-(2-(2,3,4,6-tetra-O-benzyl-α-D-mannopyranosyl)indole-3-yl]propionic acid [compound (XII-2) wherein R1 to R4 are benzyl and Ar is phenyl].

Provenance & Evidence