反应详情

First, 2.08 g (3.24 mmol) of (1R)-1,5-anhydro-1-C-(2-indolyl)-2,3,4,6-tetra-O-benzyl-D-mannitol [compound (VII) wherein R1 to R4 are benzyl] was dissolved in dichloromethane (160 ml). Then, 1.36 g (6.49 mmol) of 3-bromo-2-hydroxyiminopropionic acid ethyl ester [compound (VIII) wherein R6 is ethyl] and 1.03 g (9.74 mmol) of sodium carbonate powder were added to the mixture and stirred at room temperature for about 1.5 hours. Then, a saturated aqueous solution of sodium hydrogen carbonate was added to the reaction 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 the solvent by distillation, the residue was fractionated by column chromatography on silica gel [silica gel: Merck Kieselgel 60 (230-400 mesh ASTM); elution solvent: n-hexane and ethyl acetate (3:1)] to give 1.04 g (recovery 50%) of the starting material and 0.93 g (yield 37%) of 2-hydroxyimino-3-[2-(2,3,4,6-tetra-O-benzyl-α-D-mannopyranosyl)indole-3-yl]propionic acid ethyl ester [compound (IX) wherein R1 to R4 are benzyl and R6 is ethyl].

1. extractionwas then subjected to extraction with dichloromethane
2. washThe extracted solution was washed with water
3. dry with materialdried on anhydrous sodium sulfate
4. customAfter removal of the solvent
5. distillationby distillation