反应详情

0.4 g of N-methylpiperidine was added to a solution containing 0.8 g of N-isopropoxycarbonyl-L-valine dissolved in 25 ml of methylene chloride, at -20° C. After the mixture was stirred for 10 minutes at the same temperature, 0.6 g of isobutyl chloroformate was added to the mixture at -20° C., and stirred for 1 hour at -20° C.~-10° C. After 0.8 g of (R)-1-(6-fluoro-2-benzothiazolyl)ethylamine was added to this mixture at -60° C., the refrigerant was put off, and then the reaction mixture was warmed naturally to room temperature while being stirred. After completion of the reaction, the resulting mixture was washed successively with water, a 5% aqueous solution of sodium bicarbonate, and water. The organic layer was dried over anhydrous magnesium sulfate, and then the solvent was removed under reduced pressure. The obtained crude crystals were purified by column chromatography on silica gel, thus yielding 0.95 g of the desired product in the form of a white powder (yield: 63%).

1. additionwas added to the mixture at -20° C.
2. stirringwhile being stirred
3. customAfter completion of the reaction
4. washthe resulting mixture was washed successively with water
5. dry with materialThe organic layer was dried over anhydrous magnesium sulfate
6. customthe solvent was removed under reduced pressure
7. customThe obtained crude crystals
8. customwere purified by column chromatography on silica gel