反应详情

A mixture of 1.0 g of Compound 40-a, 0.7 g of valine methylester hydrochloride, 0.5 g of molecular sieves and 15 ml of THF was stirred at room temperature for 2 days. After ice cooling, 3 ml of methanol and subsequently 0.4 g of sodium cyanoborohydride were added to the mixture. After the mixture was stirred overnight, insoluble matters were filtered off, and the filtrate was concentrated. The residue was diluted with dichloromethane, washed with a saturated aqueous solution of sodium chloride, and dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure, and the residue was purified by silica gel column chromatography [eluent: hexane/ethyl acetate (1/1)] to give 1.2 g (82%) of the product as a yellow oily substance.

1. stirringAfter the mixture was stirred overnight
2. filtrationinsoluble matters were filtered off
3. concentrationthe filtrate was concentrated
4. additionThe residue was diluted with dichloromethane
5. washwashed with a saturated aqueous solution of sodium chloride
6. dry with materialdried over anhydrous magnesium sulfate
7. distillationThe solvent was distilled off under reduced pressure
8. customthe residue was purified by silica gel column chromatography [eluent: hexane/ethyl acetate (1/1)]