反应详情

(3S,4S)-4-(1-Hydroxy-1-methylethyl)-3-(1-(R)-hydroxyethyl)-1-di(p-anisyl)methyl-2-azetidinone (26 g) and 4-dimethylaminopyridine (16 g) were dissolved in dry dichloromethane (200 ml). Benzyl chloroformate (20 g) was added dropwise thereto over a period of 1 hour with ice-cooling, and the resultant mixture was stirred for 2 hours and warmed to room temperature, followed by stirring at the same temperature as above for 10 hours. 5% Hydrochloric acid (100 ml) was poured into the reaction mixture with ice-cooling, and the resulting mixture was stirred for 0.5 hour and allowed to stand. The organic layer was washed successively with water, a saturated sodium bicarbonate solution and brine and dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated in vacuo to give (3S,4S)-4-(1-hydroxy-1-methylethyl)-3-(1-(R)-benzyloxycarbonyloxyethyl)-1-di(p-anisyl)methyl-2-azetidinone.

1. temperatureover a period of 1 hour with ice-cooling
2. temperaturecooling
3. stirringthe resulting mixture was stirred for 0.5 hour
4. washThe organic layer was washed successively with water
5. dry with materiala saturated sodium bicarbonate solution and brine and dried over anhydrous sodium sulfate
6. filtrationAfter filtration
7. concentrationthe filtrate was concentrated in vacuo