反应详情

To a solution of benzyl alcohol (1.29 g) in tetrahydrofuran (60 ml) was added dropwise n-butyl lithium (6.6 ml, 1.6M n-hexane solution) at 2-8° C. and the mixture was stirred for 20 minutes. A solution of (4S)-3-[3-(1-tert-butoxycarbonyl-2-n-butylimidazol-4-yl)-2-(3,4-methylenedioxyphenyl)propionyl]-4-isopropyloxazolidin-2-one (4.86 g) was added dropwise to the mixture and the resulting solution was stirred at 2° C. for 2 hours. The reaction was quenched with saturated ammonium chloride aqueous solution, and then the solution was extracted with ethyl acetate. The organic layer was washed successively with saturated sodium bicarbonate aqueous solution and brine. Drying, filtering and removal of the solvents afforded a crude product. The crude product was purified by a silica gel column chromatography (eluent; n-hexane:ethyl acetate=4:1) to give benzyl 3-(1-tert-butoxycarbonyl-2-n-butylimidazol-4-yl)-2-(3,4-methylenedioxyphenyl)propionate (2R:2S=1:4) (3.67 g) as a slightly yellow oil.

1. stirringthe resulting solution was stirred at 2° C. for 2 hours
2. customThe reaction was quenched with saturated ammonium chloride aqueous solution
3. extractionthe solution was extracted with ethyl acetate
4. washThe organic layer was washed successively with saturated sodium bicarbonate aqueous solution and brine
5. customDrying
6. filtrationfiltering
7. customremoval of the solvents
8. customafforded a crude product
9. customThe crude product was purified by a silica gel column chromatography (eluent; n-hexane:ethyl acetate=4:1)