反应详情

To a stirred solution of (s)-(−)-3-(Benzyloxycarbonyl)-4-oxazolidinecarboxylic acid 9 (1.75 g, 6.96 mmol) in anhydrous methanol (15 mL) was added thionyl chloride (1.02 mL, 13.9 mmol) at 0° C. After 30 minutes, the ice/water bath was removed and the reaction mixture continued to be stirred at room temperature for 3.5 hours. The reaction was quenched by addition of saturated sodium bicarbonate and diluted with dichloromethane (100 mL) and water (50 mL). The mixture was separated and the aqueous layer was extracted with dichloromethane (2×50 mL). The combined organic layers were washed with brine, dried over anhydrous sodium sulfate and filtered. The solvents were removed under reduced pressure and the residue was purified by silica gel chromatography (Hexanes/AcOEt, 1.5:1) to give (s)-(−)-3-(Benzyloxycarbonyl)-4-oxazolidinecarboxylic methyl ester 10 as colorless oil (1.84 g, y=99%). 1H NMR (400 Hz, CDCl3): the compound appears as a pair of distinct rotomers. δ 7.35 (bs, 5H), 5.22-4.99 (m, 4H), 4.53-4.45 (m, 1H), 4.22-4.09 (m, 2H), 3.76 (s, 1.5H), 3.65 (s, 1.5H); MS (m/z): found 288.0 (M+Na)+.

1. customthe ice/water bath was removed
2. customThe reaction was quenched by addition of saturated sodium bicarbonate
3. additiondiluted with dichloromethane (100 mL) and water (50 mL)
4. customThe mixture was separated
5. extractionthe aqueous layer was extracted with dichloromethane (2×50 mL)
6. washThe combined organic layers were washed with brine
7. dry with materialdried over anhydrous sodium sulfate
8. filtrationfiltered
9. customThe solvents were removed under reduced pressure
10. customthe residue was purified by silica gel chromatography (Hexanes/AcOEt, 1.5:1)