反应详情

(4R)-4-Methyl-4-[2-(1-ethylpyrrol-2-yl)ethyl]-1,3-oxazolidin-2-one (4.90 g, 22.0 mmol) obtained in Reference example 3 (3d) was dissolved in a mixture of tetrahydrofuran (80 mL) and methanol (40 mL) and a 5.5 N aqueous potassium hydroxide solution (40 mL) was added thereto, followed by heating under reflux of the mixture for 4 days. After cooling, water and methylene chloride were added to the reaction mixture to separate it. The thus obtained organic phase was separated and dried over anhydrous sodium sulfate. After filtration, the solvent was evaporated under reduced pressure and the residue was dissolved in 200 mL of ethanol. After a solution of D-(−)-tartrate (1.59 g, 10.5 mmol) in ethanol (20 mL) was added thereto and the mixture was left to stand for 4 hours, the precipitated crude crystal was recrystallized from a mixture of ethanol (100 mL) and water (10 mL). The obtained crystal was recrystallized again from a mixture of ethanol (50 mL) and water (5 mL) to obtain the title compound (2.80 g, yield: 37%) as a colourless plate-like crystal.

1. temperatureby heating
2. temperatureunder reflux of the mixture for 4 days
3. temperatureAfter cooling
4. customto separate it
5. customThe thus obtained organic phase was separated
6. dry with materialdried over anhydrous sodium sulfate
7. filtrationAfter filtration
8. customthe solvent was evaporated under reduced pressure
9. dissolutionthe residue was dissolved in 200 mL of ethanol
10. waitthe mixture was left
11. customthe precipitated crude crystal
12. customwas recrystallized from a mixture of ethanol (100 mL) and water (10 mL)
13. customThe obtained crystal was recrystallized again from a mixture of ethanol (50 mL) and water (5 mL)