Synthesis
GENERAL STEPS: Example 3: Preparation of (R)-3-[3-fluoro-4-(4-morpholinophenyl)]-5-hydroxymethyl-2-oxazolidinone [131] To a mixed solution of n-butanol (51.5 g) and THF (100 ml) was added slowly at 20-30°C under nitrogen protection n-butyllithium (1.6 M in hexanes, 391.7 g), keeping the reaction temperature at 10-20°C. The process was continued for 45-60 minutes. In another reactor, N-carboxyphenylmethoxy-3-fluoro-4-morpholino aniline (100 g) was dissolved in THF (500 ml) under nitrogen protection and stirred at 20-30 °C. Subsequently, the mixture was cooled to -15 to -5°C, and the n-butyllithium solution prepared as described previously was slowly added, maintaining the temperature at -15 to -5°C for 45-60 minutes of reaction. Then, (R)-(-)-glycidyl butyrate (48.0 g) was slowly added to this solution and kept at -10 to -5°C for 1 hour. After the addition was completed, the reaction temperature was raised to 8-13°C maintained at 8-13°C for 1 hr, and then raised to 13-15°C for 4-5 hrs of reaction. After completion of the reaction, water (800 ml) and ethyl acetate (300 ml) were added for layering. The organic layer was washed with ethyl acetate-hexane mixture and the solid was dried in an air pan drier at 55-60 °C. Yield: 0.765 g in 85% yield. [132]
References
[1] Synthetic Communications, 2010, vol. 40, # 6, p. 789 - 798
[2] Patent: WO2011/77310, 2011, A1. Location in patent: Page/Page column 12
[3] Organic Syntheses, 2005, vol. 81, p. 112 - 120
[4] Patent: WO2013/111048, 2013, A1. Location in patent: Page/Page column 19; 20
[5] Patent: US2015/25236, 2015, A1. Location in patent: Paragraph 0131; 0132
