反应详情

An emulsion of (R)-ethoxy-(2-fluoro-4-methoxy-phenyl)-acetic acid ethyl ester (416 mg) in 0.1M NaCl, 3 mM Natriumphosphat buffer pH 7.0 (75 ml) was cooled to 4–5° C. was treated with hog liver esterase suspension (0.175 ml). The reaction mixture was stirred for 4 days while maintaining the pH at 7 by gradual addition of 0.1N NaOH (totally 12.8 ml). The reaction mixture was washed with CH2Cl2, then brought to pH 2 by the addition of 2N HCl and extracted with EtOAc. The EtOAc layer was dried over Na2SO4, filtrated and concentrated to give (R)-ethoxy-(2-fluoro-4-methoxy-phenyl)-acetic acid (304 mg, 97.1% ee) as yellow semisolid.

1. temperaturewhile maintaining the pH at 7
2. washThe reaction mixture was washed with CH2Cl2
3. additionbrought to pH 2 by the addition of 2N HCl
4. extractionextracted with EtOAc
5. dry with materialThe EtOAc layer was dried over Na2SO4
6. filtrationfiltrated
7. concentrationconcentrated