反应详情

A solution of tert-butyl (R)-4-(2-methylphenyl)-4-(2-nitro-5-(3-pyridylmethoxy)phenoxy)butanoate (800 mg) in methanol (20 mL) containing 5 N sodium hydroxide (10 mL) is stirred at ambient temperature for 48 hours. The reaction mixture is poured into water (50 mL), acidified to pH 5 with 1 N HCl and extracted three times with ethyl acetate (50 mL). The combined organic phases are washed with brine (50 mL), dried over magnesium sulphate, filtered and concentrated under reduced pressure The residual brown gum is purified by flash chromatography on silica eluting with ethyl acetate. Fractions homogeneous in the required product are combined and evaporated to give a yellow oil. Trituration with pentane afforded (R)-4-(2-methylphenyl)-4-(2-nitro-5-(3-pyridylmethoxy)phenoxy)butanoic acid as a white solid (150 mg), m.p. 117-119° C. [Elemental analysis:- C,65.4, H, 5.21, N, 6.64%. Calculated:- C,65.3, H, 5.17, N, 6.59%]

1. extractionextracted three times with ethyl acetate (50 mL)
2. washThe combined organic phases are washed with brine (50 mL)
3. dry with materialdried over magnesium sulphate
4. filtrationfiltered
5. concentrationconcentrated under reduced pressure The residual brown gum
6. customis purified by flash chromatography on silica eluting with ethyl acetate
7. customevaporated
8. customto give a yellow oil