反应详情

5-[2-(2-Chloro-4-hydroxy-phenyl)-1-hydroxy-1-trifluoromethyl-propyl]-3-methyl-3H-benzooxazol-2-one (80 mg, obtained in Example 172) and ethyl 2-bromoisobutyrate (0.2 mL) were dissolved in dimethylacetamide (2 mL). Powdered sodium hydroxide (54 mg) was added to this solution and the mixture was allowed to stir at r.t. for 12 hours. The mixture was poured into water and ice and was acidified to pH 3 with 2N HCl. The aqueous phase was extracted with ethyl acetate two times and the organic extracts were washed with brine, dried over Na2SO4 and evaporated in vacuo. The residue was purified by flash chromatography (silica gel, ethyl acetate:hexanes=4:1) to provide the title compound 2-{3-chloro-4-[3,3,3-trifluoro-2-hydroxy-1-methyl-2-(3-methyl-2-oxo-2,3-dihydro-benzooxazol-5-yl)-propyl]-phenoxy}-2-methyl-propionic acid ethyl ester as a colorless foam (113 mg). MS (m/e, ISP neg. ion)=514.1 [M−H+].

1. extractionThe aqueous phase was extracted with ethyl acetate two times
2. washthe organic extracts were washed with brine
3. dry with materialdried over Na2SO4
4. customevaporated in vacuo
5. customThe residue was purified by flash chromatography (silica gel, ethyl acetate:hexanes=4:1)