[O-]I(=O)(=O)=O.[Na+].[CH3:7][O:8][C:9]([C:11]1[N:12]([CH3:40])[N:13]=[C:14]([O:16][CH2:17][C:18]2[C:19]([C:33]3[CH:38]=[CH:37][C:36]([F:39])=[CH:35][CH:34]=3)=[N:20][O:21][C:22]=2[C@@H:23]([OH:32])[C@H](O)C2C=CC=CC=2)[CH:15]=1)=[O:10]>C1COCC1.O>[CH3:7][O:8][C:9]([C:11]1[N:12]([CH3:40])[N:13]=[C:14]([O:16][CH2:17][C:18]2[C:19]([C:33]3[CH:34]=[CH:35][C:36]([F:39])=[CH:37][CH:38]=3)=[N:20][O:21][C:22]=2[CH:23]=[O:32])[CH:15]=1)=[O:10]Sodium (meta)periodate (3.67 g, 17.2 mmol) was added at 0° C. to a mixture of 5-[5-((1S,2R)-1,2-dihydroxy-2-phenyl-ethyl)-3-(4-fluoro-phenyl)-isoxazol-4-ylmethoxy]-2-methyl-2H-pyrazole-3-carboxylic acid methyl ester (5.35 g, 11.4 mmol) in THF (29.6 ml) and water (6.1 ml) and the resulting mixture stirred at 0° C. over night. The reaction mixture was extracted with water and ethyl acetate, and the organic phases were washed with brine, dried over sodium sulfate, filtered and evaporated. Purification by chromatography (silica, heptane:ethyl acetate=1:0 to 4:1) afforded the title compound (3.63 g, 88%) as a white solid. MS: m/e=418.1 [M+OAc]−.
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