[F:1][C:2]1[C:7]2[N:8]=[C:9]([CH2:11][C:12]3[CH:13]=[C:14]([CH2:18][C:19]([O:21]C)=[O:20])[CH:15]=[CH:16][CH:17]=3)[S:10][C:6]=2[C:5]([F:23])=[CH:4][C:3]=1[F:24].[OH-].[Na+]>O.O1CCOCC1>[F:1][C:2]1[C:7]2[N:8]=[C:9]([CH2:11][C:12]3[CH:13]=[C:14]([CH2:18][C:19]([OH:21])=[O:20])[CH:15]=[CH:16][CH:17]=3)[S:10][C:6]=2[C:5]([F:23])=[CH:4][C:3]=1[F:24]To a solution of methyl 3-[(4,5,7-trifluorobenzothiazol-2-yl)methyl]phenylacetate (231 mg, 0.66 mmol) in a mixture of water (5 ml) and dioxane (5 ml) was added dropwise 2N sodium hydroxide (2 ml, 4 mmol). After the addition was complete, the mixture was stirred for 2 hours, then diluted with water, washed with ether, acidified with 10% hydrochloric acid and extracted with ethyl acetate. The organic layer was dried, then evaporated to yield a residue, which was recrystallized from isopropyl ether to give 3-[(4,5,7-trifluorobenzothiazol-2-yl)methyl]phenylacetic acid (134 mg, 90%) as a colorless powder. m.p. 132° to 134° C.
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