C[O:2][C:3]([C:5]1[S:9][C:8](/[CH:10]=[CH:11]/[C:12]2[C:13]([CH2:18][CH2:19][CH2:20][CH3:21])=[N:14][O:15][C:16]=2[CH3:17])=[N:7][C:6]=1[CH3:22])=[O:4].O.[OH-].[Li+].CO>C1COCC1.O>[CH2:18]([C:13]1[C:12](/[CH:11]=[CH:10]/[C:8]2[S:9][C:5]([C:3]([OH:4])=[O:2])=[C:6]([CH3:22])[N:7]=2)=[C:16]([CH3:17])[O:15][N:14]=1)[CH2:19][CH2:20][CH3:21]
To a suspension of 2-[(E)-2-(3-butyl-5-methyl-isoxazol-4-yl)-vinyl]-4-methyl-thiazole-5-carboxylic acid methyl ester (150 mg, 0.47 mmol) in THF (1.5 mL) was added a solution of lithium hydroxide monohydrate (39 mg, 0.93 mmol) in water (1.5 mL) followed by methanol (1 mL) and the resulting mixture stirred at room temperature for 1 h. The mixture was then evaporated to half volume and then acidified to pH 4 with HCl (1 N) and cooled to 0° C. for 30 min. A solid precipitated and was filtered off and dried to afford the title compound (130 mg, 91%) which was obtained as a light yellow solid. MS: m/e=305.2 [M−H]−.
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