C([O:3][C:4]([C:6]1[N:7]=[C:8]([C:11]2[CH:16]=[CH:15][CH:14]=[CH:13][C:12]=2[CH3:17])[S:9][CH:10]=1)=[O:5])C.[OH-].[Na+]>C1COCC1.CO.C(Cl)Cl>[C:12]1([CH3:17])[CH:13]=[CH:14][CH:15]=[CH:16][C:11]=1[C:8]1[S:9][CH:10]=[C:6]([C:4]([OH:5])=[O:3])[N:7]=12-o-Tolyl-thiazole-4-carboxylic acid ethyl ester (550 mg, 2.22 mmol) was dissolved in a mixture of THF (1.0 mL) and MeOH (1.0 mL). To this was added NaOH (20% aqueous, 0.444 mL). The reaction mixture was stirred overnight and was then diluted with CH2Cl2 (30 mL) and washed with 1M NaHSO4 (30 mL). The aqueous layer was extracted with CH2Cl2 (2×30 mL), then the combined organic layers were washed with water (1×30 mL), dried over Na2SO4, filtered and concentrated under reduced pressure to give the product (434 mg, 1.98 mmol, 89%) as a white solid.
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