C[O:2][C:3](=[O:15])[C:4]1[CH:9]=[C:8]([O:10][CH3:11])[CH:7]=[C:6]([O:12][CH3:13])[C:5]=1[Cl:14].[OH-].[K+]>CO>[Cl:14][C:5]1[C:6]([O:12][CH3:13])=[CH:7][C:8]([O:10][CH3:11])=[CH:9][C:4]=1[C:3]([OH:15])=[O:2]Into a solution of 12 g (52.0 mmol) of 2-chloro-3,5-dimethoxy-benzoic acid methyl ester (prepared according to the method of T. R. Kasturi and E. M. Abraham, Indian Journal of Chemistry, 1973; 11:1099-1104) in 40 mL of methanol was added 60 mL (60 mmol) of 1N potassium hydroxide solution. After stirring overnight at room temperature, the methanol was removed in vacuo, and the residue was suspended in 800 mL of water. The aqueous layer was extracted three times with diethyl ether and the acidified with concentrated hydrochloric acid to a pH of 3. The resulting white solid was filtered, washed well with water, and air-dried to give 9.82 g (87%) of the title compound.
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