C([O:3][C:4](=[O:21])/[C:5](=[N:14]/[O:15][CH:16]1[CH2:20][CH2:19][CH2:18][CH2:17]1)/[C:6]1[CH:11]=[CH:10][C:9]([Cl:12])=[C:8]([Cl:13])[CH:7]=1)C.[OH-].[Li+].O>C(O)C.C(Cl)(Cl)Cl>[CH:16]1([O:15]/[N:14]=[C:5](\[C:6]2[CH:11]=[CH:10][C:9]([Cl:12])=[C:8]([Cl:13])[CH:7]=2)/[C:4]([OH:21])=[O:3])[CH2:20][CH2:19][CH2:18][CH2:17]1(E)-Cyclopentyloxyimino-(3,4-dichloro-phenyl)-acetic acid ethyl ester (332 mg, 1.01 mmol) was dissolved in ethanol (10 mL) and cooled to 0° C. A 2.0 N solution of lithium hydroxide in water (1.51 mL, 3.02 mmol) was added dropwise. The reaction mixture was allowed to gradually warm to 25° C. over 1.5 h, then diluted with chloroform (125 mL) and washed with 0.3 M potassium bisulfate solution (60 mL). The aqueous phase was extracted with chloroform (75 mL) and the combined organic phases were dried over magnesium sulfate and evaporated in vacuo to afford (E)-cyclopentyloxyimino-(3,4-dichloro-phenyl)-acetic acid as a faintly yellow semi-solid (304 mg, quant.) that was used without further purification.
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