[F:1][C:2]1[CH:7]=[C:6]([Cl:8])[C:5]([OH:9])=[CH:4][C:3]=1[NH:10][C:11](=[O:15])[O:12][CH2:13][CH3:14].C(=O)([O-])[O-].[K+].[K+].[CH:22]1(Br)[CH2:26][CH2:25][CH2:24][CH2:23]1>C(#N)C>[F:1][C:2]1[CH:7]=[C:6]([Cl:8])[C:5]([O:9][CH:22]2[CH2:26][CH2:25][CH2:24][CH2:23]2)=[CH:4][C:3]=1[NH:10][C:11](=[O:15])[O:12][CH2:13][CH3:14]Then, a solution of the resulting ethyl N-(2-fluoro-4-chloro-5-hydroxyphenyl)carbamate (10.0 g, 42.8 mmol) and potassium carbonate (8.87 g, 64.2 mmol) in acetonitrile (150 ml) was stirred for 1 hour at 80° C. Then, cyclopentyl bromide (9.57 g, 84.2 mmol) was added dropwise thereto, followed by reacting for further 7 hours. After completion of the reaction, tile solvent was distilled off under reduced pressure, and the residue was made acidic by adding 1N hydrochloric acid (100 ml) and extracted with ethyl acetate (100 ml×3 times). The organic layer was washed with water, dried, and the solvent was distilled off under reduced pressure to obtain ethyl N-(2-fluoro-4-chloro-5-cyclopentyloxyphenyl)carbamate (12.7 g, 98% yield).
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