A solution of [4-(2-Benzyloxy-4-ethylphenoxy)-3-fluorophenyl]-carbamic acid-benzyl ester (500 mg, 1.06 mmol) in 5 ml tetrahydrofuran under nitrogen atmosphere was cooled to −78° C. To this added 2.8M n-butyl lithium (0.075 g, 1.16 mmol) dropwise and the stirring at −78° C. for 1 h. Condensed ethylene oxide (0.5 ml, 9.9 mmol) was then added dropwise to the reaction mixture and warmed slowly to rt. The reaction was stirred at rt overnight and then quenched with saturated ammonium chloride solution. The aqueous phase was extracted with dichloromethane and the combined organic phase was dried over anhydrous Na2SO4 and concentrated. The crude obtained was purified by column chromatography on silica gel using 25% ethyl acetate in petroleum ether as eluant to obtain 350 mg, 81% of the title compound as a brown oil.
