Analogously to Method A, 2.90 g of tert-butyl 3-{2-[2-(2-acetylaminoethyl)-5-fluorophenoxy]ethoxy}-4-(4-hydroxyphenyl)piperidine-1-carboxylate (Example 223) are reacted. The resulting crude product is subsequently taken up in 50 ml each of ethyl acetate and saturated aqueous sodium hydrogencarbonate solution. The reaction mixture is cooled in an ice bath and admixed with 1.00 ml of benzyl chloroformate and subsequently stirred at 0° C. for a further 30 minutes. The reaction mixture is admixed with 300 ml of water and extracted with ethyl acetate (2×250 ml). The combined organic phases are dried over sodium sulphate, filtered and concentrated by evaporation. The title compound is used further as the crude product Rf=0.30 (EtOAc); Rt=4.33
