A mixture comprising 0.459 g of Compound 1B, 0.445 g of 1-(2-trifluoromethoxyphenyl)piperaine (prepared as described by D. Clarke et al, in European Patent EP 711 757, 1996), 0.634 g sodium triacetoxyborohydride, 0.23 mL of glacial acetic acid and 15 mL of 1,2-dichloroethane was stirred for 4 h, under a nitrogen atmosphere. The resultant solution was then kept overnight at room temperature, followed by the addition of 10 mL of water, and alkalinization with a 20% aqueous Na2CO3 solution. This was followed by separation of phases, with the isolated aqueous phase being extracted with 2×20 mL dichloromethane, and with the collected organic phases being dried over anhydrous sodium sulphate. This was followed by the removal of solvents, via vacuum evaporation to dryness. The obtained product residue was purified by flash chromatography (ethyl acetate—petroleum ether gradient 90:10 to 10:0). This was followed by evaporation of the solvents, affording 0.44 g of the title compound (yield 51%).
