After suspending 200 mg of 4-(2-methylphenoxymethyl)piperidine hydrochloride in 5 ml of dichloromethane, 137 mg of 3-methoxypyrazine-2-carboxaldehyde [CAS No. 63874-90-8] and 264 mg of sodium triacetoxyborohydride were added while stirring, and the stirring was continued overnight at room temperature. Aqueous sodium carbonate solution was added to the reaction mixture and extraction was performed with ethyl acetate. The organic layer was washed with saturated brine and dried over anhydrous magnesium sulfate, and then the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (solvent: n-hexane/ethyl acetate) to obtain the title compound (236 mg, 87% yield).
