To a solution of 4-[4-(3-chloropropoxy)phenyl]pyridine 1-oxide (231 mg) and triethylamine (366 μL) in N,N-dimethylformamide (5 mL) are added potassium carbonate (363 mg) and (3S)-3-methylpiperidine mandelate (264 mg). The mixture is stirred at a temperature close to 60° C. for four hours. An additional amount of (3S)-3-methylpiperidine mandelate (100 mg) is added and heating is continued overnight. The suspension is filtered and the precipitate washed with ethyl acetate. The combined organic phases are concentrated under reduced pressure. The residue is purified twice by column chromatography over silica gel using a gradient dichloromethane/methanol/triethylamine from 100/0/0 to 95/5/0.1. Fractions containing the expected product are pooled and concentrated under reduced pressure to give 90 mg of the crude base which is converted to the hydrochloride with an ethereal solution of hydrogen chloride in ethanol to give 75 mg of (3S)-4-{4-[3-(3-methylpiperidin-1-yl)propoxy]phenyl}pyridine 1-oxide, hydrochloride melting at 74° C.
