1-Benzyl-4-[N-ethyl-N-(3-amino-2-pyridinyl)amino]methylpiperidine (EXAMPLE 177, 2.35 g, 7.27 mmol) is dissolved in 18 ml methanol and cooled to 0°. Acetaldehyde (0.45 ml, 8.0 mmol) and sodium cyanoborohydride (685 mg, 10.9 mmol) is added. The mixture is stirred at 0° for one hr, then warmed to 20°-25°. Acetaldehyde and sodium cyanoborohydride are added in the same amounts as above two more times, cooling to 0° before and warming to 20°-25° after each addition. The mixture is poured into 1N sodium hydroxide, extracted with chloroform, dried over sodium sulfate, filtered and concentrated. Flash column chromatography (silica gel, 100 g; methanol/chloroform (5/95)), gives the title compound, NMR (300 MHz, CD3OD) 7.58, 7.31, 6.98, 3.49, 3.18, 3.00, 2.87. 1.93, 1.70, 1.40, 1.15 and 1.01δ.
