Acetaldehyde → HCID 58365208, compound

To a solution of methylpiperidin-4-yl-carbamic acid tert-butyl ester (2.0 g, 9.4 mmol) in dichloromethane (50 mL) was added acetaldehyde (1.65 mL, 27.9 mmol). The resultant dark red solution was stirred for 10 minutes, then sodium triacetoxyborohydride (2.97 g, 14.0 mmol) was added portionwise. After 20 hours at ambient temperature, the reaction mixture was partitioned between saturated aqueous sodium hydrogen carbonate solution (100 mL) and dichloromethane (100 mL). The organic layer was separated and the aqueous layer extracted with dichloromethane (3×100 mL). The combined organic layer was (Na2SO4), filtered and concentrated in-vacuo. The resultant residue was purified by flash chromatography (silica, 70 g column, Si-SPE, ethyl acetate followed by 10% methanol in dichloromethane) to afford the title compound as an orange oil (1.64 g, 72%). 1H NMR (300 MHz, CDCl3): 3.01 (d, J=11.3 Hz, 2H), 2.74 (s, 3H), 2.41 (q, J=7.2 Hz, 2H), 1.98 (t, J=11.6 Hz, 2H), 1.76-1.72 (m, 5H), 1.46 (s, 9H), 1.08 (t, J=7.2 Hz, 3H).