Acetaldehyde → Methyl 3-{[(2R,6R)-1-benzyl-2,6-dimethylpiperidin-4-yl](ethyl)amino}-5-fluoro-2-methylbenzoate

Participants

Reaction Steps

To a stirred solution of methyl 3-{[(2R,6R)-1-benzyl-2,6-dimethylpiperidin-4-yl]amino}-5-fluoro-2-methylbenzoate (269 mg, 0.701 mmol) in dichloromethane (5 mL) and acetic acid (500 uL) was added acetaldehyde (124 mg, 2.80 mmol) and sodium triacetoxyborohydride (469 mg, 2.10 mmol) at 0° C. The reaction mixture was stirred at rt for 12 hours. Then the reaction mixture was quenched with aq. NaHCO3 until pH8-9. The content was extracted with ethylacetate. The organic layer was dried over MgSO4 and filtered. The filtrate was concentrated in vacuo. The residue was purified by silica gel column chromatography (NH—SiO2; heptane/ethylacetate=5/1) to give the titled compound as a light yellow oil (277 mg, 96% yield). 1HNMR (400 MHz, CDCl3) δppm; 7.19-7.36 (m, 6H), 6.97 (dd, J=2.4, 10.4 Hz, 1H), 3.89 (s, 3H), 3.86 (d, J=10.4 Hz, 1H), 3.39 (d, J=10.4 Hz, 1H), 3.02-3.10 (m, 4H), 2.74-2.80 (m, 1H), 2.43 (s, 3H), 1.74-1.82 (m, 1H), 1.51-1.63 (m, 2H), 1.32-1.40 (m, 1H), 1.05 (d, J=6.4 Hz, 3H), 0.93 (d, J=7.2 Hz, 3H), 0.86 (t, J=6.8 Hz, 3H); MS (ES) [M+H] 413.0.

Provenance & Evidence