Acetic Acid → Methyl 3-{[(2R*,6S*)-1-benzyl-2,6-dimethylpiperidin-4-yl]amino}-2-methyl-5-(trifluoromethyl)benzoate

Participants

Reaction Steps

To a stirred mixture of MS3A (1.0 g), methyl 3-amino-2-methyl-5-(trifluoromethyl)benzoate (350 mg, 1.50 mmol) and (2R,6S)-1-benzyl-2,6-dimethylpiperidin-4-one (359 mg, 1.65 mmol) in chloroform (10 mL) was added acetic acid (500 uL) at 0° C. and stirred at r.t. for 7 hours. To the reaction mixture was added sodium triacetoxyborohydride (670 mg, 3.00 mmol) at 0° C. The reaction mixture was stirred at 23° C. for 1.5 hours. Then the reaction mixture was quenched with aq. NaHCO3 until pH8-9. The MS 3 Å was removed by Celite filtration and the content was extracted with ethylacetate, dried over MgSO4, filtered and the filtrate was concentrated in vacuo. The residue was purified by silica gel column chromatography (heptane/ethylacetate=5/1 to 3/1). Target fractions were collected and 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 (223 mg, 62% yield.). For major isomer; 1H-NMR (400 MHz, CDCl3) δppm; 7.40-7.21 (m, 6H), 6.85 (s, 1H), 4.00-3.95 (m, 1H), 3.91 (s, 3H), 3.88 (d, 2H), 3.84-3.76 (m, 1H), 2.83-2.73 (m, 2H), 2.25 (s, 3H), 1.83-1.69 (m, 4H), 1.13 (d, J=6.4 Hz, 6H).

Provenance & Evidence