Acetic Acid → (3R,4R)-4-(4-Bromo-2-nitro-phenylamino)-1-methyl-piperidin-3-ol

Participants

Reaction Steps

Add formaldehyde (20.5 mL, 37-41% aqueous solution) to a solution of (3R,4R)-4-(4-bromo-2-nitro-phenylamino)-piperidin-3-ol.hydrochloride salt (0.0.024 mol, 8.68 g) and acetic acid (10.2 mL) in water (42 mL) and stir the reaction mixture at room temperature for 30 min. Add sodium cyanoborohydride (0.073 mol, 4.6 g) and stir the reaction mixture for 3 h. Quench the reaction mixture with sodium bicarbonate solution and extract with dichloromethane. Dry the organic layer over anhydrous sodium sulfate, filter, and concentrate to obtain the title compound (7.8 g, 97%). 1H NMR (400 MHz, CDCl3) δ 1.63-1.71 (m, 1H), 2.16-2.21 (m, 2H), 2.33 (s, 3H), 2.35-2.38 (m, 1H), 2.60 (br s, 1H), 2.80 (d, 1H), 3.54-3.56 (m, 1H), 3.75-3.79 (m, 1H), 6.92 (d, 1H), 7.48 (dd, 1H), 8.14 (d, 1H), 8.30 (d, 1H).

Provenance & Evidence