Reaction Steps
To a stirred solution of (1R)-1-(2-naphthyl)-N-(phenylmethylene) ethanamine (4, 10 g, 0.038 mol) in ethanol (200 mL) was added sodium cyanoborohydride (3.63 g, 0.057 mol) at 25-30° C. The reaction mass was further stirred at 45-50° C. for 5-6 h. Upon completion of the reaction (by TLC), the reaction mass was cooled, quenched with water (100 mL), and extracted with n-heptane (100 mL). The organic layer was separated, washed with water (100 mL), and concentrated under reduced pressure to provide a thick oil. The oil was dissolved in n-heptane (90 mL) and stirred, and the pH of the solution was adjusted to 1-2 using concentrated hydrochloric acid. The precipitated solid was filtered, washed with n-heptane (10 mL), and dried under vacuum to yield the title compound as a white crystalline solid. Yield: 8.2 g, (81.42%); HPLC purity: 99.10%; IR (KBr) cm−1: 3445, 2965, 2759, 2728, 2682, 1596, 1457, 1378, 801, 781, 779; MS: m/z=262.07 [M+H]+; 1H NMR (400 MHz, CDCl3): δ=1.73-1.75 (d, J=8.8 Hz, 3H), 3.95-3.99 (br dd, 1H), 4.16-4.19 (br dd, 1H), 5.24-5.26 (q, J=8.8 Hz, 1H), 7.38-7.39 (m, 3H), 7.48-7.50 (t, 2H), 7.57-7.59 (m, 2H), 7.64-7.66 (d, 1H), 7.98-8.03 (m, 3H), 8.08-8.11 (d, J=9.2 Hz, 1H), 9.72 (bs, 1H), 10.48 (bs, 1H). 13C NMR (100 MHz, CDCl3): δ=21.15 (CH3), 48.34 (CH2), 51.48 (CH), 121.35, 125.04, 125.9, 126.69, 128.52, 129.0, 129.11, 129.61, 130.21, 130.76, 132.11, 133.60.
