Reaction Steps
25 (6.25 g, 22.05 mmol) and 200 ml of ethanol were placed in a 500 ml flask. 6.25 g (165 mmol) of powdered NaBH4 were added to the solution and the reaction mixture was stirred at 40° C. for 48 hours. It was subsequently cooled to room temperature and the reaction was stopped by means of 10 ml of cold water. After stirring for a further 10 minutes, the reaction mixture was extracted twice with 100 ml of DCM and the combined organic phases were dried over Na2SO4. The crude product was purified by flash chromatography on silica gel (EtOAc/NEt3, 10:1). This gave a pale yellow solid. Rf=0.23 (EtOAc/NEt3, 10:1); 1H NMR: (300 MHz, CDCl3): δ=3.99 (s, 1H, N—H), 4.59 (s, 2H, 2,3-H), 4.62 (s, 1H, N—H), 6.39 (d, 3J=5.4 Hz, 1H, 8-H), 6.80 (dd, 4J=1.2 Hz, 3J=9.3 Hz, 2H, 2,6-phenyl-H), 6.84 (dd, 4J=1.2 Hz, 3J=9.3 Hz, 2H, 2,6-phenyl-H), 7.12 (m, 6H, 3,4,5-phenyl-H) ppm. 13C NMR (75 MHz, CDCl3): δ=58.6, 60.1 (C-2,3), 108.0 (C-8), 127.9-128.4 (phenyl-C), 129.8 (C-4a), 139.8 (Cq, phenyl-C), 140.0 (Cq, C-8a), 134.9 (C-5), 141.3 (C-7) ppm; MS (EI): m/e (%) 288 (22), 287 (M+, 100), 286 (24), 285 (7), 284 (6), 283 (8), 282 (5), 211 (13), 210 (78), 209 (5), 208 (13), 197 (4), 196 (26), 181 (13), 179 (3), 127 (4), 104 (7), 92 (3), 91 (32), 77 (5); IR (neat): ν=3215 (w), 2830 (w), 1596 (s), 1519 (s), 1493 (w), 1466 (w), 1452 (s), 1360 (m), 1290 (s), 1250 (m), 1231 (m), 1174 (s), 1120 (m), 1072 (m), 1050 (w), 1029 (w), 1005 (w), 989 (w), 950 (w), 905 (w), 844 (w), 810 (m), 770 (m), 723 (m), 675 (vs), 668 (w), 645 (w), 618 (m) cm−1. HRMS (EI): calculated for C19H17N3 287.1422 [M+], found: 287.1402.
