Reaction Steps
During the preparation of 6a, the mother liquor from the DMF/ether (25:75) solution was kept and washed thoroughly 4 times with 40 ml of water. The organic layer was then washed with brine and dried over MgSO4. The solvent was evaporated down to a dark residue. Column chromatography (Silica, DCM as elutant) afforded 5 (140 mg; 0.485 mmol) as a beige powder in a 50% yield. Rf=0.75 in 100% ethyl acetate; mp: 99-100° C.; 1H NMR (CDCl3, 400 MHz): δ 7.64 (d, 1H, J=7.60 Hz), 7.60 (d, 1H, J=7.60 Hz), 7.22 (t, 1H, J=7.60 Hz), 7.13 (t, 2H, J=7.60 Hz), 7.01 (d, 1H, J=7.60 Hz), 6.77 (t, 1H, J=7.60 Hz), 6.62 (d, 1H, J=7.60 Hz), 4.27 (s, 2H), 3.64 (t, 2H, J=7.80 Hz), 3.44 (t, 2H, J=7.80 Hz); 13C NMR (CDCl3, 100 MHz): δ 145.02 (C), 132.71 (C), 132.19 (C), 129.68 (CH), 128.55 (CH), 128.22 (CH), 125.96 (CH), 124.44 (CH), 124.22 (C), 123.59 (CH), 119.19 (CH), 112.51 (CH), 53.38 (CH2), 53.26 (CH2), 27.78 (CH2); IR (KBr, cm−1): 3429 (s), 2924 (w), 1716 (w), 1628 (s), 1601 (s), 1525 (w), 1493 (s), 1442 (s), 1340 (m), 1290 (m), 1269 (s), 1196 (s), 1022 (m), 758 (s), 725 (m), 615 (m) MS (FAB): 289 (M+H) (100), 222.1 (7), 194.1 (35), 180.1 (22), 166.1 (6), 152.1 (4), 107.2 (2), 85.7 (1), 58.1 (7); Anal. Calcd for C15H14NBr: C, 62.51; H, 4.89; N, 4.86. Found: C, 62.30; H, 4.96; N, 4.75.
