Bromine → 7-Bromo-3-methyl-5-phenyl-1,3-dihydro-benzo[e][1,4]diazepin-2-one

Participants

Reaction Steps

To a stirred solution of 131 (66.5 g, 265 mmol) in glacial acetic acid (400 mL), sulfuric acid (80 mL) was added to the solution. Bromine (28 mL, 530 mmol) dissolved in acetic acid (150 mL) was added dropwise into the mixture. The reaction mixture was allowed to stir until analysis by NMR spectroscopy indicated that all of the starting material 131 had been consumed. The solution was concentrated under reduced pressure and then brought to pH 7 by addition of 1N aq NaOH solution and then extracted with EtOAc. The crude product 132 was purified by recrystallization from CH2Cl2 to afford 132 (68.66 g, 79%). mp 210-212° C.; IR (KBr, cm−1) 2931, 1692, 1603, 1563, 1475, 1445, 1375, 1259, 1235, 1130, 1090; 1H NMR (CDCl3) δ 9.36 (s, 1H), 7.63 (dd, J=2.22, 8.58 Hz, 1H), 7.54-7.39 (m, 6H), 7.12 (d, J=8.611H), 3.76 (q, J=6.3 Hz, 1H), 1.76 (d, J=6.45 Hz, 3H). MS (EI) m/e (relative intensity) 330 (M++1, 21), 329 (M+, 50), 328 (22), 327 (48), 289 (44), 288 (46), 287 (100), 286 (45), 285 (60) 205 (25), 77 (49).

Provenance & Evidence