N-Bromosuccinimide (0.335 g, 1.88 mmol) was added to a solution of 2-oxo-5-phenyl-1-(2,2,2-trifluoroethyl)-2,3-dihydro-1H-1,4-benzodiazepine (H. G. Selnick et al., J. Med. Chem., 1997, 40, 3865-3868) (0.500 g, 1.57 mmol) in carbon tetrachloride (20 mL) at room temperature. After 15 min, trifluoroacetic acid (1.0 mL) was added, and the reaction refluxed for 5 h. The reaction was cooled and concentrated. The residue was dissolved in 5% aqueous sodium acetate (15 mL) and acetone (10 mL) and stirred overnight. The reaction was concentrated and worked up, and the crude product purified by chromatography (silica gel, 0-30% ethyl acetate in hexane gradient elution), providing the title compound. MS 335 (M+1) 1H NMR (500 MHz, CDCl3) □ 7.92-7.30 (9H, m), 5.21 (dq, J=15, 8 Hz, 1H), 5.07 (d, J=10 Hz, 0.5H), 4.51 (d, J=10 Hz, 0.5H), 4.22 (t, dq, J=15, 8 Hz, 1H).
