Reaction Steps
A solution of 5-[(3S)-3-(4-chlorophenyl)-4-[(R)-1-(4-chlorophenyl)ethyl]-7-iodo-2,5-dioxo-3,4-dihydro-1H-1,4-benzodiazepin-1-yl]valeric acid tert-butyl ester (300 mg, 0.42 mmol), dichloro bis-(triphenylphosphine)Pd(II) (21 mg, 0.030 mmol), and triethylamine (200 μL, 1.43 mmol), in DMF (4 mL) and methanol (1.5 mL) was stirred under a carbon monoxide atmosphere at 80° C. for 24 h. After the solution was cooled to room temperature, the solvent was evaporated under reduced pressure. The crude reaction product was purified by column chromatography on silica gel (EtOAc/hexanes, 1:2) to give the title compound (226 mg, 83%): 1H NMR (400 MHz, CDCl3) δ 1.45 (s, 9H, 3 CH3), 1.58–1.62 (m, 2H, CH2), 1.75 (d, J=5.4 Hz, 3H, CH3), 2.24 (t, J=10.5 Hz, 2H, CH2), 3.62–3.90 (m, 3H, 3 CH), 3.91 (s, 3H, CH3), 4.23–4.31 (m, 1H, CH), 5.34 (s, 1H, CH), 6.45 (q, J=5.4 Hz, 1H, CH), 6.50 (d, J=6.3 Hz, 2H, ArH), 6.84 (d, J=6.3 Hz, 2H, ArH), 6.94 (d, J=6.6 Hz, 1H, ArH), 7.32 (d, J=6.6 Hz, 2H, ArH), 7.50 (d, J=6.3 Hz, 2H, ArH), 7.84 (dd, J=6.3 Hz, J=1.5 Hz, 1H, ArH), 8.33 (d, J=1.5 Hz, 1H, ArH).
