1-(2-Chloro-4-nitrophenyl)-7,8-methylenedioxy-3,5-dihydro-2,3-benzodiazepin-4(4H)-one → 1-(4-Amino-2-chlorophenyl)-7,8-methylenedioxy-3,5-dihydro-2,3-benzodiazepin-4(4H)-one

To a suspension of 7,8-methylenedioxy-1-(2-chloro-4-nitrophenyl)-3,5-dihydro-2,3-benzodiazepin-4(4H)-one (1.4 g, 3.9 mmol) in 1:1:1 ethanol/acetone/water (45 mL) was added 5% Pd/C (106 mg) and HCO2NH4 (2.5 g, 40 mmol). The mixture was stirred at room temperature for 3 h and 15 mL of ethanol was added to the mixture which was then stirred at room temperature for three days. The catalyst was filtered out. The filtrate was extracted with EtOAc (100 mL). The organic phase was washed with water and brine, dried over Na2SO4 and concentrated in vacuo. The residue was purified by chromatography (1:4 hexane/EtOAc) to afford the title compound as a light yellow solid (0.27 g, 0.82 mmol, 21%), mp: 238°-240° C. 1H NMR (CDCl3) 8.34 (s, 1H), 7.41 (d, J=8.6, 1H), 6.81 (s, 1H), 6.69-6.67 (m, 3H), 6.02 (s, 2H), 3.92 (s, 2H), 3.42 (s, 2H).