3(R,S)-[(Benzyloxycarbonyl)amino]-5-cydohexyl-1,3-dihydro-1-methyl-2H-1,4-benzodiazepin-2-one → 3(R,S)-amino-5-cyclohexyl-1,3-dihydro-1-methyl-2H-1,4-benzodiazepin-2-one

Participants

Reaction Steps

A mixture of 3(R,S)-[(benzyloxycarbonyl)amino]-5-cyclohexyl-1,3-dihydro-1-methyl-2H-1,4-benzodiazepin-2-one (3.0 g) and hydrobromic add (45% in acetic add, 6.2 ml) was stirred for 1 h at room temperature under an atmosphere of nitrogen. The mixture was then diluted with cold anhydrous diethyl ether (40 ml) and stirred at 0° C. for 45 min. The white precipitate was collected by filtration, washed with cold diethyl ether (4×30 ml) and then dissolved in a mixture of water (30 ml) and aq. sodium hydroxide (2M, 15 ml). The basic aqueous phase was extracted with ethyl acetate (3×70 ml) and the combined organic layers were washed with brine (30 ml), dried (Na2SO4) and concentrated. The residue was chromatographed on silica gel, using 94:6, dichloromethane:methanol as the eluant, to afford the title compound (1.6 g) as a pale pink solid. Mp 133°-136° C. 1H NMR (360 MHz, CDCl3) δ 1.02-1.40 (4H, m), 1.47-1.56 (1H, m), 1.61-1.74 (3H, m), 1.84-1.91 (1H, m), 1.96-2.06 (1H, m), 2.17 (2H, brs), 2.70-2.80 (1H, m), 3.39 (3H, s), 4.29 (1H, s), 7.20-7.27 (2H, m), 7.44-7.54 (2H, m).

Provenance & Evidence