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

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Reaction Steps

To a refluxing solution of 3(R,S)-[(benzyloxycarbonyl)amino]-5-cyclohexyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one (5 g) in anhydrous toluene (400 ml) was added dimethylformamide dimethylacetal (7.3 ml) and the mixture was refluxed for 3.5 hours under nitrogen before additional dimethylformamide dimethyl acetal (1 ml) was added. After a further 50 minutes at reflux, solvents were removed under vacuum and the residue was triturated with diethyl ether (50 ml). The white solid was collected by filtration, washed with diethyl ether (2×20 ml) and dried to give the title compound (5 g); mp 205°-207° C.; dH (360 MHz, CDCl3) 7.55-7.25 (9H, m), 6.52 (1H, d, J=8.0 Hz), 5.10 (3H, m), 3.36 (3H, s), 2.76 (1H, m), 2.04-1.03 (10H, m).

Provenance & Evidence