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

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Reaction Steps

3(R,S)-[(Benzyloxycarbonyl)amino]-5-cycloheptyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one (Example 1, Step 3, 500 mg) in anhydrous toluene (40 ml) was heated to reflux. A solution of dimethylformamide dimethyl acetal (786 μl) in anhydrous toluene (10 ml) was added dropwise and the mixture was heated at reflux for a further hour. The solvent was evaporated and the residue triturated with diethyl ether to afford the title compound (441 mg) as a colourless solid. 1H NMR (360 MHz, CDCl3) δ 1.24-1.90 (11H, m), 2.00-2.14 (1H, m), 2.90-3.00 (1H, m), 3.40 (3H, s), 5.04-5.18 (3H, m), 6.52 (1H, d, J=7.5 Hz), 7.24-7.60 (9H, m). TLC (silica, petrol (60/80): ethyl acetate 2:1). Rf=0.30.

Provenance & Evidence