Methanol → Urea, N-(5-(2-fluorophenyl)-2,3-dihydro-1-methyl-2-oxo-1H-1,4-benzodiazepin-7-yl)-N(sup 1)-(2-hydroxyethyl)-

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Reaction Steps

1.5 g (0.003 M) of 1-benzyl-1-(2-tert.butoxyethyl)-3-[5-(o-fluorophenyl)-2,3-dihydro-1-methyl-2-oxo-1H-1,4-benzodiazepin-7-yl]urea are dissolved in 15 ml of 48% aqueous hydrogen bromide solution, the mixture is heated on a steam-bath for 10 minutes, made alkaline with sodium bicarbonate, treated with a small amount of methanol and extracted three times with methylene chloride. The extracts are combined, dried over sodium sulphate, filtered and concentrated. The residue is purified in a pressure column (0.2-0.4 atmospheres of nitrogen) on 300 g of silica gel (particle size 0.04-0.06 mm) using acetone as the eluting agent and crystallised from acetone/ether. There is obtained 1-[5-(o-fluorophenyl)-2,3-dihydro-1-methyl-2-oxo-1H-1,4-benzodiazepin-7-yl]-3-(2-hydroxyethyl)urea which, according to the IR spectrum, is identical with a sample of this substance prepared in another manner (see Example 7).

Provenance & Evidence