3-Amino-1,2-propanediol → 1-[(S)-6-bromo-5-(o-chlorophenyl)-2,3-dihydro-1,3-dimethyl-2-oxo-1H-1,4-benzodiazepin-7-yl]-3-[(2,2-dimethyl-1,3-dioxolan-4-yl)methyl]urea

Participants

Reaction Steps

A solution of (S)-[6-bromo-5-(o-chlorophenyl)-2,3-dihydro-1,3-dimethyl-2-oxo-1H-1,4-benzodiazepin-7-yl]isocyanate [obtained in accordance with details in Example 1(f) from 4 g (0.01 mol) of (S)-7-amino-6-bromo-5-(o-chlorophenyl)-1,3-dihydro-1,3-dimethyl-2H-1,4-benzodiazepin-2-one] in acetone is treated with a solution of 3.8 g (0.04 mol) of 3-amino-1,2-propanediol in 10 ml of water and 50 ml of acetone, the mixture is stirred at room temperature for 12 hours and extracted with methylene chloride. The organic extract is dried over sodium sulphate and evaporated, whereupon the residue is chromatographed on silica gel while eluting with chloroform. There is obtained 1-[(S)-6-bromo-5-(o-chlorophenyl)-2,3-dihydro-1,3-dimethyl-2-oxo-1H-1,4-benzodiazepin-7-yl]-3-[(2,2-dimethyl-1,3-dioxolan-4-yl)methyl]urea of melting point 135° (decomposition); [α]25D =+7.6° (0.8 percent solution in methanol).

Provenance & Evidence