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

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Reaction Steps

A dichloroethane solution of [5-(o-fluorophenyl)-2,3-dihydro-1-methyl-2-oxo-1H-1,4-benzodiazepin-7-yl]isocyanate, obtained as described in paragraph (a) of Example 1 from 4.2 g (0.015 M) of 7-amino-5-(o-fluorophenyl)-1,3-dihydro-1-methyl-2H-1,4-benzodiazepin-2-one, is treated with excess tert.butylamine. After concentration of the mixture, the residue is taken up in methylene chloride/water and the methylene chloride solution is washed several times with water. After drying the organic phase over sodium sulphate, the sodium sulphate is filtered off and the methylene chloride is evaporated off. The residue is purified on a silica gel column (150 g of SiO2) using 40% ethyl acetate in methylene chloride as the eluting agent and crystallised from ethanol/petroleum ether. There is obtained 1-tert.butyl-3-[5-(o-fluorophenyl)-2,3-dihydro-1-methyl-2-oxo-1H-1,4-benzodiazepin-7-yl]urea which melts at 210° C. with decomposition.

Provenance & Evidence