Ammonia → 6-phenyl-8-chloro-4H-s-triazolo [4,3-a][1,4]benzodiazepine-1-carbonitrile

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Reaction Steps

A solution of 4.8 g (0.015 mole) of 6-phenyl-8-chloro-4H-s-triazolo[4,3-a][1,4]benzodiazepine-1-carboxaldehyde [see Example 1 a)] in abs. benzene is saturated with ammonia. After cooling of the solution to 0°, an addition is made portionwise, with a light flow of ammonia gas and in the course of 45 minutes, of 14.0 g (0.030 mole) of lead tetraactetate. The reaction mixture is then stirred for a further 24 hours at 25°; it is subsequently diluted with ether and filtered through kieselguhr. The filtrate is washed with 1N hydrochloric acid, water and saturated sodium chloride solution, dried over magnesium sulphate and concentrated by evaporation. The residue is chromatographed through silica gel with the use of ethyl acetate as eluant. The fractions containing the desired nitrile [Rf = 0.63 in the eluant system ethyl acetate/isopropanol (7:1)] are combined, and concentrated by evaporation. The residue is crystallised from ethyl acetate/petroleum ether to obtain 6-phenyl-8-chloro-4H-s-triazolo [4,3-a][1,4]benzodiazepine-1-carbonitrile, M.P. 191°-192°.

Provenance & Evidence