Ethyl chloroacetimidate → (S)-1-(5-chloromethyl-1,3,4-oxadiazol-2-yl)-12,12a-dihydro-9H,11H-azeto[2,1-c]imidazo[1,5-a][1,4]benzodiazepin-9-one

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Reaction Steps

A solution of 5 g (17.64 mmol) of (S)-12,12a-dihydro-9-oxo-9H,11H-azeto[2,1-c]imidazo[1,5-a][1,4]benzodiazepine-1-carboxylic acid hydrazide and 3.06 g (19.41 mmol) of ethyl chloroacetimidate in 40 ml of dimethylformamide and 10 ml of ethanol was stirred at 90° for 12 hours. The solvent was evaporated and the residue was partitioned between methylene chloride and water. The aqueous phase was back-washed once with methylene chloride. The organic phases were dried with magnesium sulfate, filtered and evaporated. Chromatography of the residue (silica gel, methylene chloride/methanol 93:3) yielded 3.26 g (55%) of (S)-1-(5-chloromethyl-1,3,4-oxadiazol-2-yl)-12,12a-dihydro-9H,11H-azeto[2,1-c]imidazo[1,5-a][1,4]benzodiazepine-9-one as a colourless foam, RF=0.5 (methylene chloride/methanol 10:1).

Provenance & Evidence