Dichloromethane → Ethyl 7-chloro-2,3-dihydro-2-oxo-5-phenyl-1H-1,4-benzodiazepine-3-carboxylate

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Reaction Steps

A solution of 2 g. of ethyl 2'-benzoyl-4'-chloro-mesoxalanilate 2-oxime in 40 ml. of methylene chloride is treated with 2 g. of zinc dust. 4 ml. of glacial acetic acid are added dropwise within 5 minutes with stirring. After the addition, the mixture is stirred at room temperature for 1 hour. The reaction mixture is filtered and the filtrate evaporated. The residue is boiled under reflux for 2 hours in 20 ml. of benzene and 2 ml. of glacial acetic acid. The reaction mixture is washed out with 10% soda solution, dried over sodium sulphate and evaporated. Crystallization of the residue from alcohol yields ethyl 7-chloro-1,3-dihydro-5-phenyl-2H-1,4-benzodiazepin-2-one-3-carboxylate, m.p. 232°-234°. Further material crystallizes from the mother liquor.

Provenance & Evidence