Phosphorus oxychloride → 7-chloro-5-methyl-6-oxo-5,6-dihydro-4H-imidazo[1,5-a][1,4]benzodiazepine-3-carbonitrile

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Reaction Steps

19.0 g 7-Chloro-5,6-dihydro-5-methyl-6-oxo-4H-imidazo[1,5-a][1,4]benzodiazepine-3-carboxamide were suspended under stirring and argon atmosphere in 95 ml 1,4-dioxane and 6.58 ml phosphorous oxychloride were added in one portion. The reaction mixture was heated to reflux for one hour giving a yellow solution, which was concentrated at 50° C. under reduced pressure. The residue was digested in 100 ml deionized water for two hours at r.t. The precipitate (7-chloro-5,6-dihydro-5-methyl-6-oxo-4H-imidazo[1,5-a][1,4]benzodiazepine-3-carbonitrile) was filtered off, washed three times with 30 ml deionized water and dried under vacuum at 80° C. for 18 hours. Crude product: 17.3 g as a light yellow powder. m.p. 238.5-239.5° C.

Provenance & Evidence