Lawesson's reagent → 3-chloro-4,5-dihydro-5-methyl-6H-imidazo[1,5-a][1,4]benzodiazepine-6-thione

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Reaction Steps

3.71 g (15 mmol) of 3-chloro-4,5-dihydro-5-methyl-6H-imidazo[1,5-a][1,4]benzodiazepin-6-one in 10 ml of toluene are heated to boiling under reflux for 4 hours together with 3.03 g (7.5 mmol) of 2,4-bis(p-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulphide. The solution is washed with water and evaporated. By chromatography on a silica gel column and subsequent recrystallization from ethyl acetate there is obtained 3-chloro-4,5-dihydro-5-methyl-6H-imidazo[1,5-a][1,4]benzodiazepine-6-thione of melting point 197.5°-198.5°.

Provenance & Evidence