| 摘要 |
The invention is concerned with a novel process for the manufacture of 4H-imidazo¢1,5-a!¢1,4!benzodiazepine derivatives of general formula I <IMG> I wherein R1 signifies phenyl or mono- or disubstituted phenyl; R2 signifies hydrogen, halogen, nitro, cyano, trifluoromethyl or lower alkyl; R3 signifies hydrogen or lower alkyl; and R4 signifies hydrogen or lower alkyl and of pharmaceutically usable salts of these compounds by decarboxylating a 4H-imidazo¢1,5-a!¢1,4!benzodiazepine-carboxylic acid of general formula II <IMG> II wherein R1, R2, R3 and R4 have the above significances, at elevated temperature and under elevated pressure in the presence of an organic solvent. The compounds of formula I and their pharmaceutically usable acid addition salts are known muscle relaxants, sedatives and anticonvulsants.
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