| abstract |
The present invention relates to the process for the preparation of 1-(3,4-dimethoxy-phenyl)-5-ethyl-7,8-dimethoxy-4-methyl-5H-2,3-benzodiazepine of the Formula (I) by reacting 3,4,3',4'-tetramethoxy-6-(a-aceto-propyl)-benzofenon of the general Formula (II) with hydrazine or hydrazine-hydrate in alcoholic medium, and isolating and purifying the reaction product with a clarifier, which comprises using during the clarifying step a recrystallization solution having an iron content lower than 7 ppm. |