The invention relates to a process for the preparation of 1-(3-chlorophenyl)-4-methyl-7,8-dimethoxy-5 H-2,3-benzodiazepine of formula (I) ##STR1## in high purity and in a quality suitable for pharmaceutical purposes. According to the invention the reaction of 1 mole of 2-acetonyl-3'-chloro-4,5-dimethoxybenzophenone of formula (II) ##STR2## with 3-7 moles of hydrazine hydrate in an organic solvent or in a mixture of organic solvents at a temperature between 15.degree. C. and 85.degree. C. is carried out in the absence of air oxygen, optionally in the presence of water. The crude product is then recrystallized from an aliphatic alcohol containing 1 to 5 carbon atom(s).
本发明涉及一种制备1-(3-
氯苯基)-4-甲基-7,8-二甲氧基-5H-2,3-苯并二氮
杂环(I)的高纯度工艺,适用于制药目的。根据本发明,在有机溶剂或有机溶剂混合物中,在15°C至85°C的温度下,在无空气
氧气的情况下,用3-7摩尔的
水合
肼与式(II)的2-乙酰基-3'-
氯-4,5-二
甲氧基苯基酮的1摩尔反应,可选地在
水的存在下进行。然后,从含1至5个碳原子的
脂肪醇中重结晶得到粗品。