- Preparation method of lorazepam intermediate
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The invention discloses a preparation method of a lorazepam intermediate. The preparation method comprises the following steps: taking 7-chloro-5-(-2-chlorphenyl)-1, 3-dihydro-2H-1, 4-benzodiazepine-2-ketone as a raw material, carrying out oxidation reaction with hydrogen peroxide in an aprotic polar solvent without an acidic solvent, and after the reaction is finished, carrying out aftertreatmentto obtain the 7-chloro- dioxo-5-(2chlorphenyl) 1, 3-dihydro-2H-1, 4-benzodiazepine. The invention relates to a 4-benzodiazepine-4-oxide. According to the preparation method, expensive raw materials do not need to be used for catalysis in the reaction process, operations such as reaction quenching, solvent extraction and concentration distillation do not need to be carried out in the post-treatment process, operation steps are reduced, the production period is shortened, the production cost is reduced, and the preparation method is suitable for industrial production.
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Paragraph 0036-0047
(2021/03/18)
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- Preparation method of lorazepam intermediate
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The invention provides a preparation method of a lorazepam intermediate, the lorazepam intermediate is 7-chloro-5-(2-chlorphenyl)-1, 3-dihydro-2H-1, 4-benzodiazepin-2-one-4-oxide, and the preparationmethod comprises the following steps: (1) carrying out acylation reaction on 2-amino-2', 5-dichlorobenzophenone and chloroacetyl chloride to prepare 2-chloroacetamido-2', 5-dichlorobenzophenone, (2) reacting 2-chloroacetamido-2', 5-dichlorobenzophenone with urotropine and ammonium acetate to prepare 7-chloro-5-(2-chlorphenyl)-1, 3-dihydro-2H-1, 4-benzodiazepin-2-one, and (3) carrying out a reaction on the 7-chloro-5-(2-chlorphenyl)-1, 3-dihydro-2H-1, 4-benzodiazepin-2-one and ammonium acetate to obtain 7-chloro-5-(2-chlorphenyl)-1, 3-dihydro-2H-1, 4-benzodiazepin-2-one-4-oxide. The preparationmethod disclosed by the invention is simple and convenient, mild in reaction condition, high in yield, good in product quality and low in cost.
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Paragraph 0076-0079; 0088-0091
(2020/12/15)
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