Preparation method of 2-chloracetylamino-5-nitro benzophenone

Abstract

The invention provides a preparation method of 2-chloracetylamino-5-nitro benzophenone. The method comprises: taking 2-amino-5-nitro benzophenone and chloroacetyl chloride as raw materials, and performing an acylation reaction in an organic solvent for 1-3.5 h, wherein the acylation reaction is carried out in a reflux condition, the raw material ratio of 2-amino-5-nitro benzophenone to chloroacetyl chloride to the organic solvent is 50 g to (16-48.5) ml to (1000-2000) ml, and the organic solvent is a mixed solvent of cyclohexane and toluene with the volume ratio of cyclohexane to toluene being 1:1-2; and after the acylation reaction is finished, reducing the temperature to the room temperature, performing filtration, washing the obtained filter residue with water till the filter residue is neutral, and performing drying to obtain 2-chloracetylamino-5-nitro benzophenone. Compared with a preparation method in the prior art, the preparation method is reasonable in processing step design, good in operability, and less in by-products. The obtained product is high in purity and yield, and the method can meet industrial application requirements.

Description

technical field [0001] The invention relates to a preparation method of a chemical substance, in particular to a preparation method of 2-chloroacetamido-5-nitrobenzophenone Background technique [0002] Nitroazepam, the chemical name is 1,3-dihydro-7-nitro-5-phenyl-2H-1,4-benzodiazepine-2. The preparation method is listed in "National Compilation of Raw Materials Processes" , 1980 edition, the 801~802 pages have been introduced, and this method is to be raw material with 2-amino-5-nitro-benzophenone and chloroacetyl chloride, carry out acylation in benzene reflux reaction 4 hours, obtain 2 -Chloroacetamido-5-nitro-benzophenone. Then use urotropine as a cyclizing agent, use ethanol as a solvent, and reflux for 20 hours to obtain nitroazepam, the reaction formula: [0003] [0004] The disadvantage of this method is that the yield is low: the yield of 2-chloroacetamido-5-nitrobenzophenone prepared by acylation reaction is only 70%, and the yield of nitroazepam prepared by...

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Problems solved by technology

[0004] The disadvantage of this method is: low yield: the yield of 2-chloroacetamido-5-nitrobenzophenone prepared by acylation reaction is only 70%, and the yield of nitroazepam prepared by cyclization reaction is only 28.5%. -40%, and the product contains many impurities, does not meet the standards of the British Pharmacopoeia, and cannot be exported

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