2646-90-4Relevant articles and documents
Synthesis method for improving yield of 2, 5-difluorobenzaldehyde by adopting negative ion stabilizer
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Paragraph 0022; 0046-0125, (2021/02/06)
The invention provides a synthesis method for increasing the yield of 2, 5-difluorobenzaldehyde by adopting a negative ion stabilizer, which comprises the following steps: S1, dissolving a raw material p-difluorobenzene in a solvent, adding the negative ion stabilizer into the mixed solution, and controlling the temperature at -70 to -40 DEG C, S2, adding n-butyllithium into the reaction solutionobtained in the step S1, carrying out heat preservation and stirring for 30 minutes, and controlling the temperature to be -70 to -40 DEG C, S3, dropwise adding N, N-dimethylformamide into the reaction solution of the element in S2, and determining the HPLC content of the raw materials in the reaction solution, and S4, carrying out aftertreatment quenching, extraction, acid regulation, concentration and rectification on the reaction solution obtained in the step S3 to obtain the product.Wherein the negative ion stabilizer in S1 is any one of pentamethyldiethylenetriamine, tetramethylethylenediamine and hexamethylphosphoramide, and the negative ion stabilizer is 0.7-1.4 molar equivalents of p-difluorobenzene. The complexing agent and the organic lithium reagent are subjected to complexing reaction, so that the stability of the lithium reagent is improved, the reaction yield is greatly improved, and industrial production is easy to realize.
Ethanobenzazepines
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, (2008/06/13)
Novel ethanobenzazepines, processes for the preparation thereof, and a method of alleviating pain utilizing compounds or compositions thereof are disclosed.