Method for preparation of 2-benzyl-5-(trifluoromethyl)benzoic acid

Abstract

The invention belongs the technical field of organic synthesis, and particularly relates to a method for preparation of 2-benzyl-5-(trifluoromethyl)benzoic acid. The method comprises the steps: enabling N-(8-quinolyl)-3-(trifluoromethyl) benzamide as an original material to be subjected to three steps of reaction including benzylation, methylation, and hydrolysis and acidification, thereby obtaining 2-benzyl-5-(trifluoromethyl) benzoic acid. The benzylation reaction adopts cobalt diacetylacetonate to serve as a catalyst, use of alkali is not needed, and the catalysis system has the advantagesof cheap price and high yield of a target product. A small amount of water is added in the hydrolysis step, to promote hydrolysis of an intermediate, and shorten reaction time and obtain a higher yield of the target product.

Description

technical field [0001] The application belongs to the field of organic synthesis, and in particular relates to a preparation method of 2-benzyl-5-trifluoromethylbenzoic acid. Background technique [0002] Diaryl alkane derivatives are a very important class of compounds. Many of these compounds have biological activity or are the skeleton structure of some drugs, such as the anti-cold drug Benadryl, anti-diabetic drugs and some anti-depressant drugs diphenhydramine Lun et al. Because of this, the synthesis of diaryl alkane derivatives has also received extensive attention from organic chemists. At present, one of the traditional and main methods of this kind of compounds is to use the coupling reaction of halides (such as benzyl bromide) and some nucleophiles under the catalysis of transition metals. [0003] Benzene homologues headed by toluene and xylene are bulk industrial products with low price, large output and large reserves. In terms of chemical properties, the la...

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Problems solved by technology

However, using toluene as a benzylation reagent often requires complex and harsh reaction conditions, such as high temperature, expensive transition metal catalysts such as Ru / Rh, etc.

Although the prior art has also reported the use of cheap transition metal catalysts such as Cu or Ni to catalyze the reaction of toluene as a benzyl source reagent, these catalytic systems still need to use expensive ligands, perfluoroalkanes as free radical initiators , and must be carried out under alkaline reaction, the reaction cost is high, not suitable for industrial production

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