Method for Synthesizing Cyclopropaneformic Acid Ester in Low Alcohol Solubility Solvent

Abstract

The invention discloses a method for synthesizing cyclopropanecarboxylate by using a low-alcohol solubility solvent. The method comprises the following steps: 1, mixing gamma-chlorobutyrate with a solvent to obtain a mixed base material, heating the obtained mixed base material to 120-130 DEG C, continuously dropwise adding a corresponding alcohol solution of sodium alkoxide or potassium alkoxide to the 120-130 DEG C mixed base material, distilling off solvent-alcohol azeotrope in an azeotropic distillation manner, condensing the obtained azeotrope to layer the azeotrope, and separating the obtained alcohol phase which is a lower condensate layer, and obtaining a cyclization reaction solution after the cyclization reaction ends when no alcohol phase is separated from the azeotropic condensate, wherein the solvent is the low-alcohol solubility solvent; 2, washing the separated alcohol phase obtained in step 1 with water, and separating the obtained organic layer positioned at an upper layer; and 3, mixing the cyclization reaction solution obtained in step 1 with the organic phase obtained in step 2, and carrying out normal pressure rectification to obtain the cyclopropanecarboxylate.

Description

technical field [0001] The invention relates to a synthesis method of cyclopropanecarboxylate, especially a synthesis method using gamma-chlorobutyrate as a starting material. Background technique [0002] Cyclopropyl carboxylate (s-1) is an important intermediate for the synthesis of cyclopropylamine, and cyclopropylamine is an important intermediate for quinolone antibacterial agents, insecticides, and pesticides. [0003] [0004] At present, in the synthetic method of cyclopropanate, most are starting raw material with γ-chlorobutyrate, utilize sodium alkoxide or potassium alkoxide as the strong base of cyclization reaction, aromatic hydrocarbon solvents such as toluene, xylene are solvents, Carry out ring closure reaction at 60~130°C to prepare cyclopropanecarboxylate. [0005] Patent US3711549 utilizes solid sodium methoxide as a strong base and toluene as a solvent to synthesize methyl cyclopropanate by dropping methyl gamma-chlorobutyrate into a sodium methoxide-...

AI Technical Summary

Problems solved by technology

In the azeotropic composition of aromatic hydrocarbons such as toluene and xylene and alcohol, the content of alcohol is relatively low, and because alcohol and aromatic hydrocarbons are miscible, the azeotrope will not be separated after condensation, resulting in low efficiency of solvent azeotropic band sodium methoxide and evaporation. Methanol takes a long time, requires a large amount of solvent, and is difficult to recycle.

Therefore, aromatic hydrocarbon solvents are not very suitable as solvents for the cyclization reaction, and there are problems such as increased generation of by-products, long time for distilling methanol, large amount of solvent, and difficulty in recycling.

[0007] Although the patent CN1125715A provides a solvent-free process for synthesizing methyl cyclopropanate, the process still has problems such as high content of by-products and long time for distilling methanol

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