Racemization method of trans-levochrysanthemic acid

A technology of levochrysanthemic acid and ethyl levochrysanthemum acid, which is applied in organic chemistry methods, chemical instruments and methods, organic chemistry, etc., can solve the problems that racemization cannot be applied, and achieve high yield of racemate and smooth reaction process Mild Conditions and Versatile Effects

Active Publication Date: 2022-05-27
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, these racemization methods of the first chrysanthemic acid cannot be applied to the racemization of trans-L-DV-chrysanthemic acid and trans-L-3-acetyl-2,2-dimethylcyclopropanecarboxylic acid
At present, there is no report on the racemization of trans-L-DV-chrysanthemic acid, but there has been no literature on the racemization of trans-L-3-acetyl-2,2-dimethylcyclopropanecarboxylic acid. According to the report, the racemization of trans-L-chrysanthemic acid is still an important challenge faced by the current pyrethroid production enterprises

Method used

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  • Racemization method of trans-levochrysanthemic acid
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  • Racemization method of trans-levochrysanthemic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] 17.0 g (0.1 mol) of trans-L-3-acetyl-2,2-dimethylcyclopropane ethyl ester prepared by esterification, 50 g of toluene, and 2.67 g (0.02 mol) of aluminum trichloride were heated under reflux. React for 5 hours, add 50 g of water, continue to reflux for 2 hours, drop to room temperature, stand for liquid separation, after the organic layer is concentrated under reduced pressure to remove the solvent, add 50 g of 2mol / L hydrochloric acid, stir at room temperature for 1 hour, and separate out trans-racemic 3-acetyl 12.5 g of base-2,2-dimethylcyclopropanecarboxylic acid, yield 80%. Toluene is added to the aqueous solution for extraction, and the organic layer is concentrated to recover trans-L-3-acetyl-2,2-dimethylcyclopropanecarboxylic acid, which can be recycled and applied mechanically. 1 H NMR (400MHz, Chloroform-d) δ 2.56 (d, J=5.8Hz, 1H), 2.37 (dd, J=5.5, 1.7Hz, 1H), 2.28 (d, J=1.4Hz, 3H), 1.38 (d, J=1.6 Hz, 3H), 1.20 (d, J=1.7 Hz, 3H). The detected product is trans-...

Embodiment 2

[0028] Heat 17.0 g (0.1 mol) of ethyl trans-L-3-acetyl-2,2-dimethylcyclopropane carboxylate prepared by esterification, 50 g of dichloroethane, and 2.73 g (0.02 mol) of zinc chloride React under reflux for 4 hours, add 50 g of water, continue to reflux for 2 hours, drop to room temperature, stand for liquid separation, after the organic layer is concentrated under reduced pressure to remove the solvent, 50 g of 2mol / L hydrochloric acid is added, and stirred at room temperature for 1 hour to precipitate trans-racemic 3 -Acetyl-2,2-dimethylcyclopropanecarboxylic acid 13.2g, yield 84.6%. Toluene is added to the aqueous solution for extraction, and the organic layer is concentrated to recover trans-L-3-acetyl-2,2-dimethylcyclopropanecarboxylic acid, which can be recycled and applied mechanically.

Embodiment 3

[0030] Heat 17.0 g (0.1 mol) of ethyl trans-L-3-acetyl-2,2-dimethylcyclopropane carboxylate prepared by esterification, 50 g of dioxane, and 5.9 g (0.02 mol) of iron bromide. React under reflux for 4 hours, add 50 g of water, continue to reflux for 2 hours, drop to room temperature, stand for liquid separation, after the organic layer is concentrated under reduced pressure to remove the solvent, 50 g of 2mol / L hydrochloric acid is added, and stirred at room temperature for 1 hour to precipitate trans-racemic 3 -Acetyl-2,2-dimethylcyclopropanecarboxylic acid 12.2g, yield 78.2%. Toluene is added to the aqueous solution for extraction, and the trans-L-3-acetyl-2,2-dimethylcyclopropane carboxylic acid is concentrated and recovered, which can be recycled and applied mechanically.

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Abstract

The invention discloses a universal racemization method of trans-levochrysanthemic acid, and belongs to the field of organic synthesis. The preparation method comprises the following steps: esterifying trans-levorotatory acid, carrying out racemization reaction on the esterified trans-levorotatory acid and lewis acid in a solvent at 70-120 DEG C for 4-6 hours, adding water, continuously reacting for 2 hours, washing an oil layer with water, desolventizing, acidifying and filtering to obtain the trans-racemic chrysanthemic acid, and the structure of the trans-racemic chrysanthemic acid is shown as the following I. The invention aims to provide the preparation method of the trans-racemic chrysanthemic acid with low drug effect or ineffective trans-levorotatory chrysanthemic acid. The trans-racemic chrysanthemic acid is obtained through esterification, racemization and other two-step reaction, recycling of ineffective chrysanthemic acid bodies is achieved, and the purposes of saving raw materials, reducing resource waste, reducing three wastes and saving the production cost of chiral chrysanthemic acid are achieved.

Description

technical field [0001] The present invention relates to the technical field of chemical synthesis, in particular to a general racemization method of trans-levothrinate. Background technique [0002] Pyrethroids are widely used worldwide as an important class of sanitary and agricultural pesticides. Most pyrethroids contain cyclopropane structures and have multiple optical isomers. There are great differences in biological activity between different optical isomers, one optical isomer has a prominent effect, while other isomers are usually ineffective or inefficient or even produce high toxic side effects, such as allethrin, There are eight chiral isomers of cypermethrin, among which the trans-(R,S)-form has the best insecticidal activity, while the cis-(R,S)-form has the highest activity among the eight isomers of cypermethrin Therefore, the efficient preparation of pyrethroid compounds with high optical purity has been a long-term goal of the scientific community and the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/09C07C61/37C07C61/40C07C61/16C07C67/08C07C69/743C07C69/747C07C69/757
CPCC07C51/09C07C67/08C07C2601/02C07B2200/07C07C61/37C07C61/40C07C61/16C07C69/743C07C69/747C07C69/757
Inventor 胡向平陈松
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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