CS268475B1 - 3- / 2-Chloro-3,3,3-trifluoroprop-1-enyl / -2,2-dimethyl-cyclopropanecarboxylic acid-cyan-3-phenoxybenzyl ester preparation method - Google Patents

Abstract

The preparation method consists in treating the salt of 3-/2.chloro-3,3,3-trifluoroprop-1-enyl/-2,2-dimethylcyclopropanecarboxylic acid of the general formula +II, where Q represents a group -0 M , in which M is an alkali metal cation, with —< - -cyano-3-phenoxybenzyl-p-toluenesulfonate of the formula III in an inert organic solvent, or in a mixture of water - inert organic solvent, optionally in the presence of a phase transfer catalyst selected from the group of quaternary ammonium salts at a temperature of 20 to 80 C. The said substance exhibits high insecticidal and acaricidal activity.

Description

The invention relates to a process for the preparation of 3- [2-chloro-3,3,3-trifluoroprop-1-yl] -2,2-dimethylcyclopropanecarboxylic acid o-quan-3-phenoxybenzyl ester of the formula I. It is known that this ester shows high insecticidal and acaricidal activity (see, e.g., PO Bentley et al. Pestic. Sci. 1980, 11, 156; 0E 2802962, Czech Pat. No. 205108).

It is known from the prior art that said ester can be obtained by reacting an acid halide of formula II, wherein Q represents a halogen atom, with -cyano-3-phenoxybenzyl alcohol. It is also known that this ester can also be obtained from the free acid of formula II, wherein Q is hydroxyl, or from an alkaline salt of formula II, wherein Q is -O-M, in which M is an alkaline cation, by reaction with -cyano-3-phenoxybenzyl halide. These processes are described in the above-mentioned patents, their disadvantage being the low availability of starting materials. The process for the preparation of 3- (2-chloro-3,3,3-trifluoroprop-1-yl) -2,2-dimethylcyclopropanecarboxylic acid .alpha.-cyano-3-phenoxybenzyl ester according to the invention eliminates this disadvantage, which process consists in: that the 3- (2-chloro-3,3,3-trifluoroprop-1-enyl) -2,2-dimethylcyclopropanecarboxylic acid salt of formula II, wherein Q is -O M, _wherein m ⁺ is an alkali metal cation is treated cyano-3-phenoxybenzyl p-toluenesulfonate of formula III in an inert organic solvent, or in a water-inert organic solvent mixture, optionally in the presence of a phase transfer catalyst selected from the group of quaternary ammonium salts at a temperature of 20 to 80 ° C.

The reaction can also be carried out with a two-phase mixture of water - an inert, water-immiscible organic solvent.

The advantage of the process according to the invention is in particular the very easy availability of this p-toluenesulfonyl derivative, its stability and its excellent crystallization ability, allowing easy purification. Another advantage is the possibility of performing in a two-phase environment using phase transfer catalysis, which significantly speeds up the synthesis, increases yields and purity of the product.

The present invention therefore provides a process for the preparation of an ester of formula I, which comprises reacting a salt of an acid of formula II wherein Q is -O-M, in which M is an alkali metal ion, with -cyano-3-phenoxybenzyl-p '. the toluenesulfonate of the formula III in an inert organic solvent or, preferably, in a water-inert water-immiscible organic solvent mixture. The organic solvent is from the group of hydrocarbons, chlorinated hydrocarbons or ketones. If the ester of the formula I is prepared in a two-phase medium, phase transfer catalysts known per se are used (described, for example, in the monograph EM Dehmlow, SS Dehmlow Phase Transfer Catalysis, 2nd Ed., Verlag Chemie 1983), preferably selected from the group quaternary ammonium salts. For example, a water-aromatic hydrocarbon or water-chlorinated hydrocarbon mixture at a temperature of up to 90 [deg.] C. is used as the reaction medium.

The preparation of the ester of the formula I according to the invention can be carried out with any geometric or optical isomer of the salt of the abovementioned cyclopropanecarboxylic acid or with any isomeric mixture thereof, the configuration of the cyclopropane ring always being retained. Working with one antipode salt of said cis-cyclopropanecarboxylic acid gives an optically active ester of formula I with increased insecticidal activity.

The process according to the invention is further illustrated by the following examples, which in no way limit the scope of the invention.

Example 1

510 mg of racemic cis-3- (2-chloro-3,3,3-trifluoroprop-1-enyl) -2,2-dimethylcyclopropanecarboxylic acid was dissolved in 1.1 ml of 1.95N aqueous sodium hydroxide solution, and the solution was added to the solution. 2 ml of toluene, 725 mg of X-cyano-3-phenoxybenzyl p-toluenesulfonate and 15 mg of triethylbenzylammonium bromide and the reaction mixture was stirred vigorously with a magnetic stirrer at 70 ° C for 6 hours. After cooling, the mixture was diluted with ether, the organic layer was separated, washed twice with water, dried over magnesium sulfate, filtered and evaporated. 842 mg of a yellowish oil (98% of theory) were obtained, which according to gas and liquid chromatography consisted of two components in a ratio of about 1: 1, corresponding to the two expected diastereoisomers (diastereoisomeric pairs) of the ester of formula I, differing in configuration on benzyl carbon.

Example 2 ’

The procedure of Example 1 was followed, but instead of the sodium salt of the cis-acid of formula II (where Q is -O-Na), the potassium salt of the same acid was used. The product was obtained in practically identical yield and diastereomeric composition.

Example 3

The procedure of Example 1 was followed, but instead of the sodium salt of the cis-acid of formula II (where 1 is -O ^- Na ⁺ ), the sodium salt of the same acid in the trans configuration was used. 830 mg (97% of theory) of product were obtained consisting of two diastereoisomeric pairs of esters of the formula I, different from diastereoisomeric pairs obtained from the sodium salt of the acid in the cis configuration.

Example 4

The procedure of Example 1 was followed, except that the dextrorotatory cis-acid of formula II (where Q is a hydroxyl group) was treated with its dextrorotatory enantiomer θ = +29.3 (ic = 1, ^{CHCl 3).} The dextrorotatory product, Jq = 11.56 ° (c = 2, ethanol), was obtained in practically quantitative yield in the form of two diastereoisomers differing in configuration on the benzyl carbon.

Example 5 mmol of racemic sodium salt of cis-3- (2-chloro-3,3,3-trifluoroprop-1-enyl) -2,2-dimethylcyclopropanecarboxylic acid and 2 mmol of cyano-3-phenoxybenzyl p-toluenesulfonate were dissolved in 10 ml of acetone and heated to reflux for 4.5 hours. Standard work-up gave a residue (700 mg) containing about 50% of the desired product by gas chromatography.

Example 6

The procedure of Example 1 was followed, but instead of in toluene, the reaction was carried out in dichloroethane. The yield was the same.

Example 7

The procedure was as in Example 1, but instead of triethylbenzylammonium bromide, tetrabutylammonium bromide was used. The yield was the same.

Example 8

The procedure was as in Example 1, except that tetraethylammonium bromide was used instead of trethylbenzylammonium bromide. The yield was the same.

Example 9

The reaction was carried out according to Example 1, but instead of toluene the reaction was carried out in ehax.

Claims (2)

OBJECT OF THE INVENTION A process for the preparation of 3- (2-chloro-3,3,3-trifluoroprop-1-enyl) -2,2-dimethylcyclopropanecarboxylic acid N-cyano-3-phenoxybenzyl ester of the formula I, characterized in that the salt 3 - (2-chloro-3,3,3-trifluoroprop-1-enyl) -2,2-dimethylcyclopropanecarboxylic acid of general formula II, wherein Q represents a group -O M in which M is an alkali metal cation, preferably in the cis configuration on a cyclopropane ring or optically active, is treated with cyano-3-phenoxybenzyl p-toluenesulfonate of formula III in an inert organic solvent or in a water-inert organic solvent mixture selected from the group consisting of hydrocarbons, chlorinated hydrocarbons or ketones, optionally in the presence of a catalyst. phase transfer selected from the group of quaternary ammonium salts at a temperature of 20 to 80 ° C. 2. The preparation process according to claim 1, characterized in that the reaction is carried out in a two-phase mixture of a water-inert, water-immiscible organic solvent.