HU176536B - Insecticide containing ester derivatives and process for preparing the active material - Google Patents

Abstract

Esters of formula I wherein R1 and R2 represent halogen radicals or lower alkyl groups; R3 and R4 represent halogen radicals; and R5 represents a hydrogen atom or the cyano radical, useful as insecticides. <IMG>

Description

The present invention relates to insecticides containing novel ester derivatives and to a process for their preparation.

The invention can be used in the agricultural and horticultural insecticide comprising the compound is from 0.0001 to 80% by weight of an amount (S) of the ester derivative (that is a halogen atom or a lower alkyl group of R ¹ and R ² are absent;

R ³ and R ⁴ are halogen and

^R5 is hydrogen or cyano), and an inert diluent or carrier and optionally a surfactant, preferably an alkyl aryl polyether alcohol, or ethylene-C ₈ _ ₁₈ alkyl phenol condensation product.

As used herein, the term "halogen" includes fluorine, chlorine and bromine. The term "lower alkyl group" refers to C 1-4 alkyl groups.

In preferred embodiments of the compounds of formula I, R ¹ and R ^{2 have the} same meaning and represent a methyl group, a chlorine atom or a bromine atom. Particularly preferred are compounds of formula I wherein R ¹ , R ² , R ³ and R ⁴ both represent chlorine. 25

Stereochemical conditions were not mentioned in the naming of the compounds of general formula (I). The compounds of formula (I) may be cis or trans isomers relative to the position of the substituents relative to the diisopropyl ring, and may also exist in different stereoisomeric forms. These isomers are not referred to by the general formula (I). The present invention relates to insecticides containing a compound of formula (I) present in any geometric or optical isomeric form, or to the preparation of such a compound of formula (I). The term "compound", as used herein, thus encompasses isolated isomers of compounds of Formula I as well as mixtures thereof (i.e., racemic or diastereoisomeric mixtures).

Preferred compounds of formula (I) are the following: 3- (2,2-Dichloro-vinyloxy) -benzyl- (±) -cis / trans-chrysanthemate (hereinafter referred to as Compound 1);

3- (2,2-Dichloro-vinyloxy) -benzyl - (± cis / trans -2- (2,2-dichloro-vinyl) -3,3-dimethyl-cyclopropanecarboxylate (hereinafter referred to as SEQ ID NO: 2). compound);

3- (2,2-Dichloro-vinyloxy) -benzyl- (±) -cis-2- (2,2-dichloro-vinyl) -3,3-dimethyl-cyclopropanecarboxylate (Compound 3 in the next 20 aka) );

3- (2,2-Dichloro-vinyloxy) -benzyl- (±) -trans-2- (2,2-dichloro-vinyl) -3,3-dimethyl-cyclopropanecarboxylate (hereinafter referred to as Compound 4). );

(± a-cyano-3- (2- (2-dichloro-vinyloxy) -benzyl- (±) -cis / tris-2- (2-dichloro-vinyl) -3,3-dimethyl-cyclopropanecarboxylate) 5);

(±) nz-cyano-3- (2,2-dichloro-yloxy) -benzyl- (±) -cis-2- (2-dichloro-vinyl) -3,3-dimethyl-cyclopropanecarboxylate;

("> -? - cyano) 3- (2-dimethyl-dichloro-vinoxy) -yl} -is> -2- (2,2-dichloro-vinyl) -3,3-dimethyl-cyclopropane- carboxylate;

3- (2,2-Dichloro-vinoxy) -benzyl- (±) -cis / trans -2- (2,2-dibromo-vinyl) -3,3-dimethyl-cyclopropanecarbonyl;

3- (2,2-dibromo-vinyloxy) -benzyl- (±) -cis / trans -phosphanthemate;

3- (2,2-dibromo-vinyloxy) -benzyl- (±) -cis / trans -2- (2,2-dichloro-vinyl) -3,3-dimethyl-cyclopropanecarboxylate;

(±) -α-cyano-3- (2,2-dichloro-vinyloxy) -benzyl- (+) - cis / trans-chrysanthemate;

(±) -α-Cyano-3- (2,2-dichloro-vinyloxy) -benzyl (+) -cis / trans-2- (2,2-dibromo-vinyl) -3,3-dimethyl-cyclopropane carboxylate.

The present invention further provides a process for the preparation of compounds of formula I by:

a) reacting a compound of formula II (wherein R ¹ and R ² are as defined above) or a metal salt thereof with a compound of formula III (wherein X is halogen and R ³ , R ⁴ and R ⁵ are as defined above); defined above); obsession

b) reacting a compound of formula IV (wherein Y is halogen and R ¹ and R ² are as defined above) with a compound of formula V (wherein R ³ , R ⁴ and R ⁵ are as defined above) ; obsession

c) a mixture of a lower alkyl ester of a carboxylic acid of formula (III) wherein R ¹ and R ² are as defined above and a compound of formula (V) wherein R ³ , R ⁴ and R ⁵ are as defined above heated in a diluent or solvent in the presence of a base.

A variant of our process a) is carried out by reacting a compound of formula II or a metal salt thereof with a compound of formula III (wherein X is halogen, preferably chlorine or bromine and R ¹ , R ² , R ³ , R ⁴ and R ⁵ are as defined above).

In variant b) of the process, a compound of formula IV is reacted with a compound of formula V (wherein Y is halogen, preferably chlorine and R ¹ , R ² , R ³ , R ⁴ and R ⁵ are as defined above).

In variant c) of the process, the esters of formula I can be prepared by transesterification by reacting a simple ester of an acid of formula II (e.g., a lower alkyl ester such as methyl or ethyl ester) with an alcohol of formula V The mixture is heated in a diluent or solvent, preferably in the presence of a base such as a lower alcohol such as sodium methylate or ethylate.

In the above processes, the reactants are heated in the presence or absence of diluent and / or base. Preferably, a diluent or solvent and a base are employed. As a solvent, e.g. solvents without hydroxyl groups, e.g. aliphatic ketones (e.g. acetone), dimethylformamide, dimethylsulfoxide, sulfolane, acetonitrile or tetrahydrofuran. Aliphatic ketones (such as acetone) are particularly preferably used as media. In some cases, when the hydroxyl group does not interfere with the reaction, solvents containing a hydroxyl group (e.g., methanol or ethanol) may be used. sodium hydride (for solvents or diluents that do not contain a hydroxyl group), alkali metal carbonates (e.g., cataphatite Fb <tag> and alkaline metal hydroxides · (e.g., potassium hydroxide) may be used. The reaction is usually carried out at room temperature with the use of carbonate and may be carried out at elevated temperatures (up to 10 ° C ') with other bases. The product may be purified by vacuum distillation or by appropriate chromatography to obtain the ester of formula (I) in the form of a single pure geometric isomer (II) or (III). ), or the starting material is used in the form of a cis / trans mixture and the resulting ester isomeric mixture is e.g. chromatographic separation of the components.

The compounds of formulas III and V used as starting materials are new and can be prepared as follows:

⁵ wherein R is a compound of formula H (III) by reacting be prepared from (VI) compound by reductive chemical or electrochemically with the hydrogen halide withdrawal subjected then meth the resulting compound (VII) of formula yl group of fish ogénezzük . In the compounds of formula (VI), Z is a halogen atom, preferably a halogen atom selected from the group consisting of R ³ and R ⁴ .

Compounds of formula (VI) were prepared according to von Hesse and Moll [J. Pract. Chemie (1974), 316, (2), 304] is prepared analogously to mcresol in the presence of anhydrous chlorinated or brominated acyl halide.

The electrochemical reduction process is carried out in an organic solvent (e.g., a lower alcohol such as methanol or ethanol; a cyclic ether such as dioxane or tetrahydrofuran; an aliphatic ketone such as acetone or cyclohexanone or these solvents with water or water containing strong mineral acid. , hydrochloric acid or phosphoric acid).

The reduction is believed to occur at the high hydrogen cathode (e.g., mercury, lead amalgam or lead cathode). The reaction is preferably carried out in a cell equipped with a ceramic or sintered diaphragm, a stirrer, a working electrode and a reference electrode. The process is also suitable for continuous production of the desired product; then the solvent is used to extract the reaction product

The reductive hydrogen halide removal may also be carried out with a suitable reducing agent (e.g., zinc powder and acetic acid).

The halogenation of the compounds of formula (VII) is preferably carried out with a positive halogen source (e.g., an N-halosimide such as N-bromosuccinimide or N-chlorosuccinimide).

Compounds of formula (V) wherein R ⁵ is hydrogen are preferably selected from the corresponding compounds of formula (III) 60, e.g. by treatment with an alkali metal hydroxide or by conversion to the corresponding tosylate (e.g. p-toluenesulfonate) followed by hydrolysis of the tosylate.

(III) Compounds of formula wherein R ⁵ is hydrogen John álra65 (eg. Alkáli50 system (eg. Methylene chloride) is used ciaiad- ^ source.

The treatment medium is treated with an insecticide containing a compound of formula (I).

The insecticides of the present invention are effective against a wide variety of insects and other invertebrate pests, e.g. against the following pests:

metal cyanide such as by treatment with sodium cyanide) followed by halogenation of the obtained (VIII) is converted to compounds of formula wherein A is ^{a 5-cyano} group (III) R. The reaction with the cyanide is preferably carried out in a polar aprotic solvent (e.g. dimethylformamide) at 50-100 ° C. The halogenation can be carried out as described for producing compounds of the formula above wherein R ⁵ = H (III) above. 10

^R5 is appropriate compounds of formula a cyano group (V) may be prepared by analogous Mo-15, Don previously, compounds containing a hydrogen atom in the corresponding R ⁵ is appropriate given the procedure from compounds of formula ⁵ wherein A is cyano (III) R.

^R5 is appropriate mixture of compounds containing cyano group (V) is preferably carried out by other means. In this process, a compound of formula (VII) is oxidized to a compound of formula (IX) by selective oxidation, and the resulting compound is converted to a cyanohydrin by reaction with hydrogen cyanide or, preferably, treatment with a cyanide ion such as sodium cyanide. The compounds of formula (IX) may also be prepared by Oppenauer oxidation (aluminum isopropylate and acetone) of compounds of formula (V) wherein R ⁵ is hydrogen.

Preferably, the active compounds used in the insecticides of the present invention are the esters of formula (I) listed at the beginning of this specification.

The compositions of the present invention are useful in agriculture and horticulture. The particular formulation type may be selected depending on the intended use. 35

The insecticides of the present invention may be formulated in the form of granules or powders containing the active ingredient and a solid diluent or carrier. Liquid compositions for use as dip baths or spray formulations may also be prepared, typically in the form of aqueous dispersions or emulsions.

Sprays may also be formulated in aerosol form; these compositions are kept under pressure in a container in the presence of a propellant (e.g., fluorotrichloromethane or dichlorodifluoromethane). '45

Aqueous formulations containing from 0.0001 to 1.0% by weight of active ingredient may generally be used for agricultural and horticultural purposes.

The insecticides of the present invention may optionally contain one or more other biologically active components (e.g., insecticidal or fungicidal) in addition to the active ingredient of formula (I). The compositions may also contain agents for the synergization of pyrethroid insecticides.

The compositions of the present invention can be used in a variety of ways to control insects. Thus, the insects themselves, their environment or their hiding place can be treated with a composition containing the active ingredient of formula (I).

The insecticides of the present invention may be used to reduce their susceptibility to insect damage by treating plants 60 by applying the plants, seeds, bulbs, tubers, rhizomes, or other plants suitable for propagation, or where the plants grow.

Blatella germanica Musca domestica Píeris brassicae Plutella maculipennis.

Tetranychus telarius

Aphis fabae

Megoura viceae

Aedes aegypti

Further details of the invention are set forth in the Examples, without limiting the invention to the Examples.

Example 1

In this example, FIG. Preparation of Compound II (Process variant j).

A mixture of 1.2 g of dl-chrysanthemic acid (50:50 mixture of cis and trans isomer) was mixed with 2.0 g of 3- (2,2-dichloro-vinyloxy) -benzyl bromide, 1.0 g of anhydrous potassium carbonate and 25 ml of acetone. and stirred at room temperature (about 18-22 ° C) for 18 hours. The insoluble material was removed by filtration and the filtrate was concentrated in vacuo. The residual oil was dissolved in chloroform, washed with saturated aqueous sodium bicarbonate solution and then with water. The chloroform solution was dried over anhydrous magnesium sulfate, the solvent removed in vacuo and the residual oil subjected to preparative thin layer chromatography; eluting with chloroform-petroleum ether (b.p. 40-60 ° C) containing 10% v / v chloroform. The desired product is identified by IR and NMR spectra.

Example 2

In this example, no. Preparation of compound (process variant (a)).

0.75 g of dl-3- (2,2-dichloro-vinyl) -2,2-dimethyl-cyclopropanecarboxylic acid (80:20 trans / cis mixture), 1.0 g of 3- (2,2-dichloro-vinyloxy) A mixture of benzyl bromide, 0.5 g of anhydrous potassium carbonate and 25 ml of acetone was stirred at room temperature for 18 hours. The product from the reaction mixture is

Isolate in analogy to the procedure described in Example 1, except that diethyl ether is used as the solvent instead of chloroform, and a mixture of 20% chloroform and 80% petroleum ether (b.p. 40-60 ° C) is used as the eluent for TLC.

Example 3

In this example, (+) -? - cyano-3- (2,2-dichloro-vinyloxy) -benzyl- (±) -cis / trans-2- (2,2-dichloro-vinyl) -3,3 the preparation of dimethylcyclopropanecarboxylate (Compound 5; R ¹ , R ² , R ³ and R ⁴ is chloro and R ⁵ is cyano) (process variant b).

1.29 g of 2- (2,2-dichloro-vinyl) -3,3-dimethyl-cyclopropanecarboxylic acid (40:60 mixture of cis / trans isomer) were added to 5.0 g of thionyl chloride and the mixture was heated at 100 ° C in a steam bath. is heated for 1 hour. The excess thionyl chloride is then removed by toluene azeotropic distillation. The remaining acid chloride was dissolved in 3.0 mL of n-hexane

And the resulting solution was added dropwise at room temperature to a solution of 1.5 g of 3- (2,2-dichlorovinyloxy) -benzaldehyde cyanohydrin in 7.0 ml of hexane and 0.5 ml of pyridine. After the addition was complete, the reaction mixture was stirred at room temperature for 2 hours. The precipitated solid precipitate was filtered off, the filtrate was washed with water (2 x 10 mL), dried over anhydrous magnesium sulfate and concentrated in vacuo. The residual oil was subjected to thin layer chromatography on silica gel plates; eluting with a mixture of 2 parts by volume of chloroform and 3 parts by volume of petroleum ether (b.p. 60-80 ° C). Practically pure (+) -? -Cyano-3- (2,2-dichloro-vinyloxy) -benzyl- (±) -cis / trans-2- (2,2-dichloro-vinyl) -3,3-dimethyl- cyclopropanecarboxylate is obtained, consisting of 40% of the cis isomer and 60% of the trans isomer.

Example 4

3 and 4 in this example. The preparation of the compound is described.

250 mg of the product of Example 2 were subjected to preparative thin layer chromatography on silica gel coated plates. Elution was carried out with a mixture of 35% v / v chloroform and 65% v / v petroleum ether (b.p. 60-80 ° C). The desired product is identified by its IR and NMR spectra. 70 mg NO. compound ((±) -cis isomer) and 100 mg of N-4. compound ((±) -transomer) was obtained.

point fraction) was redistilled and the fraction boiling at 84 ° C / 0.2 mm Hg was collected.

Electrochemically Reductive Hydrogen Halide Cleavage.

15.8 g of 1- (3-tolyloxy) -2,2,2-trichloroethyl acetate, 9.8 g of 98% w / v sulfuric acid and 220 ml of methanol are ca. It is fed to an electrolysis cell with a cylindrical diaphragm, a stirrer, a reference electrode (SCE) and a working electrode, surrounded by a cooling bath having a temperature of 15 ° C. The lead cathode used is a lead plate (surface area about 40 cm ² ). The reaction is carried out at a current density of 5 to 10 mA / cm ^{2 in} a voltage range of 1100 to 1700 mV (SCE). After completion of the reduction, the cathodic electrolyte is neutralized with caustic soda, extracted with methylene chloride, dried over anhydrous sodium sulfate and evaporated. Crude 3-tolyl-2,2-dichloro-vinyl ether was obtained.

c) Preparation of 3- (2,2-dichloro-vinyloxy) -benzyl bromide.

12.2 g of 3-tolyl-2,2-dichlorovinyl ether are dissolved in 75 ml of carbon tetrachloride and 12.0 g of N-bromosuccylimide and a trace amount of wet benzoyl peroxide are added and the reaction mixture is refluxed for 3 hours. After filtration, the solvent was distilled off from the filtrate and the residue was dissolved in ether and extracted with 1% (w / v) aqueous sodium hydroxide. The ethereal solution was dried over anhydrous magnesium sulfate, the solvent was distilled off in vacuo and the residual oil was evaporated. The fraction having a boiling point of 150 ° C / 0.5 mmHg was approximately ca. 65% desired final product and approx. Contains 30% unchanged starting material and little dibromomethyl compound.

Example 5

This example illustrates the preparation of 3- (2,2-dichloro-vinyloxy) -benzyl bromide.

a) Preparation of 1- (3-tolyloxy) -2,2,2-trichloroethyl acetate.

To a solution of anhydrous chlorine (37.0 g) in dry ether (125 ml) was added m-cresol (27.0 g), stirred at room temperature for 20 minutes, cooled to 10 ° C, and a solution of triethylamine (25.25 g in 100 ml . 20.0 g of acetyl chloride were carefully added to the reaction mixture with stirring, followed by stirring for 1 hour. The insoluble material was filtered off and the filtrate was dried over anhydrous magnesium sulfate. The ether was removed in vacuo and the residual oil was evaporated in a gentle vacuum and the fraction boilinged at 132-134 ° C / 0.5 mmHg was collected. The IR and NMR spectra of the product confirmed the structure of 1- (3-tolyloxy) -2,2,2-trichloroethyl acetate.

b) Preparation of 3-tolyl-2,2-dichloro-vinyl ether.

With metallic reductive hydrogen halide cleavage.

1- (3-Tolyloxy) -2,2,2-trichloroethyl acetate (14.2 g) was dissolved in glacial acetic acid (40 ml) and zinc powder (3.6 g) was slowly added with stirring at room temperature. The temperature rises to 60 ° C as a result of the exothermic reaction, and the reaction mixture is heated at 50-60 ° C for 4 hours. The mixture was filtered and the filtrate was poured into excess water and extracted with chloroform. The extracts were washed twice with water, washed with saturated sodium bicarbonate solution, and then with water. The chloroform extract was dried over anhydrous magnesium sulfate, the solvent was distilled off in vacuo and the residual oil was evaporated in vacuo. The crude 3-tolyl-2,2-dichlorovinyl ether (92-95 ° C / 0.3 mm Hg)

Example 6

This example illustrates the preparation of 3- (2,2-dichloro-vinyloxy) -benzyl alcohol.

A mixture of 2.8 g of 3- (2,2-dichloro-vinyloxy) -benzyl bromide, 2.0 g of sodium p-toluenesulfonate and 20 ml of methanol was heated at 50 ° C for 1 hour, followed by stirring with 20 ml of water. and toluene (20 mL) was added. The toluene layer was separated, washed with water and the solvent removed in vacuo. The concentrate was added dropwise to 100 ml of a 15% w / v aqueous potassium hydroxide solution, the reaction mixture was heated at 60 ° C for 1 hour, then cooled to room temperature and extracted with 10 ml of toluene and 10 ml of methyl isobutyl ketone. The extracts were dried over anhydrous magnesium sulfate and the solvent was evaporated in vacuo. 3- (2,2-Dichloro-vinyloxy) -benzyl-alcohols are obtained in the form of a pale yellow oil. 50

Example 7

In this example, the conversion of the 3- (2,2-dichloro-vinoxy) -benzalde 55 bridge to the cyanohydrin is demonstrated through the bisulfite compound.

3- (2,2-Dichloro-vinyloxy) -benzaldehyde (2.0 g) was added at room temperature with stirring to a solution of 3.2 g of sodium metabisulfite in a mixture of 5.2 ml of water and 5.2 ml of methanol. The white precipitate was collected after 30 minutes, washed with cold methanol and dried. 2.5 g of 3- (2-dichloro-vinyloxy) -benzaldehyde-bisulfite are obtained, which are suspended in 5 ml of water and 0.4 g of sodium ciamcta 65 in 5 ml of water are added at room temperature. The mixture was stirred for 2 hours and then extracted with diethyl ether (2 x 10 mL). The extracts were combined, washed with water (2 x 10 mL), dried over anhydrous magnesium sulfate and evaporated in vacuo. 3- (2,2-Dichloro-vinyloxy) -benzaldehyde-cyanohydrin is obtained as a yellow oil.

Example 8

The efficacy of the pesticides containing the compounds of the formula I against a number of insects and other invertebrate pests is determined. The test compound is used in the form of a liquid formulation containing 0.1% w / w of the active ingredient, except for the Aedes aegypti test, which uses a 0.01% w / w spray. The composition is prepared by dissolving the test compound in a mixture of 4 volumes of acetone and 1 volume of diacetone alcohol. The solution is diluted with water containing 0.01% by weight of Lissapol NX wetting agent to the desired active ingredient (trademark "Lissapol").

During the assay, a number of pests are grown on a suitable medium (usually the host plant or insect's food) and the pest and / or medium treated with the composition.

Pest mortality is determined 1 to 3 days after treatment.

The results are summarized in Table I below. Column 1 shows the pest species, further columns show the host plant or insect feed, the number of days between treatment and pest determination and the results obtained for each test compound. The evaluation is expressed as a scale from 0 to 3, as follows:

0 = less than 30% mortality

1 = 30-49% mortality

2 = mortality above 50-90%

3 = Death above 90%.

The notation "-" used in Table I means no. experiment.

In the "contact test", both the pest and the insect were treated, while in the "contact test", the medium was treated before infection with the pest.

Example 9

1% by weight directly applied to plants or other surfaces. and a 99% w / w talc.

Example 10

25 parts by weight No. 2 65 parts by weight of xylene and 1 part by weight of alkylaryl polyether alcohol ("Triton" X-100; trademark "Triton") are mixed in a suitable mixing apparatus. The resulting emulsion concentrate is mixed with water to form an emulsion for agricultural use.

Example 11

10 parts by weight No. 2 A mixture of 10 parts by weight of ethylene oxide-octylphenol condensation product ("Lissapol" NX; trademark "Lissapol") and 80 parts by weight of diacetone alcohol is thoroughly mixed. The resulting concentrate, when diluted with water, provides an aqueous dispersion in the form of a spray liquid which can be used as an insecticide.

Lissapol NX is a condensation product of 1 mol of nonylphenol with 8 mol of ethylene oxide.

Example 12

This example illustrates the preparation of 3- (2,2-dichloro-vinyloxy) -benzaldehyde.

2.5 g of 3- (2,2-dichloro-vinyloxy) -benzyl bromide are stirred gently with 2.1 g of hexamethylenetetramine and 20 ml of

Table I

Pest species medium Number of days Number of compound « 1 2 3 4 5 Tetranychus telarius (velvety mite, adult) green beans 3 1 0 0 1 Aphis fabae (black aphid) wide beans 2 3 3 2 0 0 Megoura viceae (green aphid) wide beans 2 0 3 3 3 2 Aedes aegypti (mosquito, adult) veneer 1 2 2 3 3 2 Musca domestica (house fly - contact test *) milk / sugar 2 3 3 3 2 3 Plutella maculipennis (diamond back butterfly, larva) mustard 2 0 3 3 2 3 - contact test * Pieris brassicae (white cabbage butterfly) cabbage 2 3 3 3 3 3 - contact test * Musca domestica (house fly —- remaining test *) veneer 2,. 0 3 3 3 3

Add π carbon tetrachloride solution at room temperature. After 5 minutes, the precipitate was filtered off and washed with acetone. The resulting solid product was added to 16 ml of a 50% aqueous acetic acid solution and refluxed for 1 hour. A mixture of water (16 mL) and concentrated hydrochloric acid (4.5 mL) was added and refluxed for a further 15 minutes. After cooling, the mixture was extracted with chloroform and the extracts were washed twice with water, dried over anhydrous magnesium sulfate and concentrated in vacuo. Practically pure 3- (2,2-dichloro-vinyloxy) -benzaldehyde is obtained, which structure is confirmed by IR and NMR spectra.

Example 13 Weight Part 2 15 parts of Triton X-100 and 5 parts of xylene are mixed. The emulsifiable concentrate thus obtained can be diluted with water to form a spray for insecticide application.

Example 14 25 parts by weight, all. The concentrate prepared according to Example 1 by dilution with water was 0.0001% by weight. compound.

Claims (4)

Patent claims An agricultural and horticultural insecticide, wherein the active ingredient is from 0.0001% to 80% by weight of an ester derivative of formula (I) R ¹ and R ² are halogen or lower alkyl; R ³ and R ⁴ are halogen and R ³ represents a hydrogen atom or a cyano group - and an inert diluent or carrier and optionally a surfactant, preferably an alkyl aryl polyether alcohol, or _ethylene-C8 _i ₈ alkyl phenol condensation product. A process for the preparation of the ester derivatives of the formula I for use as an active ingredient in the insecticides according to claim 1, wherein R ¹ and R ² is halo or lower 10 alkyl; R ³ and R ⁴ are halogen and R ³ is hydrogen or cyano, characterized in that a) reacting a compound of formula II (wherein R ¹ and R ² are as defined above) or a metal salt thereof with a compound of formula III (wherein X is halogen and R ³ , R ⁴ and R ³ are as defined above); defined above); obsession b) (IV) a compound of formula (wherein Y is halogen and R ¹ and R ² are as defined above) is reacted with a compound (V) of the formula (wherein R ^3, R ⁴ and R ^s are as defined above) ; obsession c) a mixture of a lower alkyl ester of a carboxylic acid of formula II wherein R ¹ and R ² are as defined above and a compound of formula V wherein R ³ , R ⁴ and R ³ are as defined above heated in a diluent or solvent in the presence of a base. 3. A process according to claim 2, variant a), wherein the starting material is a compound of formula III wherein X is chlorine or bromine. A process according to claim 2, variant b), wherein the starting material is a compound of formula IV wherein Y is chlorine (wherein R ¹ and R ² are as defined in claim 2). 5. A process according to claim 2, variant c), wherein the base is a lower alcohol.