HU184193B - Process for preparing /s/-alpha-cyano-3-phenoxy-benzyl-alcohol ester with insecticide activity formed with d-2-isopropyl-2-/4-chloro-phenyl/-acetic acid - Google Patents

Description

The present invention relates to a process for the preparation of an ester of formula (I) with (S) -alpha-cyano-3-phenoxybenzyl alcohol with D-2-isopropyl-2- (4-chlorophenyl) acetic acid.

According to the invention, D-2-isopropyl-2- (4-chlorophenyl) -acetic acid or its reactive derivative, preferably its halide, is in the (S) -configuration or (RS) -configuration alpha-cyano-3-phenoxy. with benzyl alcohol and isolating the ester with (S) -alcohol.

The compound of the present invention has insecticidal activity and is therefore useful as an active ingredient in insecticidal compositions.

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The present invention relates to a process for preparing an insecticidal ester of (S) α-α-cyano-3-phenoxybenzyl alcohol with D-2-isopropyl-2- (4-chlorophenyl) acetic acid.

Compound according to the invention (!) A melting point of 62 ° C ^[delta AlN value = + 13.15 ° (c = 2% in benzene).

The ester of alpha-cyano-3-phenoxybenzyl alcohol with 2- (4-chlorophenyl) -isovaleric acid has become known from German Patent Nos. 2,651,341 and 2,335,347 and French Patent No. 2,342,960. In these patents, the asymmetric center of the alcohol moiety is designated as allowing separation of racemic mixtures. This is obviously an unsubstantiated claim, since no method was known to separate the racemic alpha-cyano-3-phenoxybenzyl alcohol to its optically active isomers prior to the filing date of the respective patents.

The compound of formula (I) is prepared according to the invention by reacting D-2-isopropyl-2- (4-chlorophenyl) -acetic acid or a reactive derivative thereof, preferably its (RS) - and (S) -alpha-cyano-halide. Reaction with 3-phenoxybenzyl alcohol and, if desired, isolation of the ester with (S) -alcohol.

D-2-isopropyl-2- (4-chlorophenyl) -acetic acid used as starting material in the process of the present invention can be prepared by treating DL-2-isopropyl-2- (4-chlorophenyl) acetic acid with (-) - with alpha-phenylethylamine and recrystallizing from a mixture of water and ethanol the salt of D-2-isopropyl-2- (4-chlorophenyl) acetic acid with (-) - alpha-phenylethylamine and the salt treatment with acid in the medium liberates D-2-isopropyl-2- (4-chlorophenyl) acetic acid.

The salt of D-2-isopropyl-2- (4-chlorophenyl) -acetic acid with alpha-phenylethylamine may conveniently be crystallized from ethanol containing 70% (v / v) water.

Resolution of DL-2-isopropyl-2- (4-chlorophenyl) -acetic acid with alpha-phenylethylamine as described above affords D-2-isopropyl-2- (4-chlorophenyl) in good yield. - the production of acetic acid which has not yet been produced.

The subsequent esterification with (S) -alpha-cyano-3-phenoxybenzyl alcohol can be conveniently carried out with the chloride of the D-acid, especially when the operation is carried out in the presence of a tertiary base such as pyridine or triethylamine in an organic solvent such as benzene, methylene chloride or toluene.

The esterification may advantageously also be carried out using the anhydride or mixed anhydride of D-2-isopropyl-2- (4-chlorophenyl) acetic acid.

The chloride of D-2-isopropyl-2- (4-chlorophenyl) acetic acid can be conveniently prepared with thionyl chloride. Other reactive derivatives may be prepared by known chemical methods.

Preferably, D-2-isopropyl-2- (4-chlorophenyl) -acetic acid is reacted with thionyl chloride in benzene and the resulting D-2-isopropyl-2- (4-chlorophenyl) -acetic acid chloride is obtained. in petroleum ether in the presence of pyridine (Sj-alpha-cyano-phenoxyl-benzyl alcohol).

Thus, the ester of (S) -alpha-cyano-3-phenoxy-benzyl alcohol with D-2-isopropyl-2- (4-chlorophenyl) -acetic acid can also be prepared by treating (R5) -alpha-cyano with The D-2-isopropyl-2- (4-chlorophenyl) -acetic acid ester of -3-phenoxybenzyl alcohol is reacted with a base in a solvent or mixture of solvents in which the (S)-alcohol ester is insoluble. Ammonia is preferably used as the base in this epimerization, and as a solvent isopropanol.

If isopropanol (in which (S) -alfacyano-3-phenoxybenzyl alcohol is only slightly soluble) is used as solvent in Example 3 of the Experimental Part, it is also possible to initiate crystallization with (S) alpha-cyano-3. a phenoxybenzyl alcohol ester is added as a initiator to a solution of (RS) -alpha-ctano-3-phenoxybenzyl alcohol and, after a while, the D-acid is obtained with (S) -alpha-cyano-3-phenoxybenzyl alcohol. Concentration of the mother liquor yields a mixture of the (R) -alcohol ester and the (S) -alcohol ester, which is rich in the (R) -alcohol ester. If this mixture is reacted with an alkali in a solvent, in which the (S) -alcohol ester becomes insoluble, the (R) -alcohol ester will first form a mixture with the (RS) -alcohol ester. However, due to the insolubility of the (S) -alcohol esters in the medium, the equilibrium is shifted and the (S) -alcohol ester is obtained in a yield of more than 50%.

The (S) -alcohol ester used as the crystallization initiator is obtained by esterifying (S) -alpha-cyano-3-phenoxybenzyl alcohol with D-2-isopropyl-2- (4-chlorophenyl) -acetic acid chloride (see 3). example).

The compound of formula (I) produced by the process of the present invention has a valuable insecticidal property which makes it useful for controlling insects around the house and in agriculture.

Indeed, this compound has a greater insecticidal activity than the corresponding non-resolved known compounds containing asymmetric carbon.

The compound of formula (I) obtained according to the invention is particularly suitable for controlling harmful insects in agriculture. These include, for example, aphids and larvae of butterflies and beetles, which can be effectively used against them. It can also be used against insects around the household (flies, mosquitoes).

The compound of formula (I) can be converted into an insecticidal agent in a known manner.

The active ingredient of formula (I) may also be mixed with other pesticidal active ingredients. These formulations may be marketed in various forms, for example, in the form of powders, granules, suspensions, emulsions, solutions, aerosol solutions, lozenges, baits, or other formulations commonly used in such compounds.

These formulations will generally contain, in addition to the active ingredient, carriers or nonionic surfactants which will result in the uniform distribution of the constituents of the formulation. The carriers used may be liquids such as water, alcohols, hydrocarbons or other organic solvents, mineral, animal or vegetable oils, or powders such as talc, brain brain, silicates, silica or fumigants such as Machyl Thumbergii wood bark. meal,

According to the invention! The insecticidal activity of the compound prepared by the above process is enhanced by addition of conventional synergistic components, such as 1- (2,5,8-trioxadodecyl-2-propyl-4,5-methylenedioxy) benzo [piperonyl butoxide], N- (2-ethyl-heptyl) -bicyclo- (2,2,11) -5-heptene-2,3-dicarboximide or piperonylbis [2- (2'-n-butoxyethoxy) ethyl] - acetal (tropital).

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Insecticidal compositions preferably contain from 0.005 to 10% by weight of the active ingredient.

Compounds similar to those of formula (I) having two asymmetric carbon atoms in a racemic configuration were previously known. 5

The (S) -alpha-cyano-3-phenoxybenzyl ester of formula (I) is a novel compound and its preparation may require the use of (S) -alpha-cyano-3-phenoxybenzyl alcohol, i.e., a compound which is French Patent No. 875. 10

The ester of D-2-isopropyl-2- (4-chlorophenyl) -acetic acid with (S) -alpha-cyano-3-phenoxy-benzyl alcohol [hereinafter (S) -alpha-cyano-3-phenoxy-benzyl] alcohol ester, or, to a lesser extent, (S) alcohol ester only), wherein the (RS) alcohol ester is reacted with a strong base in a solvent suitable to render the (S) alcohol ester insoluble therein. , is only possible if the (S) -alpha-cyano-3-phenoxybenzyl alcohol ester initiator is already available. It has been proved by several experiments that when (RS) -alpha-cyano-3-phenoxybenzyl alcohol is reacted in a solvent such as isopropanol with an alkali such as ammonia, but the (S) alcohol ester is not present as an initiator, the (S) -alpha-cyano-3-phenoxybenzyl alcohol ester is formed, which becomes insoluble. This is the reason why it has been impossible so far to prepare the ester of (S) -alpha-cyano-3-phenoxybenzyl alcohol with D-2-isopropyl-2- (4-chlorophenyl) acetic acid, for the preparation of this ester, we must have a crystallization initiator which is itself the (S) -alpha-cyano-3-phenoxybenzyl alcohol ester and which has been previously synthesized by an unknown compound, (S) -alpha may be prepared by esterification of cyano-3-phenoxybenzyl alcohol (see Example 2).

Reference Example Step

Preparation of the (+) alpha-phenylethylamine salt of L-2-isopropyl-2- (4-chlorophenyl) -acetic acid in 4 liters of water containing 4% by volume of DL-2-isopropyl-2- (4-Chlorophenyl) acetic acid was added and, after stirring, 140 g of (4-) alpha-phenylethylamine were added to the resulting solution, causing precipitation. The reaction mixture is heated to reflux, alcohol (70% by volume) is added, and the mixture is allowed to cool slowly. At about 65 ° C, crystallization begins. The mixture was stirred at 20 ° C for 48 hours, and the resulting precipitate was collected by vacuum filtration and washed with ethanol. 188.9 g of crude product are obtained which is the (+) - alpha-phenyl (ethylamine) salt of L-2-isopropyl-2- (4-chlorophenyl) -acetic acid.

Mp ⁼ 4-3.5 ° (c = 0.5%, methanol).

Cleaning:

The crude product (188.9 g) was dissolved in 4 L of ethanol containing 70% water by heating under reflux and then about 2 L of ethanol containing 70% by volume of water was added until the product was completely dissolved. The mixture was allowed to cool to 20 ° C and stirred at this temperature for 20 hours, and the resulting precipitate was isolated by vacuum filtration, washed and dried.

147.9 g of pure (+) - alpha-phenylethylamine-L-2-isopropyl-2- (4-chlorophenyl) acetate are obtained.

~ + 4.5 ° (c = 0.8%, ethanol)

O. p. = 210 ° C (dec.).

Step B.

1- (2-isopropyl) -2- (4-chlorophenyl) acetic acid

In 300 mL of methylene chloride was dissolved 147.5 g of (-) - alpha-phenylethylamine L-2-isopropyl-2- (4-chlorophenyl) acetate, which was obtained in Step A. To the solution was added 300 ml of 2N aqueous hydrochloric acid with stirring, and after stirring for another 15 minutes, the mixture decomposed into two clear phases which were separated by decantation. The organic phase is washed with water and the wash water is extracted with methylene chloride. The organic phase is dried, filtered and evaporated to dryness. 94 g of L-2-isopropyl-2- (4-chlorophenyl) acetic acid are obtained. [α] ²⁰ D = -41.5 ° (c = 0.9%, ethanol)

O. p. = 105 C.

Circular Dichroism (dioxane)

Ae = - 4 at 218 nm (max);

Ae = +0.029 at 251 nm (max),

Ae = + 0.0111 at 259 nm (max);

Ae = -0.01 at 263 nm (max).

Ae = +0.021 at 267 nm (max);

Ε -0.018 at 271 nm (max).

Ae = +0.04 at 275 nm (max);

Ae = -0.008 at 278 nm (max).

Example 1

Preparation of D-2-Isopropyl-2- (4-chloro-phenyl) -acetic acid (RS) -alpha-cyano-3-phenoxy-benzyl ester

Recovery of a mixture of D-2-isopropyl-2- (4-chlorophenyl) -acetic acid and DL-2-isopropyl-2- (4-chlorophenyl) -acetic acid

The mother liquors obtained in the reference procedure or purification are evaporated to dryness and the resulting residue is suspended in 300 ml of methylene chloride. While stirring, 2N hydrochloric acid was added until the pH of the mixture was 1 (about 350 ml of hydrochloric acid was required). Upon completion of stirring, the organic phase was separated by decantation and the aqueous phase was extracted with methylene chloride. The combined organic phases are washed with water and the wash water is extracted with methylene chloride. The organic phase is dried, filtered and evaporated to dryness under reduced pressure. A mixture of D-2-isopropyl-2- (4-chlorophenyl) acetic acid and DL-2-isopropyl-2- (4-chlorophenyl) acetic acid is obtained.

Yield: 153.5 g.

Step B.

Preparation of the (-) - alpha-phenyl (ethylamine) salt of D-2-isopropyl-2- (44-dorophenyl) acetic acid in water-containing ethanol is dissolved in 153 g of the mixture from Step A and the (g) (-) - alpha-phenylethylamine (86 g) was added over 15 minutes and the mixture was heated to reflux and stirred. Ethanol (70% v / v) was added until complete dissolution (about 2.25 L) and the solution was allowed to cool slowly,

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After stirring at 20 ° C for a further 20 hours, the resulting precipitate was collected and filtered under vacuum, washed with ethanol and dried. The (-) - alpha-phenyl (ethylamine) salt of D-2-isopropyl- (4-chloro-phenyl) -acetic acid is obtained as a crude product (168.2 g).

[α] D = -5 ° (c = 0.6%, methanol).

Purification Dissolve 168 g of (-) - alpha-phenyl (ethylamine) salt of D-2-isopropyl-2- (4-chlorophenyl) -acetic acid in 4 liters of ethanolic aqueous solution and add The mixture was heated to reflux while ethanol (70% by volume) was added until completely dissolved (about 1.5 liters). The solution was slowly allowed to cool to 20 ° C and stirred at this temperature for 48 hours. The resulting precipitate was collected by vacuum filtration, washed with ethanol and dried. 143.1 g of (-) - alpha-phenyl (ethylamine) salt of D-2-isopropyl-2- (4-chloro-ferthyl) -acetic acid are obtained.

[ ^.alpha. ] ^D @ 20 = -5 DEG (c = 0.8% in methanol)

O. p. = 210 ^a C (dec).

Step C

Preparation of D-2-isopropyl-2- (4-chlorophenyl) acetic acid

Using the procedure described in Step B of the Reference Example and Example 1, Step B, the (-) - alpha-phenyl (ethylamine) salt of D-2-isopropyl-2- (4-chlorophenyl) -acetic acid.

Starting from 143 g, 91 g of D-2-isopropyl-2- (4-chlorophenyl) acetic acid are obtained.

b ⁼ + 42 ° (c = 1%, ethanol)

Melting point: 105 ° C.

Step D.

Preparation of D-2-isopropyl-2- (4-chlorophenylacetic acid chloride) in a mixture of petroleum ether (b.p. 35-70 ° C) and 20 ml of thionyl chloride gave 10 g of D-2-isopropyl-2- (4-chloro). phenylacetic acid was added and the mixture heated to reflux for 4 hours, after cooling to dryness under reduced pressure to give D-2-isopropyl-2- (4-chlorophenyl) -acetic acid chloride (10.8 g).

This step

Preparation of D-2-isopropyl-2- (4-chlorophenyl) -acetic acid (RS) -alpha, -Cummo-3-phenoxybenzyl ester in a mixture of benzene and 5 ml of pyridine (5.5 g) Dissolve half-cyano-3-phenoxybenzyl alcohol and add 6 g of D-2-isopropyl-2- (4-chlorophenyl) acetic acid chloride in 20 ml of benzene at 20 ° C. The mixture was stirred at 20 ° C for 15 h, stirred with water, allowed to stand, decanted and the aqueous layer was extracted with benzene. The organic phase is washed with water and the wash water is extracted with benzene. The benzene solution was dried, filtered and evaporated to dryness under reduced pressure. The residue was chromatographed on silica gel eluting with 95: 5 cyclohexane-ethyl ether. 8.57 g of D-2-isopropyl-2- (4-chlorophenyl) -acetic acid (RS) -alpha-cyano-3-phenoxybenzyl ester are obtained.

And] b ° = -5 ° (c = 1.2%, ethanol)

Analysis

c? 5. h ₂₂ o ₃ NC1 - (419.88) c% H% N% Cl% calculated 71.51 5.28 3.33 8.44 Found 71.5 5.3 3.3 8.6

Ultraviolet spectrum (ethanol) at 225 nm (E * - 534), λ = 22,400, at 260 nm (E1 - 36).

Inflexion at 269 nm (Ej = 48), inflexion at 272 nm (E * = 50).

At max 278 nm (Ej = 53), e = 2200, at 283 nm (E * - 40).

Circular Dichroism (dioxane)

Ae = -0.13 at 282 nm (max);

Ae = -0.17 at 274 nm (max).

Ae = -0.12 at 267 nm (max);

Ae = -0.08 at 258 nm (max).

Ae = -6.78 at 228 nm (max).

Nuclear Magnetic Resonance Spectrum (deutero chloroform)

Peaks: 0.62-0.73 ppm; 0.63-0.75 ppm; 0.88-0.98 ppm;

Peaks: 0.98-1.05 ppm; typical of methyl group of isopropyl group;

Peak: 1.92-2.66 ppm; the asymmetric carbon atom is characterized by the hydrogen atom of the alpha isopropyl group.

Peak: 3.16-3.33 ppm; characterized by a hydrogen atom on an asymmetric carbon atom.

Peak: 6.32-6.36 ppm; characterized by a hydrogen atom on a carbon atom bearing a nitrile group.

Peak: 6.83-7.58 ppm; characteristic of the hydrogen atom of the aromatic core.

Example 2

Preparation of D-2-isopropyl-2- (4-chlorophenylphenylacetic acid (S) -alpha-cyano-3-phenoxybenzyl ester per ml of benzene: 3 g of (S) -alpha-cyano-3-phenoxybenzyl alcohol and 3.1 g of D-2-isopropyl-2- (4-chlorophenyl) acetic acid chloride, prepared according to Step D of Example 1, are added. The mixture was cooled to + 15 ° C and a mixture of 4 ml of pyridine and 10 ml of benzene was added dropwise. After stirring at 20 ° C for 2 hours, the reaction mixture was poured into 2N aqueous hydrochloric acid. The organic phase is separated by decantation, dried, filtered and evaporated to dryness under reduced pressure. The residue was chromatographed on silica gel eluting with benzene. 4.4 g of (S) -alpha-cyano-3-phenoxybenzyl-D2-isopropyl-2- (4-chlorophenyl) acetate are obtained.

= + 13.15 ° (c = 2%, benzene).

The product crystallizes. Mp 62 ° C.

Analysis:

C 5 H ₂ j c% H% cl Cl% NO, (4-19,98) N% calculated: 71.50 5.28 8.44 3.34 Found: 71.4 5.3 9.1 3.3

Circular Dichroism (dioxane) Δe - +0.1 at 2.53 nm (max); Ae = + 0.23 at 277 nm (max; Ae = 282 nm (max);

Ae = + 0.27 at 286 nm (max).

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Nuclear Magnetic Resonance Spectrum (deutero chloroform)

Peaks: 0.63-0.75 ppm; characteristic of the hydrogen atoms of the methyl groups of the isopropyl group.

Peaks at 2.25 ppm; the asymmetric carbon atom is characterized by the hydrogen atoms of the isopropyl group at the alpha position.

Peak: 3.17-3.33 ppm; characterized by hydrogen atoms on the asymmetric carbon of the acid.

Peaks at 6.4 ppm; the nitrile group is characterized by a hydrogen atom at the alpha carbon atom;

Peak: 6.91-7.58 ppm; characteristic of the hydrogen atoms of the aromatic nucleus.

The (S) -alpha-cyano-3-phenoxybenzyl alcohol can be prepared as follows:

The step

(1R, 5S) -6,6-Dimethyl-4 (R} [(S) -cyano- (3'-phenoxyphenyl) methoxy] -3-oxabicyclo [3.1.0] hexan-2-one and (1R, 5R) -6,6-dimethyl-4 (R) - [(R) -cyano- (3'-phenoxyphenyl] methoxy] -3-oxabicyclo (3.10) hexan-2-one preparation of a mixture thereof

22.5 g of (RS) -alpha-cyano-3-phenoxybenzyl alcohol, 9.4 g of cis-2,2-dimethyl-3-S-dihydromethylcyclopropane-1R-carbolactone and 0.150 g of paratoluene are mixed. sulfonic acid monohydrate. The mixture was heated at 80 ° C under a vacuum of ² mmHg for 2 hours while the water formed during the reaction was removed by distillation. The mixture was then cooled to 20 ° C as 30.70 g of crude (1R, 5S) -6,6-dimethyl-4 (R) -1 (S) -cyano (3'-phenoxyphenyl) methoxy as a crude product. } -3-oxabicyclo (3.1.0) hexan-2-one and (1R, 5S) -6,6-dimethyl-4 (R) - [(R) -cyano- (3'-phenoxy) a mixture of phenylmethoxy-3-oxabicyclo (3.1.0) hexan-2-one is obtained (containing mainly unreacted starting material as impurity). (The mixture)

Step B (1R, 5S) -6,6-Dimethyl-4 (R) - [(S) -cyano- (3'-phenoxyphenyl) methoxy] -3-oxabicyclo (3.1.0) hexane- 2-on

The A mixture obtained in Step A is chromatographed on silica gel, eluting with 95: 5 benzene: ethyl acetate. 10.9 g of (1 R, 5 S) -6,6-dimethyl-4 (R) - [(S) -cyano- (3'-phenoxyphenyl) methoxy] -3-oxabicyclo (3.1.0) hexane We get a -2-on.

Mp 126 ° C;

(? d = -71 ° (c = 1, benzene).

Ultraviolet spectrum (ethanol)

Inflexion at 226 nm (ε = 319); inflexion at 267 nm (ε = 52);

Inflection at 271 nm (ε = 56); at maximum 276 nm (Ej = 60);

Inflexion at 280 nm (ε = 46).

Circular Dichrism (dioxane)

Ae = -4.2 at 225 nm (max)

Ae = +0.39 at 287 nm (max).

NMR Spectrum (deutero chloroform)

Peak: 1.18-1.23 ppm; characteristic of hydrogen atoms of geminal methyl groups;

Peaks at 1.98-2.08 and 2.15-2.25 ppm; isopropyl groups are characterized by hydrogen;

Peak: 5.53-5.54 ppm; characterized by hydrogen atoms on the carbon bearing the nitrile group and hydrogen at the 4-position.

Step C (Preparation of 6-alpha-cyano-3-phenoxybenzyl alcohol

Dissolve 10 g of (1R, 5S) -6,6-dimethyl-4 (R) - [(S) -cyano43'-phenoxyphenyl) methoxy] -3-oxa- in a mixture of 100 ml of dioxane and 50 ml of water. bicyclo (3.1.0) hexan-2-one, prepared according to Step B above, followed by the addition of 1 g of para-toluenesulfonic acid monohydrate. The mixture was heated at reflux for 23 hours and then concentrated under reduced pressure to half its original volume. It is mixed with ethyl ether, the organic phase is separated by decantation, washed with water and dried. Distillate under reduced pressure to dryness. The residue (9.5 g) was chromatographed on silica gel eluting with 9: 1 benzene: ethyl acetate. 6.1 g of (S) alpha-cyano-3-phenoxybenzyl alcohol are obtained.

- 16 _; 5 ° + 1.5 ° ( _c = 0.8%, benzene). Nuclear Magnetic Resonance Spectrum: (deutero chloroform)

Peaks at 3.25 ppm; characteristic of the hydrogen function of the alcohol function; peaks at 5.41 ppm; characterized by a hydrogen atom on a carbon atom bearing a nitrile group.

Example 3

Preparation of D-2-isopropyl-2- (4-chlorophenyl) -acetic acid (S) -alpha-cyano-3-phenoxybenzyl ester in a mixture of ml of isopropanol and 2 ml of triethylamine (3.15 g) alpha-cyano-3-phenoxybenzyl-D-2-isopropyl-2- (4-chlorophenyl) acetate was dissolved and the mixture was stirred for 24 hours at 20 ° C and for 24 hours at 0 ° C. Crystallization was initiated by the addition of a small amount of (S) -? - cyano-3-phenoxybenzyl-D-2-isopropyl-2- (4-chlorophenyl) acetate (m.p. 62 ° C). The mixture was stirred at 0 ° C for a further 24 hours, then at -10 ° C for 48 hours and the precipitate formed was collected by vacuum filtration and dried.

6.1 g of product are obtained in the first crop. Melting point = 62 ° C. The mother liquor was concentrated by distillation under reduced pressure, and 60 ml of petroleum ether (b.p. 35-75 ° C) and 10 ml of isopropanol were added to the residue followed by 2 ml of aqueous ammonium hydroxide solution at 22 ° B. The mixture was stirred for 72 hours at -30 ° C and the resulting precipitate was collected by vacuum filtration, washed and dried. 13.5 g (m.p. 62 ° C) were obtained in a second crop.

The two yields obtained above were combined and recrystallized from isopropanol. 17.9 g of (S) -alpha-cyano-3-phenoxybenzyl-D-2-isopropyl-2- (4-chlorophenyl) acetate are obtained. Mp 62 ° C.

Example 4

Preparation with insecticidal effect

In the form of an emulsifiable concentrate, an insecticidal composition is prepared by homogeneously mixing the following:

- (S) -alpha-cyano-3-phenoxybenzyl-D-2-isopropyl-2- (4-chlorophenyl) acetate 0.3 g

- Piperonyl Bufoxide ................... 0.5 g

- Topanol A ................................................. ...... 0.1 g

- Xilol ................................................. .............. 99.1 g

Claims (3)

Patent claims A process for the preparation of an ester of formula (S) -alpha-cyano-3-phenoxybenzyl alcohol with D-2-isopropyl-2- (4-chlorophenyl) -acetic acid, characterized in that a) Reaction of D-2-isopropyl-2- (4-chlorophenyl) acetic acid or its reactive derivative, preferably its halide, with (S) -configuration alpha-cinoo-3-phenoxybenzyl alcohol in an organic solvent medium, optionally formed in the presence of a base and (S) -alcohol ester elkülö- _one upon heating, or b) reacting D-2-isopropyl-2- (4-chlorophenyl) acetic acid or its reactive derivative, preferably its halide, with (RS) -confined alpha-cyano-3-phenoxybenzyl alcohol in an organic solvent medium, optionally in the presence of base 1 and isolating the ester with (S) -alcohol by crystallization by inoculation with the same ester and basic treatment with the (S) -alcohol ester in a non-solvent organic solvent medium. Process for carrying out process a) according to claim 1 in a fixed volume solution of 2% benzene solution (S) -alpha-cyano-3-phenoxy-benzyl-D-2-isopropyl-2- (4-chloro-phenyl) -acetate, m.p. 62 DEG C. ^{= +} 13.15 °. characterized in that D-2-isopropyl-2- (4-chlorophenyl) acetic acid is reacted with thionyl chloride θ in petroleum ether and the resulting D-2-isopropyl-2- (4-chlorophenyl) is obtained. acetic acid chloride is reacted with (S) -alpha-cyano-3-phenoxy-benzyl alcohol in a benzene medium in the presence of pyridine. 3. Process for the preparation of process b) according to claim 1 for the preparation of (S) -alpha-cyano-3-phenoxybenzyl-D5 2-isopropyl-2- (4-chlorophenyl) -acetate having a fixed structure: treating (RS) -alpha-cyano-3-phenoxybenzois'-D-2-isopropyl-2- (4-chlorophenyl) acetate with ammonium hydroxide as the base in isopropanol. (1 drawing) -6184 193 - NSZL: C 07 C 121/75