DE2128465A1 - - Google Patents

Description

2128465 ■ Dr. ϊ-ruiiz Lederer, ~ June 2, 1971

PATENT LAWYERS

RAH 6101/39

F. Hoffmann-La Roche & Co. Aktiengesellschaft, Basel / Switzerland

Cyclopropane derivatives

The present invention relates to cyclopropanecarboxylic acid esters and a process for the preparation of these esters.

The cyclopropanecarboxylic acid esters prepared according to the invention correspond to the general formula

H, C ^ C-0-CH _o - CSC - CIL- 0 - // Vv

³ IJ ^{2 2} \ _ /

ο ^N '

1098.51 / 197 1

wherein R is a hydrogen atom, a chlorine atom or a lower alkyl group.

These cyclopropanecarboxylic acid esters have an insecticidal effect and can thus be used as insecticides.

The term "lower alkyl" refers to straight chain and branched alkyl groups with a relatively low number of carbon atoms, for example methyl, ethyl, propyl and Isopropyl. The methyl group is preferred here.

An interesting class of esters according to the invention of formula I includes those compounds in which R is a hydrogen atom, a chlorine atom or a lower alkyl group in ortho or para position. A preferred ester of the formula I is 4-phenoxy-2-butynyl-2,2,3,3-tetrainethylcyclopropanecarboxylic acid ester. Other examples of esters of the formula I are 4- (2-methyl-phenoxy) -2-butynyl-2,2,3,3-tetramethyl-cyclopropanecarboxylic acid ester, 4- (3-methyl-phenoxy) -2-butynyl ^^^^ - tetramethyl-cyclopropanecarboxylic acid ester, 4- (4-methyl-phenoxy) -2-butynyl-2,2,3,3-tetramethyl-cyclopropanecarboxylic acid ester, 4- (2-chlorophenoxy) -2-butynyl-2,2,3> 3-tetramethyl-cyclopropanecarboxylic acid ester, 4- (3-chlorophenoxy) -2-butynyl-2,2,3,3-tetramethyl-cyclopropanecarboxylic acid ester and 4- (4-chlorophenoxy) -2-butynyl-2,2,3,3-tetramethyl-cyclopropanecarboxylic acid ester.

The above cyclopropanecarboxylic acid esters can be used according to the invention be prepared by adding 2,2,3,3-tetramethyl-cyclopropanecarboxylic acid chloride or 2,2,3,3-tetramethylcyclopropanecarboxylic acid bromide with an alcohol of the general formula

10 9 8 5 1/19 7 1

II

where R has the above meaning,

converts, or that one an alkali metal salt, the silver salt or a tri (lower-alkyl) amine salt of 2, 2, 3,3-tetr.amethyloyclopropanecarboxylic acid with a halide of the general formula

Hal-CH -C = C-CH-O

where R has the above meaning and Hai Denotes halogen atom,

converts, or that the compound of the general formula

H, C CH,
R ₂ CCH

³ \ /

HC CO-CH ₀ -CS = C-CH ₀ -Cl IV

3 η ^{2 2}

with an alkali metal salt of a phenol of the general formula

109851/197 1

H0 - </ Μ V

wherein H has the meaning given above.

According to one embodiment of the process according to the invention, 2,2, S ^ -tetramethyl-cyclopropanecarboxylic acid chloride or Z, 2,3-tetramethyl-cyclopropanecarboxylic acid bromide is reacted with an alcohol of the formula II.

The Z, 2, 5, 3-Tetrarne thy! -Cyclopropane ar bonsäurec hl orid starting material and the 2,2,3,3-tetramethyl-cyclopropanecarboxylic acid bromide starting material are known compounds and can be prepared by using, for example, tetramethylethylene Methyl- or ethyl-diazoacetic acid ester in the presence of copper powder or preferably of anhydrous copper sulfate in an excess of tetramethylethylene or, preferably, of toluene as solvent and that the 2,2,3 , ^ -tetramethyl-cyclopropanecarboxylic acid obtained is reacted by means of thionyl chloride or thionyl bromide chlorinated or brominated.

The alcohol starting product of the formula II can /..B. be prepared by using a halo-butynol of the general formula

Hal-CH ₂ -CSC-CH ^ -OH VI

109851/1971

where Hal has the above meaning,

with an alkali metal salt of a phenol of formula V above. A chloride of the formula VI is preferably used with the Sodium salt of a phenol of the formula V implemented. The reaction is conveniently carried out at high temperatures, e.g. 50-70 C, in one inert organic solvent, e.g. a lower alkanol, carried out.

The implementation of the 2,2,3,3-tetramethyl-cyclopropanecarboxylic acid chloride or of 2,2,3 »3-tetramethyl-cyclopropanecarboxylic acid bromide with an alcohol starting material of the formula

II can conveniently be carried out in the presence of an acid-binding agent. Suitable acid-binding agents are alkali metal carbonates, e.g. sodium carbonate, alkali metal bicarbonates e.g. sodium bicarbonate and tertiary organic amines e.g. Triaethylamine or pyrldjn. The preferred acid binding agent is pyridine. The reaction can conveniently in the presence of a inert organic solvent, for example a hydrocarbon, e.g. benzene, toluene or xylene, an ether, e.g. Dlaethy1ether or dioxane, or a halogenated hydrocarbon, e.g. methylene chloride or chloroform will. The reaction can expediently in a temperature range from about 0 to about 30 C and below an inert Atmosphere, e.g. under nitrogen or argon.

Another embodiment of the process according to the invention consists in that an alkali metal salt, the silver salt or a tri (lower-alkyl) amine salt of 2,2,3-3-tetramethyl-cyelopropanecarboxylic acid with a halide of the formula

III implements »

The alkali metal salts and the tri-lower alkyl} amine salts 10 9851/1971

can be prepared, for example, that 2,2,3,3-tetramethyl-cyclopropanecarboxylic acid in an inert organic Solvents such as a lower alkanol, e.g. ethanol, treated with the calculated amount of an alkali metal hydroxide solution or a tri (lower-alkyl) amine. The preferred alkali metal salts are the sodium and potassium salts and the preferred tri (lower alkyl) amine salt is the triethylamine salt. The silver salt can through treatment an alkali metal salt, for example the sodium salt, can be obtained in aqueous solution with silver nitrate.

The halide starting materials of the formula III can be obtained, for example, by using a dihalobutyn the general formula

Hal-CH-C = C-CH ₂ -HaI VII

in which shark has the above meaning,

with an alkali metal salt of a phenol of the formula V is reacted. The preferred dihalo-butyne of Formula VII is 1,4-dichlorobutyne. This is expediently reacted with the sodium salt of a phenol of the formula V. The reaction is conveniently carried out in an inert organic solvent such as a lower alkanol, e.g. methanol or ethanol, at increased Temperature, e.g. carried out at a temperature between about 50 and 70 C. The ones used as starting countries Halide © of the formula III can also be used, for example Implementation of an alcohol of the formula II with a two-dimensional Halogenating agents, for example with thionyl chloride or Phosphorus, tribromide are produced in fyridln.

■ 'Implementation of an alk & li metal salts. ¹ ^ des Silber-109851/1971

2128A65

salt or a tri (lower-alkyl) amine salt of 2,2,3,3-tetramethyl-cyclopropanecarboxylic acid with a halide of formula III is conveniently in an inert organic solvent carried out. Any inert organic solvents can be used here. Preferably be However, ketones such as acetone or methyl ethyl ketone or diglyme are used. Implementation is preferred carried out at elevated temperature, expediently at the reflux temperature of the reaction mixture. Advantageous it is here to carry out the reaction under an inert atmosphere, for example under nitrogen or argon.

Another embodiment of the method according to the invention consists in reacting a compound of the formula IV with an alkali metal salt of a phenol of the formula V.

The compound of the formula IV can, for example, by reacting 2,2,3,3-tetremethyl-cyclopropanecarboxylic acid chloride or 2,2,3,3-Tetramethyl-cyclopropanecarboxylic acid bromide with 4-chloro-2-butyn-1-ol getting produced. This reaction can be carried out in the same manner as the above-described reaction of 2,2,3,3-tetramethyl-cyclopropanecarboxylic acid chloride or carboxylic acid bromide carried out with an alcohol starting material of the formula II will.

The alkali metal salts of the phenols of the formula V are known and can be prepared by customary processes.

The reaction of a compound of the formula IV with an alkali metal salt of a phenol of the formula V can be advantageous in the presence of an organic solvent such as a hydrocarbon, e.g. benzene, toluene or Xylene, a halogenated hydrocarbon, e.g. chloroform or methylene chloride or a high-boiling ether,

109851/1971

ζ. B. diglyme. The reaction is preferred at elevated temperature, expediently at the reflux temperature of the reaction mixture. Furthermore is it is also expedient to carry out the reaction under an inert atmosphere, for example under nitrogen or argon.

As already mentioned, the inventive esters are as Insecticides can be used. They have an effect against a large number of insects, in particular against Musca domestica. In addition, the esters have very low toxicity in mammals and humans. For example, it has 4-phenoxy-2-butynyl-2,2,3 ^ -tetramethyl-cyclopropanecarboxylic acid ester the mouse had an LD .__ of 1600 mg / kg p.o. and shows an activity

50

activity against Musca domestica in the order of magnitude as pyrethrin extract and DDT. This connection is also against the black bean aphid, against the Colorado potato beetle, against the codling moth and effective against the spider mite.

The 4- (4-chlorophenoxy) -2-butynyl-2,2,3,3-tetramethyl-

ester
Cyclopropanecarboxylic acid / has an LD ^ ₀ of 10000 mg / kg po in the mouse and is not only effective against Musca domestica, but also against the Colorado beetle and the codling moth.

The esters according to the invention can be used in the form of the customary insecticidal mixtures which they combine included with a compatible carrier. These mixtures can be in liquid form, e.g. as spray solutions or suspensions, or in solid form, e.g. as dusts or granules, in each case together with a compatible carrier. The term "compatible carrier" is used in the present specification to denote a substance which the esters of the formula I is inert towards the esters in which the esters are soluble or dispersible without reducing their effectiveness

109851/197 1

and which do not permanently damage the environment in which they are used. For example, liquid Mixtures are diluted with water and dust powder or granules are stretched with inert solid carriers. When in the making If solid carriers are used in the insecticidal preparations, these can be talc, fine clay, silica or the like which do not cause the esters to decompose. If the esters of the formula I are used in liquid mixtures, so these mixtures can contain emulsifiers and / or suitable solvents. The insecticidal preparations can, if desired conventional additives, for example wetting agents or the like, and they can also contain other insecticides and / or contain synergists.

An effective amount of an insecticidal mixture can be obtained by a conventional method such as spraying, dusting etc., used in an insect infested area will. Solid mixtures and liquid mixtures preferably contain about 0.5 to 25, preferably about 0.5 to 10 percent by weight of the ester of the formula I. The choice of the concentration of the ester of the formula I and the frequency of treatment an insect infested area with such an ester will of course depend on several factors, for example the nature and degree of development of the insects, the type of insecticidal preparation used and the method of application . .

It is noteworthy that the insecticidal mixtures can be in the form of storable concentrates, for example of wettable dust or of an emulsion concentrate, which contain from approximately 10 to 80 percent by weight of an ester of the formula I. The concentrates may be diluted with a carrier or with a plurality of different carriers to a ¹ concentration, which for the treatment of

109851/197 1

insect-infested area is appropriate. Emulsified concentrates can be obtained, for example, by dissolving an ester of the formula I in an appropriate solvent and by adding an emulsifying agent which is soluble in the solvent. Appropriate organic solvents which are usually immiscible with water are hydrocarbons, for example toluene and xylene, chlorinated hydrocarbons, for example perchlorethylene, ketones, esters or mixtures thereof. Aromatic hydrocarbons and ketones are the preferred solvents. Surfactants can be used as emulsifiers, which make up from about 5 to 15 percent by weight of the emulsion concentrate. It is preferred to use nonionic, surface-active substances.

example 1

7.5 ^{ml of} dry pyridine are added to a solution of f , h g (0.0 ^ 57 mol) of 4-phenoxy-2-butyn-1-ol in 65 ml of dry benzene . A solution of 7 * 3 S (0.0455 mol) of 2,2,3,3-tetramethyl-cyclopropanecarboxylic acid chloride in 50 μl of dry benzene is added dropwise to the solution thus obtained over half an hour. The mixture is stirred for 16 hours at room temperature, the precipitated pyridine hydrochloride is filtered off and washed with benzene. The combined benzene solutions are washed twice with 5N hydrochloric acid, once with water, twice with a 2N sodium hydroxide solution, twice with 5N hydrochloric acid, twice with saturated sodium bicarbonate solution and twice with saturated sodium chloride solution and then dried over anhydrous sodium sulfate. The sodium sulfate is filtered off, the piltrate is evaporated under reduced pressure and the remaining syrup is filtered under high vacuum, where 10.3 g of 4-phenoxy-2-butynyl-2,2,3,3-tetramethyl-cyclo ~ propanecarboxylic acid ester is obtained in the form of a colorless liquid

10 9 8 5 1/19 7 1

with a boiling point of 135-137 ° C / 10 mmHg; n ^ ^v = 1.5227.

Example 2

8.5 ml of dry pyridine are a solution of 10.5 δ (0.534 mol) 4- (4-chlorophenoxy) -2-butyn-1-ol in 70 ml dry benzene was added. The resulting solution is dropwise and while stirring with crude 2,2 ^^ - tetramethyl-cyclopropanecarboxylic acid chloride, which by chlorinating 7.5Ö g (0.534 mol) the corresponding carboxylic acid was obtained with thionyl chloride in OG rr.l benzene for half an hour at 20 ° C treated under a nitrogen atmosphere. The mixture will Stirred for 16 hours under a nitrogen atmosphere at room temperature. The precipitated pyridine hydrochloride is filtered off and washed with benzene. The combined benzene solutions are twice with 5N hydrochloric acid, once with water, three times with a 2N sodium hydroxide solution, once with 2N hydrochloric acid, twice with saturated sodium bicarbonate solution and twice with saturated sodium chloride solution and dried over anhydrous sodium sulfate. The sodium sulfate is filtered off and the filtrate was evaporated to a syrup under reduced pressure. By distilling the crude product twice 8.3 g of 4- (4-chlorophenoxy) -2-butynyl-2,2,3,3-tetramethyl-cyclopropanecarboxylic acid ester are obtained in the form of a colorless

ο -4 liquid with a boiling point of 140 C / 10 mmHgj

4 ° = 1.5329-

Example 3

A solution of 8.8 g of 4- (4-methylphenoxy) -2-butyn-1-ol 8 ml of dry pyridine are added in 80 ml of dry benzene. The resulting solution is added dropwise and with stirring with crude 2,2,3,3-tetramethyl-cyclopropanecarboxylic acid chloride,

109851/197 1

-12- 2 1 28A65

which has been obtained by chlorinating J, l g of the corresponding carboxylic acid with thionyl chloride in 20 ml of benzene. The mixture is stirred at 20 ° C. for 16 hours under a nitrogen atmosphere. The precipitated pyridine chloride is filtered off and washed with benzene. The combined benzene solutions are washed twice with 5N hydrochloric acid, once with saturated sodium chloride solution, twice with 2N sodium hydroxide solution, once with 2N hydrochloric acid, twice with saturated sodium bicarbonate solution and twice with saturated sodium chloride solution and dried over anhydrous sodium sulfate. The sodium sulfate is filtered off, the filtrate is evaporated and the residue is distilled under high vacuum, whereby 11.65 g of H- (4-methylphenoxy) -2-butynyl-2,2,3,3-tetramethyl-cyclopropanecarboxylic acid ester with a boiling point of 120- 126 ° C / l0 " ⁴ mmHg; n ^ ° = 1.5213 received.

4- (3-methylphenoxy) -2-butynyl-2,2,313 "'tetramethyl-cyclopropanecarboxylic acid ester is obtained in a similar manner with a boiling point of 145 C / 10 mmHg; n ~ = 1.5215 if one instead of 4- (4-methylphenoxy) -2-butyn-l-ol 4- (3-methylphenoxy) 2-butyn-l-ol used as starting material.

Example 4

A solution of 9.82 g of 4- (3-chlorophenoxy) -2-butyn-1-ol 8 ml of dry pyridine are added in 80 ml of dry benzene. The resulting solution is added dropwise with stirring

cyclopropane reacted with a solution of crude 2,2,3,3-tetramethyl-lcarboxylic acid chloride, which was obtained by chlorinating 7.1 g of the corresponding carboxylic acid with thionyl chloride, in 20 ml of benzene. The mixture is stirred for 16 hours at 20 ° C. under a nitrogen atmosphere. The precipitated pyridine hydrochloride is filtered off and washed with benzene. The combined benzene solutions are successively twice with 5N hydrochloric acid

109 851/197 1

washed once with water, twice with a 2N sodium hydroxide solution, once with 2N hydrochloric acid, twice with a saturated sodium bicarbonate solution and twice with a saturated sodium chloride solution and dried over anhydrous sodium sulfate. The sodium sulfate is filtered off, the filtrate is evaporated and the residue is distilled under high vacuum, 12.35 S 4- (3-chlorophenoxy) -2-butiny1-2,2,3,3-tetra-

, Pyropan
methyl-cyclofcarboxylic acid ester in the form of an oil with a boiling point of 124-132 C / 10 mmHgj η _η = 1.53O4.

Example 5

7.1 g of 2,2,3j3-tetramethyl-cyclopropanecarboxylic acid become dissolved in 100 ml of ethanol and the pH of the resulting solution is increased by adding 2N aqueous sodium hydroxide solution 7 posed. The mixture is evaporated under reduced pressure and the residue is added twice to constant weight Ethanol and codestilated three times with benzene, whereby the Sodium salt of 2,2,3,3-tetramethyl-cyclopropanearboxylic acid receives.

A slurry of the sodium salt obtained in 400 ml of dry diglyme is mixed with 9 g of 1-chloro-4-phenoxy-butyne implemented. The mixture is stirred and heated to 140 ° C. for 6.5 days under a nitrogen atmosphere. The diglym is evaporated under reduced pressure, the residue is treated with a mixture of water and diethyl ether and finally extracted with diethyl ether. The extracts are treated twice with a 2N sodium hydroxide solution, once with a saturated sodium bicarbonate solution, twice with water and washed twice with a saturated sodium chloride solution and dried over anhydrous sodium sulfate. By filtering off of the sodium sulfate, evaporation of the filtrate and distillation of the residue under high vacuum, 7 * 05 g of 4-phenoxy-

109851/197 1

2-butynyl-2,2,3,3-tetramethyl-cyclopropanecarboxylic acid ester in

ο -k form of an oil with a boiling point of 140-150 C / 10 mmHg; = 1.5227-

Example 6

A solution of 10.7 g of 2,2,3,3-tetramethyl-cyclopropanecarboxylic acid in 25 ml of petroleum ether is at room temperature with 7.5 ml of distilled thionyl chloride and 2 drops of dimethylformamide treated. After 1.5 hours the carboxylic acid is completely resolved. The solution is evaporated and the residue is codistilled with benzene, whereupon 2,2,3,3-tetramethylcyclopropanecarboxylic acid chloride receives.

A solution of 7.83 g of 4-chloro-2-butyn-1-ol in 100 ml of dry benzene and 12 ml of pyridine is treated under a nitrogen atmosphere with a solution of the acid chloride obtained above in 20 ml of benzene. The mixture is stirred for one hour at room temperature and the precipitated pyridine hydrochloride is filtered off and washed with benzene. The combined benzene solutions are washed twice with 5N hydrochloric acid, once with a 2N sodium hydroxide solution, once with a 2N hydrochloric acid, twice with saturated sodium bicarbonate solution and twice with saturated sodium chloride solution and then dried over anhydrous sodium sulfate. By filtering off the sodium sulfate, evaporating the piltrate and distilling the residue under high vacuum, one obtains

10.0 g of ty-chlorine - ^ - butynyl - ^^^^ - tetramethyl-cyclopropanecarbon ster mi 1.4900.

o acid esters with a boiling point of 115-120 C / 0.7 mmHgj

A solution of 0.57 g of sodium in 50 ml of dry ethanol is treated with a solution of 2.35 g of phenol in 20 ml of dry ethanol and the mixture is left to stand for 2 hours

109851/1971

calmly. The ethanol is evaporated and the residue three times codestilated with benzene, the sodium salt of phenol in the form of a white powder.

The sodium salt obtained is in 100 ml dry

Slurried diglyme and added 5.71 g of 4-chloro-2-butynyl-2,2,3,3-

ester tetramethyl-cyclopropane-carboxylic acid 7 added. The mixture will heated at 120 ° C. for 48 hours under a nitrogen atmosphere. The precipitated sodium chloride is filtered off, the solution is evaporated under the vacuum of a water pump and water is added to the resulting residue. After that, will the mixture extracted three times with diethyl ether and the combined diethyl ether extracts once with a 2N sodium hydroxide solution and washed twice with a saturated sodium chloride solution and dried over anhydrous sodium sulfate. By filtering off the sodium sulfate, evaporating the filtrate and distilling the residue under high vacuum, one obtains 3.95 g of U-phenoxy-2-butynyl-2,2,3,3-tetramethyl-cyclopropane-

o -4 carboxylic acid esters with a boiling point of 140-145 C / 10 mmHg;

n ^ ° = 1.5227.

The following examples illustrate the inventive Ester-containing insecticidal mixtures:

Example 7

2.5 g of 4-phenoxy-2-butynyl-2,2,3,3-tetramethyl-cyclopropanecarboxylic acid ester are dissolved in enough kerosene to make a final volume of 100 ml. The solution obtained is suitable for use as a spray liquid.

Example 8 - _'-. After mixing 5 g of 4- (4-chlorophenoxyj-2-butiriyl-

1 0 9 8 5 ^{1/1 9 7 1 r} ■ ' ^{B b} ° ^r

2,2,3,3-tetramethyl-cyclopropanecarboxylic acid ester with 5 g Ligninsulphonate and 90g kaolin is the resulting mixture under Stirring the addition of 10 ml of water in a mortar, stirring the moist mixture further and then granulating it. The received After air-drying, granules contain 5% active ingredient.

Example 9

20 g ^ -

carboxylic acid esters are mixed with 10 g of Nonoxylon 15 (a non-ionic, surfactant) and 70 g xylene to a solution mixed, which can be used as an emulsifiable concentrate. Before use, this concentrate is mixed with enough water emulsified to give a ten-fold dilution.

1 09851/1971

Claims (1)

Claims 1 / Process for the preparation of cyclopropanecarboxylic acids esters of the general formula CC HC ^ C- 0-CH _o - CSC - CH_-O - VV ^ 3 I. wherein R denotes a hydrogen atom, a chlorine atom or a lower alkyl group, characterized in that one 2,2,3 »3-tetramethyl-cyclopropanecarboxylic acid chloride or 2,2,3j3-tetramethylcyclopropanecarboxylic acid bromide with an alcohol of the general formula HO-CH ₂ - CSC-CH ₂ -O- "^ ^ΐτ where R has the above meaning, converts, or that one an alkali metal salt, the silver salt or a tri (lower-alkyl) amine salt of 2,2,3,3-tetramethyl-cyclopropanecarboxylic acid with a halide of the general formula 109851/1971 Hal _{- CH 2} - C se C - CH ₂ - O III where R has the above meaning and Hal denotes a halogen atom, converts, or that the compound of the general formula H, C C H, C C H ³ \ HC C 0 IV with an alkali metal salt of a phenol of the general formula HO where R has the meaning given above, implements. 109851/1971 - 19 - 21 28A65 2. The method according to claim 1, characterized in that 2,2,3,3-tetramethyl-cyclopropanecarboxylic acid chloride is reacted with an alcohol of the formula II in which R is a hydrogen atom or a chlorine atom or a lower alkyl group in the ortho or para position . 3. Process according to Claim 2, characterized in that 4-phenoxy-2-butyn-1-ol is used as the alcohol. 4. The method according to claim 2, characterized in that 4- (4-chlorophenoxy) -2-butyn-1-ol is used as the alcohol . 5. The method according to any one of claims 1-4, characterized in that the reaction of 2,2,3,3-tetrarnethyl cyclopropanecarboxylic acid chloride or bromide with an alcohol of the formula II is carried out in the presence of an acid-binding agent. 6. The method according to claim 5 »characterized in that an alkali metal carbonate, an alkali metal bicarbonate or a tertiary organic amine is used as the acid-binding agent, 7. The method according to claim 6, characterized in that that pyridine is used as an acid binding agent. 8. The method according to claim 1, characterized in that that an alkali metal salt, the silver salt or a tri (lower-alkyl) amine salt of 2,2,3,3-tetramethyl-cyclopropanecarboxylic acid with a halide of the formula III, in which R is a hydrogen atom, denotes a chlorine atom or a lower alkyl group in the ortho or para position. 9. The method according to claim 1 or 8, characterized 109851/197 1 draws that an alkali metal salt of 2,2,3,3-tetramethylcyclopropanearboxylic acid is used as the starting material. _:; , 10. The method according to claim 9, characterized in ,,, that the sodium or potassium salt is used as the alkali metal salt. 11. The method according to claim 1 or "one of the claims 8-10, characterized in that a "chloride or bromide of formula III is used as the starting material. 12. The method according to claim 11, characterized in that the sodium salt of 2,2,3 »3-tetrarcethyl-cyclopropanecarboxylic acid is reacted with l-chloro-4-phenoxy-butyne . 13. The method according to claim 1, characterized in that the compound of the formula IV is reacted with an alkali metal salt of a phenol of the formula V, wherein R denotes a hydrogen atom, a chlorine atom or a lower alkyl group in the ortho or para position. 14. The method according to claim 1 or I3, characterized in that the sodium salt of a phenol of the formula V is used as starting material. 15. The method according to claim 14, characterized in that the compound of formula IV is reacted with the sodium salt of phenol. 10985 1/1 9 7 Y ^ 2128A65 l6. Process for the preparation of an insecticidal agent, characterized in that one uses a cyclopropanecarboxylic acid ester of the general formula I mixed with a compatible carrier. 109851/1971 17 · Insecticidal agent * characterized in that it as the active ingredient a cyclopropanecarboxylic acid ester of the general formula I, together with a compatible carrier, contains. 109851/1971 2128A65 l8. Cyclopropanecarboxylic acid esters of the general formula C-O-CIL-CsC-CIL-O ^{2 2} wherein R denotes a hydrogen atom, a chlorine atom or a lower alkyl group. 19. Cyclopropanecarboxylic acid ester of the formula I according to claim l8, wherein R is a hydrogen atom, a chlorine atom or denotes a lower alkyl group in the ortho or para position. 20. U-Phenoxy-2-butynyl-2,2,3,3-tetramethyl-cyclopropanecarboxylic acid ester. 21. 4- (4-Chlorophenoxy) -2-butynyl-2,2,3,3-tetramethylcyclopropane carboxylic acid ester. 109851