GB2095675A

GB2095675A - Cyclopropane carboxylic acid esters

Info

Publication number: GB2095675A
Application number: GB8208934A
Authority: GB
Original assignee: Roussel Uclaf SA
Current assignee: Sanofi Aventis France
Priority date: 1981-03-27
Filing date: 1982-03-26
Publication date: 1982-10-06
Also published as: DE3211296A1; CH651557A5; GB2095675B; NL8201209A; IT1186676B; IT8248027A0; FR2502462B1; JPS57169467A; FR2502462A1; HU190788B

Abstract

Compounds of formula <IMAGE> (in which X1 represents a hydrogen, fluorine, chlorine or bromine atom, X2 represents a fluorine, chlorine or bromine atom, X3 represents a chlorine, bromine or iodine atom, one of the radicals A and B represents a carbonyl group and the other represents a methylene, ethylidene or propylidene group and R1 represents a lower alkyl, lower alkenyl or lower alkynyl radical containing up to three carbon atoms) exhibit antiparasitic and pesticidal activity, e.g. against insects, acarids and nematodes. They may be formulated for use against parasites of plants and animals and pests found in premises, including as pharmaceutical compositions. Processes for the preparation of the compounds are described. <IMAGE>

Description

SPECIFICATION Cyclopropane carboxylic acid esters The present invention relates to new esters of cyclopropane carboxylic acids containing a polyhalogenated substituent, a process for preparing them and their use in the control of parasites and pests.

Accordingly, in a first aspect the invention provides compounds of formula (I):

(in which X1 represents a hydrogen, fluorine, chlorine or bromine atom, X2 represents a fluorine, chlorine or bromine atom, X3 represents a chlorine, bromine or iodine atom, one of the radicals A and B represents a carbonyl group and the other represents a methylene, ethylidene or propylidene group and R, represents a lower alkyl, lower alkenyl or lower alkynyl radical containing up to three carbon atoms), in all their possible stereoisomeric forms including mixtures thereof.

The compounds of formula (I) can exist in numerous stereoisomeric forms. In fact, the cyclopropane carboxylic acids forming the acid moiety of the esters of formula (I) possess at least 3 asymmetric carbons, namely the asymmetric carbons at positions 1 and 3 of the cyclopropane group and the carbon at position 1 ' of the polyhalogenated ethyl side chain attached thereto at position 3.

In the case in which the three substituents X1, X2 and X3 are different from one another, an additional asymmetric carbon exists at position 2' of the polyhalogenated side chain.

In the case in which the substituents X1 and X2 are the same, for a steric configuration determined by the asymmetric carbons at positions 1 and 3 of the cyclopropane ring, two diastereoisomeric forms ol the products of formula (I), due to the existence of the asymmetric carbon at position 1', can exist and be characterized for example by their NMR spectrum or their speed of migration in thin-layer chromatography. These isomers can, in general, be separated and isolated in the pure state for example by chromatography.

When R, is a lower alkyl radical, it is preferably a methyl, ethyl or propyl radical.

When R, represents a lower alkenyl radical, it is preferably the radical -CH2CH = CH2.

When R, represents a lower alkynyl radical, it is preferably the radical -CH2-C OH.

A preferred group of compounds according to the invention comprises compounds of the formula

(wherein X1,X2 and X3 are as hereinbefore defined).

A further group of preferred compounds of the invention includes those compounds of formula (I) in which the cyclopropane acid moiety is of IR trans or IR cis structure and the compounds of formula (I) for which X1,X2 and X3 represent the same halogen, for example a bromine atom.

The compounds of formula (I) have interesting properties which enable them to be used in the control of parasites and pests. They may be useful, for example, in the control of parasites and pests in various loci, including parasites of vegetation and of warm-blooded animals, and also pests found in premises, e.g. homes and commercial premises. Thus the compounds of the invention can be used to control insects, nematodes and acarids which may be parasites of plants or of animals or pests found in premises.

The compounds of formula (I) can be used especially to control insects in the agricultural sphere, to control for example aphids and the larvae of lepidoptera and coleoptera. They may be used for example at doses of from 10 g to 300 g of active substance per hectare.

The Examples set out hereinafter illustrate the remarkable "knock-down" potential of the products of the invention, as well as their lethal effects after potentiation by synergistic agents.

The compounds of the invention (and in particular isomer B obtained in Example 4) offer, in addition, the advantage of having good light stability which enables them to be used for example in the agricultural sphere.

The compounds of formula (I) can also be used to control insects found in premises, especially flies, mosquitoes and cockroaches.

The compounds of formula (I) can also be used to control acarid and nematode parasites of plants.

The compounds of formula (I) can further be used to control acarid parasites of animals, for example ticks and especially ticks of the species Boophilus, those of the species Hyalomnia, those of the species Amblyomnia and those of the species Rhipicephalus, and to control all kinds of scabies, especially sarcoptic scabies, psoroptic scabies and chorioptic scabies.

Accordingly the invention further provides compounds of formula (I) for use in the control of parasites and pests, for example parasites of vegetation and of warm-blooded animals and pests found in premises.

In a further aspect the invention thus provides compositions for use in the control of parasites and pests, for example parasites of vegetation and of warm-blooded animals and pests found in premises, containing, as active ingredient, at least one compound of formula (I) as defined above.

Such compositions may be prepared according to the usual processes of the art concerned, e.g.

the agrochemical industry, the veterinary industry or the animal foodstuffs industry.

In such compositions the active substance or substances may have added to them possibly one or more other pesticidal agents. Such compositions may be presented in the form of powders, granules, suspensions, emulsions, solutions, solutions for aerosols, combustible strips, baits or other preparations normally employed for this kind of compound.

In addition to the active ingredient, such compositions may contain, in general, a vehicle and/or a non-ionic, surface-active agent to ensure uniform dispersion of the components of the mixture. The vehicles can be liquids such as water, alcohols, hydrocarbons or other organic solvents, mineral, animal or vegetable oils, powders such as talc, clays, silicates or kieselguhr or combustible solids.

In particular, the invention provides insecticidal compositions containing as active ingredient at least one compound of formula (I) as defined above.

Such insecticidal compositions according to the invention contain, preferably, from 0.005% to 10% by weight of active substance.

According to an advantageous modus operandi, for domestic use, the insecticidal compositions according to the invention may be used in the form of fumigating compositions.

The non-active portion of the compositions according to the invention may in that case advantageously be a combustible insecticidal coil, or an incombustible fibrous substrate. In the latter case, the fumigant obtained after incorporation of the active substance may be placed in a heating apparatus such as an electric mosquito destroyer.

Where an insecticidal coil is used, the inert carrier can be for example composed of pyrethrum marc, Tabu powder (or powder of Machilus Thumbergii leaves), pyrethrum stem powder, cedar needles powder, wood dust (such as pinewood sawdust), starch or coconut shell powder.

The active substance may be, for example, used at a rate of from 0.03 to 1% by weight in such a composition.

Where an incombustible fibrous support is used, the active substance may be, for example, used at a rate of from 0.03 to 95% by weight.

Insecticidal compositions according to the invention for domestic use may also be obtained by preparing a sprayable oil based on the active ingredient this oil being for example impregnated in the wick of a lamp and subsequently being subjected to combustion.

The concentration of the active ingredient incorporated in such an oil is, preferably, from 0.03 to 95% by weight.

Likewise acaricidal and nematocidal compositions may be provided containing as active ingredient at least one compound of formula (I) as defined above.

As with the insecticidal compositions according to the invention, such acaricidal and nematocidal compositions may have added to them possibly one or more other pesticidal agents. The acaricidal and nematocidal compositions may be presented for example in the form of powders, granules, suspensions, emulsions and solutions.

For acaricidal use preferably wettable powders forfoliar spraying are used, containing for example from 1 to 80% by weight of active ingredient, or liquids for foliar spraying containing for example from 1 to 500 g/l of active ingredient. Powders forfoliar dusting can likewise be used, containing for example from 0.05 to 3% by weight of active substance.

For nematocidal use preferably liquids for soil treatment are used, containing for example from 300 to 500 g/l of active ingredient.

The acaricidal and nematocidal compounds according to the invention are used preferably at doses of from 1 to 1 00 g of active substance per hectare.

The compounds of formula (I) offer excellent general tolerance and the invention accordingly further provides compounds of formula (I) for use as medicaments to control for example diseases caused by ticks, and scabies.

The compounds of the invention can be used as medicaments both in human medicine and in veterinary medicine.

The compounds of the invention may be used for example in human medicine to control lice, by way of prevention or cure, and to control scabies. They can also be used as anthelmintics.

The compounds of the invention when used as medicaments can be administered for example externally, by vaporization, by bath or by painting-on.

The compounds of the invention for veterinary use can also be administered by painting on to the dorsal spine according to the so-called "pour-on" method. They can also be administered internally by the digestive or parenteral routes.

Accordingly, the invention further provides pharmaceutical compositions containing as active ingredient at least one compound of formula (I) as defined above, and especially such compositions for use in the control of acarid parasites of animals, to control for example all kinds of ticks, and scabies.

For the purpose of controlling acarid parasites of animals, the products of the invention can be incorporated in food compositions in association with a nutrient medium adapted for animal feeding.

The nutrient medium can vary according to the animal species: for example it may contain cereals, sugars and grains, soya-bean-, peanut- and sunflower-cake, meals of animal origin, for example fish meals, synthetic amino acids, mineral salts, vitamins and anti-oxidants.

Such food compositions accordingly constitute further aspects of the invention.

The compounds of the invention also have a repellent effect towards the parasites and pests above-mentioned. The compounds may also find use as biocides or growth-regulants.

To enhance the biological activity of the compounds of the invention, they may be used in conjunction with standard synergistic agents such as 1-(2,5,8-trioxadodecyl)-2-propyl-4,5- methylenedioxybenzene (piperonyl butoxide), N-(2-ethylheptyl)bicyclo-[2,2,1]-5-heptene,2,3- dicarboximide, piperonyl-bis-2-(2'-n-butoxyethoxy)ethylacetal (tropital) or S,S,Stributylphosphorotrithioate.

According to the use which it is desired to make of them, it may be interesting to use the products of formula (I) in association with other well-known products, for example products having insecticidal activity such as organochlorinated compounds, organophosphorus compounds, carbamates and pyrethrinoids, with products having acaricidal activity such as chlorinated carbinols, benzene derivatives, quinoxalines, formamidines, stannic derivatives, benzimidazoles, derivatives of benzhydroxamic acid and pyrethrinoid derivatives, with products having nematocidal activity such as carbamates and products decomposing to form carbamates and to form organophosphorus compounds, with products having herbicidal or ixodicidal activity such as organophosphorus compounds, carbamates and pyrethrinoids or with products having growth-regulating activity.

Accordingly, in a still further aspect the invention provides compositions comprising at least one compound of formula (I) in association with at least one compound selected from the chrysanthemic acid esters of allethrolones, of 3,4,5,6-tetrahydrophthalimidomethyl alcohol, of 5-benzyl-3-furylmethyl alcohol, of 3-phenoxybenzyl alcohol and of -cyano-3-phenoxybenzyl alcohols; 2,2-dimethyl-3-(2-oxo 3-tetra hydrothiophenylidenemethyl)cyclopropane- 1 -carboxylic acid esters of 5-benzyl-3-fu rylmethyl alcohol; 2,2-dimethyl-3-(2,2-dichlorovinyl)cyclopropane-1 -carboxylic acid esters of 3-phenoxybenzyl alcohol and of a-cyano-3-phenoxybenzyl alcohols; 2,2-dimethyl-3-(2,2-dibromovinyl)cyclopropane- - carboxylic acid esters of a-cyano-3-phenoxybenzyl alcohols; 2-parachlorophenyl-2-isopropylacetic acid esters of 3-phenoxybenzyl alcohol; and 2,2-dimethyl-3-(1 ',2',2' ,2'-tetrahaloethyl)cyclopropane- 1 - carboxylic acid esters of allethrolones, of 3,4,5,6-tetrahydrophthalimidomethyl alcohol, of 5-benzyl-3furylmethyl alcohol, of 3-phenoxybenzyl alcohol and of a-cyano-3-phenoxybenzyl alcohols (in which "halo" represents a fluorine, chlorine or bromine atom), it being understood that the compounds (I) can exist in any of their stereoisomeric forms, as can the acid and alcohol moieties of the pyrethrinoid esters or their analogues.

Such associations of compounds according to the invention with other agents are of especial interest either in enabling, through the varied nature of their activity, a more extensive range of parasites to be combated, in manifesting, in certain cases, a synergistic effect, or in associating, for example, pesticidal activity with herbicidal activity, with growth-regulating activity or with any other activity.

In a still further aspect the invention provides a process for preparing the compounds of formula (I), in which an acid of formula (all):

wherein X1,X2and X3 are as hereinbefore defined or a functional derivative thereof is reacted with an alcohol of formula (III):

wherein A, B and R1 are as hereinbefore defined, or a functional derivative thereof, whereby the corresponding compound of formula (I) is obtained.

By functional derivative of the acid there is understood preferably an acid chloride or an anhydride.

The esterification reaction is carried out preferably by reacting the acid of formula (II) with the alcohol of formula (III) in the presence of dicyclohexylcarbodiimide or diisopropylcarbodiimide.

The compounds of formula (II) used as starting materials are known products which can be prepared according to the process described in French Patent 2,364,884.

The compounds of formula (III) used likewise as starting materials are also known products which can be prepared according to the process described in French Patent Application 2,415,105.

The following non-limiting Examples illustrate the invention.

EXAMPLE 1 [3-(propyn-2-yl)-2,5-dioxoimidazolidinylmethyl(1R,trans)-2,2-dimethyl-3-[1'-(RS) 2',2',2' tetrabromoethyl]cyclopropane carboxylate.

A mixture containing 4 g of (IR,trans)-2,2-dimethyl-3-[1 '-(RS) 2',2',2'-tetrabromoethyl] cyclopropane carboxylic acid, 50 cm3 of methylene chloride, 1 5 mg of dimethylamino pyridine and 1.8 g of dicyclohexylcarbodiimide is kept under agitation and under a current of nitrogen for 30 minutes.

1.5 g of [3-(propyn-2-yl)-2,5-dioxo-imidazolidinyl] methanol are then added. The reaction mixture is kept under agitation for 16 hours then filtered and the filtrate is concentrated to dryness.6,17 g of the product sought are obtained in "crude" form which is purified by chromatography on silica, elution being carried out with cyclohexane/ethyl acetate mixture, 73:27. 3.5 g of the title compound are thus obtained.

NMR CDCI3 p.p.m.

- 1.27-1.31-1.33-1.35 H of the methyls at 2 - 1 6.2 to 2.33 H of the carbons at 1 and 3 -4.3-4.4 and 4.4-4.6 H of the 1 2,2,2-tetrabromo ethyl radical - 5.6 and 5.63 H of the carbon of the chain at a of the CO2 - 4.03 and 4.06 H of the carbon at 3 of the imidazolidinyl radical

-2.34-2.38-2.43 H of the triple bond-C =-CH EXAMPLE 2 [3-(propyn-2-yl)-2,5-dioxoimidazolidinyl] methyl (1R, cis)-2,2-dimethyl-3-[1'-(S)-2',2',2' tetrabromoethyl]cyclopropane carboxylate and [3-(propyn-2-yl)-2,5-dioxoimidazolidinyl] methyl (1R, cis)-2,2-dimethyl-3-[1'-(R) 2',2',2'-tetrabromoethyl] cyclopropane carboxylte.

2 g of dicyclohexylcarbodiimide are introduced under gitation and under a current of nitrogen into a solution containing 5.2 g of (lR,cis)-2,2-dimethyl-3-[1 '-(RS)-2',2',2'-tetrabromoethyl] cyclopropane carboxylic acid, 20 cm3 of methylene chloride and 1 50 mg of dimethylaminopyridine. The reaction mixture is kept under agitation for 1 5 to 20 minutes at ambient temperature and 1.8 g of 3-(propyn-2yl)-2,5-dioxoimidazolidinyl methanol are introduced. The reaction mixture is kept under agitation for 2 hours, 30 minutes and the urea formed is filtered and rinsed with methylene chloride. The filtrate is washed with a 1 N solution of hydrochloric acid, then with water, dried and concentrated to dryness under reduced pressure. 8.2 g of an oil are obtained which is chromatographed on silica, elution being carried out with benzene/ethyl acetate mixture, 85:15.

The following compounds were obtained: (A) 2.2 g of the diastereoisomer S [α]D = - 101 5 # 3 (c = 0.75% CHCl3) NMR CDCI3 p.p.m.

- 1.36 and 1.42 H of the methyls at 2 of the cyclopropane - 5.3 to 5.4 H of the tetrabromoethyl radical # # 5.4-5.5 5.6-5.7 H of the carbon of the cham at α of the CO2

-2.37-2.39-2.41 acetylenic H.

(B) 1.6 g of the distereoisomer R [α] = + 71.5 (c = 1.5% in CHCl3) NMR CDCI3 p.p.m.

- 1.23 and 1.47 H of the methyls at 2 - 5.0 to 5.1 H of the tetrabromoethyl radical # # 5.4-5.6 5.6-5.7 H of the carbon of the side chain at α of the CO2

- 2.36-2.38-2.40 H -C = OH EXAMPLE 3 1-[3-(propyn-2-yl)-2,5-dioxoimidazolidinyl] methyl (1R, trans)-2,2-dimethyl-3-[2'-bromo-2',2'-dichloro 1 '-bromoethyll cyclopropane carboxylate.

The product was prepared according to the process indicated above, starting with the corresponding acid and alcohol.

[α]D = +12 # 2 (c = 0.5% CHCl3).

EXAMPLE4 1-[3-(propyn-2-yl)-2,5-dioxoimidazolidinyl] methyl (1R, cis)-2,2-dimethyl-3-(2[-bromo-2',2'-dichloro-1'bromoethyl) cyclopropane carboxylate (isomer A) and 1-[3-(propyn-2-yl)-2,5-dioxoimidazolidinyl] methyl (1R, cis)-2,2-dimethyl-3-[2'-bromo-2',2'-dichloro-1'-bromoethyl]cyclopropane carboxylate (isomer B).

The products were prepared according to the process indicated above in Example 2, starting with the corresponding acid and alcohol. Isomer A and isomer B were separated by chromatography.

[α]D = -112 + 20 (c = 1% CHCI3) (isomer A) [α]D = + 85 # 2.5 (c = 1% CHCl3) (isomer B).

EXAMPLE 5 A: Study of the knock-down activity on house flies.

Experiment no. 1: The test insects are female house flies, 4 to 5 days old and raised under constant conditions in the laboratory (25 C - 70% relative humidity). Work is carried out by direct spraying in a Kearns and March chamber, using as solvent a mixture of acetone (5%) and of petroleum solvent Isopar L (95%) (amount of solution used 2 x 0.2 cm3). About 50 insects are used per treatment. Checks are carried oL every minute up to 10 minutes, then at 1 5 minutes and the KTso is determined by the usual methods.

The experimental results obtained are summarized in the following table: Ktso (in minutes) for a concentration of 0.25 g/l Product of Example 1 2.8 Product of Example 2 (isomer S) 1 Product of Example 2 (isomer R) 1.1 Conclusion: The products of the application show remarkable knock-down activity in this test.

Experiment no. 2: The same technique is used and the same concentrations, but the checks are carried out every fifteen seconds up to 10 minutes and the KT, is determined by the usual methods.

The experimental results obtained are summarized in the following table: KT50 (in minutes) for a concentration of 0.25 g/1 Product of Example 1 1.82 Product of Exampel 2 (isomer S) 1.34 Product of Example 2 (isomer R) 1.32 Conclusion: Confirming and particularizing the conclusions of Experiment 1, the products of the application show remarkable knock-down activity in this test.

-B: Studies ofpotentiation of the products of the application.

The insects used are female house flies, 4 to 5 days old and raised under constant conditions in the laboratory (25or and 70% RH). The LDso is investigated and work is carried out by topical application with the Arnold microapplicator of a microlitre of toxic acetonic solution of each of the products to insects previously anaesthetised with carbon dioxide.

The synergistic compounds used are on the one hand piperonyl butoxide (PB) and on the other hand DEF or SSS tributyl phosphorotrithioate. They are used in solution with the products of the application.

The mortality checks are carried out 24 hours after the topical application.

The experimental results obtained are summarized in the following table: LDso in nanograms per insect Product of Example 1 :191 Product of Example 1 + PB 10 (used at 10 times the dose of the product) : 87 Product of Example 1 + DEF 10 (used at 10 times the dose of the product) : 35 Product of Example 1 + PB 10 + DEF 10 : 13 LD50 in nanograms per insect Isomer R of Example 2 :327 Isomer R of Example 2 + PB 10 : 77 Isomer R of Example 2 + DEF 10 : 38 Isomer R of Example 2 + PB 10 + DEF 10 : 13.7 Conclusion: The products of the application can be strongly potentiated by synergists and then show remarkable lethal activity.

EXAMPLE 6 Preparation of a soluble concentrate or aqueous spray.

A homogeneous mixture is made up, of: Product of Example 1 0.25 g Piperonyl butoxide 1 g Tween 80 0.25 g Topanol A 0.1 g Water 98.4 g EXAMPLE 7 Preparation of an emulsifiable concentrate.

Intimately mixed are: Product of Example 1 0.015g Piperonyl butoxide 0.5 g Tween 80 3.5 g Topanol A 0.1 g Xylene 95.885 g EXAMPLE 8 Preparation of an emulsifiable concentrate.

A homogeneous mixture is made up, of: Product of Example 1 1.5 9 Tween 80 20 g Topanol A 0.1 g Xylene 78.4 g EXAMPLE 9 Preparation of a smoke-producing composition.

Product of Example 1 0.25 g Tabu powder 25 g Cedar-needle powder 40 g Pine-wood dust 33.75 g Brilliant green 0.5 g p-nitrophenol 0.5 g

Claims

1. Compounds of formula (I):

(in which X, represents a hydrogen, fluorine, chlorine or bromine atom, X2 represents a fluorine, chlorine or bromine atom, X3 represents a chlorine, bromine or iodine atom, one of the radicals A and B represents a carbonyl group and the other represents a methylene, ethylidene or propylidene group and R, represents a lower alkyl, lower alkenyl or lower alkynyl radical containing up to three carbon atoms), in all their possible stereoisomeric forms including mixtures thereof.

2. Compounds as claimed in claim 1 having the formula (IA)

in which X1, X2 and X3 are defined as in Claim 1.

3. Compounds as claimed in claim 1 or claim 2, in which the cyclopropane carboxylic acid moiety is of 1 R,trans or 1 R,cis structure.

4. Compounds as claimed in any one of claims 1 to 3 in which X,, X2 and X3 represent the same halogen atom.

5. Compounds as claimed in claim 4 in which X,, X2 and X3 each represent a bromine atom.

6. Compounds of formula (I) as claimed in claim 1 substantially as herein described in any one of the Examples.

7. Compounds of formula (I) as claimed in any one of claims 1 to 6 for use in the control of parasites and pests.

8. Antiparasitic and/or pesticidal compositions containing as active ingredient at least one compound as claimed in any one of claims 1 to 7.

9. Compositions as claimed in claim 8 for use in the control of parasites of vegetation or of warm blooded animals and pests in premises.

10. Compositions as claimed in claim 8 or claim 9 having insecticidal activity.

11. Compositions as claimed in claim 8 or claim 9 having acaricidal and/or nematocidal activity.

12. Compounds as claimed in any one of claims 1 to 6 for use in antiparasitic therapy of the human or animal body.

1 3. Pharmaceutical compositions containing as active ingredient at least one compound of formula (I) as claimed in claim 12.

14. Antiparasitic compositions intended for animal feeding containing as active ingredient at least one compound as claimed in any one of claims 1 to 6, associated with a nutrient mixture intended for animal feeding.

1 5. Compositions as defined in any one of claims 9, 1 0, 11, 1 3 and 14, containing, in addition to the active ingredient(s), one or more synergising agent(s).

1 6. Compositions for use in the control of parasites of vegetation or warm-blooded animals and of pests of premises containing at least one compound of formula (I) as defined in any one of claims 1 to 6 in association with at least one compound selected from the chrysanthemic acid esters of allethrolones, of 3,4,5,6-tetrahydrophthalimidomethyl alcohol, of 5-benzyl-3-furylmethyl alcohol, of 3-phenoxybenzyl alcohol and of a-cya no-3-phenoxybenzyl alcohols; 2,2-dimethyl-3-(2-oxo-3tetrahydrothiophenylidenemethyl)cyclopropane-1 -carboxylic acid esters of 5-benzyl-3-furylmethyl alcohol; 2,2-dimethyl-3-(2,2-dich lorovinyl)cyclopropa ne- 1 -carboxylic acid esters of 3-phenoxybenzyl alcohol and of a-cyano-3-phenoxybenzyl alcohols; 2,2-dimethyl-3-(2,2-dibromovinyl)cyclopropane-1 carboxylic acid esters of a-cyano-3-phenoxybenzyl alcohols; 2-parachlorophenyl-2-isopropylacetic acid esters of 3-phenoxybenzyl alcohol; and 2,2-dimethyl-3-(1 ',2',2',2'-tetrahaloethyl)cyclopropane-1 carboxylic acid esters of allethrolones, of 3,4,5,6-tetrahydrophthalimidomethyl alcohol, of 5-benzyl-3 furylmethyl alcohol, of 3-phenoxybenzyl alcohol and of a-cyano-3-phenoxybenzyl alcohols (in which "halo" represents a fluorine, chlorine or bromine atom), it being understood that the compounds (I) can exist in any of their stereoisomeric forms, as can the acid and alcohol moieties of the pyrethrinoid esters or their analogues.

17. A process for preparing compounds of formula (I) as defined in any one of claims 1 to 5, in 'which an acid of formula (all):

in which X1, X2 and X3 are defined as in Claim 1, or a functional derivative thereofis reacted with an alcohol of formula (111) :

in which A, B and R, are defined as in Claim 1, or a functional derivative thereof, wherein the corresponding compound of formula (I) is obtained.

18. A process for the production of compounds of formula (I) as defined in claim 1 substantially as herein described.

19. A process for the production of compounds of formula (I) as defined in claim 1 substantially as herein described in any one of the Examples.

20. Compounds of formula (I) as defined in claim 1 whenever prepared by a process as claimed in any one of claims 17-19.

21. Antiparasitic or pesticidal compositions containing at least one compound of formula (I) as claimed in claim 1 substantially as herein described.

22. Pharmaceutical compositions containing at least one compound of formula (I) as defined in claim 1 substantially as herein described.

23. A method of exterminating or preventing or inhibiting infestation by parasites or pests which comprises administering to a locus infested with or susceptible to infestation by parasites or pests an effective amount of a compound of formula (I) as defined in claim 1.

24. A method of exterminating or preventing or inhibiting infestation by parasites or pests substantially as herein described.