GB2062620A - Haloalkyl cyclopropane carboxylic acid derivatives - Google Patents

Abstract

Novel compounds of formula I where R is substituted benzyloxy, R<1> is haloalkyl and R is hydrogen, haloalkyl, methyl or optionally substituted phenyl are useful as insecticides and acaicides. They are prepared by conventional esterification processes from novel compounds of formula I where R is hydroxy, halo or lower alkyl. <IMAGE>

Description

SPECIFICATION Esters of haloalkyl acids This invention relates to novel esters useful as insecticides, to methods for preparing them, to compositions comprising them, and to novel compounds useful as intermediates in the preparation of the esters.

Accordingly the invention provides compounds of formula:

wherein R1 is haloalkyl of 1 or 2 carbon atoms, R2 is haloalkyl of 1 or 2 carbon atoms, methyl, phenyl (optionally substituted with halogen, alkyl or haloalkyl) or hydrogen, and R is hydroxy, halogeno, alkoxy of from 1 to 6 carbon atoms or substituted benzyloxy, for example, halobenzyl or phenoxybenzyl.

Compounds of the invention wherein R is a substituted benzyloxy group are useful as insecticides.

R is preferably a pentafluorobenzyl or a 3-phenoxybenzyloxy or an er-ethynyl- or a-cyano-3- phenoxybenzyloxy group, R' is preferably a trifluoromethyl, difluoromethyl or chlorodifluoromethyl group and R is methyl, or identical with R1.

One preferred group of compounds having insecticidal properties are those according to the formula:

wherein R3 is hydrogen, cyano or ethynyl. Specific examples of compounds according to formula II are set out in Table I below wherein the meanings for R', R2 and R3 are given for each compound.

TABLE I

Compound No. R' R1 R R 1 CF3 OF3 H 2 CF3 CF3 CN 3 CF3 CH3 CN 4 CHF2 CHF2 CN 5 CF3 CH3 H 6 CHF2 CHF2 H 7 CF2Cí CF2CI CN 8 CF2CI CF2CI H 9 CF3 C6H5 CN 10 OF3 06H, H 11 CF3 CF2CI CN 12 OF3 CHF2 CN 13 CF2CI CHF2 CN Another preferred group of compounds also having insecticidal properties are those represented by the general formula:

and examples of such compounds are set out in Table II wherein the meanings for R' and R2 are given for each compound.

TABLE II

Compound No. R R 14 CH F2 CHEF, t5 CF3 CH3 It will be appreciated by those skilled in the art that tile compounds represented by formulae II and Ill are capable of existing in various geometrical and stereoisomeric forms. Thus there may be cis and trans isomers arising from the substitution pattern of the cyclopropane ring, when R' is not the same as R2. In addition two of the three carbon atoms of the cyclopropane are capable of existing in either R- or S-configurations when they are asymmetrically substituted, and when R3 is not hydrogen the carbon atom to which it is attached is also capable of existing in either the R- or S-configuration.

Thus for a compound according to formula I where R1 and R2 are not the same and R3 is hydrogen, there are four isomeric possibilities, arising from the cyclopropane ring substitution. These may be named by reference to their absolute configuration as (1R, 3R), (1R, 3S), (15, 3S) and ( 1 S, 3R). When R3 is not hydrogen there are eight possible isomers since each of the four possible cyclopropane ring configurations must exist in two forms, one corresponding to the S-configuration and one to the Rconfiguration of the carbon atom bearing the R3 group. Alternatively if R3 is hydrogen, and R1 is the same as R2 there are only two isomeric possibilities, optical enantiomers of (1 R) and (1 S) configuration.

Finally when R' is the same as R2, and R3 is not hydrogen, each compound may exist in four diastereo isomeric forms.

Examples of the mixtures of isomers which may be present in the compounds of the invention when prepared by the processes set out hereinafter include the following.

3-phenoxybenzyl (#)-cis/trans-2,2,3-trimethyl-3-trifluoromethyl-cyclopropane carboxylate, (+)-a-cyano-3-phenoxybenzyl (+)-cis/trans-2,2,3-trimethyl-3-trifluoromethylcyclopropane carboxylate, (#)-&alpha;-ethynyl-3-phenoxybenzyl (#)-cis/trans-2,2,3-trimethyl-3-trifluoromethylcyclopropane carboxylate, 3-phenoxybenzyl (+)-2,2-dimethyl-3,3-bis(trifl uoromethyl)cyclopropane carboxylate, (+)-a-cyano-3-phenoxybenzyl (+)-2,2-dimethyl-3,3-bis(trifluoromethyl)cyclopropane carboxylate, (+)--cyano-3-phenoxybenzyl (+)-cis/trans-2,2-dimethyl-3-trifluoro-methylcyclopropane carboxylate, and (+)-cL-cyano-3-phenoxybenzyl (+)-2,2-dimethyl-3,3-bis(difluoromethyl)cyclopropane carboxylate.

The insecticidal compounds of the invention according to formulae I, II and Ill are esters and may be prepared by conventional esterification processes, of which the following are illustrated with reference to compounds of formula 11.

(a) An acid of formula:

where R' and R2 have any of the meanings given hereinabove, may be reacted directly with an alcohol of formula:

where R3 represents the hydrogen atom, or the cyano or ethynyl group, the reaction preferably taking place in the presence of an acid catalyst, for example, dry hydrogen chloride.

(b) An acid halide of formula:

where Q represents a halogen atom, preferably a chlorine atom, and R1 and R2 have any of the meanings given hereinabove, may be reacted with an alcohol of formula:

wherein R3 represents the hydrogen atom or the cyano or ethynyl group, the reaction preferably taking place in the presence of a base, for example, pyridine, alkali metal hydroxide or carbonate, or alkali metal alkoxide. As an alternative when R3 is to be the cyano group, a mixture of alkali metal cyanide and 3-phenoxybenzaldehyde may be employed in place of cr-cyano-3-phenoxybenzyl alcohol.

(c) An acid of formula:

or, preferably, an alkali metal salt thereof, may be reacted with a halide of formula:

where Q' represents a halogen atom, preferably the chlorine atom, and R3 represents the hydrogen atom, or the cyano or ethynyl group, or with the quaternary ammonium salts derived from such halides with tertiary amines, for example pyridine, or trialkyl amines such as triethylamine.

(d) A lower alkyl ester of formula:

where R4 represents a lower alkyl group containing up to six carbon atoms, preferably the methyl or ethyl group, and R' and R2 have any of the meanings given hereinabove, is heated with an alcohol of formula

to effect a transesterification reaction. Preferably the process is performed in the presence of a suitable catalyst, for example, an alkali metal alkoxide, such as sodium methoxide, or an alkylated titanium derivative, such as tetramethyl titanate.

All of these conventional processes for the preparation of esters may be carried out using solvents and diluents for the various reactants where appropriate, and may be accelerated or lead to higher yields of product when performed at elevated temperatures or in the presence of appropriate catalysts, for example phase-transfer catalysts.

The compounds of formula Ill may be prepared by similar processes to those set out herein for those of formula II but using the appropriate pentafluorobenzyl derivative.

The preparation of individual isomers may be carried out in the same manner but commencing from the corresponding individual isomers of compounds of formula II. These may be obtained by conventional isomer separation techniques from mixtures of isomers. Thus cis and trans isomers may be separated by fractional crystallisation of the carboxylic acids or salts thereof, whilst the various optically active species may be obtained by fractional crystallisation of salts of the acids with optically active amines, followed by regeneration of the optically pure acid.

The optically pure isomeric form of the acid (or its equivalent acid chloride or ester) may then be reacted with 3-phenoxybenzyl alcohol to produce the compounds of formula I in the form of an individually pure isomer thereof. In the case of a-cyano-3-phenoxybenzyl alcohol the product will be a mixture of two isomers since it is not possible to react optically pure a-cyano-3-phenoxybenzyJ alcohol with the acid or its equivalent without racemisation of the alcohol occurring. Typical products of this procedure include: (+)-y-cyano-3-phenoxybenzyl(l R)-2,2,3-trimethyl-3-trifluoromethylcyclopropane carboxylate, and (i)-a-cyano-3-phenoxybenzyl (1R)-2,2-dimethyl trifluoromethylcyclopropane carboxylate.

These compounds are believed to be especially useful as insecticides.

The preparation of single isomers of these compounds may be achieved by preparing the optically pure acid chloride and reacting it with (+)-3-phenoxymandelamide to give the corresponding (+)-a- carboxamido ester. The two isomeric esters may be separated by fractional crystallisation, and individually subjected to dehydration to the corresponding a-cyano-3-phenoxybenzyl ester. In this way the following single isomers may be obtained.

(S)-cu-cyano-3-phenoxybenzyl (1 R)-2,2,3-trimethyl-3-trifl uoromethylcyclopropane carboxylate, and (S)-(r-cyano-3-phenoxybenzyl (1 R)-2,2-dimethyl-3-trifl uoromethylcyclopropane carboxylate which are believed to be the insecticidally most effective isomers of those particular compounds.

The various cyclopropane compounds referred to hereinabove as being useful as intermediates in the processes by which the invention compounds of Formula I may be prepared are themselves novel compounds.

In further aspect therefore the present invention provides compounds according to the general formula:

wherein one of R1 and R2 have any of the meanings given above, and Q represents the hydroxy group, a lower alkoxy group containing from one to three carbon atoms, or the chlorine or bromine atom.

The compounds represented by formula IV are also capable of existing in various geometrical and stereoisomeric forms in the same way as the compounds of formulae II and Ill. Thus there may be cis and trans isomers arising from the substitution pattern of the cyclopropane ring when R' is not the same as R2. In addition two of the three carbon atoms of the cyclopropane are capable of existing in either Ror S-configurations when they are asymmetrically substituted.

Examples of specific intermediate compounds according to the invention include those represented by formula IV which correspond to the specific individual compounds of Tables I and II, and isomers thereof, wherein Q represents a chlorine atom, hydroxy group or ethoxy group.

The compounds of formula IV wherein Q is hydroxy may be obtained by hydrolysis of the compounds of formula IV wherein Q is lower alkoxy, and may be converted to the compounds of formula IV wherein Q is chloro or bromo by reaction with for example thionyl chloride or thionyl bromide respectively. All of the compounds of formula IV may be used either directly or indirectly to prepare the insecticidally active esters of formulae II and Ill, as described hereinabove.

The compounds of formula IV wherein R is alkoxy may be prepared by the heat-stimulated decomposition of the corresponding pyrazolines of formula.

which may themselves be prepared by treating a compound of formula: R'R2C=CH--COO-R (Vl) with 2-diazopropane. The compounds of formula VI can be prepared by the reaction of the appropriate ketone of formula:

with the phosphonium ylid of formula: + - (C6H5)3P-CH-CO-R the latter being prepared by, for example, the method set out in Helv. Chem. Acta, XL, 1247, (1957).

The compounds of formula V and formula VI are novel compounds. Accordingly in a further aspect the invention provides compounds of formula V and formula VI wherein R' and R2 have any of the meanings given hereinabove and R is a lower alkoxy group of from 1 to 6 carbon atoms, and methods for their preparation as set out herein.

The compounds of formulae II and III may be used to combat and control infestations of insect pests and also other invertebrate pests, for example, acarine pests. The insect and acarine pests which may be combated and controlled by the use of the invention compounds include those pests associated with agriculture (which term includes the growing of crops for food and fibre products, horticulture and animal husbandry), forestry, the storage of products of vegetable origin, such as fruit, grain and timber, and also those pests associated with the transmission of diseases of man and animals.

In order to apply the compounds to the locus of the pests they are usually formulated into compositions which include in addition to the insecticidally active ingredient or ingredients of formula I suitable inert diluent or carrier materials, and/or surface active agents. The compositions may also comprise another pesticidal material, for example another insecticide or acaricide, or a fungicide, or may also comprise a insecticide synergist, such as for example dodecyl imidazole, safroxan, or piperonyl butoxide.

The compositions may be in the form of dusting powders wherein the active ingredient is mixed with a solid diluent or carrier, for example kaolin, bentonite, kieselguhr, or talc, or they may be in the form of granules, wherein the active ingredient is absorbed in a porous granular material for example pumice.

Alternatively the compositions may be in the form of liquid preparations to be used as dips or sprays, which are generally aqueous dispersions or emulsions of the active ingredient in the presence of one or more known wetting agents, dispersing agents or emulsifying agents (surface active agents).

Wetting agents, dispersing agents and emulsifying agents may be of the cationic, anionic or nonionic type. Suitable agents of the cationic type include, for example, quaternary ammonium compounds, for example, cetyltrimethyl ammonium bromide. Suitable agents of the anionic type include, for example, soaps, salts of aliphatic monoesters or sulphuric acid, for example sodium lauryl sulphate, salts of sulphonated aromatic compounds, for example sodium dodecylbenzenesulphonate, sodium, calcium or ammonium lignosulphonate, butylnaphthalene sulphonate, and a mixture of the sodium salts of diisopropyl- and triisopropylnaphthalene sulphonates. Suitable agents of the nonionic type include, for example, the condensation products of ethylene oxide with fatty alcohols such as oleyl alcohol or cetyl alcohol, or with alkyl phenols such as octyl phenol, nonyl phenol and octyl cresol.Other non-ionic agents are the partial esters derived from long chain fatty acids and hexitol anhydrides, the condensation products of the said partial esters with ethylene oxide, and the lecithins.

The compositions may be prepared by dissolving the active ingredient in a suitable solvent, for example, a ketonic solvent such as diacetone alcohol, or an aromatic solvent such as trimethylbenzene and adding to the mixture so obtained to water which may contain one or more known wetting, dispersing or emulsifying agents. Other suitable organic solvents are dimethyl formamide, ethylene dichloride, isopropyl alcohol, propylene glycol and other glycols, diacetone alcohol, toluene, kerosene, white oil, methylnaphthalene, xylenes and trichloroethylene, N-methyl-2-pyrrolidone and tetrahydro furfuryl alcohol (THFA).

The compositions to be used as sprays may also be in the form of aerosols wherein the formulation is held in a container under pressure in the presence of a propellant such as fluorotrichloromethane or dichlorodifluoromethane. The compositions which are to be used in the form of aqueous dispersions or emulsions are generally supplied in the form of a concentrate containing a high proportion of the active ingredient or ingredients, the said concentrate to be diluted with water before use. These concentrates are often required to withstand storage for prolonged periods and after such storage, to be capable of dilution with water to form aqueous preparations which remain homogeneous for a sufficient time to enable them to be applied by conventional spray equipment. The concentrates may contain 10R-85% by weight of the active ingredient or ingredients.When diluted to form aqueous preparations, such preparations may contain varying amounts of the active ingredient depending upon the purpose for which they are to be used.

For agricultural or horticultural purposes, an aqueous preparation containing between 0.0001% and 0. 1% by weight of the active ingredient is particularly useful.

In use the compositions are applied to the pests, to the locus of the pests, to the habitat of the pests, or to growing plants liable to infestation by the pests, by any of the known means of applying pesticidal compositions, for example, by dusting or spraying.

The compositions of the invention are very toxic to wide varieties of insect and other invertebrate pests, including, for example, the following: Aphis fabae (aphids) Me go ura viceae (aphids) Aedes aegypti (mosquitoes) Dysdercus fasciatus (capsids) Musca domestica (houseflies) Pieris brassicae (white butterfly, larvae) Plutella maculipennis (diamond back moth larvae) Phaedon cochleanae (mustard beetle) Telarius cinnabarinus (carmine spider mite) Aonidiella spp. (scale insects) Trialeuroides spp. (white flies) Blattella germanica (cockroaches) Spodoptera littoralis (cotton leaf worm) Chortiocetes terminifera (locusts) The compounds of formula I and compositions comprising them have shown themselves to be particularly useful in controlling lepidopteran pests of cotton, for example Spodoptera spp. and Heliothis spp. They are also very useful in combating insect and acarine pests which infest domestic animals, such as Lucilia sericata, and ixodid ticks such as Boophilus spp., Ixodes spp., Amblyomma spp., Rhipicephalus spp., and Dermaceutor spp. They are effective in combating both susceptible and resistant strains of these pests in their adult, larval and intermediate stages of growth, and may be applied to the infested host animal by topical, oral or parenteral administration.

The following Examples illustrate the various aspects of the invention.

EXAMPLE 1 This Example illustrates the preparation of ethyl 4,4-difluoro-3-difluoromethylbut-2-enoate, of formula: (CHF2)2C=CHC 2C2Hs Carbethoxymethylene triphenylphosphorane (0.70 g - obtained from ethyl bromoacetate and triphenylphosphine by the process set out in Helv. Chim Acta, XL, 1247, (1957)) was cooled to OOC and agitated whilst 1 ,1 3,3-tetrafluoroacetone (0.30 g) was added dropwise. The mixture was kept at the ambient temperature for 3 days and then distilled using a Kugelruhr apparatus. The distillate obtained at an oven temperature of 820C at a pressure of 100 mmHg was identified by infra-red and n.m.r.

spectroscopy as ethyl 4,4-difluoro-3-difluoromethylbut-2-enoate.

Infra-red: - 1740, 1700, 1400, 1280, 1200, 1130, 1080 cm-1 EXAMPLE 2 By the use of procedures similar to that illustrated in Example 1 the following unsaturated esters were obtained by reaction of the appropriate ketones with carbethoxymethylene triphenylphosphorane.

Ethyl 4,4,4-trifluoro-3-trifluoromethylbut-2-enoate (b.p. 128 C. from hexafluoroacetone.

Infra-red: - 1750, 1690, 1390 (d), 1300, 1240, 1150, 1030, 1000 cm-1, Ethyl 4-chloro-4,4-difluoro-3-chlorodifluooromethylbut-2-enoate, from 1,3dichlorotetrafluoroacetone.

Infra-red: - 1750, 1680, 1380 (d), 1260, 1170, 1120, 1050, 1000 950 cm-1.

Ethyl 3-trifluoromethylbut-2-enoate, from 1,1,1 -trifluoroacetone.

Ethyl 4,4,4-trifluoro-3-difluoromethylbut-2-enoate from pentafluoroacetone.

Ethyl 4,4,4-trifluoro-3-chlorodifluoromethylbut-2-enoate from chloropentafluoroacetone.

In addition ethyl 4,4,4-trifluorobut-2-enoate was prepared by the method of J. Amer. Chem. Soc.

76,3722, (1957).

Infra-red:- 1750, 1680, 1390, 1330, 1290, 1150, 1050, 990 cm~1.

EXAMPLE 3 This Example illustrates the preparation of 4-ethoxycarbonyl-3,5,5-trimethyl-3-trifluoromethyl-1 1- pyrazoline, of formula:

Acetone (2.0 g) was added dropwise to hydrazine hydrate (strength 99100%) at OOC with agitation, and the resultant mixture added dropwise to an ice-cooled suspension of yellow mercuric oxide (10.0 g) in dry ether (30 ml) to which had been added a freshly prepared solution of potassium hydroxide in ethanol (0.5 ml, concentration 100 g/l), the temperature during the addition being maintained in the range of OOC to 1000 by external cooling. When the addition had been completed the red solution containing 2-diazopropane was decanted and filtered through glass wool to remove any solid particles.To the filtrate was added dropwise a portion of cooled solution of ethyl 3trifluoromethylbut-2-enoate (1.0 g) in dry ether (15 ml) at 00C until the red colour of the filtrate was just discharged at which point about 0.65 g of the ethyl 3-trifluoromethylbut-2-enoate had been added. The mixture was allowed to warm to the ambient temperature whilst stirring was continued for a period of 1.5 hours, after which it was washed with water, dried over anhydrous magnesium sulphate and concentrated by evaporation of the solvents under reduced pressure. The residual oil was distilled in a Kugelruhr apparatus at an oven temperature which was slowly increased to 1000C, the pressure being 10 mm Hg. The distillate was identified by infra-red and n.m.r. spectroscopy as the required 4ethoxycarbonyl-3,5,5-trimethyl-3-trifluoromethyl-1 -pyrazoline.

Infra-red: 1750, 1590, 1480, 1400, 1320 (d), 1200, 1100, 1050 cm-1.

EXAMPLE 4 By use of a similar procedure to that illustrated in Example 3 the following pyrazolines were obtained by reaction of 2-diazopropane with the appropriate unsaturated esters.

4-ethoxycarbonyl-5,5-dimethyl-3,3-bis (trifluoromethyl)-1-pyrazoline (b.p. 600C/0.05 mm Hg) from ethyl 4,4,4-trifluoro-3-bis (trifluoromethyl)-1-pyrazoline Infra-red: 1750, 1580, 1460, 1380, 1300-1100, 1020 (d), 970 cm~'.

4-ethoxycarbonyl-5,5-dimethyl-3-trifluoromethyl- 1 -pyrazoline, from ethyl 4,4,4-trifl uorobut-2enoate.

Infra-red: 1750, 1580, 1480, 1390, 1350, 1300 - 1150, 1050, 940 cm-1, 4-ethoxycarbonyl-5,5-dimethyl-3,3-bis(chlorodifluoromethyl)-1 -pyrazoline, from ethyl 4-chloro 4,4-difluorn-3-chlorndifluoromethylbut-2-enoate.

Infra-red : 1760, 1590, 1480, 1380, 1240-1140, 1100, 1050, 900 cm-1.

4-ethoxycarbonyl-5,5-di methyl-3,3-bis(difl uoromethyl)-1 -pyrazoline, from ethyl 4,4-difluoro-3difluoromethylbut-2-enoate.

Infra-red: 1740, 1580, 1470, 1380, 1250-1010,960,860(d) cm1.

4-ethoxycarbonyl-5,5-dimethyl-3-trifluoromethyl-3-chloro-diffuoromethyl-1-pyrazoline, from ethyl 4,4,4-trifluoro-3-chloro-difluoromethylbut-2-enoate.

4-ethoxycarbonyl-5,5-dimethyl-3-difluoromethyl-3-trifluoromethyl-1 -pyrazoline, from ethyl 4,4,4trifluoro-3-difluoromethylbut-2-enoate.

EXAMPLE 5 This Example illustrates the preparation of ethyl 2,3,3-trimethyl-3-trifluoromethylcyclopropane carboxylate, of formula:

4-Ethoxycarbonyl-3,5,5-trimethyl-3-trifluoromethyl-1-pyrazoline (1.0 g) was heated to a temperature of 2000C for 1 hour, and then cooled to the ambient temperature. The product was identified by infra-red and n.m.r. spectroscopy as ethyl (#)-2,3,3-trimethyl-3-trifluoromethylcyclo- profane carboxylate.

Infra-red: 1750,1340,1250,1200, 1150,1120(d), 1070 cm-'.

A similar result was obtained when the pyrazoline starting material was heated at 1 500C for 1.5 hours.

EXAMPLE 6 By the use of a procedure similar to that illustrated in Example 5 the following cyclopropane carboxylates were obtained from the corresponding pyrazolines.

Ethyl (#)-2,2-dimethyl-3,3-bis (trifluoromethyl) cyclopropane carboxylate.

N.m.r. ('H): 5.83 (2H,q); 7.60 (1H,s); 8.55 (6Hs); 8.75 (3H,t).

Ethyl (#)-2,2-dimethyl-3,3-bis (chlorodifluoromethyl) cyclopropane carboxylate N.m.r. ('H): 5.75 (2H,q); 7.47 (1H,s); 8.53 (6H,s); 8.70 (3H,t).

Ethyl (+)-2,2-dimethyl-3,3-bis(difiuornmethyl)cycloprnpane carboxylate.

N.m.r. ('H): 3.00--4.25 (2H,m); 5.85 (2H,q); 7.80 (1 H,s); 8.60 (6H,s); 8.72 (3H,t) Ethyl (i)-2,2-dimethyl-3-difluoromethyl-3-trifluoromethylcyclopropane carboxylate.

Ethyl (#)-2,2-dimethyl-3-chlorodifluoromethyl-3-trifluoromethylcyclopropane carboxylate.

EXAMPLE 7 This Example illustrates the preparation of (i)-2,2,3-trimethyl-3-trifluoromethylcyclopropane carboxylic acid, of formula

A mixture of ethyl (+)-2,2,3-trimethyl-3-trifluoromethylcyclopropane carboxylate, ethanol (5.8 ml) and 2N sodium hydroxide solution (2.9 ml) was stirred together for 3 hours at the ambient temperature, then kept at that temperature for 18 hours. The mixture was diluted with water (10 ml) then extracted with chloroform to remove any neutral impurities.The aqueous solution was acidified with concentrated hydrochloric acid and extracted with chloroform (3 x 10 ml), the combined extracts washed with water, dried over anhydrous magnesium sulphate, and the solvents evaporated under reduced pressure, yielding (+)-2,2,3-trimethyl-3-trifluoromethylcyclopropane carboxylic acid as a white crystalline solid, m.p. 76-77 C.

Infra-red (Oil film):- 3400-2400, 1720, 1470, 1330, 1250, 1200, 1150 cm1.

EXAMPLE 8 By the use of procedures similar to that illustrated in Example 7 the following carboxylic acids were obtained from the corresponding esters.

(#)-2,2-dimethyl-3,3-bis (trifluoromethyl) cyclopropane carboxylic acid (m.p. 65-66 C) (~)-2,2-dimethyl-3,3-bis(chlorodifluoromethyl)cyclopropane carboxylic acid.

N.m.r. ('H): 0.20 1 H, broad s); 4.72 (1 H,s); 8.48 (6H,s).

(+)-2,2-dimethyl-3,3-bis(difluoromethyl)cyclopropane carboxylic acid.

N.m.r. ('H): 0.12 (1 H, broad s); 2.90-4.15 (2H,m); 7.74 (1 H,s): 8.53 (6H,s).

(#)-2,2-dimethyl-3-chlorodifluoromethyl-3-trifluoromethylcyclopropane carboxylic acid.

(#)-2,k2-dimethyl-3-difluoromethyl-3-trifluoromethylcyclopropane carboxylic acid.

EXAMPLE 9 This Example illustrates the preparation of (+)-1 -chlorocarbonyl-2,2,3-trimethyl3- trifluoromethylcyclopropane, of formula

A misture of (#)-2,2,3-trimethyl-3-trifluoromethylcyclopropane carboxylic acid (130 mg) and thionyl chloride (5.0 g) was heated at the reflux temperature for 1 hour, after which the excess thionvi chloride was removed from the mixture by evaporation at 10--120C under reduced pressure. The last traces of thionyl chloride were removed by azeotropic distillation with benzene. The residual oil was identified by infra-red spectroscopy as (#)-1-chlorocarbonyl-2,2,3-trimethyl-3-trifluoromethylcyclopropane carboxylate.

EXAMPLE 10 This Example illustrates the preparation of (#) -&alpha;-cyano-3-phenoxybenzyl (#) cis/trans-2,2,3- trimethyl-3-trifluoromethylcyclopropane carboxylate (Compound no. 3, Table 1), of formula :

A solution of dry pyridine (70 mg) in toluene (2.0 ml) was added to a stirred mixture of (+)-1 - chlorocarbonyl-2,2,3-trimethyl-3-trifluoromethylcyclopropane (140 mg) and (+)-c-cyano-3- phenoxybenzyl alcohol (160 mg) in dry toluene (5.0 ml) at the ambient temperature. The mixture was stirred for 45 minutes and then kept at the ambient temperature for 18 hours.After diluting with toluene (5.0 ml) the mixture was washed with 2N hydrochloric acid, with water, finally with saturated sodium bicarbonate solution, and then dried over anhydrous magnesium sulphate. Removal of the toluene by evaporation under reduced pressure left a pale yellow oil, which was purified by preparative thick layer chromatography (silica gel (2 mm thick) on glass plates, chloroform eluent) to yield pure (+)- &alpha;-cyano-3-phenoxybenzyl (#)-2,2,3-trimethyl-3-trifluoromethylcyclopropane carboxylate, identified by infra-red and n.m.r. spectroscopy.

Infra-red: 1760, 1600, 1500, 1330, 1240, 1170(d), 1050 (d) cm~'.

EXAMPLE 11 By the use of procedures similar to those illustrated in Examples 9 and 10, the following compounds were prepared from the corresponding carboxylic acids via the acid chlorides: 3-phenoxybenzyl (#)-2,2-dimethyl-3,3-bis (trifluoromethyl) cyclopropane carboxylate, (Compound no. 1, Table 1).

Infra-red: 1760, 1600, 1500, 1360, 1330, 1280, 1230, 1200 cm~'.

(#)-&alpha;-cyano-3-phenoxybenzyl (#)-2,2-dimethyl-3,3-bis (trifluoromethyl) cyclopropane carboxylate, (Compound no. 2, Table 1), Infra-red : 1780, 1600, 1500, 1360, 1300, 1290--1200 cm-1.

(+)-a-cyano-3-phenoxybenzyI (~)-2,2-dimethyl-3,3-bis(difluoromethyl)cyclopropane carboxylate (Compound no. 4, Table I).

3-phenoxybenzyl (~)-cis/trans-2,2,3-trimethyl-3-trifluoromethyl-cyclopropane carboxylate (Compound no. 5, Table I).

3-phenoxybenzyl (+)-2,2-dimethyl-3,3-bis(difluoromethyl )cyclopropane carboxylate (Compound no. 6, Table I).

(#)-&alpha;-cyano-3-phenoxybenzyl (#)-2,2-dimethyl-3,3-bis (chlorodifluolomethyl) cyclopropane carboxylate (Compound no. 7, Table I).

3-phenoxybenzyl (~)-2,2-dimethyl-3,3-bis(chlorodifluoromethyl)cyclopropane carboxylate (Compound no. 8, Table I).

(#)-&alpha;-cyano-3-phenoxybenzyl (#) cis/trans-2,2-dimethyl-3-trifloromethkyl-3-phenylcyclopropane carboxylate (Compound no.9, Table I).

3-phenoxybenzyl (#)-cis/trans-2,2-dimethyl-3-trifluoromethyl-3-phenylcyclop (Compound no. 10, Table I).

(+)--cyano-3-phenoxybenzyl (+)-cis/trans-2,2-dimethyl-3-trifluoromethyl-3- chlorodifluoromethylcyclopropane carboxylate (Compound no. 11, Table I).

(#)-&alpha;-cyano-3-phenoxybenzyl (#) cis/trans-2,2-dimethyl-3-trifluoromethkyl-3- difluoromethylcyclopropane carboxylate (Compound no. 12, Table I).

(#)-&alpha;-cyano-3-phenoxybenzyl (#) cis/trans-2,2-dimethyl-3-difluoromethkyl-3- chlorodifluoromethylcyclopropane carboxylate (Compound no. 13, Table I).

Pentafl uorobenzyl ( +)-2,2-dimethyl-3,3-bis(difluoromethyl)cyclopropane carboxylate (Compound no.

14, Table II).

pentafluorobenzyl (#)-cis/trans-2,2,3-trimethyl-3-trifluoromethyl-cyclopropane carboxylate (Compound no. 14, Table II).

EXAMPLE 12 This Example illustrates the insecticidal properties of the Compounds of Tables I and II.

The activity of the compound was determined using a variety of insect pests. The compound was used in the form of liquid preparations containing 1000 or 100 p.p.m. by weight of the compound. The preparations were made by dissolving the compound in a mixture of solvents consisting of 4 parts by volume of acetone and 1 part by volume of diacetone alcohol. The solutions were then diluted with water containing 0.01% by weight of a wetting agent sold under the trade name "LISSAPOL" NX until the liquid preparations contained the required concentration of the compound. "Lissapol" is a Trade Mark.

The test procedure adopted with regard to each pest was basically the same and comprised supporting a number of the pests on a medium which was usually a host plant or a foodstuff on which the pests feed, and treating either or both the pests and the medium with the preparations. The mortality of the pests was then assessed at periods usually varying from one to three days after the treatment. Details are given in Table II IA.

The results of the tests are given in Table IlIB for each of the products A to Z at the rate in part per million given in the second column as a grading of mortality on a scale of 0-9 wherein 0 represents less than 10% mortality 1 represents from 10 to 19% mortality 2 represents from 20 to 29% mortality 3 represents from 30 to 39% mortality 4 represents from 40 to 49% mortality 5 represents from 50 to 59% mortality 6 represents from 60 to 69% mortality 7 represents from 70 to 79% mortality 8 represents from 80 to 89% mortality 9 represents from 90 to 100% mortality In Table IlIB the pest organism used is designated by a letter code and the pest species, the support medium or food, and the type and duration of test is given in Table IIIA.

TABLE IIIA

Code Letters Support Type of Duration (Table Pest species Medium/Food Test * (days) MD Musca domestica Cotton wool/ Contact 2 (houseflies - adults milk, sugar SL # Spodoptera littoral is Cotton leaves 1 Residual 1 (cotton leaf worm - larvae PX Plutella xylostella Mustard leaves Residual 3 (diamond back moth larvae) AF Aphis tabae Broad bean Contact 3 (aphids) leaves MV Megoura viceae Filter Paper Contact 3 "Contact" test indicates that both pests and medium were treated and "residual" indicates that the medium was treated before Infestation with the pests.

TABLE IllS

Compound Rate Pest Species (Table IIIA) No. (ppm) MD SL PX AF MV 1 1000 4 1 4 - 4 2 1000 5 5 9 2 9 3 100 8 9 9 9 9 4 100 9 9 9 9 9 6 100 1 9 9 9 9 11 100 7 - 3 - - 12 100 9 8 - 9 In a further test compound 6 gave 100% control of red-spider mites Tetranychus telerius (adults, numphs and eggs) on french beans at a rate of 100 ppm.

Claims (31)

1. A compound of formula:

wherein R' is is haloalkyl of 1 or 2 carbon atoms, R2 is haloalkyl of 1 or 2 carbon atoms, methyl, phenyl (optionally substituted with halogen, alkyl or haloalkyl) or hydrogen, and R is hydroxy, halogeno, of 1 to 6 carbon atoms or substituted benzyloxy.

2. A compound as claimed in claim 1 wherein R is a halobenzyloxy or phenoxybenzyloxy.

3. A compound as claimed in claim 2 where R is pentafluorobenzyloxy, 3-phenoxybenzyloxy, a cyano-3-phenoxybenzyloxy, or &alpha;-ethynyl-3-phenoxybenzyloxy.

4. A compound as claimed in claim 1 wherein R' is trifluoromethyl. difluoromethyl or chlorodifluoromethyl and R is methyl or identical with R'.

5. A compound as claimed in claim 1 of the formula:

where Rr, R2 and R3 have the meanings set forth in Table I for any of the Compounds numbered from 1 to 13.

6. A compound as claimed in claim 1 of the formula:

where R' and R2 have the meanings set forth in Table II for either of the compounds numbered 14 and 15.

7. A compound as claimed in any of claims 1 to 6 wherein R' is not the same as R2 and the substitution pattern of the cyclopropane ring is cis with respect to R2 and the hydrogen atom.

8. A compound as claimed in any of claims 1 to 6 wherein R' is not the same as R2 and the substitution pattern on the cyclopropane ring is trans with respect to R2 and the hydrogen atom.

9. A compound as claimed in any of claims 1 to 8 where the absolute stereochemical configuration of the carbon atom bearing the hydrogen atom in the cyclopropane ring is (1 R).

10. A compound as claimed in any of claims 1 to 8 where the absolute stereochemical configuration of the carbon atom bearing the hydrogen atom in the cyclopropane ring is (1 S).

11. (*)-a-Oyano-3-phenoxybenzyl (1 R)-2,3,3-trimethyl-3-trifluoromethylcyclopropane carboxylate.

12. (+)--Cyano-3-phenoxybenzyl (1R)-2,2-dimethyl-3-trifluoromethylcyclopropane carboxylate.

13. (S)-a-Cyano-3-phenoxybenzyl (1 R)-2,2,3-trimethyl-3-trifluoromethylcyclopropane carboxylate.

14. (S)-&alpha;-Cyano-3-phenoxybenzyl (1R)-2,2-dimethyl-3-trifluoromethylcyclopropane carboxylate.

15. A process for preparing a compound according to claim 1 where R is 3-phenoxybenzyloxy or cr-cyano- or a-ethynyl 3-phenoxy benzyloxy which comprises either (a) reacting an acid of formula.

with an alcohol of formula:

or (b) reacting an acid chloride of formula

with an alcohol of formula

or (c) reacting an acid of formula

or an alkali metal salt thereof with a halide of formula

or with the quaternary ammonium salts derived from such halides with tertiary amines, or (d) reacting a lower alkyl esterofformula:-

with an alcohol of formula:

to effect a transesterification reaction; wherein R', R2 and R3 are as defined in claim 1, R4 is lower alkyl and Q and 0' are halogen.

16. A process as claimed in claim 1 5 (a) carried out in the presence of an acid catalyst.

17. A process as claimed in claim 1 5 (b) carried out in the presence of a base.

1 8. A process as claimed in claim 15 (d) carried out in the presence of a catalyst selected from alkali metal alkoxides and alkylated titanium derivatives.

19. A process for preparing a compound according to claim 1 where R is a-cyano-3phenoxybenzyloxy which comprises reacting an acid chloride of formula:

where Q is chlorine or bromine, with 3-phenoxybenzyaldehyde and alkali metal cyanide.

20. A process for making a compound according to claim 1 where R is pentafluorobenzyloxy wherein a process as claimed in claim 15 is used except that the corresponding pentafluoro benzyl derivative is used in place of the phenoxybenzyl derivative.

21. A compound as claimed in claim 1 of formula.

wherein R' and R2 are as defined in claim 1 and Q is hydroxy, chloro, bromo or alkoxy of 1 to 3 carbon atoms.

22. A compound of formula

wherein R' and R2 are as defined in claim 1 and R is alkoxy of 1 to 3 carbon atoms.

23. A compound of formula R'RC=CH-CO-R wherein R', R2 and R are as defined in claim 23.

24. A process for preparing a compound according to claim 21 wherein R is alkoxy of 1 to 3 carbon atoms which comprises the step of heating a compound according to claim 22.

25. A process for preparing a compound according to claim 22 which comprises reacting a compound according to claim 23 with 2-diazopropane.

26. A process for preparing a compound according to claim 23 which comprises reacting a ketone of formula

with the phosphonium ylid of formula + - (C6H5)3P-CH-COR

27. An insecticidal or acaiscidal composition which comprises a compound according to claim 1 in association with insecticidally inert diluent or carrier materials and/or surface active agents.

28. A composition as claimed in claim 27 comprising an insecticide synergist, and/or another pesticidal material in addition to the compound according to claim 1.

29. A method of combating insect or a carrier pest, which comprises applying to the pests, to the locus of the pests, to the habitat of the pests or to growing plants liable to infestation by the pests a composition as claimed in claim 27 or claim 28.

30. A method as claimed in claim 29 wherein the pests are ixodid ticks of domestic animals.

31. Compounds as claimed in claim 1 and processes for their preparation substantially as herein defined, with particular reference to Tables I and II and any one of the Examples.