GB2093830A - Haloalkenyl esters of cyclopropane carboxylic acids - Google Patents

Abstract

Compounds of formula I wherein R<1> and R<2> are each selected from methyl, halo and halomethyl and R<3>, R<4> and R<5> are each selected from hydrogen, halo and halomethyl, provided that at least one of R<1> and R<2> and at least one of R<3>, R<4> and R<5> is halo or halomethyl, are useful as insecticides. A typical compound is that where R<1>, R<4> and R<5> are chloro, R<2> is trifluoromethyl and R<3> is hydrogen. <IMAGE>

Description

SPECIFICATION Haloalkenyl esters of cyclopropane carboxylic acids This invention relates to novel cyclopropane derivatives useful as insecticides, to processes for their preparation, to compositions comprising them and to methods of combatting insect and similar invertebrate pests using them.

Certain naturally occurring esters of cyclopropane carboxylic acids have long been known to possess insecticidal properties, but these compounds have been too easily degraded by ultra violet light to be of much use in agriculture. Several groups of synthetic compounds based on cyclopropane carboxylic acids (for example those disclosed in British patent specifications nos. 1 ,243,B58 and 1,413,491) have been evaluated in an attempt to discover compounds of sufficient light stability for use as general agricultural insecticides.

A particularly useful group of such compounds is that disclosed in British patent specification no.

2,000,764 and Belgian patent no. 863,151. These compounds combine good light stability with excellent contact and residual insecticidal properties, but, in common with the compounds described in British patent specifications 1,243,858 and 1,413,491, they possess little or no fumigant activity.

The present invention relates to certain novel haloalkenyl esters of 3-(2,2-dihalovinyl)-2,2dimethylcyclopropane carboxylic acids and 3-(2-halo(or trifluoromethyl)-3,3,3-trifluoropropenyl)-2,2- dimethylcyclopropane carboxylic acids with an extremely high level of insecticidal and acaricidal activity which may be used not only as contact or residual insecticides but also as fumigant insecticides.

Accordingly this invention provides compounds of formula:

wherein R1 and R2 are each selected from methyl, halomethyl, and halo; and R3, R4 and R5 are each selected from hydrogen, halo, and halomethyl, provided that at least one of R' and R2 and at least one of R3, R4 and R5 is halo or halomethyl.

Preferably R1 and R2 are both chloro or one is chloro and the other is trifluoromethyl. Specific compounds according to the invention are set out in Table I below.

TABLE I

Compound No. R1 R2 R3 R4 R5 1 CF3 Cl CI H H 2 CF3 Cl Cl Cl H 3 CF3 Cl Br H H 4 CF3 Cl H Cl Cl 5 CF3 Cl H H CH2Cl 6 CF3 Cl H Br Br 7 CI Cl H Br iBr 8 CF3 Cl Br Br H It will be appreciated by those skilled in the art that the compounds represented by formula I 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, and E- and Z-isomers arising from the substituted vinyl group when R1 is not identical with RZ. In addition two of the three carbon atoms of the cyclopropane are capable of existing in either R- or S-configurations since they are asymmetrically substituted. Within the group of compounds represented by Formula I the cis isomers usually have better insecticidal properties than the trans isomers or the mixture of cis and trans isomers; the (+)-cis isomers being particularly preferred.

A particularly useful single isomer of a compound according to the invention is the 3,3dibromoallyl ester of (+)-cis-3-(Z-2-chloro-3,3,3-trichloroprop-1 -en-yl)-2,2-dimethylcyclopropane carboxylic acid, which is believed to have the (1R, 3R) configuration in the cyclopropane ring.

The compounds of the invention according to Formula I are esters and may be prepared by conventional esterification processes, of which the following are examples.

(a) An acid of formula:-

where Q represents the hydroxy group and R1 and R2 have any of the meanings given hereinabove, may be reacted directly with an alcohol of formula:

where X, R3, R4 and R5 have any of the meanings given herein above, the reaction preferably taking place in the presence of an acid catalyst, for example, dry hydrogen chloride.

(b) An acid halide of formula II 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.lll, the reaction preferably taking place in the presence of a base, for example, pyridine, alkali metal hydroxide or carbonate, or alkali metal alkoxide.

(c) An acid of formula II or, preferably, an alkali metal salt thereof, may be reacted with halide of formula:

where Q1 represents a halogen atom, preferably the chlorine atom, X, R3, R4 and R5 have any of the meanings given hereinabove, 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 Il where Q represents a lower alkoxy group containing up to six carbon atoms, preferably the methoxy or ethoxy group, and R1 and R2 have any of the meanings given hereinabove, is heated with an alcohol of formula Ill 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 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, foliowed by regeneration of the optically pure acid.

The optically pure isomeric form of the acid (or its equivalent acid chloride in ester) may then be reacted with the appropriate alcohol to produce a compound of formula I in the form of an individually pure isomer thereof.

The preparation of the compounds of formula Il wherein Q is hydroxy, alkoxy or halo, and R1 and R2 are as defined hereinabove, useful as intermediates in the preparation of the compounds of the invention, is fully described in British Patent Specification 2,000,764 and in Belgian patent no. 8631 51, or British Patent Specification 1,413,491.

When the processes for preparing the compounds of Formula ! are performed using intermediates which are themselves mixtures of isomers the products obtained will also be mixtures of isomers. Thus, the product would be a mixture of (+)-cis and (+)-trans isomers (perhaps with one form predominating) if the intermediate acid or acid derivative was used in the form of a mixture of (+)-cis and (+)-trans isomers. If a single isomer, of the acid, e.g. the (+)-cis isomer with Z-configuration in the 2-chloro-3,3,3trifluoropropenyl group, was used, the product would also be the single isomer of that stereochemical configuration, or a pair of isomers if there is an asymmetric carbon atom in the alcohol moiety.

In order to avoid confusion the products obtained by the processes described in the Examples herein are referred to as Products A to H, each product being defined in terms of isomeric composition with reference to the compounds of Table I as follows:- Product A 2-chloroallyl 3-(2-chloro-3,3,3-trifluoroprop-l -en-l -yl)-2,2-dimethylcyclopropane carboxylate (compound no. 1, Table I) consiting of 100% w/w of the (+)-cís isomer.

Product B E/Z-2,3-dichloroallyl 3-(2-chloro-3,3,3-trifluoroprop- 1 -en-1 -yl)-2,2-dimethylcyclopropane carboxylate (compound no. 2, Table I) consisting of 100% w/w of the (+)-cis isomer.

Product C 2-bromoallyl 3-(2-chloro-3,3,3-trifluoroprop-1 -en-i -yl)-2,2-diemthylcyclopropane carboxylate (compound no.3, Table I) consisting of 100% w/w of the (+)-cis isomer.

Product D 3,3-dichloroallyl 3-(2-chloro-3,3,3-trifluoroprop-1 -en-I -yl)-2,2-diemthylcyclopropane carboxylate (compound no. 4, Table I) consisting of 100% w/w of the (+)-cis isomer.

Product E Z-4-chlorobut-2-en- -yl 3-(2-chloro-3,3,3-trifl uoroprop- 1 -en- 1 -yl)-2,2 dimethylcyclopropane carboxylate (compound no. 5,Table I) consisting of 100% w/w of the (+)-cis isomer.

Product F 3,3-dibromoallyl 3-(2-chloro-3,3,3-trifluoroprop-1 -en-i -yl)-2,2-diemthylcyclopropane carboxylate (compound no. 6, Table I) consisting of 100% w/w of the (+)-cis isomer.

Product G 3,3-dibromoallyl 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylate (compound no. 7, Table I) consisting of 50% w/w of the (+)-cis isomer and 50% w/w of the (+)-trans isomer.

Product H E/Z-2,3-dibromoallyl 3-(2-chloro-3,3,3-trifluoroprop-1 -en-1 -yl)-2,2- dimethylcyclopropane carboxylate (compound no. 8, Table I) consisting of 100% w/w of the (+)-cis isomer.

The compounds of formula I 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 combatted 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 anima 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 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 dodecylbenzensulphonate, sodium, calcium or ammonium lignosulphonate, butylnaphthalene sulphonate, and a mixture of the sodium salts of diisopropyl- and triisopropylnaphthalene sulphonates. Suitable agents of the non-ionic 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 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 -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 horitcultural 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, ol 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) Megoura viceae (aphids) Aedes aegypti(mosquitoes) Dysdercus fasciatus (capsids) Musca domestica (houseflies) Pieris brassicae (white butterfly, larvae) Plutella maculipennis (diamond back month, larvae) Phaedon cochleariae (mustard beetle) Telarius cinnabarinus (carmine spider mite) Aonidiella spp. (scale insects) Trialeuroides spp. (white fliesi Blattella germanica (cockroaches) Spodoptera littoralis (cotton leaf worm) Chortiocetes terminifera (locusts) Diabrotica spp. (rootworms) 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. The fumigant properties of the compounds enable them to be used to combat pests which inhabit the soil, for example Diabrotica spp. They are also excellent knock down agents and as such may be used in conjunction with other insecticides to combat public health pests such as flies. They are also very useful in combatting 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 combatting both susceptible and resistant strains of these pests in their adult, larval and intermedite 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 The Example illustrates the insecticidal properties of the Products A to H.

The activity of the products was determined using a variety of insect pests. The product was used in the form of liquid preparations containing 500, 1 00 or 50 p.p.m. by weight of the product. The preparations were made by dissolving the product 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 product. "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 varing from one to three days after the treatment. Details are given in Table IIA.

The results of the tests are given in Table IIB for each of the products A to H at the rate in parts 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 " from 10 to 19% " 2 " 20to29% 3 " " 30to39% 4 t " 40 to 49% 5 tt " 50 to 59% 6 " " 60to69% 7 tt " 70 to 79% 8 " " to 89 S ^ 9 ,, " 90to100% In Table IIB the pest organism used is designated by a letter code and the pest species, the support medium or food, and the type of duration of test is given in Table IIA.

TABLE IIA

Code Letters Support Duration (Table IIB) Pest Species Medium/Food Type of Test* (days) MD Musca domestica Cotton wool /milk, Contact 1 (houseflies - adults) sugar SL Spodoptera littoralis Cabbage leaves Contact/Residual 3 (cotton leaf worm larvae) PX Plutella xylostella Cabbage leaves Residual 3 (diamond back moth larvae) SG Sitophilus granarius Grain Contact 3 (grain weevil -- adults) DB Diabrotica balteata Filter paper Contact 3 (rootworm - larvae) * "Contact" test indicates that both pests and medium were treated and "residual" indicates that the medium was treated before infestation with the pests.

TABLE IIB

Pest Species Rate Product (ppm) MD SL PX SG DB A 500 9 9 2 9 9 B 500 9 9 7 9 9 C 500 9 9 0 0 2 D 500 9 9 9 0 9 E 500 9 0 8 0 9 F 500 9 9 9 0 9 H 100 7 0 0 0 9 EXAMPLE 2 A mixture of (+)-cis-3-(Z-2-chloro-3,3,3-trifluoropro 1-2-en-1 -yl)-2,2-dimethylcyclopropa ne carboxylic acid (1.21 g), 3,3-dibromoallylbromide (1.5 g), anhydrous potassium carbonate (0.98 g) and acetone (50 ml) was stirred at the ambient temperature (ca. 250C) for 3 hours, and then partitioned between ether and water. The ethereal phase was separated, washed with dilute aqueous sodium carbonate solution and dried over anhydrous magnesium carbonate. After evaporation of the ether the residue was distilled to yield 3,3-dibromoallyl ( +)-cis-3-(Z-2-chloro-3,3,3-trif luoroprop-l-en-l -yi)-2,2- dimethyicycloprnpane carboxylate, b.p. 160 C/0.5 mm Hg.

N.m.r. (CDCl3) T: 3.1 0(d,1 H); 3.40(t,i H); 5.46(d,2H); 7.78--88-10(m,2H); 8.68(s,6H) Infra red (liquid film): 1730 cm-' EXAMPLE 3 The procedure of Example 2 was used to prepare the following haloalkenyl esters according to the invention from the appropriate cyclopropane carboxylic acids and haloalkenyl bromides as follows: (i) 2-ch loroallyl ()-cis-3-(Z-2-chloro-3,3,3-trifluoroprop- 1-en-1 -yl)-2,2-dimethylcyclopropane carboxylate (b.p. 1 10-1200C/0.045 mm Hg) N.m.r. (CDCl3) s: 3.1 0(d,1 H); 4.58(m,2H); 5.36(s,2H); 7.65-8.05(m,2H); 8.70(s,6H) Infra red (liquid film): 1730 cm-t (ii) E/Z-2,3-dichioroa llyl ()-cis-3-(Z-2-chloro-3,3,3-trifluornprnp-1 -en-i -yl)-2,2- dimethylcyclopropane carboxylate (b.p. 140-150 C/0.05 mm Hg).

N.m.r. (CDCl3) T: 3e.1 0(d,1 H); 3.40,3.60(ss,1 H); 5.08(s,1 H); 5.26(s,lH); 7-65-8.05(m,2H); 8.68(s,6H) Infra red (liquid film): 1730 cm-' (iii) 2-bromoa llyl (+)-cis-3-(Z-2-chlorn-3,3,3,trifluornprnp-i -en-1 -yl)-2,2-dimethylcyclopropane carboxylate (b.p. 110--120 C/0.045 mm Hg) N.m.r. (CDCl3) l: 3.1 0(d,1 H); 4.1 0(d,1 H); 4.34(d,1 H); 5.38(s,2H); 7.65-8.05(m,2H); 8.70(s,6H) Infra red (liquid film): 1730 cm-l (iv) 3,3-dichloroal lyl ()-cis-3-(Z-2-chloro-3,3,3-trifluoroprop- 1-en-1-yl)-2,2-dimethylcyclopropane carboxylate (b.p. 1400C/0.5 mm Hg N.m.r. (CDCI3) l: 3.1 0(d,1 H); 3.96(t,1 H); 5.34(d,2H); 7.70-8.1 0(m,2H); 8.70(s,6H) Infra red (liquid film): 1730 cm-1 (v) Z-4-chlorobut-2-en- 1 -yl (+)-cis-3-(Z-2-chlorn-3,3,3-trifluornprnp- 1 -en-1 -yl)-2,2- dimethylcyclopropane carboxylate (b.p. 120--1300C/0.5 mm) N.m.r. (CDCI3)T: 3.1 0(d,1 H); 4.1 0(m,2H); 5.42(m,2H); 5.96(m,2H); 7.70--8.05(m,2H); 8.70(m,6H) Infra red (liquid film): 1730 cam~' (vi) 3,3,dibromoallyl (~)-cis/trans-3-(2,2-dich lorovinyl-2,2-di methylcyclopropane carboxylate.

N.m.r. (CDCI3) T: 3.52(t,1 H); 3.90(d,1 H); 5.50(d,2H); 7.80-8.30(m,2H); 8.80(s,6H) Infra red (liquid film): 1725 cm-l

Claims (6)

1. A compound of formula:

wherein R' and R2 are each selected from methyl, halomethyl and halo; and R3, R4 and R5 are each selected from hydrogen, halo and halomethyl, provided that at least one of R' and R2 and at least one of R3, R4 and R6 is halo or halomethyl.

2. A compound as claimed in claim 1 wherein R1 and R2 are both chloro or one is chloro and the other is trifluoromethyl.

3. A compound as claimed in claim 2 wherein R3 is hydrogen and R4 and R5 are both chlorine or both bromine.

4. A process for preparing a compound according to claim 1 wherein an acid of formula

wherein Q represents the hydroxy group and R' and R2 have any of the meanings given in claim 1, or an alkali metal salt thereof, is reacted with a halide of formula:

wherein Q1 represents a halogen atom and R3, R4 and R5 have any of the meanings given in claim 1.

5. An insecticidal composition comprising as an active ingredient thereof a compound according to claim 1.

6. A method of combating insect pests at a locus which comprises treating the locus with an insecticidally effective amount of a composition according to claim 5.