GB2210878A - Insecticidal ether compounds - Google Patents

Abstract

The invention provides insecticidally active compounds of formula (I): <IMAGE> wherein R<1> represents C1-4 alkyl or C1-4 alkenyl; R<2> represents H, OH or OR<4> where R<4> represents C1-4 alkyl, C1-4 alkenyl or C1-4 alkynyl; and R<3> represents a group of formula <IMAGE> wherein X represents -N- or -CH-; W represents O-, -CH2-, and NH; and Y and Z are selected from H or halogen. The invention also provides processes for the preparation of the compounds of formula (I), insecticidal compositions comprising them, and methods of their use in combating insect pests.

Description

INSECTICIDAL COMPOUNDS This invention relates to novel, insecticidally active ethers, to processes and intermediates for their preparation, to compositions comprising them and to methods of combating insect pests therewith.

In a first aspect the invention provides a compound of general formula (I)

wherein R is selected from alkyl containing one, two, three or four carbon atoms and alkenyl containing one, two, three or four carbon atoms, R2 is selected from hydrogen, hydroxy and OR4 where R4 represents alkyl containing one, twc, three or four carbon atoms, alkenyl containing one, two, three or four carbon atoms or alkynyl contairing one, two, three or four carbon atoms, and R3 represents a group selected from those groups represented by R5 in insecticidally active compounds of formula

Preferred compounds according to the invention are those wherein R3 represents a group of formula::

wherein X represents nitrogen or carbon bearing a hydrogen atom, W is selected from oxygen, methylene and nitrogen bearing a hydrogen atom, and Y and Z are selected from hydrogen and halogen. Examples of compounds according to the invention are given in Table I. In Table I, the compounds listed correspond to the formula (IA), and values are given for R1, R2, X, Y, W and Z.

TABLE I

COMPOUND NO R R X Y W Z 1 CH3 OH CH F O H 2 CH3 H CH F O H 3 CH3 OH CH H O H 4 CH3 H CH H O H 5 CH3 OH CH F CH2 H 6 CH3 H CH F CH2 H 7 CH3 OH N H O H 8 CH3 | H N H O H 9 CH3 OCH2CH=CH2 CH F O H 10 CH3 OCH2C#CH CH F O H 11 CH=CH2 OH CH F O H 12 CH=CH2 H CH F O H 13 CH=CH2 OH CH H O H 14 CR=CR2 H CH H O H 15 CH=CH2 OH CH F CH2 H 16 CH=CH2 H CH F CH2 H The compounds of formula (I) contain at least one asymmetrically substituted carbon atom, each of which may exist in more than one isomeric form (the R-form and the S-form). In addition, where the group R4 represents alkenyl of three or four carbon atoms the possibility of geometrical isomerism around the carbon-carbon double bond arises. The scope of the invention includes all individual isomers of invention compounds and all isomeric mixtures, including racemic mixtures.

The compounds of formula (I) wherein R2 represents hydroxy and R1 has any of the meanings given above may be prepared from the corresponding compound of formula (II), wherein Hal represents halo, preferably bromo or chloro, by reaction with an alcohol of formula R3CH2OH, where R3 has any of the meanings given above, in the presence of a base, optionally in a two-phase system in the presence of a phase transfer catalyst.

The compounds of formula (11) may themselves be prepared from a ketone of formula CF3COCR2-Hal, wherein Hal represents halo, preferably bromo or chloro, by reaction with a Grignard reagent of formula RlMgBr.

The compounds of formula (I) wherein R2 represents the group OR41 wherein R4 has any of the meanings given above, may be prepared from the corresponding compounds of formula (I) where R2 represents hydroxy by reaction with a compound of formula R4-Hal, wherein Hal represents halo, preferably bromo or chloro, preferably in the presence of a base, for example, sodium hydride.

The compounds of formula (I) wherein R2 represents hydrogen may be prepared from the corresponding compounds of formula (I) wherein R2 represents hydroxy by elimination of H20 to give an alone of formula (III) (with the possibility of the sinultaneous formation of isomeric compounds in those cases where the group R1 has a saturated carbon atom bearing at least one hydrogen at the point of attachment),

followed by reduction of the alkene or mixture of alkenes using, for example, hydrogen under pressure in the presence of a hydrogenation catalyst such as Rhodium; this sequence is illustrated in Scheme I, by way of example, in the particular case where R1 represents methyl and R3 represents 4-fluoro-3phenoxyphenyl.Further details of the processes described above are given ir. the Examples hereinafter.

The alkenes of formula (III) and their isomers as described above, wherein R3 has any of the meanings given above, have themselves been found to exhibi- insecticidal activity.

Scheme I

Key : DAST = Diethylaminosulphur trifluoride 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 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 compounds of the invention may be the sole active ingredient of the composition or they may be admixed with one or more additional active ingredients such as insecticides, insecticide synergists, herbicides, fungicides or plant growth regulators where appropriate.

Suitable additional active ingredients for inclusion in admixture with the compounds of the invention may be compounds which will broaden the spectrum of activity of the compounds of the invention or increase their persistence at the locus of the pest. They may synergise the activity of the compounds of the invention or complement the activity for example by increasing the speed of effect, improving knockdown or overcoming repellency.

Additionally multi-component mixtures of this type may help to overcome or prevent the development of resistance to individual components.

The particular insecticide, herbicide or fungicide included in the mixture will depend upon its intended utility and the type of comrlementary action required.

Examples of suitable insecticides include the following: (a) Pyrethroics such as permethrin, esfenvalerate, deltamethrin, cyhalothrin, biphenthrin, fenpropathrin cyfluthrin, tefluthrin, fish safe pyrethroids for example ethofenprox, natural pyrethrin, tetramethrin, s-bioallethrin, fenfluthrin, prallethrin and 5-benzyl-3- furylmethyl-(E)-(lR,3S)-2,2-dimethyl-3-(2- oxothiolan-3-ylidenemethyl)cyclopropane carboxylate;; (b) Organophosphates such as profenofos, sulprofos, methyl parathion, azinphos-methyl, demeton-s methyl, heptenophos, thiometon, fenemiphos, monocrotophos, profenophos, triazophos, methamidophos, dimethoate, phosphamidon, malathion, chlorpyrifos, phosalone, fensulfothion, fonofos, phorate, phoxim, pyrimiphos-methyl, fenitrothion or diazinon; (c) Carbamates (including aryl carbamates) such as pirimicarb, cloethocarb, carbofuran, ethiofencarb, aldicarb, thiofurox, carbosulfan, bendiocarb, fenobucarb, propoxur or oxamyl; (d) Benzoyl ureas such as triflumuron, chlorofluazuron; (e) Organic tin compounds such as cyhexatin, fenbutatin oxide, azocyclotin; (f) Macrolides such as avermectins or milbemycins, for example such as abamectin, avermectin, and milbemycin;; (g) Hormones such as juvenile hormone, juvabione, or ecdysones; (h) Pheromones; (i) Organochlorine compounds such as benzene hexachloride, DDT, chlordane, endosulphan or dieldrin.

In addition to the major chemical classes of insecticide listed above, other insecticides having particular targets may be employed in the mixture if appropriate for the intended utility of the mixture.

For instance selective insecticides for particular crops, for example stemborer specific insecticides for use in rice such as cartap or buprofezin, can be employed. Alternatively insecticides specific for particular insect species/stages for example ovolarvicides such as clofentezine, flubenzimine, hexythiazox and tetradifon, motilicides such as dicofol or propargite, acaricides such as bromopropylate, chlorobenzilate, or insect growth regulators such as hydramethylon, cyromazin, methoprene, chlorofluazuron and diflubenzuron may also be included in the compositions.

Examples of suitable insecticide synergists for use in tne compositions include piperonyl butoxide, sesamex, and dodecyl imidazole.

Suitable herbicides, fungicides and plant growth regulators for inclusion in the cocnositions will depend upon the intended target and the effect required. An example of a rice selective herbicide which can be included is propanil, an example of a plant growth regulator for use in cotton is "Pix", and examples of fungicides for use in rice include blasticides such as blasticidin-S. The choice of other ingredients to be used in mixture with the active ingredient will often be within the normal skill of the formulator, and will be made from known alternatves depending upon the total effect to be achieved.

The ratio of the compound of the invention to any other active ingredient in the composition will depend upon a number of factors including the type of insect pests to be controlled, and the effects required from the mixture. However in general, the additional active ingredient of the composition will be applied at about the rate it would usually be employed if used on its own, or at a lower rate if synergis occurs.

The compositions may be in the form of dusting powders vherein 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 aerosols, dips or sprays Dips and sprays 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). Aerosol compositions may contain the active ingredient or ingredients, a propellant and an inert diluent, for exampl odourless kerosene or alkylated benzenes.

Wetting agents, dispersing agents and emulsifying agents may be of the cationic, anionic or non-ionic type. Suitable agents of the cationic type include, for example, quaternary ammonium compounds, for example cetyltrimethyl amnonium 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 odecylbenzenesulphonate, sodium, calcium or ammonium lignosulphonate, or butylnaphthalene sulphonate, an 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 phenoll and octy 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 tetrahydrofurfuryl alcohol (THFA).

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 homogenous for a sufficient time to enable them to be applied by conventional spray equipment. The concentrates may contain 10-85% 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 0.18 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: Myzus persicae (aphids) Aphis fabae (aphids) Megoura viceae (aphids) Aedes aegypti (mosquitos) Anopheles spp. (mosquitos) Culex spp. (mosquitos) Dysdercus fasciatus (capsids) Musca domestica (houseflies) Pieris brassicae (white butterfly, larvae) Plutella maculipennis (diamond back moth, larvae) Phaedon cochleariae (mustard beetle) Aonidiella spp. (scale insects) Trialeuroides spp. (white flies) Blattella germanica (cockroaches) Blatta orientalis (cockroaches) Periplaneta americana (cockroaches) Spodoptera littoralis (cotton leaf worm) Heliothis virescens (tobacco budworms) Chortiocetes terninifera (locusts) Diabrotica spp. (rootworms) Nilaparvata lugen. (plant hoppers) Agrotis spp. (cutworms) Chilo suppressalis (rice stem borer) Chilo partellus (maize stem borers) Nephotettix cincticeps (leaf hoppers) Tetranychus urticae (red spider mite) Tetranychus cinnabarinus (carmine spider mite) Panonychus ulmi Panonychus citri In addition to providing effective control of lepidopteran pests of cotton, for example Spodoptera spp. and Heliothis spp, the compounds of formula (I) and compositions comprising them have also been shown to be particularly useful in the control of pests of maize and rice such as Chilo spp. (stem borers), Nilaparvata spp. and Nephotettix spp. (plant and leaf hoppers).Some of the compounds show high levels of activity against rice pests at rates which are not toxic to fish, thus enabling their use in paddy rice where fish are cultivated in the paddy.

The compounds of formula (I) and compositions comprising them may also be 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 Dermocentor 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 various aspects of this invention. In the preparation Examples the products were usually identified and characterised by means of nuclear magnetic reasonance spectroscopy and infra-red spectroscopy. In each case where a product is specifically named its spectral characteristics are consistent with the assigned structure. Except where stated otherwise, exemplified compounds having one or more asymmetrically substituted carbon atoms were prepared in racemic form.

In the Examples, Gas Liquid Chromatography (GLC) retention times were determined on a Hewlett Packard 5890 Gas Chromatograph, using a Chrompak, CPSil 5CB column of 12.5m length and 0.2 mm internal diameter.

Unless otherwise stated, the injection temperature was 100 C, and a temperature gradient of 15"C/minute employed, up to a maximum temperature of 280-C, maintained for 4 ninutes. The carrier gas was helium at a column head pressure maintained at 11 psi.

Alternative injectiOn andmaximum temperature are indicated in the Examples whe appropriate.

1H Nuclear Magnetic Resonance (NMR) spectrometry was performed at a frequency of 270 MHz on a Jeol FX 270 NMR spectrometer, unless otherwise indicated. 90 MHz, 60 MHz and 4G3 MHz 1H NMR spectrometry were performed using Jeol FX 90 Q, Jeol PMX60 SI and Jeol GX400 spectrometers respectively.

19F NMR spectrometry was performed on a Jeol FX90Q spectrometer at a frequency of 84.26 MHz. All NMR shift values (t ) are quoted in ppm relative to a standard (TMS or CFCl3).

Molecular Ion (M+, peaks (measured in atomic mass units) were determined on one of three mass spectrometers: Jecl DX303, Kratos MS80 or Hewlett Packard HP 5992.

EXAMPLE 1 This Example illustrates the preparation of (RS) 1,1 ,l-trifluoro-2-methyl-3-bromopropan-2-ol.

1,1,1-Trifluoro-3-bromoacetone (80g) was dissolved in dry diethyl ether (200 cm3) and cooled, under an atmosphere of nitrogen, at 0 C with stirring.

A solution of methyl-magnesium bromide (3M in diethyl ether) (140 cm3) was added, maintaining the reaction temperature below 100C. After the addition was complete the mixture was stirred for 30 minutes, then allowed to warm to room temperature for a further 30 minutes. The mixture was quenched with dilute hydrochloric acid and the products extracted into diethyl ether. The combined extracts were washed twice with water, dried over anhydrous magnesium sulphate and the diethyl ether was carefully removed by distillation at atmospheric pressure. The title compound (30g) distilled at about 128-134 C.

H NMR (CDC13) : 1.52 (3H, s); 2.5 (lH, broad OH); 3.56 (2H, q); 19F NMR (CDC13) : -81.3 (CF3, s).

IR (liquid film) : 3469 (broad OH), 1302, 1171, 1091, 640 cm'l.

EXAMPLE 2 (RS)-l,l,l-Trifluoro-2-ethenyl-3-bromopropan-2- ol was prepared from l,l,l-trifluoroacetone and ethenylmagnesium bromide using the method of Example 1.

Boiling Point : 104 C.

1H NMR (CDCl3) : 2.8 (1H, broad OH) 3.56, 3.75 (2H, 2d); 5.58 (1H, d); 5.71 (1H, d); 5.86 (1H, dd).

EXAMPLE 3 This Example illustrates the preparation of (RS)- 1,1,1-trifluoro-2-methyl-3-(4-fluoro-3phenoxybenzyloxy)-propan-2-ol.

A mixture of (RS)-1,1,1-trifluoro-2-methyl-3- bromo-propan-2-ol (4g), 4-fluoro-3-phenoxybenzyl alcohol (4.2g), 40% aqueous sodium iydroxide solution (20 cm33, carbon tetrachloride (5 cm ) and tetra nbutylammonium hydrogen sulphate (catalytic amount ca.

O.lg) was stirred vigorously at the ambient temperatue for 3 hours. The mixture was then heated at 60 C for 5 hours with stirring. After cooling, the mixture was diluted with water, acidified with dilute hydrochloric acid and the products extracted into chloroform. The combined organic extracts were washed with water, dried over anhydrous magnesium sulphate and concentrated by evaporRtion under reduced pressure to give a viscous ail (5.5g).

Purification by column chromatography on silica gel, eluting with hexane containing 20% by volume ethyl acetate gave the title compound as a colourless oil (2.2g).

1H NMR (CDCl3) : 1.36 (3H, s); 3.0 (1H, s); 3.40 (1H, d); 3.67 (1H, d); 4.52 (2H, s); 6.9 7.4 (8H, m).

19F NMR (CDCl3) : -81.37 (CF3, s); -132.3 (1F, m).

IR (liquid film) : 3469 (broad OH), other peaks at 1732, 1591, 1511, 1491, 1428, 1376, 1282, 1162 cm'l, EXAMPLE 4 (RS )-l, 1, 1-Trifluoro-2-ethenyl-3-(3 phenoxybenzyloxy)propan-2-ol was prepared from 1,1, l-trifluoro-2-ethenyl-3-bromopropan-2-ol and 3phenoxybenzyl alcohol using the method of Example 3.

1H NMR (CDCl3) : 3.19 (1H, s); 3.54 (1H, d); 3.80 (1H, d); 4.57 (2H, s); 5.49 (1H, d); 5.7 (1H, d); 5.9 (lH, dd); 6.95-7.4 (9H, m).

EXAMPLE 5 This Example illustrates the preparation of (RS)-l,-l,l-trifluoro-2-methyl-2-propargyloxy-3-(4- fluoro-3-phenoxybenzyloxy)propane.

Sodium hydride (0.14g, 55% dispersion in oil) was washed free of oil with hexane in a flask under an atmosphere of nitrogen. (RS)-l,l,l-Trifluoro-2methyl-3-(4-fluoro-3-phenoxybenzyloxy)propan-2-ol (1.0g) in dry tetrahydrofuran (10 cm3) was added.

When effervescence had ceased, a solution of propargyl bromide (0.38g) in dry tetrahydrofuran (10 cm3) was added. The mixture was stirred at room temperature for 5 1/2 hours, then was heated at the reflux temperature for 2 days. GLC analysis showed incomplete reaction so a further portion of propargyl bromide (1.38g) was added and the mixture was stirred for 5 hours. The mixture was cooled, poured into water and the products extracted into diethyl ether.

The combined organic extracts were dried over anhydrous magnesium sulphate and the solvent evaporated under reduced pressure to leave an oil (0.238g). The product was purified by chromatography on silica gel, eluting with hexane containing 10% by volume diethyl ether, to give the title compound as a colourless oil (0.137g).

1H NMR (CDCl3) : 1.45 (3H, s); 2.41 (lH, t, acetylenic H); 3.64 (2H, ABq); 4.32 (2H, d); 4.53 (2H, ABq); 7.0-7.4 (8H, m).

19F NMR (CDC13) : -78.9 (CF3, s:; -132.76 (1F, m).

EXAMPLE 6 (RS)-1,1,1-Trifluoro-2-methyl-2-allyloxy-3-(4fluoro-3-phenoxybenzyloxy)propane was prepared from the appropriate starting materials using the method of Example 5.

1H NMR (CDC13): 1.40 (3H,s); 3.60 (2H, ABq); 4.13 (2H,d); 4.5 (2E,ABq); 5.12 (lH,d); 5.28 (lH,d); 5.9 (lH,m); 7.0-7.4 (8H,m) 19F NMR (CDCl3) : -78.6 (CF3, s); -132.8 (1F, m).

EXAMPLE 7 This Example illustrates the preparation of a mixture of l,l,l-trifluoro-2-methyl-3-(4-fluoro-3- phenoxybenzyl-oxy)prop-2-ene (Compound A) and 2trifluoromethyl-3-(4-fluoro-3-phenoxybenzyloxy)propl-ene (Compound B).

Diethylaminosulpbur trifluoride (DAST, 2 cn3) was added to l,l,l-trifluoro-2-methyl-3-(4-fluoro-3phenoxy-benzyloxy)propan-2-ol (1.2g) in dry dichloromethane (30 cm3) cooled to -78 C under an atmosphere of nitrogen. After 30 minutes the mixture was allowed to warm to the ambient temperature and stirred for a further 2 hours. The mixture was poured into saturated aqueous sodium hydrogen carbonate solution and the products extracted into chloroform. The organic layer was washed twice with water, then dried over anydrous magnesium sulphate and the solvent evaporated under reduced pressure.

The residual oil was purified by chromatography on silica gel eluting with hexane containing 7% by volume ethyl acetate, to give a 1:1 mixture of Compounds A and B (0.wog).

The mixture of Compound A and Compound B was separable by high pressure liquid chromatography on a Dupont silica column (internal diameter 2.54 cm), eluting with hexane containing 1t by volume ethyl acetate; Compound A was obtained as the faster running component.

Compound A 1H NMR (CDC13) : 1.69 (3H, s); 4.83 (2H, s); 6.66 (1H, s); 7.0-7.4 (8H, m).

Compound B 1H NMR (CDC13) : 4.12 (2H, s); 4.47 (2H, s); 5.65 (lH, s); 5.83 (1H1 s); 7.0-7.4 (8H, m).

EXAMPLE 8 This Example illustrates the preparation of (RS)-l,-l,l-trifluoro-2-methyl-3-(4-fluoro-3- phenoxybenzyloxy)-propane.

The mixture of l,l,1-trifluoro-2-methyl-3-(4- fluoro-3-phenoxybenzyloxy)prop-2-ene and 2trifluoromethyl-3-(4-fluoro-3-phenoxybenzyloxy)propl-ene (0.6g), prepared according to the method of Example 7, was dissolved in ethanol (30 cm3) and hydrogenated at a pressure of 3 bar over a catalyst of 58 rhodium on carbon (0.025g) for one hour. The mixture was filtered and the solvent evaporated under reduced pressure. Analysis of the residual oil by GLC showed two products, which were separated by high pressure liquid chromatography on a Dupont silica column (internal diameter 2.54 cm), eluting with hexane containing 1% by volume ethyl acetate.The second fraction eluted was identified as (RS)-l,l,l trifluoro-2-methyl-3- (3-cyclohexyloxy-4-fluoro- benzyloxy)propane, resulting from excessive hydrogenation of the starting material. The title compound, for which characteristic data are given below, was the first product eluted.

1H NMR (CDC13) : 1.15 (3H, d); 2.5 (1H, m); 3.42 (1H, dd); 3.66 (1H, dd); 4.44 (2H, s); 7.0-7.4 (8H, m).

19F NMR (CDCl3) : -72.1 (CF3, d, J=8Hz); -132.8 (1F, m).

EXAMPLE 9 This Example illustrates the insecticidal properties of the Products of this invention.

The activity of the Product was determined using a variety of insect pests. The Product was used in the form of liquid preparations containing 500, 100 or 10 parts per million (ppm) by weight of the Product.

The preparations were made by dissolving the Product in acetone and diluting the solutions with water containing 0.0;s by weight of a wetting agent sold under the trade name "LISSAPOL" NX until the liquid preparations obtained the required concentration of the Product. '';issapol" is a Registered 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.

In the case of the species Musca domestica (housefly), aditional tests to determine the knockdown effect of the compounds were performed.

Details are given in Table II.

The results of the tests are given in Table III for each of the Products, at the rate in parts per million given an the second column, as a grading of mortality designated as A, B or C wherein A indicates 80-100% mortality or knockdown, B indicates 50-79% mortality or knockdown and C indicates less than 50% mortality or knockdown.

In Table III 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 II.

TABLE II

CODE LETIERS SUPPORT TYPE OF DURATION (TABLE III) TEST SPECIES MEDIUM/FOOD TEST (Days) TU Tetracychus urticae French bean Contact 3 (spider mites - adult) leaf MP Myzus persicae Chinese cabbage Contact 2 leaf NC Nephonettix cinctioeps Rice plant Contact 6 (green leaf hopper nymphs) HV Heliochis virescens Cotton leaf Residual 3 (toba@co budworm - larvae) DB Diabrotica balteata Filter paper, Residual 3 (roo@orm larvae) maize seed BG Blatrella genmanica Plastic pot Residual 3 (co@roach nymphs) MD Musce domestica Cooton wool/ Contact 1 (houseflies - adults) sugar MD/KD Musce domestica Cotton wool/ Knockdown 4 hours (houseflies - adults) sugar SP Spodoctera exigua Cotton leaf Residual 3 (lesser army worm larvae) "Contact" test indicates that both pests and medium were treated and "residual" indicates that the redium was treated before infestation with the pests.

TABLE III

COMPOUND RATE NO (PPM) TU MP NC HV DB BG MD MD/KG SP 1 500 B C A C A C A C C 2 500 C A A C A A A A A 9 500 C C A A A B A C A 10 500 C C A A A B A B A 13 500 C C A C B C A C B

Claims (7)

1. What we claim is:1. A compound of formula (I)

   wherein R1 is selected from alkyl containing one, two, three or four carbon atoms and alkenyl containing one, two, three or four carbon atoms; R is selected from hydrogen, hydroxy and OR4, where R4 represents alkyl containing one, two, three or four carbon atoms, alkenyl containing one, two, three or four carbon atoms or alkynyl containing one, two, three or four carbon atoms; and R3 represents a group selected from those groups represented by R5 in insecticidally active compounds of formula
2. 2.A compound according to claim 1 wherein R3 represents a group of formula :

   wherein X represents nitrogen or carbon bearing a hydrogen atom; W is selected from oxygen, methylene and nitrogen bearing a hydrogen atom; and Y and Z are selected from hydrogen and halogen.
3. 3. A process for the preparation of a compound according to claim 1 wherein R2 represents hydroxy, which comprises reastion of a compound of formula (II):

   with an alcohol of formula RCH2OH, wherein Hal represents Halo, and R1 and s3 have any of the meanings given in claim 1, it the presence of a base.
4. 4. A process for the preparation of a compound according to claim 1 wherein R2 represents a group of formula OR41 where R4 has any of the meanings given in claim 1, which comprises reaction of the corresponding compound of formula (I) wherein R2 represents hydroxy with a compound of formula R4-Hal, wherein Hal represents Halo.
5. 5. A process for the preparation of a compound according to claim 1 wherein R2 respresents hydrogen, which comprises the step of elimination of H20 from the corresponding compound of formula (I) wherein R2 represents hydroxy, followed by the step of reduction of the resulting alkene or mixture of alkenes.
6. 6. An insecticidal composition comprising an insecticidally effective amount of a compound according to claim 1 in association with an insecticidally inert diluent or carrier material.
7. 7. A method of combating insect pests at a locus which comprises treating the locus with the composition of claim 6.