GB1596903A - Insecticidal and acaricidal phenyl alkanoic acid esters - Google Patents

Description

PATENT SPECIFICATION ( 11) 1 596 903

M ( 21) Application No 21660/78 ( 22) Filed 23 May 1978 ( 19) ( 61) Patent of Addition to No 1582775 Dated 26 Sep 1977 ( 31) Convention Application No 814600 ( 32) Filed 11 Jul 1977 in Cas ( 33) United States of America (US) ( 44) Complete Specification Published 3 Sep 1981 x- ( 51) INT CL 3 CO 7 C 149/32 AO 1 N 37/12 C 07 C 147/14 147/107 // 149/30 ( 52) Index at Acceptance C 2 C 220 227 22 Y 311 314 31 Y 326 339 364 366 367 368 36 Y 371 373 37 Y 396 397 440 465 551 552 613 628 656 658 65 X 662 695 699 758 805 Y AA QN QT RG ( 72) Inventors: GERALD BERKELHAMMER VENKATARAMAN KAMESWARAN ( 54) INSECTICIDAL AND ACARICIDAL PHENYL ALKANOIC ACID ESTERS ( 71) We, AMERICAN CYANAMID COMPANY, a corporation organised and existing under the laws of the State of Maine, United States of America, of Berdan Avenue, Township of Wayne, State of New Jersey, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement 10

This invention relates to novel derivatives of phenylalkanoic acids, and to the use of the novel compounds as insecticides or acaricides The invention is a modification of that forming the subject of our co-pending Application No: 40043/77 Serial No 1582775.

The compounds of the invention are m-phenoxybenzyl esters of 2-haloalkyl (thio-, sulfinyl-, or sulfonyl) phenylalkanoic acids represented by the formula: 15 0 20 R-CF 2 X CH-C OH O I I H 2 H 3 25 ( 1) wherein RCF 2 X is meta or para to the carbon to which the alkanoic acid ester group is 30 attached, and X is S, SO or SO 2; R represents H, F, Cl, CHF 2 or CF 3; R 2 represents ethyl, n-propyl, isopropyl, isopropenyl or t-butyl and R 3 is hydrogen or cyano; and includes the optical isomers embraced by formula I.

Advantageously, the m-phenoxybenzyl esters of 2-haloalkyl (thio-, sulfinyl-, or sulfonyl) phenylalkanoic acids, depicted by formula I, can be prepared by reacting an alpha 35 substituted 2-haloalkyl (thio-, sulfinyl-, or sulfonyl) phenylacetyl halide (II), preferably chloride, with a m-phenoxybenzyl alcohol (III) The reaction is generally conducted in the presence of a solvent such as diethyl ether, benzene or toluene, at a temperature of from C to 30 C in the presence of an acid acceptor Among the acid acceptors that can be employed are the tertiary organic amines, trimethylamine, triethylamine and pyridine 40 1 596 903 This reaction can be illustrated as follows:

H-COA + CHOH 5 R-CF 2 X (I) R 3 10 Acid Acceptor 15 D CIH-C-O-C -I H 0-1 RCF 2 X 20 R 2 R 3 2 (I) 25 wherein RCF 2 X is meta or para to the carbon to which the alkanoic acid group is attached, and X is S, SO, or SO 2; and wherein R is H, F, Cl, CHF 2 or CF 3; R 2 is ethyl, n-propyl, isopropyl, isopropenyl, or t-butyl; R 3 is H or CN and A is halogen, preferably chlorine.

The compounds within the generic formula I depicted-above, can be categorized as ( 1) those wherein RCF 2 X is para to the carbon to which the alkanoic acid ester group is 30 attached and R, R 2 and R 3 are as described above; or ( 2) those wherein RCF:X is meta to the carbon to which the alkanoic acid ester group is attached and R, R 2 and R 3 are as described above.

Within each of these groups we have found that compounds where X is S and R is H or F, R 3 is H or CN or R 2 is ethyl, n-propyl, or isopropyl are preferred 35 With regard to the compounds of the present invention as depicted by formula I, it should also be understood that various optical isomers of the above-identified compounds do result from the preparations described For example, in the synthesis of formula I esters, wherein R 3 is hydrogen, a chiral center is present at R 2 and d and 1 isomeric pairs are formed Also, a-cyano substitution at R 3 introduces an additional chiral center, thus allowing for an 40 addtional d, 1 pair.

The a-substituted 2-haloalkyl (thio-, sulfinyl-, or sulfonyl) phenylacetyl halides (II) where R 2 is ethyl, n-propyl, or isopropyl, can be prepared using the appropriate toluene as a starting material as described in connection with Flow Diagram I of the parent specification except that the substituent on the starting toluene of formula IV therein is 45

RCF 2 X where R and X are as defined herein in relation to formula I.

In a modification applicable to the preparation of compounds containing a parasubstituted RCF 2 S group, the reaction may be begun by chloromethylating the appropriate haloalkyl thio-benzene (IX) using a mixture of para-formaldehyde or trioxane with zinc chloride and dry hydrogen chloride to afford the benzyl chloride (X) which can then be used 50 in place of the benzyl bromide of formula V of the aforesaid Flow Diagram I for completion of the synthesis This modification is illustrated as follows:

Zni Cl 2 5 RCF 2 S + (CH 20)n+ NC 2 RCF 2-S CH 2 C ( 1) (X) 60 It is found that in the alkaline hydrolysis of the nitriles for those examples in which RCF 2 X is HCF 2 S that the HFC 2 radical can be lost However, we have discovered that it may be reintroduced by reacting the appropriate thiophenol with chlorodifluoromethane in a mixture of aqueous alkali and dioxane 65 3 1 596 903 3 It is also to be noted that although the above described processes are suitable for the preparation of most examples where 0 O II 1 5 X = -S or -S-, 11 it is frequently better to prepare the final acids or esters(corresponding to formulae VIII 10 and I respectively in the aforesaid Flow Diagram I) in which X =-S and then to oxidize the sulfur atom to the desired O O I t I 15 -S or -S11 O analog through the use of appropriate oxidizing agents such as mchloroperbenzoic acid, 20 sodium periodate, or hydrogen peroxide.

To prepare those compounds of structure I in which R 2 is t-butyl, the following reaction sequence is used, starting with appropriate meta or para-substituted aldehyde:

( 1) reaction with t-butyl magnesium chloride; ( 2)conversion of the neopentyl alcohol to the chloride using thionyl chloride; 25 ( 3) preparation of the Grignard reagent from the chloride using magnesium in tetrahydrofuran; and ( 4) carboxylation with carbon dioxide.

For those compounds of structure I in which R 2 is isopropenyl, the introduction of the a-isopropenyl group can be accomplished by the following sequence of reactions using the 30 appropriate meta or para-substituted-phenylacetic acid:

( 1) reaction with two equivalents of isopropyl magnesium chloride and acetone; ( 2) conversion of the hydroxy acid to the ester; and ( 3) dehydration of the hydroxy ester with P 205.

With respect to the formation of the ct-cyano-m-phenoxybenzyl ester products by the 35 procedure discussed in relation to the aforesaid Flow Diagram I, it is not necessary to isolate the ac-cyano-m-phenoxybenzyl alcohol precursor It is equally or more satisfactory to allow a mixture of m-phenoxy-benzaldehyde, an alkali cyanide such as sodium cyanide, and the appropriate a-substituted 2-haloalkyl (thio-, sulfinyl-, or sulfonyl) phenylacetyl halide to react together in one step to form the final a-cyano ester 40 The compounds of the invention exhibit activity as contact and stomach poisons for ixodide ticks and for a wide variety of insects, particularly Dipterous, Lepidopterous, Coleopterous and Homopterous insects In general, those which have been tested are unusual among pyrethroids, in that they exhibit extended residual insecticidal activity on plant tissue, they are effective in the soil, and are surprisingly effective for the control of 45 ixodidae and the protection of animals against attack by insects and ixodidae when administered to the animals orally or parenterally or applied thereto as a topical insecticidal or acaricidal formulation In general, they do not require admixture with a stabilizing agent to achieve insecticidal and acaricidal compositions having stabilized effects; however, they may be used in combination with other biological chemicals; for example, pyrethroid 50 synergists such as piperonyl butoxide, sesamex or n-octyl sulfoxide of isosafrole They may also be used in combination with conventional insecticides such as the phosphates, carbamates, formamidines, chlorinated hydrocarbons or halobenzoylureas To achieve control of insects, including soil insects, which attack growing plants and/or harvested crops, including stored grain, the insecticidal compounds of this invention may be applied 55 to the foliage of plants, the insect's habitat and/or the insect's food supply Generally, the active compound is applied in the form of a dilute liquid spray; however, it may also be applied as an aerosol, a dust, a granular, or a wettable powder formulation The formulation of such liquid sprays may be in accordance with the disclosure of the parent specification 60

For use as animal systemic insecticidal and acaricidal agents, the compounds of this invention can be administered to the animal host in the same way as is described in the parent specification.

Among the specific compounds of this invention which are useful as insecticidal and acaricidal agents are: 65 4 1 596 903 4 a-Cyano-m-phenoxybenzyl a-isopropyl-4-trifluoro-methylthiophenylacetate; m-Phenoxybenzyl a-ethyl-4-trifluoromethylsulfinyl-phenylacetate; and ac-Cyano-m-phenoxybenzyl a-isopropyl-3-difluoromethylsulfonylphenylacetate; The invention is illustrated by the Examples set forth below:

5 EXAMPLE 1

Preparation of a-Bromo-4-trifluoromethylthiotoluene.

Bromine ( 20 5 g, 0 13 mol) in 20 ml of carbon tetrachloride is added slowly to a solution of 4-trifluoromethyl-thiotoluene ( 29 g, 0 15 mol) in 90 ml of carbon tetrachloride heated to gentle reflux under a 275 W sunlamp When the addition is complete, the solution is 10 maintained at reflux for one hour Most of the solvent is removed at atmospheric pressure, then the residue is vacuum distilled The 15 5 g cut with boiling point 6477 C/0 6-0 8 mm is 92 % monobromo compound by glc.

EXAMPLE 2 15

Preparation of 4-Trifluoromethylthiophenylacetonitrile.

Sodium cyanide ( 3 9 g, 0 08 mol) is added to 40 ml of dimethylsulfoxide at 65 C under N 2.

The heat is removed and a-bromo-4-trifluoromethylthiotoluene ( 14 3 g real, 0 053 mol) is added dropwise at such a rate that the exotherm never raises the temperature above 75 C.

The red-colored reaction is heated to 90-95 C for about 45 minutes, then cooled to room 20 temperature and treated with 50-100 ml of ice water The aqueous suspension is extracted with several portions of ether which are combined, washed with water, and dried over sodium sulfate Evaporation in vacuo gives 9 7 g of a dark red oil 95 % pure by glc.

EXAMPLE 3 25

Preparation of a-Isopropyl-4-trifluoromethylthiophenylacetonitrile.

Fifty percent sodium hydroxide ( 13 5 ml) is added over a 30-minute period dropwise to a suspension of 4-trifluoromethylthiophenylacetonitrile ( 9 7 g, 0 045 mol), 2-iodopropane ( 9.5 g, 0 056 mol), and 18-crown-6 ( 0 61 g, 0 0023 mol) in 13 5 ml of benzene and the exotherm reaches 43 C After stirring 2 5 hours at ambient temperature, an aliquot placed 30 on glc shows none of the starting nitrile remaining The reaction is worked up by adding ice water and extracting with ether, which is washed with 10 % HCI, water, and dried over sodium sulfate Evaporation in vacuo gave 10 2 g ( 86 8 %) of a red-brown oil.

Comparable results are obtained by substituting ethyl bromide or npropyliodide in place of 2-iodopropane to synthesize a-ethyl-4trifluoromethylthiophenylacetonitrile and a-n 35 propyl-4-trifluoromethylthiophenylacetonitrile, respectively.

EXAMPLE 4

Preparation of ac-Isopropyl-4-trifluoromethylthiophenylacetic acid.

a-Isopropyl-4-trifluoromethylthiophenylacetonitrile ( 6 9 g real, 0 0265 mol) and 50 % 40 sodium hydroxide ( 25 g, 0 312 mol) are combined in 53 ml of ethylene glycol and heated at gentle reflux for 18 hours The reaction is poured into ice water and extracted with ether.

The aqueous phase is acidified with concentrated HCI, then re-extracted with ether which is washed with water and dried over sodium sulfate Evaporation in vacuo gives 2 05 g of an oily product 45 Comparable results are obtained substituting a-ethyl-4trifluoromethylthiophenylacetonitrile or a-n-propyl 4-trifluoromethylthiophenylacetonitrile, as the starting material to synthesize a-ethyl-4-trifluoromethylthiophenylacetic acid and a-npropyl-4trifluoromethylthiophenylacetic acid, respectively 50 '50 EXAMPLE 5

Preparation of a-Cyano-m-phenoxybenzyl a-isopropyl-4trifluoromethylthiophenylacetate.

By using a-isopropyl-4-trifluoromethylthiophenylacetic acid and procedures of Examples 14 and 15 of the parent specification, the product is obtained as an oil.

Analysis calculated for C 26 H 22 F 3 NO 3 S: C,64 32 %; H, 4 57 %; F, 11 74 %; N, 2-89 %; S, 55 6.60 % Found: C, 64 27 %; H, 4 62 %; F, 11 66 %; N, 2 68 %; S, 6 43 %;.

Comparable results are obtained substituting a-ethyl-4trifluoromethylthiophenylacetic acid or a-n-propyl-4-trifluoromethylthiophenylacetic acid to synthesize acyano-mphenoxybenzyl a-ethyl-4-trifluoromethylthiophenylacetate and a-cyano-mphenoxybenzyl 60 60a-n-propyl-4-trifluoromethylthiophenyl-acetate, respectively 60 EXAMPLE 6

Preparation of m-Phenoxybenzyl a-isopropyl-4trifluoromethylthiophenylacetate.

By using a-isopropyl-4-trifluoromethylthiophenylacetic acid and procedures of Examples 65 14 and 16 of the parent specification, the product is obtained as an oil.

1 596 903 5, EXAMPLE 7

Preparation of a-Isopropyl-4-mercaptophenylacetic acid.

A solution of a-isopropyl-4-difluoromethylthiophenylacetonitrile ( 15 7 g, 0 065 mol) in sodium hydroxide solution ( 50 %, 42 g) and ethylene glycol ( 80 ml) is heated at reflux for 18 hours The reaction mixture is poured into ice water and extracted with ether The alkaline 5 layer is acidified at 15-20 C using concentrated hydrochloric acid and extracted with ether.

The ether extract is washed with water, saturated sodium chloride solution and evaporated to give an oil ( 11 4 g, 83 %) NMR and ir indicate that the -CHF 2 radical has been removed during the reaction and the product is the thiol 10 10 EXAMPLE 8

Preparation of a-Isopropyl-4-difluoromethylthiophenylacetic acid.

Sodium hydroxide ( 18 4 g, 0 46 mol) in 50 ml of water and a-isopropyl-4mercaptophenylacetic acid ( 11 g, 0 05 mol) in 40 ml of dioxane are combined and heated to a temperature of 50 C Chlorodifluoromethane is bubbled in slowly under the surface of the 15 liquid causing an immediate exotherm to 75 C The addition is continued until the exotherm slowly begins to subside (about 0 5 hour) The reaction is cooled to room temperature and treated with 100 ml of ice water The aqueous layer is extracted with 3 x ml of ether, then acidified at 15-20 C with concentrated HC 1 The resulting oil is removed by ether extraction The ether solution is washed with water and saturated sodium 20 chloride before drying over sodium sulfate and evaporation in vacuo to give 10 2 g of a dark brown gum This is used without further purification in the final esterification step.

EXAMPLE 9

Preparation of a-Cyano-m-phenoxybenzyl a-isopropyl-4difluoromethylthiophenylacetate 25 By using a-isopropyl-4-difluoromethylthiophenylacetic acid and procedures of Examples 14 and 15 of the parent specification the product was obtained as an oil.

Analysis calculated for C 26 H 23 F 2 NO 3 S: C, 66 79 %; H, 4 96 %; F, 8 13 %; N, 3 00 %; S, 6.86 % Found: C, 66 58 %; H, 5 13 %; F, 8 02 %; N, 2 87 %; S, 6 95 %.

30 EXAMPLE 10

Preparation of m-Phenoxybenzyl a-isopropyl-4trifluoromethylsulfinylphenylacetate.

A mixture of 10 0 g of m-phenoxybenzyl a-isopropyl-4trifluoromethylthiophenylacetate of Example 6, and 4 1 g of m-chloroperbenzoic acid ( 85 %) are warmed in 100 ml of methylene chloride for several hours The mixture is filtered and the concentrated residue is 35 purified on a silica gel dry column using a 2:1 methylene chloride-hexane mixture The product is collected as a pale yellow oil.

Comparable results are obtained by substituting m-phenoxybenzyl a-ethyl-4trifluoromethylthiophenylacetate or m-phenoxybenzyl a-n-propyl-4trifluoromethylthiophenylacetate to synthesize m-phenoxybenzyl a-ethyl-4 40 trifluoromethylsulfinylphenylacetate and m-phenoxybenzyl a-n-propyl-4trifluoromethylsulfinylphenylacetate, respectively.

EXAMPLE 11

Preparation of a-Cyano-m-phenyoxybenzyl a-ethyl-3difluoromethylsulfonylphenylacetate 45 A mixture of 10 0 g of a-cyano-m-phenoxybenzyl a-ethyl-3difluoromethylthiophenylacetate and 9 0 g of m-chloroperbenzoic acid ( 85 %) are refluxed in 100 ml of ethylene dichloride overnight The mixture, after filtering and concentrating, is purified by dry column chromatography on silica gel using a 2:1 methylene chloride-hexane mixture The product is collected as a yellow oil 50 Comparable results are obtained by substituting a-cyano-m-phenoxybenzyl aisopropyl4-trifluoromethylthiophenylacetate or a-cyano-m-phenoxybenzyl a-n-propyl4trifluoromethylthiophenylacetate to synthesize a-cyano-m-phenoxybenzyl aisopropyl-4trifluoromethylsulfonylphenylacetate and at-cyano-m-phenoxybenzyl a-npropyl-4trifluoromethylsulfonylphenylacetate, respectively 55 EXAMPLE 12

Insecticidal Activity The insecticidal activity of the compounds of this invention is demonstrated in the following tests, wherein Tobacco budworm, Heliothis virescens (Fabricius); Western Potato 60 Leafhopper, Empoasca abrupta (De Long) and Bean Aphid, Aphis fabae (Scopoli), are employed as test insect species Procedures employed are as follows:

Tobacco Budworm, Heliothis virescens (Fabricius).

First Instar A cotton plant with two true leaves expanded is dipped for 3 seconds with agitation in a 65 1 596 903 5.

6 1 596 903 6 test solution ( 35 % water/65 % acetone) containing 300, 100 or 10 ppm of test compound.

Each leaf is placed in a cup with a wick and a piece of cheesecloth infested with 5-100 newly hatched larvae is added before covering the cup with a lid After 3 days at 80 F, 50 % r h, the cups are examined and the kill of newly hatched larvae noted Data obtained are reported as percent killed in Table I 5 Bean Aphid, Aphis fabae (Scopoli).

Five cm fiber pots, each containing a nasturtium plant 2 inches high and infested with 100 to 150 aphids 2 days earlier are placed on a 4 rpm turntable and sprayed with a 35 % water/65 % acetone solution containing 100, 10, 1 0 and 0 1 ppm of test compound for two 10 revolutions using a "De Vilbiss" (registered Trade Mark) Atomizer and 20 psi air pressure.

The spray tip is held about 15 cm from the plants and the spray directed so as to give complete coverage of the aphids and the plants The sprayed plants are laid on their sides on white enamel trays Mortality estimates are made after one day at 70 F, 50 % r h.

Data are reported as percent mortality determined at the rate indicated (Table I) 15 Western Potato Leafhopper, Empoasca abrupta (De Long) A Sieva lima bean plant with the primary leaf expanded to 3 to 4 inches is dipped into a % water/65 % acetone solution containing 100, 10 or 1 ppm of test compound The dipped plant is placed in the hood to dry and then a 2 5 cm piece of the tip of one leaf is cut 20 off and placed in a 4-inch petri dish with a moist filter paper in the bottom From 3 to 10 second-instar nymphs are placed in the dish and the dish is then covered Mortality counts are made after holding the thus-prepared dishes for 2 days at 80 F and 50 % r h Data obtained are reported in Table I In these tests, permethrin is used as a standard or check.

1 596 903 TABLE 1 % Mortality Tobacco Budworm Larvae 1st instar 300 100 10 ppm ppm ppm Leafhopper 10 1 ppm ppm ppm Aphids 10 1 0 1 ppm ppm ppm ppm 61 to 100 70 100 t J^ \ O 100 80 71 0 to to 85 40 0 100 50 = Not Tested.

Compound 8 1 596 903 8 EXAMPLE 13

Insecticidal Activity.

The insecticidal activity of the compounds of the present invention is further demonstrated by the following tests.

The procedures employed for evaluation against mosquito larvae, Mexican Bean Bettles 5 and Southern Armyworms are as follows:

Malaria Mosquito, Anopheles quadrimaculatus (Say).

One milliliter of a 35 % water/65 % acetone solution containing 300 ppm of test compound is pipetted in a 400 ml beaker containing 250 ml of deionized water and stirred 10 with the pipette, giving a concentration of 1 2 ppm Aliquots of this solution are taken and further diluted to 0 4, 0 04 and 0 004 ppm A wax paper ring 0 6 cm wide to fit inside the beaker is floated on the surface of the test solution to keep the eggs from floating up the meniscus curve and drying out on the side of the glass A spoon made of screen is used to scoop up and transfer about 100 eggs ( 0-24 hours old) into the test beaker After 2 days at 15 'F, 50 % r h, observations of hatching are made Percent mortality records are presented in Table II.

Mexican Bean Beetle, Epilachna varivestis (Mulsant).

Sieva lima bean plants ( 2 per pot) with primary leaves 7 5 to 10 cm long, are dipped in the 20 30, 100, 10 or 1 ppm test solution and set in the hood to dry One leaf is removed from the plant and placed in a 10 cm petri dish containing a moist filter paper on the bottom and 10 last-instar larvae ( 13 days from hatching) The day after treatment, another leaf is removed from the plant and fed to the larvae after removing the remains of the original leaf Two days after treatment, the third leaf is fed to the larvae, this usually being the last needed 25 The fourth leaf is used on the third day after treatment if the larvae have not finished feeding The test is now set aside and held until adults have emerged, usually in about 9 days after treatment began After emergence is complete, each dish is examined for dead larvae, pupae or adults; deformed pupae or adults; larval-pupal intermediates or pupal-adult intermediates; or any other interference with normal molting, transformation 30 and emergence of pupae or adults.

Data obtained are reported in Table 11.

Southern Armyworm, Spodoptera eridania (Cramer).

Methods: 35 Sieva lima been plants, with two expanded 7 5 to 10 cm primary leaves, are dipped three seconds with agitation in the treatment solutions and then set in a hood to dry After the leaves are dry they are excised and each excised leaf is placed in a 10 cm petri dish containing a piece of moist filter paper and 10 third-instar southern armyworm larvae approximately 1 cm long The petri dishes are covered and placed in a holding room for 2 40 days at a temperature of 80 'F and 50 % relative humidity.

Mortality counts are made after 2 days Results obtained are presented in Table II.

1 596 903 TABLE 11

Mosquito Larvae 1.2 0 4 0 04 0 004 ppm ppm ppm ppm % Mortality Southern Armyworm Mexican Bean Bettle 1000 100 10 300 100 10 1 ppm ppm Pm ppm pp ppm ppm ppm ppm ppm ppm ppm CN 86 1 to F 3 CS HM-WO-U-CH 100 100 99 CH (CH 3)2 86 to 99 86 to 100 0 90 0 100 100 100 90= Not Tested.

\ O Compound L' 0 \ w,0 ui 1 596 903 EXAMPLE 14

Insecticidal Activity Two-Spotted Spider Mite, Tetranchus urticae (Koch).

Sieva lima bean plants, with primary leaves three 7 5 to 10 cm long, are infested with about 100 adult phosphate-resistant mites per leaf 4 hours before use in this test, in order to 5 allow egg laying before treatment The infested plants are dipped for 3 seconds with agitation into the 1000, 300, 100 or 10 ppm solution, and the plants set in the hood to dry.

After 2 days at 80 F, the adult mite mortality is estimated on one leaf under a 10 X stereoscopic microscope The other leaf is left on the plant an additional 5 days and then examined at l OX power to estimate the kill of eggs and of newly hatched nymphs, giving a 10 measure of ovicidal and residual action, respectively Test results are provided in Table III.

Tobacco Budworm, Heliothis virescens (Fabricus).

Third Instar Three cotton plants with just expanded cotyledons are dipped in 1000 or 100 ppm 15 solution and placed in the hood to dry When dry, each cotyledon is cut in half, and 10 leaf sections are each placed in a 28 g plastic medicine cup containing a 1 25 cm dental wick saturated with water and one third-instar budworm larva is added The cup is capped and held for 3 days at 80 F, 50 % r h, after which mortality counts are made Test results are provided in Table 111 20 Cabbage Looper, Trichoplusia ni (Huibner).

Third Instar A true leaf on a cotton plant is dipped into the test solution containing 1000, 100 or 10 ppm of test compound, agitated for 3 seconds, and removed to dry in an exhaust hood 25 When dry, the leaf is placed in a 9 0 cm petri dish with moist filter paper on the bottom Ten third-instar larvae are added and the lid placed on the dish Mortality counts are made after 3 days at 80 F and 50 + 10 % r h.

Data obtained are reported in Table III below.

TABLE Ill % Mortality 3rd Instar 3rd Instar Tobacco Budworm Cabbage Looper Phosphate Resistant Mites Compound 1000 300 100 10 pp In ppm pp In pp In 1000 100 10 ppm pprn ppni 1000 100 ppm pp In 100 100 100 100 L 4 \ 10 a C) W F 2 CHS- CH-M-01 Di (CH 3)2 100 100 O 20 = Not Tested.

N 1 F 3 CS- CH-CD-O-CH-( -0- ( 1 CH (CH 3 )2 12 1 596 903 12 EXAMPLE 15

Ixodicidal Activity.

Effective control of acarina larvae is demonstrated in the following tests with larvae of Boophilus microplus, a one-host tick which can remain on a single host through its three life stages; i e, larvae, nymph and adult In these tests, a 10 % acetone/90 % water mixture 5 contains 100 ppm of test compound Twenty ( 20) larvae are enclosed in a pipette sealed at one end with a gauze material and solution containing the test compound is then drawn through the pipette with a vacuum hose, thereby simulating a spray system The ticks are then held for 48 hours at room temperature and mortality is determined The results achieved are set forth below 10 TABLE V

Percent Mortality of Boophilus microplus Larvae 15 15 Compound 100 ppm CN F 2 g 1 HC) i O _ 20 CH-CO-O-CH O O wel (%)1 2 25

Claims (1)

1. WHAT WE CLAIM IS:-

   1 A compound having the formula:

   30 Rffi 2 Xe 1 WCO-O-CHH O RCF 2 X "'0 J R 2 R 3 35 wherein the substituent RCF 2 X is meta or para to the carbon to which the alkanoic acid ester group is attached, and X is S, SO or SO 2, R is H, F, Cl, CHF 2 or CF 3; R 2 is ethyl, n-propyl, isopropyl, t-butyl or isopropenyl; and R 3 is hydrogen or cyano.

   2 A compound according to Claim 1, wherein R is H or F; X is S; and R 2 is ethyl, 40 isopropyl or n-propyl; and R 3 is hydrogen or cyano.

   3 A compound according to Claim 1, a-cyano-m-phenoxybenzyl a-isopropyl-4trifluoromethylthiophenylacetate.

   4 A compound according to Claim 1, a-cyano-m-phenoxybenzyl a-isopropyl-4difluoromethylthiophenylacetate 45 A method for controlling insects or acarina, comprising contacting the insects or acarina, or their habitat, breeding grounds or feed, with an insecticidally or acaricidally effective amount of a compound according to any preceding claim.

   6 A method for the systemic control of insects and acarina that feed on the body fluids of livestock and domestic animals comprising, orally or parenterally administering to the 50 animal host a systemically effective amount of a compound according to any one of Claims 1 to 4.

   7 A method for the preparation of a compound having the formula:

   55 CH-O-fl-CH ( RC 2 X&I I 1 I 1 R 3 60 wherein the RCF 2 X substituent is meta or para to the carbon to which the alkanoic acid ester group is attached, and X, R; R 2 and R 3 are as defined in Claim 1; comprising treating a compound having the structure: 65 1 596 903 13 1 596 903 13 WH-COA RCF 2 X R 2 5 where A is halogen and R and R 2 are as defined above; with a mphenoxybenzyl alcohol having the formula: 10 1 15 R 3 where R 3 is as defined above, in the presence of a tertiary organic amine acid acceptor and an inert organic solvent at a temperature of from 10 C to 30 C 20 8 An insecticidal composition comprising a compound according to any one of Claims 1 to 4, and a carrier therefor.

   9 A composition according to Claim 8, for oral or parenteral administration to livestock or domestic animals, wherein the carrier is a pharmaceutically acceptable carrier.

   10 A composition according to Claim 8 for use in a method according to Claim 5, 25 wherein the carrier is a liquid and the composition also comprises an emulsifying agent and a surfactant.

   11 A compound according to Claim 1 and substantially as described in any one of Examples 5, 6, 9, 10 or 11 herein.

   12 A method for the preparation of a compound according to Claim 1, substantially as 30 described in any one of Examples 5, 6, 9, 10 or 11 herein.

   13 A compound according to Claim 1, whenever prepared by a method according to Claim 7 or Claim 12.

   14 A method for controlling insects or acarina, according to Claim 5 and substantially as described in any one of Examples 12 to 15 herein 35 An insecticidal composition, according to Claim 8 and substantially as hereinbefore described.

   TREGEAR, THIEMANN & BLEACH, Chartered Patent Agents, 40 Enterprise House, Isambard Brunel Road, Portsmouth, PO 1 2 AN.

   and 49/51, Bedford Row, 45 London, WC 1 V 6 RL.

   Printed for Her Majesty's Stationery Office, by Croydon Printing Company Limited, Croydon Surrey 1981.

   Published by The Patent Office, 25 Southampton Buildings London, WC 2 A l AY from which copies may be obtained.