CA1157771A - Insecticidal compositions - Google Patents

Abstract

Abstract:
The invention relates to insecticidal compositions comprising: (A) compound of the general formula I

wherein R1 is hydrogen or a methoxy, ethoxy, propoxy, butoxy, tetrafluoroethoxy, methylthio, ethylthio, propyl-thio, fluoro, chloro, bromo, methyl, ethyl, or nitro group, and R2 is hydrogen or a methyl group, or R1 and R2 together form a methylenedioxy group, R3 is one of the following groups (a) to (f) :- (a) 3-phenoxybenzyl (b) 2-benzyl-4-furylmethyl (c) n-cyano-3-phenoxybenzyl (d) 3,4-methylenedioxybenzyl (e) .alpha.-ethynyl-3-phenoxybenzyl (f) .alpha.-cyano-3-(4'-chlorophenoxy)-benzyl and Y1,Y2, Y3,Y4,Y5, and Y6 are the same or different groups and each is hydrogen or a fluoro, bromo or chloro group, with the proviso that R1 is hydrogen, fluoro, chloro, bromo or methyl and R2 is hydrogen or methyl, then at least one Y1 to Y6 is other than hydrogen;
and (B) at least one synergist or potentiating agent of the class of microsomal oxidase inhibitors. These ingredients are incorporated into a suitable inert liquid or solid carrier.

Description

Insecticidal compositions This invention relates to new insecticidal compositions containing certain novel compounds.
Throughout this specification, where the context permits, the word "insect" is used in its broad common S usage and includes spiders, mites, nematodes and other pests which are not classed as insects in the strict biological sense. Thus the term implies reference not only to those small invertebrate animals belonging mostly to the class Insecta, comprising six-legged, usually winged forms, such as beetles, bugs, flies and the like, but also to other allied classes of arthropods whose members are wingless and usually have more than six legs, such as spiders, wood lice and the like, and expecially to the order Acaridae which includes the mites and ticks.
The words n insecticide" and n insecticidal" are similarly used.
According to the invention there is provided insecticidal compositions comprising one or more of the compounds of formula I

~ CooR3 Y
Rl ~ 1 C y2 l l I
y6_ C- C - Y3 Y Y

wherein Rl is hydrogen or a methoxy, ethoxy, propoxy, butoxy, tetrafluoroethoxy, methylthio, ethylthio, propyl-thio, fluoro, chloro, bromo, methyl, ethyl, or nitro group, and R2 is hydrogen or a methyl group, or Rl and R2 together form a methylenedioxy group;
R3 is one of the following groups (a) to (f):-(a) ~
CH2 ~
0~

(b) O

( C ) .

CN

(d) ~ ~CH2 CH2 ~

~e) C--C~O ~

- CH ~~~ O ~

I ~ \ ~ Cl and yl y2 y3 y4 Y5 and y6 are the same or different groups and each is hydrogen or a fluoro, bromo or chloro group, with the proviso that when Rl is hydrogen, fluoro, chloro, bromo or methyl and R2 is hydrogen or methyl, then at least one of yl to y6 is other than hydrogen; said compound(s) being incorpor-ated in a suitable inert liquid or solid carrier, and additionally containing at least one synergistic or potentiating agent of the class of microsomal oxidase inhibitors.
Our related application 318,086 filed on December 18, 1978, of which the present application is a division, claims the compounds of formula I (and the related free acid and lower alkyl esters) by themselves i.e. in the absence of any synergistic agent, as these compounds are novel.
Known compounds which can be regarded as related to the said novel compounds are those in which the groups (a) to (f) are present as esterifying groups with chrysanthe-mic acid in commercial or experimental pyrethroids. Our Australian Patent No. 502,950 describes and claims a similar class of esters.
West German Patent Specification D~-OS 27 33 740 descri~es compounds of the formula I in which all of the groups yl to y6 are hydrogen, Rl and R2 are each hydrogen, or a fluoro, chloro, bromo or methyl group and R3 is one of the groups (a), (c) and (e) above. Such compounds are excluded from the present invention.
In the compositions of this invention it is prefer-able to employ compounds of formula I in which Rl is a ~ 1~7771 methoxy, ethoxy or propoxy group and R2 is hydrogen.
Compounds in which Rl and R2 form the methylenedioxy group are also preferred.
Preferably also, R3 is one of groups (a), (c) and (e) as defined above.
It is also preferred that from one to all six of the groups yl to y6 is a fluoro group, the remainder (if any) being hydrogen. Tetrafluoro-substitution (yl, y2 Y3, Y4 = F; y5, y6 = H) is especially preferred.
Specifically preferred compounds for use in the compositions of the invention are as follows:-3'-phenoxybenzyl 1-(3,4-methylenedioxyphenyl)-

2,2,3,3-tetrafluorocyclobutanecarboxylate, and its 'a-cyano and -ethynyl derivatives; 3'-phenoxybenzyl 1-(4-ethoxy-phenyl)-2,2,3,3-tetrafluorocyclobutane carboxylate, and its a-CyanO and ~-ethynyl derivatives.
The compounds of formula I are in themselves extremely active insecticides, having an insecticidal activity an order of magnitude greater than most known insecticides. These compounds also possess the property of contact repellency to insects, and are generally more active against flies than the compounds of our afore-mentioned Australian patent.
However, the compounds of formula (I) are unex-pectedly further improved in insecticidal activity whencombined with certain other substances found to have a synergistic or potentiating action. Such substances are of the class of microsomal oxidase inhibitors i.e., they inhibit the detoxification of insecticides in insects produced by the action of oxidative enzymes. Typical substances of this type are the pyrethrin synergists of which the following are examples:-- 5 _ ) 157771 Common Name Chemical Name Piperonyl butoxide ~[2-(2-butoxyethoxy)etllo~y]-4,5-methylenedioxy-2-propyl-toluene Piperonyl cyclonene 3-he~yl-5(3,4-methylenedioxy-phenyl)-2-cyclohexanone "Se~oxane" (Sesame~) 2-(3,4-methylenedioxy-phenoxy)-

3,fi,9-trioxaundecane "S~lfoxide" 1,2-(methylenedioxy)-4-[2-ln (octylsulfinyl)propyll-benzene n-Propyl isome dipropyl-5,6,7,8-tetrahydro-7-methylnaphtho-~2,3-dl-1, 3-dioxole-5,6-dicarboxylate ("Sesoxane", "Sesam~x~ and "Sulphoxide" are Registered Trade Marks).
We have found that 'Sesoxane' (made by Shulton Inc., Clifton, N.J., U.S.A.) is particularly useful as a potentiator. The amount of 'Seso~ane' used may vary from l/lOOOth to five times the wei~ht of the compound I,the preferred range being ~rom about l/lOOth to an equal part by ~-eight. Piperonyl butoxide also is a useful potentiator in similar amounts.
The compounds of formula I are optically active and can be resolved into their optical isomers by conventional methods. ~ither the individual (+) and (-) optical isomers of the compounds or the racemic (+) forms can be employed, although it should also be noted that the insecticidal activities of the optical isomers of the compounds I may differ by an order of magnitude or more.
The compounds I may be prepared by esterification of the free acid (formula I, R3 = H) with the appropriate alcohol R30H, where R3 is one of the groups (a) to (f). Such esterification may be carried out by any suitable known method, e.g., by direct reaction or by prior conversion of the acid and/or the alcohol to a suitable reactive derivative, or by an ester interchange reaction between the alcohol R30H (R3 =
(a) to (f)) and a lower alkyl ester of the acid.
The acid (formula I, R3 = H) is prepared by the reaction of an appropriately substituted benzyl compound 40 with an appropriately substituted 1,3-dihalopropane to form a l-phenylcyclobutane compo~nd which can be l 1S7771 hydrolysed to the acid. This reaction scheme is as follows: R2 >~
Ph = Rl ~
yl y3 yS z yl Ph-CH2Z + X- C - C - C X ~ Ph - C - C y2 y2 y4 y6 y6 _ C - C - y3 ~/~ydro/lysis COOH yl Ph - C - C y2 y6 _ 1 - C y3 y5 y4 where Z represents a group which activates the benzylic methylene and is itself later hydrolysable to a carboxyl group, e.g., -C-N or -COOEt; X represents a chloro, bromo i d p Rl R2 yl y2, y3~ y4, yS and y6 are as defined above.
An alternative method of preparation of the acid (formula I, R3 = H) as its lower alkyl ester is by addition of the olerin YlY2C CY Y to the substituted phenylacrylic ester of formula II
R\
~\
Rl ~ C COOR II

y6 \y5 ~ 157771 where R is a lower alkyl group and R , R , yl~ y , y , y4, Y5 and y6 are as defined above.
Esters of formula I (R = lower alkyl) wherein 3 y4 F and yl = y2 = yS = y~ = H can be made by first preparing the compounds wherein Y3 = Y4 = F, yl = y = Cl according to the preceding method (using dichloro-difluoroethylene) and then hydrogenating the product to replace the chlorine groups by hydrogen. -The esters II wherein y5 = y6 = H may be obtained according to the following general procedure:(1) A lower alkyl ester of the appropriately substituted phenylacetic acid (V) is condensed with a di(lower alkyl) oxalate in the presence of a basic catalyst, to produce an enolate salt (IV).
(2) The solution of the enolate salt is acidified to give the corresponding phenyloxaloacetate (III).
(3) The compound III is reacted with formaldehyde under alkaline conditions to give the phenyl hydroxymethyl acetate which on dehydration (sometimes spontaneously) yields the phenylacrylic ester (II).
This reaction sequence is illustrated in the following overall reaction scheme. It will be appreciated that the specific acids and bases indicated may be replaced by other suitable compounds. Also lower alkyl esters, other than the ethyl esters shown may be employed.

Ph-Cl~2-CEt EtO-CO-CO-OEt Ph-CH-COOEt NaOET
~ OET
C (IV) ¦ ONa COOEt Ph-CH-COOEt Ph-CH-COOEt CO HCHO/K2C03 l H2 COOEt OH

(III) ~~

5 Ph-C-COOEt CH2 (II R=Et, y5 = y6 = H) When y5 = y6 = F, the esters II can be made according to the method described by D.G. Naae and D.J.
Burton, Synthetic Communications, 3, 197-200 (1973) .
In this method the appropriate phenvl keto ester of formula VI is reacted with dibromodifluoromethane (CBr2F2) in the presence of 2 moles of tris (dimethylamino)phosphine and a suitable solvent such as diglyme or triglyme I ~S7771 Ph - C - COOR + CF2Br2 ~ Ph - C - COOR
Il 11 VI II (yS = y6 = F

where Ph is as defined above and R is a lower alkyl group.
The general approach to formation of the esters S of the invention is as follows:-* A - COOEt ~ j A - COOH
A - Coo~{ ~ A - COCl A -- COCl + R OH > A - CoOR3 where A is R yl Rl ~ y2 y6 1 I y3 y5 y4 Rl R2 R3 yl y2 y3 y4 Y5 and y6 are as defined above.
Alternatively the ethyl ester can be directly converted as follows:-A - COOEt + R30H ~ A - CoOR3 + EtOH
The compositions described herein may be in liquid or solid form. Useful liquid compositions, which may be incorporated, for example, into aerosol-type dispersions with the usual propellants, may be made by dissolving the insecticidal compound(s) of Formula I and the chosen synergist in a suitable organic solvent, or mixture of solvents, to form solutions or by dispersing such organic solvent solutions in water to form aqueous suspensions.
Useful solid compositions may include inert solid diluents or carriers in addition to the active in-gredients. Such compositions may also include other ,, substances such as wetting, dispersing or sticking agents, and may be prepared in granular or other forms to provide slow release of the compounds over an extended period of time. The compositions may contain other insecticides such as pyrethrum, rotenone, or with fungicidal or bacter-icidal agents, to provide compositions useful for household and agricultural dusts and sprays, textile coating and impregnation, and the like.
The preparation and properties of the compositions Of the invention are illustrated by the following specific examples. It should be noted, of course, that these Examples are intended to be illustrative of the methods and procedures utilized in preparing the compositions and the constituents employed therein and that they are not intended to be restrictive of the invention.
Examples 1 to 20 illustrate the preparation of the compounds of formula I and related compounds, and Examples 21 and 22 show the effects of the compositions of this invention compared to the compounds of formula I above.
EX~lPLE 1 (Prior Art Compound) (a) l~ chlorophenyl)cyclobutane nitrile

4-Chloroben~yl cyanide (10 g) in dry DMS0 (20 ml) was added over 5 min to a stirred suspension of sodium hydrid~ (4.4 g) in DI~lSO at 25C under argon. The mixture was stirred for 30 minu~es then a solution of 1,3-dibromopropane (27 q) in dry DMSO (50 ml) was added over 30 minutes while maintaining the tem~erature of the reaction mixture at 25-30C. After stirring an additional ~0 minutes at this temperature the reaction 3~ mixture was added to ice water (500 ml) and extracted ~ith dic;~lorolrethane ~3 x 75 ml). The e.;tracts were evaporated and the residue extracted with diethyl ether ~4 x 50 ml). The ether extracts were washed with water, dri~d over anhydrous sodium sulphate and evaporated to yield an oil (lO.8 g) which on distillation gave the nitrile lbP 90/10 Torr.] yield 5.4 g (43~

Analysis: C 68.48~ H 5.49~ Cl 18.3%. CllHloCl N
requires: C 68.93~ H 5.26~ Cl 18.5%.

(b) 1-(4-chlorophenyl)cyclobutane carboxylic acid 1-(4-chlorophenyl)cyclobutane nitrile (5 g) was mixed with ethylene glycol (60 ml~ and 40% w/w aqueous potassium hydroxide solution (80 ml) and refluxed under argon for 18 hours. The mixture was cooled, added to ice water and extracted with diethyl ether. The aqueous layer was acidified and the precipitate was filtered off, washed with water, dried and recrystallised from petroleum ether (b.p. 40 - 60) to give the acid as white needles mp 88 - 9 , yield 4.5 g (82%). Analysis:
C 62.70~ H 5.14% Cl 16.5% O 15.2~. CllH11C1O2 requires:
C 62.72% H 5.26~ Cl 16.83% o 15.2%.

(c) 3'-phenoxybenzyl 1-(4-chlorophenyl)cyclobutane-carboxylate 1-(4-Chlorophenyl)cyclobutane carboxylic acid (1 g) was dissolved in thionyl chloride (1 ml) and heated at reflux for 40 minutes. Excess thionyl chloride was removed in vacuo and the residue was taken up in petroleum eth~r 40 - 60 (40 ml) and added over 15 minutes to a stirred mixture of 3-phenoxybenzyl alcohol (1.1 g), pyridine (1 ml), benzene (50 ml) and petroleum ether 40 - 60 (50 ml) maintained at 10C. The mixture was stirred at 20 - 25C for 3 hours then added to ice water, washed with 0.5M hydrochloric acid, water, dilut2 sodium bicarbonate solution and dried over anhydrous sodium sulphate. The solvent was evaporated to give an oil (2.3 g) which a~ter chromatography on silica gel, eluting with benzene/petroleum ether, gave the ester 1.52 g (82~).
Analysis: C 72.87% H 5.30% Cl 9.2% o 12.1~
C24H21 C103 requires: C 73.37% H 5.39% Cl 9.0% O 12.2%.

EX~MPLE 2 (a) 1-(4-ethoYyphenyl-)cyclobutane -carboxylic acid Ethyl 4-ethoxyphenylacetate (14 g) in anhydrous diethyl ether (20 ml) was added to a stirred suspension of sodamide (5.3 g) in liquid ammonia (400 ml) over 3 minutes and the mixture stirred for an additional 20 minutes. 1,3-dibromopropane (14 g) in diethyl ether (10 ml) was added over 20 minutes and the mixture stirred for 17 hours. 50 ml of saturated ammonium chloride solution was added and the reaction mixture extracted with diethyl ether. Evaporation of the solvent gave a residue (17.4 g) which after chromatography on silica gel by eluting with benzene/chloroform gave an oil (7.2 g). The oil was dissolved in ethanol (50 ml) and 10% sodium hydroxide solution (50 ml) was added.
The mixture was refluxed for 3 hours, cooled, added to ice water and extracted with diethyl ether. The aqueous layer was acidified and the precipitate was filtered off, washed with water, dried and recrystallised from petroleum ether 40 - 60 to give the acid 5.2g (35%) mp 90-1C.
- Analysis: C 71.04~, H 7.23% O 22.0~ C13H16O3 requires C 70.89% H 7.32~ o 21.8%.

(b) 3'-phenoxybenzyl 1-(4~ethoxyphenyl)cyclobutane carboxylate 1-(4-ethoxyphenyl)cyclobutane carboxylic acid (1 g) was refluxed in thionyl chloride (1 ml) for 30 minutes and the excess thlonyl chloride removed in vacuo. Th~
residue was taken up in petroleum ether 40-60 (25 ml) and added over 5 minutes to a stirred mixture of 3-phenoxybenzyl alcohol (l.lg) pyridine (1 ml) benzene (25 ml) and petroleum ether 40-60~ (25 ml) at 15C. The mixture was stirred at 15C for 3 hours, then added to ice water and extracted with diethyl ether. The extract -was washed with water, 0.5M hydrochloric acid, and sodium bicarbonate solution then dried over anhydrous sodium sulphate and the solvent removed to give an oil (2.1 g).
Chromatography on silica gel, eluting with benzene, gave S the ester 1.5g (82%).
Analysis: C 77.55% H 6.65~ O 16.0% C26H26O4 requires - C 77.59% H 6.51% O 15.9%.

(a) 2-(4-ethoxyphenyl)propenoic acid ethyl ester.
-This part of the example shows the general method of forming the 2-aryl-acrylic acid esters. (Formula II) Alcohol-free sodium ethoxide freshly prepared from sodium (13.9g) and excess ethanol was slurried in dry ben~ene (200 ml). To this suspension diethyl oxalate (88.5g) was added over 15 minutes. Ethyl-p-ethoxyphen~lacetate (V) (114.2g) was added to the resulting clear yellow solution over 30 minutes at roo~
temperature. After a further 1 hour period the reaction mixture solidified. The solid, sodium diethyl-2-p-ethoxyphenyl-3-ethoxy-3-oxido-oxaloacetate (IV) was triturated and washed well with ether. The combined ether washings were evaporated to a small volume to obtain a second crop of the salt.
The combined yield was 227.4g.
The sodium salt was acidified by adding it in portions to a well stirred emulsion of equal parts of diethyl ether and dilute acetic acid (approximately 10%).
~fter separation the ether layer wi~s washed with water and dilute sodium bicarbonate solution, and dried with anhydrous sodiwn sulphate. After evaporation of the ether, the resulting oil was crystallized from petroleum ether (b.p. 60 - 80), to yield diethyl-2-p-ethoxyphenyl-oxaloacetate (III) 143.8g (85~), m.p. 59 - 60 .
The keto-ester III (1~3.8g) was stirred in dilute formaldehyde solution (62 ml 37~ formald~hyde + water ~ 157771 220 ml) and to the suspension potassium carbonate solution (54.5g, in water 280 ml~ was added aropwise. At the end of the addition, ether was added to the stirred suspension to dissolve the gummy precipitate which formed and after an additional lS minutes, gas evolution commenced. When this gas evolution ceased (after about 2 hours) the reaction mixture was extracted with additional ether and the combined ether extracts were washed with water and evaporated after drying with Na2SO4. The yield of the ethyl 2-(4-ethoxyphenyl) propenoate (ii~ (isolated as a yellow oil) was 97.8g (79.8~).

~b) ~Ethyl 1-(4-ethoxyphenyl)-2,-2,3,3-tetrafluorocyclo-butane carboxylate 2-(4-ethoxyphenyl)propenoic acid ethyl ester (13.2 g) was mixed with benzene (7.5 ml), a-pinene (2 drops) N-ethyldiisopropyl amine (2 drops) and tetrafluoroethylene (15.5 ml) and heated to 150-155 for 24 hours then 155-60C for 17 hours. After evaporation of volatile materials the residue (16.6 g) was dissolved in dichloro-methane and chromatographed on a column of silica gel to give the ester as a colourless oil 14.5g (75~). Analysis:
C 56.47%, H 5.24%, F 23.4~. ClSH16F4O3 requires C 56.25%, H 5.04~, F. 23.7%.

(c) 1-(4-ethoxypheny~-2,2,3,3-tetrafluorocyclobutane carboxvlic acid Ethyl 1-(4-ethoxyphenyl)-2,2,3,3-tetra~luorocyclobutane carboxylate (14.5 ~) was dissolved in ethanol (100 ml) and a 10% w/w solution of sodium hydroxide in water (100 ml) was added and the mixture refluxed for 2.5 hours. The mixture was cooled, added to ice water and extracted with diethyl ether. The aqueous layer was l 157771 acidified and the precipitate was filtered off, washed with water, dried and crystallised from 6Q - 80 petroleum ether to give the aci~d mp 112-3C. Yield 11.2g (85~!. Analysis: C 53.20~ H 4.22%, F 25.9%.
C13H12F4O3 requires C 53.43~ H 4.14% F 26.0%.

(d) 3'phenoxybenzyl 1-(4-ethoxyphenyl)-2,2,3,3-tetra-fluorocyclobutane-carboxylate 1-(4-ethoxyphenyl)-2,2,3,3-tetrafluorocyclo~utane carboxylic acid (0.9 g~ was refluxed with thionyl chloride (1 ml) for 45 minutes and the excess thionyl chloride was removed in vacuo. The residue was dissolved in petroleum ether 40-60 (40 ml) and added over 5 minutes to a mixture of 3-phenoxybenzyl alcohol (1 g), pyridine (1 ml~, benzene (25 ml), and petroleum ether 40 - 60 (25 ml) maintained at 20C. The mixture was stirred for 3 hours then added to ice water and extracted with diethyl ether. The extract was washed with water, O.SM hydrochloric acid, and sodium bicarbonate solution, dried over anhydrous sodium sulphate and the solvent evaporated to give an oil t2 g). Chromatography on silica gel by eluting with benzene gave the ester 1.2 g (82%). Analysis: C 65.45%, H 4.84~ F 16.0%. C26H22F44 requires C 65.82%, H 4.67~, F 16.0%.

EX~PLE 4 (a) (-) Enantiomer of 1-(4-ethoxyphenyl)-2,2,3,3-tetrafluorocyclob~a'ana carboxylic acid ~+~-(l-naphthyl)ethylamine was added to a solution of the racemic acid (2g) (prepared as in Example 3(C)) in ethyl acetate (75 ml~ and n-hexane. The salt which formed was crystallized four times ~rom ethyl acetate at room - temperature. The (+)(-) salt was decomposed with hydrochloric aci~d (lM) and the residue recrystallized twice from ethanol. The (-) acid which had ~20 =-118.2 and m.p. 194C was obtained in 15~ yield.

.. . .. .. . ..
(b) (-) 3'-PhenoXybenzyl 1-(4-ethoxyphenyl)-2,2,3,3-tetrafluorocyclobutane carboxylate The resolved (-) acid, 0.2 g., was refluxed in thionyl-chloride (1 ml) for one hour. After evaporation of excess thionyl chloride, the residue was dissolved in petroleum ether (b.p. 60 - 80) and added to 3-phenoxy-benzyl alcohol (0.139g) and pyridine (0.238g) in benzene (3 ml) and petroleum ether (3 ml). The reaction mixture was stirred overnight, quenched with ice-water, washed with water and the solvent layer separated and dried over molecular sieve. After evaporation of the solvent the pure ester was obtained as a viscous liquid by chromato-graphy in silica gel using methylene chloride as theeluent. Yield 99.1~, 20 = -58.2.

EXAMPL~ 5 (a) 1-(3,4-methylenedioxyphenyl)-2,2,3,3-tetra~luoro-cyclobutane carboxylic acid A mixture of ethyl 2-(3,4-methylene dioxyphenyl) propenoate (2.2 g), tetrafluoroethylene (5 ml.), a-pinene (1 drop), N-ethyldiisopropylamine (1 drop) and benzene (10 ml), was heated at 150 - 155C for 24 hours then at 160 - 165C
for 16 hours, then cooled. The solvent was evaporated to leav~ an oil (3.0 g). This oil was purified by chromatography on silica gel using benzene as eluent to give 1.4 g (44%) of ethyl 1-(3,4-methylene dioxyphenyl)-2,2,3,3-tetrafluorocyclobutane carboxylate.

The ethyl ester was hydrolysed by refluxing for 2 hours - 30 with a mixture of potassium hydroxide (5 g), water (50 ml) and cthanol (50 ml). The ethanol was removed by evaporation and the aqueous residue extracted with diethyl ether. The aqueous layer was acidified and the precipitate filtered off, dried and recrystallized from petroleum spirit (b.p. 60 - 80)/ diethyl ether to yield 0.9 g of the acid as white crystals m.p. 168-9 C.
Analysis: C 49.62%, H 2.72~, F 25.8%.
C12~l8F4O4 requires 49.33%, H 2.76~, F 26.o%.

(b) 3'phenoxybenzyl 1-(3,4-methylenedioxyphenyl)-2,2,3,3-tetrafl~orocyclobutane carboxylate.

.
The acid prepared in Example 5(a) (0.5g) was mixed with thionyl chloride (1 ml) and refluxed for 45 minutes.
Excess thionylchloride was removed under vacuum. The residue was dissolved in petroleum spirit (b.p. 40-60) (5 ml), and added over 5 minutes to a stirred mixture of 3-phenoxybenzylalcohol (0.4 g), pyridine (0.5 ml), benzene ~15 ml) and petroleum spirit (b.p. 40 - 60) (15 ml). After overnight stirring at room temperature the mixture was added to ice water and extracted with diethyl ether. The ether extract was washed with dilute hydrochloric acid, water, sodium bicarbonate solution and dried over anhydrous sodium sulphate. Evaporation of the ether left an oily residue (0.78 9) which was purified by chromatography on silica gel with benzene as eluent to yield 0.7 g of the 3-phenoxy benzyl ester as a clear yellow oil.
Analysis: C 63.54~, H 4.01%, F 15.9%.
C25H18F4~5 requires C 63.30(~ l 3.82~, F 16.C~.

EXAMPLES 6 to 20 .

Using the general method set out in Example 3, the compounds listed in Table 1 were obtained from the appropriate starting materials.

l lS7771 Analysis,spectra and other characterising data were consistent with the stated structures.
Table 1 includes the compounds of Examples 1, 2, 3, 4 and 5 for ease of reference.

_ _ Example Rl R2 yl y2 y3 y4 y5 y6 ~3 No.
.
1 Cl H H H H H H H - (a) 2 C2H5 H H H H H H H (a) 3 C2H50 H F F F F H H (a) 4 C2H50 H F F F F H H ~a) -0-CH2-0- F F F F H H (a) 6 CHF2cF2-o- H F F F F H H (a) 7 C2H50 H F F F F H H (c) 8 Cl H F F F F H H (b) 9 C2H50 H F F F F H H (d) C2H50 H F F F F H H (b) 11 Cl H F F F F H H (a) 12 CH30 H F F F F H H (a) 13 -0-CH2-0- F F F F H H (c) 14 C2H50 H F F F F H H (f ) Cl H F F F F H H (c) 16 C2H50 H H H F F H H (c) 17 C2H50 H H F F F H H (c) 18 Cl H F Cl F F H H (c) 19 Cl H F F F F H H (e) C2H50 H Cl Cl F F H H (c) 21 F H F F F F H H (e) 22 C2H50 H F F F F F F (e) Note* The compound of Example 4 is the R(-) optical isomer of the compound of Example 3.

EXAMPLE ~1 The biological activity of the new cyclobutane esters was examined in a series of tests, the results of which are collected in Table 2.
Insecticidal activity was investigated against the common hous~ly, Musca domestica, and the sheep blowfly, Lucilia cuprina. The methods used were as ~ollows:-(i) Housefly (a) ComPound alone Tests were carried out using a standard DDT-susceptible strain (~t~O/IN/l) of M domestica. The compound was applied in an acetone solution by microsyringe to tlle dorsum of the thorax of two day old female flies reared from pupae of average weight 2.2 - 2c5 gm/100 pupae. The adult flies were fed on water and sugar-only diet and maintained at 26C and 70% RH. The mortalities were counted at 48 hours aftér treatment and compared with acetone-treated controls. Flies unable to move or stand normally were considered dead. The LD50 value was obtained from a logit computer programme based on three replicates of 10 flies at each dose level.
The LD50 value for DDT determined under the same conditions was 0.26 l~g/fly.
(b~ Potentiation The compound was also tested on the insects described above in conjunction with the potentiator "Sesoxane" by pretreating the insect with 1 ~9 of the potentiator in acetone.
The mortalities were counted at 48 hours a~ter treat-ment and compared with acetone and acetone/potentiator controls.
The LD50 value was determined as described above.

~ 157771 For DDT, with the same potentiator the LD50 value was 0.24 ~g/fly.
~ bout the same levels of po,entiation were obtained when "Sesoxane" was replaced by an ecual amount of piperonyl butoxide.
(c) Insect Repellency Repellency tests were carried out on the same strain of housefly as in the ~ortality tests. Female flies at least two days old, not previously fed protein, ~-ere taken the day before the test, anaesthetized with C2 and counted into holding containers of twenty flies each. These were supplied with water and solid sucrose.
On the day of the tests the food and water were removed in the morning (0900 hr). As the tests were performed only between 1200 hr and 1730 hr, the flies were therefore starved for a minimum of three hours before testing.
The test involved the use of attractant baits to which the candidate compound was a~plied. These were exposed to the flies and the number of flies landing on each bait counted. The baits consisted of aluminium caps of area 5.94 cm filled with bakers yeast mixed with water and slightly heated to form a solid surface film.
Eight lots of 20 flies were used in a run in which seven discus were treated with a graded dilution series of the test chemical using acetone as solvent, together with one disc treated with acetone as a control. The concentrations of the compound ranged from 0.031 ~g/~l doubling at each level up to 2.0 ~g/~l.
One hundred microlitres of each solution was pipetted evenly over the surface of each disc and left until the acetone had evaported.
The flies to be used were released into standard 205 mm x 205 mm x 255 mm mesh ca~es and left to ~ 1~7771 acclimatize in the test room maintained at a temperature of 26C + 1C and humidity approximately 60%, for ten minutes before introducing the treated discs into--each cage. Before use the discs were marked on the reverse sides and then randomly mixed to avoid bias in counting.
In the thirty minute period of the test the number of flies on the surface of each disc was counted in the first and second minute after introducin~ the baits and thereafter every two minutes. In this way sixteen counts were obtained for each concentration, the totals of which ~ere then used or a regression analysis of the concentration effect. Also a total number of landings for each concentration was obtained and used for calculation of the Index of Repellency (IR). All replicate tests were carried out with fresh flies and baits, and the compounds were tested in three replicate runs.
The total number of flies counted on each disc for the seven concentration levels was su~med and averaged. In the following formula this figure is designated (N), where (C) equals the number of flies counted on the control:-C - N x 100 = Index of Repellency (IR) C ~ N
(ii) Sheep Blowfly (a) Insecticidal Activity _ The compounds were tested for activity against a dieldrin susceptible strain (LBB) which had been collected before dieldrin usage in the field.
The test compound was applied in acetone solution, 0.5 ~1 dispensed with a Drummond micropipette to the dorsum of the thorax of 2-3 day old females.
Adult flies were fed on water and sugar-only and maintained at 25 C and 60 - 70~O RH. The mortalities were determined after 24 hours. Moribund flies were regarded as dead. The LD50 values, in terms of concentration, were interpolated from a probit/log dose graph using a compu~er program.
Comparative LD50 figures for DDT and dieldrin are 0.17 and 0.025 ~g/insect.
(b) Potentiation Potentiation with "Sesoxane" was investigated as described above in the housefly tests.
(c) Repellency Repellency was determined as described above in the housefly tests, except that the baits consisted of an agar gel containing fresh beef blood.

~ 157771 Compound of Sheep Blowfly Example No. (Lucilia cuprina) LD50LD50 with synergist Repellency ~g/~ insect ~g/~ insect n ex 1 ' 1.78 0.04 36 2 0.77 0.06 61 3 0.05 0.001 79 4 0.024 O. 00026 73 0.04 0.003 66 6 0.40 O. 04 7 O . 02 O . 0004 62 8 0.023 0.0023 77 9 0.11 0.03 88 0.03 0.003 78 11 0.05 0.007 12 . 17 13 0.03 0.001 68 14 0.14 0.009 42 0.18 O. 006 16 a~10 0.~ OQl .17 O . 14 O. 002 18 O. 14 O. 001 19 o.n28 O. 0~2 ~ ~ Q OQ2 TABLE 2 INSECTICIDAL ACTIVITY (continued) _ ._ Compound of Housefly Example No. (Musca domestica) LD50LD50 with synergist Repellency ~g/Ot ~g/~ insect Index insect 1 1.8 0.2 49 2 1.32 0.22 81 3 0.13 0.003 81 4 0.10 0.005 86 0.26 0.017 6 0.6 0.036 12 7 0.18 0.065 89 8 0.55 0.01 9 0.58 0.05 0.13 0.005 84 11 0.34 0.018 12 >32 0.24 18 13 0.12 0.018 78 14 0.07 0.005 65 Q.26 0.6 2~

E ~PLE Z
-The following are examples of insecticidal compositions in accordance with the invention. All parts are by weight.

(a) Spray formulation The following composition is adapted for spray application.
Compound of formula I 4.0 "Sesoxane" or Piperonyl butoxide1.0 Deodorized kerosene 79.4 Alkylated naphthalene 16.0 (b) Aerosol The following materials are metered into a suitable 'bomb' container sealed and equipped with a valve in the usual way.
Compound of formula I 3.0 Potentiator 1.0 Methylene chloride 10.0 'Freon 12'* (trichlorofluo ~.ethane) 43-0 'Freon 11'* (dichlorodifluoromethane) 43 * Trademarks

Claims (5)

Claims:

1. Insecticidal compositions comprising one or more of the compounds of formula I, wherein Rl is hydrogen or a methoxy, ethoxy, propoxy, butoxy, tetrafluoroethoxy, methylthio, ethylthio, propyl-thio, fluoro, chloro, bromo, methyl, ethyl, or nitro group, and R2 is hydrogen or a methyl group, or Rl and R2 together form a methylenedioxy group;
R3 is one of the following groups (a) to (f):-(a) (b) and Yl, Y2, Y3, Y4, Y5 and Y6 are the same or different groups and each is hydrogen or a fluoro, bromo or chloro group, with the proviso that when Rl is hydrogen, fluoro, chloro, bromo or methyl and R2 is hydrogen or methyl, then at least one of Yl to Y6 is other than hydrogen; said compound(s) being incorporated in a suitable inert liquid or solid carrier, and additionally containing at least one synergistic or potentiating agent of the class of microsomal oxidase inhibitors.

2. Insecticidal compositions as claimed in claim l , wherein the synergist or potentiator is a pyrethrin synergist.

3. Insecticidal compositions as claimed in Claim l , wherein the synergist is one of the following:-.alpha.-[2-(2-butoxyethoxy)ethoxy]-4,5-methylenedioxy-2-propyltoluene;
3-hexyl-5(3,4-methylenedioxyphenyl)-2-cyclohexanone;
2-(3,4-methylenedioxy-phenoxy)-3,h,4-trioxaundecane;
l,2-(methylenedioxy)-4-[2-(octylsulfinyl)propyl]-henzene;
dipropyl-5,6,7,8-tetrahydro-7-methylnaphtho-[2,3-d]-l,3-dioxole-5,6-dicarboxylate.

4. Insecticidal compositions as claimed in Claim 1, wherein the synerqist is "Sesoxane" or piperonyl butoxide used in an amount from l/000th to 5 times the weight of the compound I.

5. Insecticidal compositions as claimed in Claim 4, wherein the amount of"Sesoxane"or piperonyl butoxide used is from about 1/100th to an equal part by weight per part of the compound I.