AU677640B2 - Pesticidal methods and compounds - Google Patents

Description

LIP~- P I I 1 TS 7002 PESTICIDAL METHODS AND COMPOUNDS The present invention relates to the combating of certain insect pests using isothiazole compounds, some of which are novel. Aspects of the invention relate to the use of such compounds in combating larval pests, to novel S.compounds, compositions and synthetic processes.

U.S. Patent No. 3541108 discloses pesticidal isothiazole derivatives of the formula Cl CN e*

N

S NHR wherein R may be COR, where R, is an alkyl radical containing 1 to 10 carbon atoms or phenyl.

Insecticidal and herbicidal activity of the compounds of U.S. Patent No. 3541108 is disclosed, the former being against Musca domestica (housefly) and Blatta orientalis (oriental cockroach).

G.B. Patent No. 1226913 discloses a method for the preparation of pesticidal, especially herbicidal and insecticidal, compounds of general formula i ~i~p~pns 1 I Ir I in which R 1 is a hydrogen atom or an alkyl radical containing up to 6 carbon atoms or is a

COR

2 radical, R 2 is Ar or a straight or branched chain alkyl or alkenyl radical containing up to 18 carbon atoms, which can be substituted by at least one halogen atom, nitrile group or radical Ar and/or in which one or more -CH 2 groups can be replaced by oxygen and/or an -NH- group which may be substituted and/or CO, andlor in which one or more =CH- groups are replaced by nitrogen, or R 2 is a cycloalkyl radical containing 3-6 carbon atoms, or is a furyl, pyrrolyl or thienyl radical which can be substituted by at least one halogen atom, nitro or sulphonic acid group or acetyl radical, Ar is a phenyl or lo naphthyl radical which can be substituted by at least one halogen atom, cyano, nitro, hydroxyl, mercapto or amino group or alkyl, alkoxy, alkylthio, alkylamino or i dialkylamino radicals, wherein the alkyl radicals or parts of radicals contain up to 4 S carbon atoms, and R 3 is a chlorine or bromine atom.

It has now been determined that certain isothiazole compounds, some of which are 15 novel, show interesting and unexpected activity in combating larval pests of lepidoptera species.

According to one aspect of the present invention there is provided a method of combating caterpillar pests [N:\libaa]00703:JVR r; 1 P~s~9~ I 3 at a locus, which comprises treating the locus with a compound of general formula X CN

N

S NR-CO-Q where X represents a halogen atom, R represents a hydrogen atom or an optionally substituted alkyl group, and Q represents an optionally substituted aryl or heteroaryl group.

Unless otherwise stated in this specification, an alkyl group may be linear or branched and suitably contains up to 10, preferably up to 6, and most preferably up to 4, carbon atoms, preferred examples being methyl and ethyl.

Unless otherwise stated in this specification, when any groups are designated as being optionally substituted, the substituent groups which are optionally present may be any of those customarily employed in the development of pesticidal compounds, and/or the modification of such compounds to influence their structure/activity, persistence, penetration or other property. In relation to a halogen atom, this may suitably denote iodine or, especially, bromine, fluorine or chlorine. In general chlorine is a preferred halogen atom. In relation to an alkyl group, specific examples of such substituents may include halogen atoms, and phenyl, alkoxy, alkylthio, hydroxy and cyano groups. In relation to an aryl or heteroaryl moiety, optional substituents may include i r q_ 1CI 4 halogen atoms, and nitro, cyano, alkoxy, haloalkoxy, hydroxy, amino, alkylamino, alkyl and haloalkyl (especially CF 3 groups. There may suitably be 0-3 substituents.

A preferred halogen atom X is a chlorine atom.

Preferably R represents a hydrogen atom or a substituted methyl group, suitably a benzyl or a 10 (C 1 alkoxy)methyl group. However, most preferably R represents a hydrogen atom.

A suitable optionally substituted heteroaryl group Q may include an optionally substituted thienyl group and an 15 optionally substituted pyridyl group. Preferably a substituted heteroaryl group has a single substituent. A preferred substituent is a halogen atom.

oo. A preferred optionally substituted aryl group is an optionally substituted phenyl group. Preferably this may have 1, 2 or 3 substituents.

S

Preferably, Q as a phenyl group has a substituent at the 3-position, and optionally one further substituent, at the 4- or, most preferably, the 5- position, or two further substituents, at the 4- and the 5- positions.

Preferred optional substituent(s) of a phenyl group Q include haloalkyl, alkyl, alkoxy, nitro and cyano group(s) and, most preferably, halogen atom(s).

Particularly preferred groups Q include phenyl groups having a halogen substituent at the 3-position, for example 3,4-dihalophenyl, 3,5-dihalophenyl groups and, especially, 3-halophenyl groups. Such compounds of i ~p~s~a I -R- 5 general formula I, which show particularly interesting activity may be regarded as a novel selected class of compounds and accordingly constitute a further aspect of the present invention. A particularly preferred compound is 3-chloro- 4-cyano-5-(3-chlorobenzoylamino) isothiazole.

A further novel class of compounds is constituted by S. compounds of the general formula I in which R represents 10 an optionally substituted alkyl group and accordingly such compounds provide a further aspect of the present invention.

In accordance with a further aspect of the present 15 invention there is provided a process for the preparation of a novel compound of the general formula I, which process comprises reacting together compounds of general formula II and III X CN

C

N II S NHR Hal-CO-Q III The reaction may suitably be effected under standard acylation conditions, in the presence of an organic solvent. Examples include pyridine, dimethylformamide and acetonitrile. A basic solvent may be employed, and/or an additional base, for example an alkali metal base, an

I-

6 example being potassium carbonate. The reaction may suitably be effected at an elevated temperature, for example from 50 0 C to the reflux temperature.

When the process is applied to prepare a novel compound of general formula I in which R represents an optionally substituted alkyl group, the required compound of general formula II may suitably be prepared via the corresponding 5-amino isothiazole, reacted with a compound 10 R-Hal, suitably in the presence of an organic solvent, for example acetonitrile, and an alkali metal base, for example potassium carbonate, suitably at an elevated temperature; or via the corresponding 5-halo isothiazole, reacted with a compound RNH 2 suitably in the presence of 15 an organic solvent, for example tetrahydrofuran, suitably at ambient temperature. Both such methods are described hereafter in greater detail.

The term Hal preferaby denotes a chlorine atom.

The invention also provides a pesticidal composition comprising a carrier and, as active ingredient, a novel compound of general formula lo The invention further provides the use of a compound of general formula II, in combating larvae of lepidoptera species.

The target pests may be the larval "caterpillar" or "worm" forms of insects of the genus Heliothis, such as H.zea (corn earworm), cotton bollworm, tomato fruitworm, and H. virescens (tobacco budworm); the genus Agrotis, such as A. ipsilon (black cutworm) the genus Trichoplusia, such as T.ni (cabbage looper); the genus Plutella, such as Plutella xylostella (diamond back moth); and the genus Spodoptera, such as S. littoralis (Egyptian 111111111111 7 cotton leafworm). A preferred aspect of the present invention therefore relates to the pesticidal treatment of such pests.

A carrier in a composition according to the invention is any material with which the active ingredient is formulated to facilitate application to the locus to be treated, which may for example be a plant, seed or soil, or to facilitate storage, transport or handling. A carrier may be a solid or a liquid, including a material which is Snormally gaseous but which has been compressed to form a liquid, and any of the carriers normally used in formulating pesticidal compositions may be used.

Preferably compositions according to the invention contain 15 0.5 to 95% by weight of active ingredient.

Suitable solid carriers include natural and synthetic clays and silicates, for example natural silicas such as diatomaceous earths; magnesium silicates, for example talcs; magnesium aluminium silicates, for example attapulgites and vermiculites; aluminium silicates, for o0* example kaolinites, montomorillonites and micas; calcium carbonate; calcium sulphate; ammonium sulphate; synthetic hydrated silicon oxides and synthetic calcium or aluminium silicates; elements, for example carbon and sulphur; natural and synthetic resins, for example coumarone resins, polyvinyl chloride, and styrene polymers and copolymers; solid polychlorophenols; bitumen; waxes; and solid fertilisers, for example superphosphates.

Suitable liquid carriers include water; alcohols, for example isopropanol and glycols; ketones, for example acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ethers; aromatic or araliphatic hydrocarbons, for example benzene, toluene and xylene; 8 petroleum fractions, for example kerosine and light mineral oils; chlorinated hydrocarbons, for example carbon tetrachloride, perchloroethylene and trichloroethane.

Mixtures of different liquids are often suitable.

Agricultural compositions are often formulated and transported in a concentrated form which is subsequently diluted by the user before application. The presence of small amounts of a carrier which is a surface-active agent 10 facilitates this process of dilution. Thus, preferably at least one carrier in a composition according to the S* invention is a surface-active agent. For example the composition may contain at least two carriers, at least one of which is a surface-active agent.

A surface-active agent may be an emulsifying agent, a dispersing agent or a wetting agent; it may be nonionic r ionic. Examples of suitable surface-active agents include the sodium or calcium salts of polyacrylic acids and lignin sulphonic acids; the condensation products of fatty acids or aliphatic amines or amides containing at least 12 carbon atoms in the molecule with ethylene oxide and/or propylene oxide; fatty acid esters of glycerol, sorbitan, sucrose or pentaerythritol; condensates of these with ethylene oxide and/or propylene oxide; condensation products of fatty alcohol or alkyl phenols, for example poctylphenol or p-octylcresol, with ethylene oxide and/or propylene oxide; sulphates or sulphonates of these condensation products; alkali or alkaline earth metal salts, preferably sodium salts, of sulphuric or sulphonic acid be ers containing at least 10 carbon atoms in the molecule, for example sodium lauryl sulphate, sodium secondary alkyl sulphates, sodium salts of sulphonated castor oil, and sodium alkylaryl sulphonates such as i 9 dodecylbenzene sulphonate; and polymers of ethylene oxide and copolymers of ethylene oxide and propylene oxide.

The compositions of the invention may for example be formulated as wettable powders, dusts, granules, solutions, emulsifiable concentrates, emulsions, suspension concentrates and aerosols. Wettable powders usually contain 25, 50 or 75% w of active ingredient and usually contain in addition to solid inert carrier, 3-10% 10 w of a dispersing agent and, where necessary, 0-10% w of stabiliser(s) and/or other additives such as penetrants or stickers. Dusts are ususally formulated as a dust concentrate having a similar composition to that of a wettable powder but without a dispersant, and are diluted 15 in the field with further solid carrier to give a composition usually containing w of active ingredient. Granules are usually prepared to have a size between 10 and 100 BS mesh (1.676 0.152 mm), and may be manufactured by agglomeration or impregnation techniques.

Generally, granules will contain w active ingredient and 0-10% w of additives such as stabilisers, surfactants, slow release modifiers and binding agents.

The so-called "dry flowable powders" consist of relatively small granules having a relatively higher concentration af active ingredient. Emulsifiable concentrates usually contain, in addition to a solvent and, when necessary, cosolvent, 10-50% w/v active ingredient, 2-20% w/v emulsifiers and 0-20% w/v of other additives such as stabilisers, penetrants and corrosion inhibitors.

Suspension concentrates are Ususally compounded so as to obtain a stable, non-sedimenting flowable product and usually contain 10-75% w active ingredient, 0.5-15% w of dispersing agents, 0.1-10% w of suspending agents such as protective colloids and thixotropic agents, 0-10% w of other additives such as defoamers, corrosion inhibitos, 10 stabilisers, penetrants and stickers, and water or an organic liquid in which the active ingredient is substantially insoluble; certain organic solids or inorganic salts may be present dissolved in the formulation to assist in preventing sedimentation or as antifreeze agents for water.

Aqueous dispersions and emulsions, for example compositions obtained by diluting a wettable powder or a 1. 0 concentrate according to the invention with water, also lie within the scope of the invention. The said emulsions o. may be of the water-in-oil or of the oil-in-water type, and may have a thick "mayonnaise"-like consistency.

15 Compositions in accordance with the invention may also contain other ingredients, for example other compounds possessing pesticidal, herbicidal, or fungicidal properties. The compounds of the invention may be found to be especially useful when applied in admixture with insecticides and/or acaricides, e.g. organophosphates, pyrethroids, ureas and organotin compounds, for example the commercial products fenvalerate, permethrin, cypermethriii, deltamethrin, alphacypermethrin, fenbutatin oxide, flufenoxuron diflubenzuron and trefluron.

The invention will be further understood from the following illustrative examples.

Example 1 Preparation of 3-chloro-4-cyano-5- (3chlorobenzoylamino) isothiazole [X=Cl; R=H; Q=3-Cl-Ph] I 11 3-Chloro-4-cyano-5-amino isothiazole (0.8g) was stirred in acetonitrile (50ml), together with potassium carbonate 3-Chlorobenzoyl chloride was added and the reaction mixture was heated to 100 0 C, for 3 hours. The solvent was removed by evaporation and the residue titurated in water, and acidified to a pH of about 1, using 2M hydrochloric acid. The solid was filtered and recrystallised from acetone-methanol v/v) to give the title compound as a cream solid (mp 260 0 C; 1.20g).

S9 SAnalysis 0 a 0 6 %C %H %N Calc. 44.3 1.7 14.1 Found 44.5 2.1 14.4 Further compounds as noted in Table 1 were prepared by processes analogous to the process of Example 1.

Characterising data for the compounds of Examples 2-31 is noted in Table 2, where available.

ft «6 12 TABLE 1 *0* a 6*000: to too I. S o Goo* of 0* 0.000 *Got 2 Cl H ____2-Cl-Ph 3 Cl H 2-F-Ph 4 Cl H 4-CF 3 -Ph Cl H 4-Cl-Ph 6 Cl H >-N0 2 Ph 7 Cl H 3 -F-Ph 8 Cl H 3 -Ph 9 Cl H 3-Br-Ph Cl H 3-CH 3 -Ph 11 Cl H 3 -OCH 3 -Ph 12 Cl H 3--CN-Ph 13 Cl H 3, 4-C1 2 -Ph 14 Cl H 3,4-F 2 -Ph Cl H 3-Cl,4-F-Ph 16 Cl H 3-Br, 4-F-Ph 17 Cl H 3, 5-C1 2 -Ph J8 Cl H 3, 5-F 2 -Ph 19 Cl H4 3,5-Br 2 -Ph Cl -CH 2 -Ph 3-Cl-Ph 21 Cl -CH 2

-O-C

2

H

5 3-Cl-Ph 22 Cl H Ph 23 Cl H 4-F-Ph 24 Cl H 6-Cl-pyrid-3-yl Cl -H 5-Cl-thien-2-yl 26 Cl H 2,4,5-F 3 l-ph 27 Cl H 3, 4, 5-F 3 Ph 28 Cl H 3-N0 2 ,4-Cl-Ph 13 Ex. jx R_ 29 Cl H 3 -N0 2 4-F-Ph {Cl -CH 2

-O-CH

3 3-Cl-Ph 31 Cl j-CH 2

-O-CH

3 3-Br,4-F-Ph *0 a 00 a 0O*~ 0* a 14 4

A

*4 TABLE 2 EXAMPLE ___ANALYSIS MP/ 0

C

NO.

2 caic _______j213-215 found12-3 3 calc12 13 found 4 caic 43.4 1.5 12.7 300 found 43.6 2.0 12.5 calc 6 caic 42.7 1.6 18.2 301 _____found 42.0 1.9 18.2 7 caic found__ 8 caic 43.4 1.5 12.7 253 43.0 2.0 13.3 9 caic 34.9 2.1 11.1 300 found 35.0 2.4 10 caic 51.9 2.9 15.1 250 found 52.4 3.0 15.3 11 caic 49.1 2.7 14.13 240 found 49.0 3.0 14.3 12 caic 49.9 1.7 19.4 300 _____found 48.9 2.0 19.3 13 caic 39.7 1.2 12.6 300 found, 39.5 1.6 12.5 14 caic 44.1 1.3 14.0 273 _____found 44.4 1.9 14.1 caic 41.8 1.3 13.3 300 _____found 41.4 1.7 13.4 16 caic 36,6 1.1 11.6 278 oud 36.9 1.5 11.6 15 EXAMPLE CANALYSIS PC 17 caic 39.7 1.2 12.6 294 found 39.8 1.5 12.4 18 caic 44.1 1.3 14 .028 43.9 1.8 14.1 19 calc 31.3 1.0 10.0 300 _____found 31.7 1.4 10.1 caic 55.7 2.8 10.8 48 found 56.1 3.1 10.5 21 caic 38.6 3.6 19.3 found 38.9 3.7 19.2 22 caic found_ 23 caic found 24 calc 35.8 2.3 16.7 300 found 36.3 1.9 16.7 caic 35.5 1.0 13.8 300 found 36.1 1.4 13.8 26 caic 41.6 1.0 13.2 213-215 found 141.7 1.3 13.2 27 calc 41.6 1.0 13.2 300 42.0 1.4 13.4 28 caic 38.5 1.2 16.3 23 t _____found 39.0 1.5 16.4 29 caic 40.4 1.2 171236 _____found 39.8 1.4 16.8 caic 45.6 2.6 12.3 130 46.4 3.1 12.2 31 caic 38.6 j 2. 0 10.4 131 39.0 J 2.4 10.2 16 Examples 32 and 33 below describe the preparation of intermediates for the compounds of Example 20 and 21, respectively.

Example 32 Preparation of 3-chloro-4-cyano-5-(N-benzyl) isothiazole.

Benzylamine (1.lg) was added to a stirring solution of 3,5-dichloro-4-cyano isothiazole (0.9g) in tetrahydrofuran (50ml) at 20 C. The mixture was stirred at S. 20°C for 3 hours. The mixture was filtered and the filtrate evaporated. The residue was chromatographed using silica gel and chloroform as eluent to give the title compound as a white solid (1.2g, mp 164 0

C).

Analysis %C %H %N Calc. 52.9 3.2 16.8 Found 53.3 3.3 16.8 Example 33 Preparation of 3-chloro-5-cyano-5-(N-ethoxymethyl) isothiazole.

Potassium carbonate (1.4g) and chloromethyl ethyl ether (2g) were added to a stirring solution of 3-chloroisothiazole (1.6g) in acetonitrile The mixture was stirred at 100°C for 2 hours. The mixture was filtered and the filtrate evaporated. The residue was chromatographed using silica gel and dichloromethane as 17 eluent to give the title compound as a white solid (l.0g, mp 200 0

C).

Analysis %C %H %N Calc. 38.6 3.6 19.3 Found 38.9 3.7 19.2 Example 34 Pesticidal Activity Pesticidal activity of compounds of the invention was assessed against larvae of the following pests:- Spodoptera littoralis Heliothis armigera Plutella xvlostella The test methods employed for each species appear below. In each test, unless otherwise stated, solutions S. 20 or suspensions of test compound were made up at a concentration in water of 0.1%w containing 10%w acetone and 0.025%w "TRITON X-100" (trade mark) surface active agent (the condensation product of ethylene oxide with an alkyl phenol). These solutions were sprayed at a rate equivalent to 340 litres per hectare (3.4 x 10-m 3 /m 2 onto Petri dishes containing either test species per se or diet onto which test species were subsequently introduced, as indicated. In some assays leaf discs infested with test species were sprayed whilst other assays involved the spraying of plants which were infested subsequently with test species after the spray solution had dried. The tests were all conducted under normal insectary conditions

~I

18 (23 0 C 2°C, fluctuating humidity and light). Mortality assessments were made as indicated below, in terms of percentage mortality figures.

Spodoptera littoralis (7 day)(Sl 7D) Test solutions were sprayed as indicated above onto Petri dishes containing a nutritious diet for Egyptian cotton leafworm larvae. When the spray deposit had dried, each dish was infested with ten 2nd instar larvae.

Mortality assessments were made 7 days after spraying.

(ii) Spodoptera littoralis (foliar)(Sl Fol) Test solutions were sprayed as described above onto Petri dishes containing 9cm discs of Chinese cabbage 15 leaves on filter papers. After drying, each dish was infested with ten 2nd instar larvae. Mortality assessments were made 24 hours after infestation.

(ii) Plutella xylostella (Px) 20 A test solution was sprayed as described above onto a 4 cm diameter Chinese cabbage leaf placed ventral side up in a pot. When the spray deposit had dried the pot was infested with 10 young instar larvae and a lid added.

Mortality was assessed after 1 or 2 days, depending on 25 when the test was carried out.

4 (iv) Heliothis armigera (Ha) A test solution was sprayed as described above onto a 4 cm diameter Chinese cabbage leaf placed ventral side up in a pot. When the spray deposit had dried the pot was infested with 10 young instar larvae and a lid added.

Mortality was assessed after 1 day.

Results of the assessments described in Examples 34 for each of the compounds of Examples 1 to 31 are provided

I

IPBY 19 in Table 3. In the Table grades A, B and C indicate mortalities of 70-100%, 40-69% and 0-39%, respectively, at the test concentration of O.1%w (1000 ppm). A blank space denotes that testing was not carried out.

9* 0* *0 0 0 •gig o 0 *c 20 TABLE 3 0* 0 0 fompound ISi I l Ha of 7D Fol Ex No. I I 1 A A _A A 2 A C 3 A A 4 A A A A A 6 A A 7 A A B 8 C B A 9 A A 10 A C C 11 C A 12 A A 13 A A 14 A A A_ A A A 16 A A A A 17 A A A A 18 A A A 19 A A B A _A 21, A A A A 22 A 23 A 24 B A C A C C 26 A A 27 A 0 0000 00 00 0 0 0 0000 0 21 Compound Sl 51 Px Ha of 7D Fol Ex No.

28 A A 29 A A B_ A AA_ 31 A A A a.

a a o a.

a.

a a a. *a a. a a a a 22 Compounds of the present invention were also tested against other insect pests, including Aedes aeqypti (yellow fever mosquito), Musca domestica (housefly), Acyrthosiphon pisum (pea aphid), Megoura viciae (vetch aphid), Phaedon cochleariae (mustard beetle), Trialeurodes vaporariorum (greenhouse whitefly), Nephotettix cincticeps (green leaf hopper) and Nilaparvata lugens (brown rice plant hopper). However, in most cases this revealed no or low activity. Preliminary conclusions are that the activity of the compounds found, in the majority of tests, against caterpillar pests, is surprising, given the otherwise unpromising insecticidal activity of the compounds.

15 Further glasshouse tests have shown particularly interesting activity against larval pests from the compounds of Examples 1, 7, 9, 13, 14, 15, 16, 17, 18 and 19.

V**

0 ooo ~1

Claims (16)

1. A method of combating a caterpillar pest at a locus, which method comprises treating the locus with a compound of general formula X CN N\ S NR-CO-Q wherein X represents a halogen atom, R represents a hydrogen atom or an optionally substituted alkyl group, and Q represents an optionally substituted aryl or heteroaryl group, the term optionally substituted being as hereinbefore defined.

2. The method as claimed in claim 1, wherein R represents an optionally substituted alkyl group.

3. The method as claimed in claim 1, wherein R represents a hydrogen atom or a benzyl or (C1. 4 alkoxy) methyl group.

4. The method as claimed in claim 3, wherein R represents a hydrogen atom.

5. The method as claimed in any one of the preceding claims, wherein X represents a chlorine atom. 15 6. The method as claimed in any one of the preceding claims, wherein Q represents an optionally substituted phenyl group. S. 7. The method as claimed in claim 6, wherein Q represents a phenyl group having a halogen substituent at the 3- position, and being optionally substituted elsewhere in the ring. 20 8. The method as claimed in claim 7, wherein Q represents a 3-halophenyl, 3,4-dihalophenyl or 3,5-dihalophenyl group.

9. A compound of general formula X CN SNR-CO-Q wherein X represents a halogen atom, R represents an optionally substituted alkyl group, and Q represents an optionally substituted aryl or heteroaryl group, the term optionally substituted being as hereinbefore defined. The compound as claimed in claim 9, wherein Q represents a phenyl group having a halogen substituent at the 3- position, and being optionally substituted elsewhere in the ring.

11. A compound of general formula X CN fA NR-CO-Q [NT O [N:\libaa]00703:JVR 24 where X represents a halogen atom, R represents a hydrogen atom or an optionally substituted alkyl group, and Q represents a phenyl group having a halogen substituent at the 3- position, and being optionally substituted elsewhere in the ring group, the term optionally substituted being as hereinbefore defined.

12. A compound as claimed in any one of claims 9 to 11, wherein Q represents a 3-halophenyl, 3,4-dihalophenyl or 3,5-dihalophenyl group.

13. A compound as claimed in claim 11 or claim 12, wherein R represents an optionally substituted alkyl group.

14. A compound as claimed in claim 11 or claim 12, wherein R represents a hydrogen atom or a benzyl or (C 1 4 alkoxy) methyl group. The compound as claimed in claim 14, wherein R represents a hydrogen atom.

16. The compound as claimed in any one of claims 9 to 15, wherein X represents a chlorine atom.

17. A process for the preparation of a compound of general formula I as defined 15 in any one of claims 9 to 16, which comprises reacting together compounds of general formula II and III. X CN S* s NHR Hal-CO-Q Swherein X, R, aid Q are as defined in any one of claims 9 to 16.

18. A process for the preparation of a compound of general formula I as claimed in any one of claims 9 to 16 and substantially as hereinbefore described with reference to S the Examples.

19. A compound prepared by the process as claimed in claim 17 or claim 18. A pesticidal composition comprising a carrier and, as active ingredient, a compound of general formula I as claimed in any one of claims 9 to 16 or 19.

21. A method of combating a caterpillar pest at a locus, which method comprises treating the locus with a compound as claimed in any one of claims 9 to 16 or 19 or with a composition as claimed in claim

22. A method as claimed in any one of claims 1 to 8 or 21 wherein the caterpillar pest is in the larval stage. Dated 20 February, 1997 Shell Internationale Research Maatschappij B.V. Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON [N:\libaa]00703:JJN i 6115*111 -I I- TS 7002 ABSTRACT PESTICIDAL METHODS AND COMPOUNDS The invention provides a method of combating caterpillar pests, using a compound of general formula X CN SS NR-CO-Q where X represents a halogen atom, R represents a hydrogen atom or an optionally substituted alkyl group, and Q represents an optionally substituted aryl or heteroaryl group. Certain compounds of general formula I are novel. e