GB2258233A - Herbicidal benzoisothiazoles - Google Patents

Abstract

A compound of formula (I): <IMAGE> in which Ar is an optionally substituted ayl or heterocyclic ring system; R<1> R<2> are independently selected from H, optionally substituted alkyl, alkenyl or alkenyl, halogen, NR<a>R<b>, or R<1> may also be optionally substituted aryl, or R<1> and R<2> together with the carbon to which they are attached form an optionally substituted alkenyl or cycloalkyl or oxirane group: R<3> is H, CO2R<4>, CN, COR<4>, CH2OR<4>, CH(OH)R<4>, CH(OR<4>)R<5>, CH2OSO2R<4>, CH(OR<4>)R<5>, CH2OSO3R<4>, CH2ONR<6>R<7>, CSNH2, COSR<4>, CSOR<4>, CONHSO2R<4>, CONR<6>R<7>, NH2, NHCOR<10>, NHCO2R<10> CONHNR<6>R<7>, CONHN<+>R<6>R<7>R<8> V<->, CO2<->M<+> or COON=CR<6>R<7>; M<+> and V<-> are agriculturally acceptable ions; R<4>, R<5> and R<10> are independently selected from H or an optionally substituted alkyl, aryl, alkenyl or alkynyl group; R<6>, R<7>, R<8>, R<9>, R<a> and R<b> are independently selected from H or an optionally substituted alkyl, alkenyl, aryl, or alkynyl group or any two of R<6>, R<7>, R<8>, R<9>, R<a> and R<b> together with the atom to which they are attached form a cycloalkyl or heterocyclic ring; R<6> and R<7> may also be a heterocyclic ring; Y is O or S; X is (CH2)m, CH=CH, CH(OR<c>)CH2, COCH2; where R<c> is H or an optionally substituted alkyl, aryl, alkynyl or alkynyl group; m is 0, 1 or 2; and n is 0 or 1, has herbicidal activity. is H

Description

HETEROCYCLIC COMPOUNDS This invention relates to novel benzisothiazole derivatives, processes for their preparation, their use as herbicides, and herbicidal compositions containing them.

European Patent No. 193700 describes certain benzisoxazolyl phenyl ether derivatives which have herbicidal activity.

According to the present invention, there are provided benzisothiazole compounds of the formula (I), in which Ar is an optionally substituted aryl or heterocyclic ring system; R1 and R2 are independently selected from H, optionally substituted alkyl, ab 1 alkenyl or alkynyl, halogen, NR@R@, or R@ also be optionally substituted aryl, or R1 and R2 together with the carbon to which they are attached form an optionally substituted alkenyl or cycloalkyl or oxirane group; R3 is H, CO2R4, CN,.COR4, CH2OR4, CH(OH)R4, CH(OR4)R5, CH2OSO2R4, CH(OR4)R5, CH2OSO3R4, CH2ONR6R7, CSNH2, COSR4, CSOR4, CONHSO2R4, CONR6R7, NH2,NHCOR10, NHCO2R10, CONHNR6R7, CONHN+R6R7R8 V-, CO2 -M+ or COON=CR6R7; M+ is an agriculturally acceptable cation; V is an agriculturally acceptable anion; R4, R5 and R10 are independently selected from H or an optionally substituted alkyl, aryl, alkenyl or alkynyl group; R6, R7, R8, R9, Ra and Rb are independently selected from H or an optionally substituted alkyl, alkenyl, aryl or alkynyl group or any two of R6 R7 R8 R9 Ra and Rb together with the atom to which they are attched form a cycloalkyl or heterocyclic ring; R6 and R7 may also be a heterocyclic ring; Y is O or S; X is (CH2)m, CH=CH, CH(ORc)CH2, COCH2; where Rc is H or an optionally substituted alkyl, aryl, alkynyl or alkynyl group; m is 0, 1 or 2; and n is O or 1.

As used herein the term "alkyl" includes straight or branched chains containing up to 10 carbon atoms preferably from 1 to 6 carbon atoms. The terms "alkenyl" and "alkynyl" refer to unsaturated straight or branched chains having from 2 to 10 and preferably from 2 to 6 carbon atoms. The term "cycloalkyl" includes rings containing from 3 to 9 carbon atoms, preferably from 3 to 6 carbon atoms. The term "alkoxy" includes straight or branched chains containing up to 10 carbon atoms preferably from 1 to 6 carbon atoms.

The term "lower" used in relation to alkyl, alkenyl or alkynyl groups means that the group contains up to 3 carbon atoms.

The term "haloalkyl" and "haloalkoxy" refer to alkyl and alkoxy groups respectively substituted by at least one halogen atom such as fluorine, chlorine or bromine. A particular haloalkyl group is trifluoromethyl. The term "aryl" includes phenyl and naphthyl. The term "heterocyclic" includes rings of up to 10 atoms, preferably up to 6 atoms up to 3 of which are selected from oxygen, nitrogen or sulphur. The term halogen includes fluorine, chlorine, bromine and iodine.

A suitable aryl ring system is phenyl.

Suitable heterocyclic ring systems for R6 R7 and Ar are rings of up to 10 atoms, up to 3 of which are selected from oxygen, nitrogen or sulphur, preferably aromatic ring systems such as pyridine and pyrazole.

Suitable optional substitutents for the aryl or heterocyclic ring systems Ar and for the aryl groups Ra, Rb, RC, R1, R4, R5, R6, R7, R8 and R9 are up to 5 preferably up to 3 members selected from halogen (fluoro, chloro, bromo or iodo), lower alkyl, haloalkyl (for example CF3), haloalkoxy (for example OCF3), nitro, cyano, lower alkoxy (for example methoxy) or S(O)pRd where p is 0, 1 or 2 and Rd is alkyl (for example thiomethyl, sulphinylmethyl and sulphonylmethyl).

Preferred positions of substitution when the aryl ring Ar is a phenyl ring are the 2, 4 and 6 positions, particularly 2,4,6-tri- substituted rings with a trifluoromethyl group at the 4-position.

Examples of optional substituents for alkyl, alkenyl, alkynyl groups Ra, Rb, Rc, R1, R2, R4, R5 R6 R7 R, R9 and R10 include one or more groups selected from balo such as fluoro, chloro or bromo; nitro; nitrile; aryl such as phenyl; CO2R11, NHCOR11 or NHCH2CO2R11 wherein R11 is hydrogen, C1-6 alkyl or an agriculturally acceptable cation; C1-6 alkoxy; oxo;S(O)~Rd where p is 0, 1 or 2 and Rd is alkyl (for example thiomethyl, p sulphinylmethyl and sulphonylmethyl); amino; mono- or di- C16 alkylamino; CONR12R13 wherein R12 and R13 are independently selected from hydrogen, C1-6 alkyl, C26 alkenyl or C26 alkynyl or R12 and R13 are joined together to form a heterocyclic ring having up to 7 ring atoms 3 of which may be selected from oxygen, nitrogen or sulphur. An example of a heterocyclic substitutent is tetrahydrofuranyl.

Examples of agriculturally acceptable cations M+ and R11 include sodium, potassium or calcium ions, sulphonium or sulphoxonium ions or for example of formula S+(O)qR6R7R8 where q is 0 or 1 R6, R7 and R8 are as hereinbefore defined, ammonium or tertiary ammonium ions of formula 6 7 8 9 6 7 8 9 N+R6R7R8R9 where R6, R7, R8 and R9 are as hereinbefore defined. Suitable substituents for the alkyl, alkenyl and alkynyl groups in these cations are hydroxy and phenyl. Suitably where any of R6, R7, R8 and R9 in the cations are optionally substituted alkyl, they contain from 1 to 4 carbon atoms.

Particular examples of R6, R7, R8 and R9 in these cations are hydrogen, ethyl, isopropyl, benzyl and 2-hydroxyethyl.

Examples of agriculturally acceptable anions for V are halides, tetrafluoroborate, mesylate and tosylate ions.

Suitable halo groups R1, and R2 include fluorine, chlorine and bromine.

Suitable heterocyclic rings formed from two of Ra, Rb, R6, R7, R8 and R9 and the atom to which they are attached are pyrrolidine, piperidine and morpholine.

Preferably R1 is H.

Preferably R2 is H or is C1-3 alkyl, in particular methyl or ethyl.

Suitably R3 is CO2R4, CN, CH2OR4, CSNH2, CONR6R7, CONHNR6R7, CONHN+R6R7R8 V-, COON=CR6R7 or CO2-M+. Preferably R3 is CO2R4, CN, CONR6R7 or COON=CR6R7, most preferably R3 is CO2R4.

R4 is preferably alkyl or substituted alkyl for example alkoxyalkyl or oxo substituted alkyl.

A preferred example of R4 is C1-6 alkyl, especially methyl.

Ar is preferably a group of formula (i): where R18 is N, CH or CR20 and R19 and R20 are independently selected from 18 20 halogen, such as chlorine or fluorine. Preferably R is CR and most preferably one of R19 and R20 is chlorine and the other is fluorine.

Another group Ar is optionally substituted pyrazole, for example optionally substituted by C1, CF3 and CH3.

Preferably X is (CH2)m where m is zero or 1, especially zero.

Y is preferably oxygen when n is 1.

The formula (I) given above is intended to include tautomeric forms of the structure drawn, as well as physically distinguishable modifications of the compounds which may arise, for example, from different ways in which the molecules are arranged in a crystal lattice, or from the inability of parts of the molecule to rotate freely in relation to other parts, or from geometrical isomerism, or from intra-molelcular or inter-molecular hydrogen bonding, or otherwise.

Some of the compounds of the invention can exist in enantiomeric forms. The invention includes both individual enantiomers and mixtures of the two in all proportions.

Particular examples of compounds of the invention are listed in Table I where A, B, C, n, R1, R2 and R3 relate to formula IA. The details of the proton magnetic resonance spectra of the compounds are listed in Table II.

TABLE I (IA) Compound A B C n R1 R2 R3 Melting point No C 1 Cl CF3 F O H H CO2Me 100-101 2 Cl CF3 F O H H CO2Et 113.5-114.5 3 Cl CF3 F O H Me C02Me 4 Cl CF3 F O H Me C02Et 5 Cl CF3 F 1 H H C02Me 141-142 6 Cl CF3 F 1 H Me CO2Et 125-125.5 7 Cl CF3 F 1 H Me C02Me 8 Cl CF3 F 1 H Me CO2Et t 9 Cl CF3 H O H H CO2Me 59-60 10 Cl CF3 H O H Me CO2Me 11 C1 CF3 H 1 H H CO2Me 128-130 12 Cl CF3 H 1 H Me CO2Me 125-127 13 Cl CF3 H 1 H H H TABLE II Compound NMR Data No 1 #H (CDCl3): 3.7(s)3H; 4.1(s)2H; 7.25(dd)1H; 7.35(d)1H; 7.45(dd)1H; 7.65(bs)1H; 7.9(dd)lH.

2 EH(CDCl3): 1.2(t)3H; 4.05(s)2H; 4.15(q)2H; 7.25(dd)1H; 7.35(d)1H; 7.45(dd)1H; 7.6(bs)1H; 7.9(d)1H.

3 #H (CDCl3): 1.7(d)3H; 3.65(s)3H; 4.3(q)1H; 7.25(dd)1H; 7.4(d)1H; 7.55(dd)1H; 7.65(bs)1H; 7.9(d)1H.

4 #H (CDC13): 1.15(t)3H; 1.7(d)3H; 4.1(m)2H; 4.3(q)1H; 7.25(dd)1H; 7.45(d+dd)2H; 7.65(bs)1H; 7.9(d)1H.

5 #H (CDCl3): 3.81(s)3H; 5.05(s)2H; 7.25(d)1H; 7.35(dd)1H; 7.45(dd)1H; 7.6(bs)1H; 7.75(d)1H.

6 #H (CDCl3): 1.3(t)3H; 4.25(q)2H; 5.05(s)2H; 7.25(d)1H; 7.35(dd)1H; 7.45(dd)1H; 7.6(bs)1H; 7.75(d)1H.

7 #H (CDCl3): 1.7(d)3H; 3.8(s)3H; 5.5(q)1H; 7.3(m)2H; 7.45(dd)1H; 8.65(bs)1H; 7.75(d)1H.

8 #H (CDCl3): 1.25(t)3H; 1.7(d)3H; 4.25(m)2H; 5.45(q)1H; 7.3(m)2H; 7.45(dd)1H; 7.6(bs)lH; 7.71(d)1H.

9 SH (CDCl3): 3.7(s)3H; 4.1(s)2H; 7.0(d)1H; 7.3(dd)1H; 7.5(dd)1H; 7.6(d)1H; 7.80(d)1H; 7.95(d)1H.

10 SH (CDCl3): 1.7(d)3H; 3.65(s)3H; 4.35(q)1H; 6.95(d)1H; 7.3(dd)1H; 7.5(dd)1H; 7.6(d)1H; 7.8(d)1H; 7.95(d)1H.

11 #H (CDCl3): 3.80(s)3H; 5.1(s)2H; 7.0(d)1H; 7.35(dd)1H; 7.50(dd)1H; 7.55(d)1H; 7.80(m)2H.

12 #H (CDCl3): 1.7(d)3H; 3.8(s)3H; 5.5(q)1H; 7.0(d)1H; 7.3(dd)1H; 7.5(dd)1H; 7.55(d)1H; 7.8(m)2H.

13 #H (CDCl3): 4.2(s)3H; 7.0(d)1H; 7.3(dd)1H; 7.45(m)2H; 7.8(m)2H.

Compounds of formula (I) may be prepared by reacting a compound of formula (II): wherein X, Y, R1, R , R3, and n are as defined in relation to formula (I) with a compound of formula (III): wherein Ar is as defined in relation to formula (I) and Z is a leaving group, optionally in the presence of a base.

Suitable leaving groups Z include halogen, such as fluorine, chlorine and bromine and sulphonates such as methanesulphonate, p-toluenesulphonate and trifluoromethylsulphonate.

Suitable bases for use in the reaction include bases such as alkali metal hydrides, carbonates and hydroxides.

The reaction is preferably, carried out in an organic solvent such as DMF, DMSO, a lower alkanol, or a lower ketone. Moderate temperatures, for example from lO0C to 200 C are suitably employed. Conveniently the reaction is carried out at 5O0C to 15O0C.

Compounds of formula (III) are known compounds or may be prepared from known compounds by known methods.

Compounds of formula (II), wherein R3 is an ester group, can be prepared from the compounds of formula (IV) by reaction with an alcohol, optionally in the presence of acid or dehydrating agents.

Suitable acids for use in the reaction include sulphuric, hydrochloric and tosic acids. Moderate temperatures, for example 10 C to 200 C are suitably employed. Conveniently the reaction is carried out at 5O0C to 15O0C.

When n is zero, R2 is H and X is (CH2)m where m is zero, compounds of formula (IV) can be prepared from compounds of formula (V), where R21 and R22 are alkyl groups; by hydrolysis of the esters and subsequent decarboxylation. For convenience, the conversion is usually acid catalysed. Suitable acids for this reaction include sulphuric, hydrochloric, hydrobromic and tosic acids. Moderate temperatures, for example 10 C to 200 C, are suitably employed. Conveniently the reaction is carried out at 5O0C to 15O0C.

Compounds of formula (V) can be prepared from compounds of formula (VI) by cleavage of the methyl ether. Suitable reagents for this conversion are Lewis acids, for example boron tribromide. Low temperatures for example -1000C to OOC are suitably employed, in particular -8O0C to -6O0C.

Compounds of formula (VI) can be preapred from compounds of formula (VII) by reaction with the a-anion of a diethylmalonate optionally substituted with R1 defined as for formula (I). The anion is usually generated in situ by a base at moderate temperatures, for example 10 C to 200 C are suitably employed. Conveniently the reaction is carried out at 50 to 100 C. Suitable bases include alkali metal carbonates, alkali metal hydrides and alkali metal alkoxides.

The reaction is preferentially carried out in organic solvents such as DMF, DMSO, THF, a lower alkanol or a lower ketone.

Compounds of formula (VII) may be prepared from compound of formula (VIII) by reaction with phosphorous oxychloride. Moderate temperatures for example from 10 C to 200 C, are suitably employed. Conveniently the reaction is carried out at 5O0C to 15O0C.

Compounds of formula (VIII) can be prepared from compounds of formula (IX) by reacting sequentially with thionylchloride, sulphurylchloride and finally aqueous ammonium hydroxide. Moderate temperatures, for example 10 C to 200 C, are suitably employed. Conveniently the reactions are carried out in organic solvents such as substituted benzenes or THF.

Compounds of formula (IX) can be prepared from compounds of formula (X) by diazotisation followed by reaction with sodium disulphide. Suitable reagents for the diazotisation include mineral acids, for example hydrochloric, and sodium nitrate in water. Reduced temperatures -1O0C to 10 C, are suitably employed. Conveniently the reaction is carried out at OOC to 50C. The reaction is preferentially carried out in an aqueous solution.

The diazonium salt is reacted without isolation with a cooled aqueous solution of sodium disulphide. Reduced temperatures, -1O0C to 10 C, are again suitably employed. Conveniently the reaction is carried out in aqueous solution at OOC to 50C.

Compounds of formula (X) are known compounds or may be prepared from known compounds by conventional methods.

Compounds of formula (I), when n is 1 may be prepared by reacting a compound of formula (XI) with a compound of formula (XII) wherein R1, R2, R3 and X are as defined in relation to formula I and Z is a leaving group, optionally in the presence of base.

Suitable leaving groups for Z include halogen, such as, bromine, chlorine or iodine and sulphonates such as methanesulphonate or ptoluenesulphonate or trifluoromethylsulphonate.

Suitable bases for use in the reaction include alkali metal hydrides, alkali metal carbonates and alkali metal hydroxides The reaction is preferably carried out in an organic solvent such as DMF, DMSO, THF, a lower ketone. Moderate temperatures, for example 10 C to 200 C are suitably employed. Conveniently the reaction is carried out at 5O0C to 15O0C.

Compounds of formula (XI) may be preapred by reacting compounds of formula (XIII); with compounds of formula (III), optionally in the presence of a base.

Suitable bases for use in the reaction include alkali metal hydrides alkali metal carbonates or alkali metal hydroxides.

The reaction is preferably carried out in organic solvents such as DMF, DMSO, THF, a lower alkanol or a lower ketone. Moderate temperatures, for example 10 to 200 C are suitably employed. Conveniently the reaction is carried out at 5O0C to 100 C.

Compounds of formula (XIII) may be prepared from compounds of formula (VIII) by reaction with boron tribromide.

The reaction is preferably carried out in an organic solvent such as a substituted benzene or dichloromethane. Lower temperatures, for example -1000C ro 10 C, are suitably employed. Conveniently the reaction is carried out at -8O0C to -1O0C. Compounds of formula (VIII), (XI) and (XII) are known compounds or can be prepared from known compounds by known methods.

If desired one or more of the following steps may be carried out: i) When R3 is an alkoxycarbonyl group hydrolysing to the corresponding acid.

ii) When R3 is an alkoxycarbonyl group acid catalysed alcohol exchange to give a different alkoxycarbonyl group.

iii) When R3 is CO2H esterfying or forming a salt, amide, sulphonamide hydrazide or hydrazinium derivative.

iv) When R3 is an alcohol, oxidation to the corresponding acid or aldehyde or esterification.

v) When R3 is an alkoxycarbonyl reduction to the corresponding alcohol.

vi) When R3 is an amide dehydration to the corresponding nitrile.

vii) When R3 is alkoxycarbonyl; m is zero and R1 or R2 or both are hydrogen, base mediated alkylation to the corresponding substituted ester or direct halogenation to the corresponding substituted ester.

viii)When R3 is an amide, conversion to the corresponding thioamide.

ix) When R3 is an unsubstituted amide, conversion to the corresponding amine by a Hofmann rearrangement.

x) When R3 is CO2H, conversion to the corresponding amine by a Curtius rearrangement.

xi) When R3 is alkoxycarbonyl, R1 is halogen and R2 is hydrogen, treatment with base and formaldehyde to form an oxirane.

The compounds of formula (I) are active as herbicides and therefore, in a further aspect the invention provides a process for severely damaging or killing unwanted plants which process comprises applying to the plants, or to the growth medium of the plants, a herbicidally effective amount of a compound of formula (I) as hereinbefore defined.

The compounds of formula (I) are active against a broad range of weed species including monocotyledonous and dicotyledonous species. They show some selectivity towards certain species; they may be used for example as selective herbicides in wheat crops.

The compounds of formula (I) may be applied directly to the plant (post-emergence application) or to the soil before the emergence of the plant (pre-emergence application). They are particularly useful when applied post-emergence.

The compounds of formula (I) may be used on their own to inhibit the growth of, severely damage, or kill plants but are preferably used in the form of a composition comprising a compound of the invention in admixture with a carrier comprising a solid or liquid diluent.

Therefore, in yet a further aspect the invention provides plant growth inhibiting, plant damaging, or plant killing compositions comprising a compound of formula (I) as hereinbefore defined and an inert carrier or diluent.

Compositions containing compounds of formula (I) include both dilute compositions, which are ready for immediate use, and concentrated compositions, which require to be diluted before use, usually with water.

Preferably the compositions contain from 0.01% to 90% by weight of the active ingredient. Dilute compositions ready for use preferably contain from 0.01% to 2% of active ingredient, while concentrated compositions may contain from 20% to 90% of active ingredient, although from 20% to 70% is usually preferred.

The solid compositions may be in the form of granules, or dusting powders wherein the active ingredient is mixed with a finely divided solid diluent, e.g. kaolin, bentonite, kieselguhr, dolomite, calcium carbonate, talc, powdered magnesia, Fuller's earth and gypsum. They may also be in the form of dispersible powders or grains, comprising a wetting agent to facilitate the dispersion of the powder or grains in liquid. Solid compositions in the form of a powder may be applied as foliar dusts.

Liquid compositions may comprise a solution or dispersion of an active ingredient in water optionally containing a surface-active agent, or may comprise a solution or dispersion of an active ingredient in a water-immiscible organic solvent which is dispersed as droplets in water.

Surface-active agents may be of the cationic, anionic, or non-ionic type or mixtures thereof. The cationic agents are, for example, quaternary ammonium compounds (e.g. cetyltrimethylammonium bromide). Suitable anionic agents are soaps; salts of aliphatic mono ester of sulphuric acid, for example sodium lauryl sulphate; and salts of sulphonated aromatic compounds, for example sodium dodecylbenzenesulphonate, sodium,calcium, and ammonium lignosulphonate, butylnaphthalene sulphonate, and a mixture of the sodium salts of diisopropyl and triisopropylnaphthalenesulphonic acid.

Suitable non-ionic agents are the condensation products of ethylene oxide with fatty alcohols such as oleyl alcohol and cetyl alcohol, or with alkylphenols such as octyl- or nonyl- phenol (e.g. Agral 90) or octyl-cresol. Other non-ionic agents are the partial esters derived from long chain fatty acids and hexitol anhydrides, for example sorbitan monolaurate; the condensation products of the partial ester with ethylene oxide; the lecithins; and silicone surface active agents (water soluble surface active agents having a skeleton which comprises a siloxane chain e.g. Silwet L77). A suitable mixture in mineral oil is Atplus 411F.

The aqueous solutions or dispersions may be prepared by dissolving the active ingredient in water or an organic solvent optionally containing wetting or dispersing agent(s) and then, when organic solvents are used, adding the mixture so obtained to water optionally containing wetting or dispersing agent(s). Suitable organic solvents include, for example, ethylene dichloride, isopropyl alcohol, propylene glycol, diacetone alcohol, toluene, kerosene, methylnaphthalene, the xylenes and trichloroethylene.

The compositions for use in the form of aqueous solutions or dispersions are generally supplied in the form of a concentrate containing a high proportion of the active ingredient, and the concentrate is then diluted with water before use. The concentrates are usually required to withstand storage for prolonged periods and after such storage, to be capable of dilution with water to form aqueous preparations which remain homogeneous for a sufficient time to enable them to be applied by conventional spray equipment. Concentrates conveniently contain 20-90%, preferably 20-70%, by weight of the active ingredient(s). Dilute preparations ready for use may contain varying amounts of the active ingredient(s) depending upon the intended purpose; amounts of 0.01% to 10.0% and preferably 0.1% to 2%, by weight of active ingredient(s) are normally used.

A preferred form of concentrated composition comprising the active ingredient which has been finely divided and which has been dispersed in water in the presence of a surface-active agent and a suspending agent.

Suitable suspending agents are hydrophilic colloids and include, for example, polyvinylpyrrolidone and sodium carboxymethylcellulose, and the vegetable gums, for example gum acacia and gum tragacanth. Preferred suspending agents are those which impart thixotropic properties to, and increase the viscosity of the concentrate. Examples of preferred suspending agents include hydrated colloidal mineral silicates, such as montmorillonite, beidellite, nontronite, hectorite, saponite, and saucorite. Bentonite is especially preferred. Other suspending agents include cellulose derivatives and polyvinyl alcohol.

The rate of application of the compounds of the invention will depend on a number of factors including, for example, the compound chosen for use, the identity of the plants whose growth is to be inhibited, the formulations selected for use and whether the compound is to be applied for foliage or root uptake. As a general guide, however, an application rate of from 0.001 to 20 kilograms per hectare is suitable while from 0.025 to 10 kilograms per hectare may be preferred.

The compositions of the invention may comprise, in addition to one or more compounds of the invention, one or more compounds not of the invention but which possess biological activity for example herbicides, fungicides, insecticides (optionally with an insecticide synergist) and plant growth regulators. Accordingly in yet a still further embodiment the invention provides a herbicidal composition comprising a mixture of at least one herbicidal compound of formula (I) as hereinbefore defined with at least one other herbicide.

The other herbicide may be any herbicide not having the formula (I).

It will generally be a herbicide having a complementary action in the particular application.

Examples of useful complementary herbicides include: A. benzo-2,1,3-thiadiazin-4-one-2,2-dioxides such as bentazone; B. hormone herbicides, particularly the phenoxy alkanoic acids such as MCPA, MCPA-thioethyl, dichlorprop, 2,4,5-T, MCPB, 2,4-D, 2,4-DB, mecoprop, trichlopyr, clopyralid, and their derivatives (eg. salts, esters and amides); C. 1,3 dimethylpyrazole derivatives such as pyrazoxyfen, pyrazolate and benzofenap; D.Dinitrophenols and their derivatives (eg. acetates) such as dinoterb, dinoseb and its ester, dinoseb acetate; E. dinitroaniline herbicides such as dinitramine, trifluralin, ethalflurolin, pendimethalin, oryzalin; F. arylurea herbicides such as diuron, flumeturon, metoxuron, neburon, isoproturon, chlorotoluron, chloroxuron, linuron, monolinuron, chlorobromuron, daimuron, methabenzthiazuron; G. phenylcarbamoyloxyphenylcarbamates such as phenmedipham and desmedipham; H. 2-phenylpyridazin-3-ones such as chloridazon and norflurazon; I. uracil herbicides such as lenacil, bromacil and terbacil; J. triazine herbicides such as atrazine, simazine, aziprotryne, cyanazine, prometryn, dimethametryn, simetryne, and terbutryn; K. phosphorothioate herbicides such as piperophos, bensulide, and butamifos;; L. thiolcarbamate herbicides such as cycloate, vernolate, molinate, thiobencarb, butylate , EPTC , tri-allate, di-allate, esprocarb, tiocarbazil, pyridate, and dimepiperate; M. 1,2,4-triazin-5-one herbicides such as metamitron and metribuzin; N. benzoic acid herbicides such as 2,3,6-TBA, dicamba and chloramben; 0. anilide herbicides such as pretilachlor, butachlor, alachlor, propachlor, propanil, metazachlor, metolachlor, acetochlor, and dimethachlor; P. dihalobenzonitrile herbicides such as dichlobenil, bromoxynil and ioxynil; Q. haloalkanoic herbicides such as dalapon, TCA and salts thereof; R. diphenylether herbicides such as lactofen, fluroglycofen or salts or ester thereof, nitrofen, bifenox, aciflurofen and salts and esters thereof, oxyfluorfen, fomesafen, chlornitrofen and chlomethoxyfen; S. phenoxyphenoxypropionate herbicides such as diclofop and esters thereof such as the methyl ester, fluazifop and esters thereof, haloxyfop and esters thereof, quizalofop and esters thereof and fenoxaprop and esters thereof such as the ethyl ester; T. cyclohexanedione herbicides such as alloxydim and salts thereof, sethoxydim, cycloxyidim, tralkoxydim, and clethodim;; U. sulfonyl urea herbicides such as chlorosulfuron, sulfometuron, metsulfuron and esters thereof; benzsulfuron and esters thereof such as DPX-M6313, chlorimuron and esters such as the ethyl ester thereof pirimisulfuron and esters such as the methyl ester thereof, 2-[3-(4-methoxy-6-methyl-1,3,5-triazin-zyl)-3-methylureido sulphonyl) benzoic acid esters such as the methyl ester thereof (DPX-LS300) and pyrazosulfuron; V. imidazolidinone herbicides such as imazaquin, imazamethabenz, imazapyr and isopropylammonium salts thereof, imazethapyr; W. arylanilide herbicides such as flamprop and esters thereof, benzoylprop-ethyl, diflufenican; X. amino acid herbicides such as glyphosate and glufosinate and their salts and esters, sulphosate and bialaphos; Y. organoarsenical herbicides such as monosodium methanearsonate (MSMA);; Z. herbicidal amide derivative such as napropamide, propyzamide, carbetamide, tebutam, bromobutide, isoxaben, naproanilide and naptalam; AA. miscellaneous herbicides including ethofumesate, cinmethylin, difenzoquat and salts thereof such as the methyl sulphate salt, clomazone, oxadiazon, bromofenoxim, barban, tridiphane, flurochloridone, quinclorac, dithiopyr and mefanacet; BB. Examples of useful contact herbicides include: bipyridylium herbicides such as those in which the active entity is paraquat and those in which the active entity is diquat; * These compounds are preferably employed in combination with a safener such as dichlormid.

The following Examples illustrate the invention: EXAMPLE 1 This example, describes the preparation of Compound No. 1 in Table I.

Step A Concentrated hydrochloric acid (1.3cm3) was added to a suspension of 5-methoxyanthranilic acid (lug) in water (20cm3) which was then cooled in an ice/salt bath. When the temperature of the acid solution was below 50C, a concentrated aqueous solution of sodium nitrate (0.40g) was added slowly to maintain the temperature. The resulting solution was then added slowly to a cooled solution of sodium sulphide nonahydrate (1.58g), sulphur (0.21g) and sodium hydroxide (0.2g) in water (20cm3) in such a way that the temperature remained below 50C. When the addition was complete, the pH of the mixture was 10 and a yellow precipitate was observed. The mixture was allowed to warm to room temperature, stand for 2 hours and then acidified by the addition of concentrated hydrochloric acid. A precipitate formed.

After stirring for 30 minutes, the precipitate was collected by filtration and washed with water, The washed precipitate was dissolved in a sodium carbonate solution (3.75g in 1.25m3 water) with heating, and the resulting solution filtered while hot. After cooling, the filtrate was acidified and a precipitate formed. The precipitate was collected by filtration and dried under reduced pressure to give a beige solid (0.73g).

Step B Thionyl chloride (60cm3) was added to a suspension of a sample of the crude dry solid, prepared as described in Step A of this example, (94.05%) in dry toluene (300cm3) and the mixture heated at reflux for 1 hour. The mixture was allowed to cool to room temperature to allow the further addition of thionyl chloride. The reaction mixture was contaminated by aqueous sodium hydroxide solution (approximately 5cm3) from a trap. The contaminated mixture was evaporated to dryness and resuspended in dry toluene (250cm3). Thionyl chloride (60cm3) was added to the suspension and the mixture heated at reflux for 3 hours. After cooling, sulphuryl chloride (24.8cm3) was added and the mixture heated at reflux for 2 hours to give an orange solution. The solution was concentrated under reduced pressure and diluted with toluene (200cm3).Excess aqueous ammonia (33% solution, 100cm3) was added slowly and the mixture allowed to stand at room temperature overnight. The mixture was concentrated under reduced pressure to give a solid, which was dissolved in 2M aqueous sodium hydroxide (500cm3). The resulting solution was heated with decolouring charcoal and filtered while hot. On cooling, the filtrate was acidified with concentrated hydrochloric acid and the resulting precipitate was collected by filtration and dried under reduced pressure to give a pale yellow solid (62.92g, 67%), 3-hydroxy-5-methoxy-1,2-benzisothiazole.

EH (CDCl3): 3.8(s)3H; 7.2(d+dd)2H; 7.8(d)1H.

Step C Triethylamine (1cm3) was added to a solution of the 3-hydroxybenzisothiazole (lOg), prepared as described in Step B of this Example, in phosphorous oxychloride (80cm3) and the mixture heated at reflux for 3 3/4 hours. After standing at room temperature overnight, the mixture was concentrated under reduced pressure and the residue dissolved in dichloromethane. The solution was washed with saturated aqueous sodium bicarbonate and brine, dried over anhydrous sodium sulphate, filtered and concentrated under reduced pressure. The crude 3-chloro-5-methoxy-1,2benzisothiazole (5.81g) was used directly without further purification.

Step D Diethylmalonate (0.54g) and anhydrous potassium carbonate (10.24g) were added to a solution of the crude 3-chlorobenzisothiazole (5.81g) prepared as described in Step C of this Example, in methylisobutylketone (50cm3) and the mixture heated at 100 C for 3 3/4 hours. After standing at room temperature overnight the reaction mixture was poured into water. The aqueous mixture was extracted with diethylether. The organic phase was washed with water and brine, dried over anhydrous sodium sulphate, filtered and the filtrate concentrated under pressure to give a mobile oil. The concentrate (11.87g) was further purified by column chromatography (4.5x30cm silica/hexane-diethyl ether, 7:3).

A faster moving compound, 2-carboxyethyl-3-hydroxy-5methoxybenzthiophene, (0.15g) SH (CDCl3): 1.4(t)3H; 3.9(s)3H; 4.4(q)2H; 7.15(dd)1H; 7.3(d)1H; 7.6(d)1H; 1O.2(bs)1H and the desired diethyl 2-(5methoxy-1,2-benzisothiazol-3-yl)-malonate (4.06g), as an oil, were recovered. SH (CDCl3): 1.25(t)6H; 3.91(s)3H; 4.3(q)4H; 5.3(s)lH; 7.2(dd)1H; 7.4(d)1H; 7.8(d)1H.

Step E A sample of the diethylmalonate, prepared as described in Step D of Example 1, (4.06g) was dissolved in dichloromethane under nitrogen and the mixture cooled to -780C with an acetone/dry ice bath. Boron tribromide (25g) was added slowly to the stirred solution. After 1 hour, the reaction mixture was allowed to warm to room temperature and stand overnight. The next day, the reaction mixture was cooled to -780C with an acetone/dry ice bath. Ethanol (approximately 100cm3) was added carefully and all solid material dissolved. The reaction mixture was allowed to warm to room temperature slowly. During this time gas was evolved.After stirring at room temperature for 1 hour, the solution was concentrated under reduced pressure to give a beige solid, a mixture of the desired phenol, diethyl 2-(5-hydroxy-1,2-benzisothiazol-3-yl)-malonate, and 2-(5-hydroxy-1,2 -benzisothiazol-3-yl)-acetic acid. This mixture (3.81g) was used directly in Step F without further purification.

Step F A sample of the crude mixture (3.81g) containing 5hydroxybenzisoxazole, prepared as described in Step E above, was suspended in 8 aqueous hydrobromic acid (40cm3) and the mixture heated at reflux for llk hours. After standing at room temperature overnight, the mixture was poured into water and extracted with diethyl ether. The organic solution was washed with brine, dried over anhydrous sodium sulphate, filtered and the filtrate concentrated under reduced pressure to give a beige solid (0.53g). The aqueous phase was concentrated under reduced pressure. A small volume of water was added and the aqueous phase extracted with diethyl acetate.The ethyl acetate solution was washed with brine, dried over anhydrous sodium sulphate, filtered and the filtrate concentrated under reduced pressure to give a beige solid (2.0g) identical to that isolated from the ether extract, 5-hydroxy-1,2-benzthiazol-3-ylacetic acid (2.53g, 100%), m.p. 151-1520C.

SH (DMSO): 4.05(s)2H; 7.15(dd)1H; 7.35(d)lH; 7.95(d)1H; 9.8(bs)2H.

Step G Concentrated sulphuric acid (3 drops) was added to a solution of the acetic acid (2.42g), prepared as described in Step F above, in methanol (30cm3) and the mixture heated at reflux for 7 hours.

room temperature overnight, the mixture was poured into water and the aqueous mixture extracted with ethyl acetate. The organic phase was washed with aqueous sodium bicarbonate solution and brine, dried over anhydrous sodium sulphate, filtered and the filtrate concentrated under reduced pressure to give a beige solid, methyl 5-hydroxy-1,2-benzthiazol-3ylacetate (2.00g, 75%).

6H (DMSO): 3.65(s)3H; 4.15(s)2H; 7.15(dd)lH; 7.3(d)1H; 7.95(d)1H; 9.85(bs)1H.

Step H Potassium carbonate (0.26g) and 5-chloro-a-a, a, 3, 4-pentafluorotoluene (0.40g) were added to a solution of a sample of the methyl acetate (0.38g), prepared as described in Step G above, dissolved in dry DMSO (1Ocm3) and the mixture stirred at room temperature for i 3/4 hours then heated at 750C for 3/4 hour. After cooling to room temperature the mixture was poured into water and extracted with diethyl ether. The ether extract was washed with brine, dried over anhydrous sodium sulphate, filtered and concentrated under reduced pressure. The concentrate (1.41g) was further purified by preparative thin layer chromatography (silica/hexane - diethyl ether, 7:3) to give a pale yellow solid, Compound No. 1 in Table 1, (0.40g, 56%) m.p.

100-1010C.

Compound No. 9 was produced in an analogous manner using appropriate reagents and starting material.

EXAMPLE 2 This example describes the preparation of Compound No. 2 in Table I.

Concentrated sulphuric acid (6 drops) was added to a solution of Compound No. 1 (0.22g), prepared as described in Example 1, (0.22g) in ethanol (10cm3) and the mixture heated to reflux for 2 hours. After standing at room temperature overnight, crystals were observed. Water was added to the solution and the solid filtered off. The solid was further purified by preparative thin layer chromatography (silica/hexane - diethyl ether, 7:3) to give Compound No. 2 as a solid (0.16g, 71%), m.p.

113.5-114.50C.

Compound No. 4 was produced in an analogous manner using appropriate reagents and starting materials.

EXAMPLE 3 This example describes the preparation of Compound No. 3 in Table I.

A 0.5M solution of potassium bis(trimethylsilyl)amide in toluene 3 (3cm") was added to a stirred solution of Compound No. 1 (0.59g), prepared as described in Example 1, in dry tetrahydrofuran (1Ocm3) cooled to -4O0C by a ethanediol/isopropanol/dry ice bath. The mixture was cooled to -40 C and stirred for 1 1/4 hours. Methyl iodide (0.21g in dry THF (2.3cm3)) was added and the reaction mixture allowed to warm and stand over night at room temperature. The mixture was poured into water and extracted with diethyl ether.The ether solution was washed with brine, dried over anhydrous sodium sulphate, filtered and the filtrate concentrated under reduced pressure to give an oil (0.70g). The oil was further purified by preparative thin layer chromatography (silica/hexane - diethyl ether, 7:3) to give a pale yellow oil, Compound No. 3 (0.42g, 69%).

Compound No. 10 was produced in an analogous manner using appropriate reagents and starting materials.

EXAMPLE 4 This example describes the preparation of Compound No. 5 in Table 1.

Step A 3-Hydroxy-5-methoxy-1,2-benzisothiazole (lOg), prepared as described in Step B of Example 1, was suspended in dry dichloromethane (100cm3) and the mixture cooled under nitrogen to -780C using a dry ice/acetone bath.

- @@ - Boron tribromide (55.3g 21cm3) in dry dichloromethane (20cm3) was added slowly over 15 minutes to the cold stirred suspension and the mixture stirred for 1 hour. On warming to room temperature a gas was evolved and the mixture recooled with an acetone/dry ice bath. The mixture was then allowed to warm slowly and gas was evolved in a steady manner. The mixture was allowed to stand at room temperature overnight, then cooled with an acetone/dry ice bath. Ethanol (150cm3) was added to solution which turned orange. The solution was allowed to warm to room temperature, then concentrated under reduced pressure. The residue was washed with acetone to give a pale yellow solid, 3,5-dihydroxy-1,2-benzisothiazole (8.18g, 89%) m.p. decomposes above 19O0C, with 5% impurities.

EH (CDCl3): 7.1(dd)1H; 7.15(d)1H; 7.75(d)1H.

Step B Potassium carbonate (1.65g) and 5-chloro-a, a, a, 3, 4-pentafluorotoluene (1.43g) were added to a solution of a sample of the crude (1.0g), prepared as described in Step A of example 4, in d and the mixture heated to 100C for 3 3/4 hours. After cooling to room temperature, the mixture was poured into water. After acidification with concentrated hydrochloric acid, the aqueous mixture was extracted diethyl ether. The ether extract was washed with brine, dried over anhydrous sodium sulphate, filtered and the filtrate concentrated under reduced pressure.The concentrate (1.65g) was further purified by preparative thin layer chromatography (silica/hexane-diethylether, 1:1) to give a pale yellow solid, 2-hydroxy-5-(2-chloro-6-fluoro-4 trifluoromethyl phenoxy)-1,2-benzisothiazole (0.23g, 11%), m.p. 183-1850C.

EH (CDC13): 7.3(d)1H; 7.45(dd)lH; 7.5(dd)1H; 7.6(bs)lH; 7.65(d)1H.

Step C Potassium carbonate (0.13g) and methyl bromoacetate (0.14g) were added to a solution of a sample of the benzisothiazole (0.3g), prepared as described in Step B of Example 4, in dry DMSO (5cm3) and the mixture stirred at room temperature for 3 hours. The mixture was poured into water and the aqueous mixture extracted with diethyl ether. The ether extract was washed with brine, dried over anhydrous sodium sulphate, filtered and concentrated under reduced pressure. The concentrate (0.23g) was further purified by preparative thin layer chromatography (silica/hexane-ether, 7:3) to give a yellow solid, Compound No. 5 in Table 1 (0.07g, 19%) m.p.

141-1420C.

Compound Nos. 6, 7, 8, 11, 12 and 13 were also produced in an analogous manner using appropriate starting materials and reagents.

Biological Data The herbicidal activity of the compounds was tested as follows: Each chemical was formulated by dissolving it in an appropriate amount, dependent on the final spray volume, of a solvent/surfactant blend, which comprised 78.2 gm/litre of Tween 20 and 21.8 gm/litre of Span 80 adjusted to 1 litre using methylcyclohexanone. Tween 20 is a Trade Mark for a surface-active agent comprising a condensate of 20 molar proportions of ethylene oxide with sorbitan laurate. Span 80 is a Trade Mark for a surface-active agent comprising sorbitan mono-laurate. If the chemical did not dissolve, the volume was made up to 5cm3 with water, glass beads were added and this mixture was then shaken to effect dissolution or suspension of the chemical, after which the beads were removed. In all cases, the mixture was then diluted with water to the required spray volume.If sprayed independently, volumes of 25cm3 and 30cm3 were required for pre-emergence and post-emergence tests respectively; if sprayed together, 45cm3 was required. The sprayed aqueous emulsion contained 4% of the initial solvent/surfactant mix and the test chemical at an appropriate concentration.

The spray compositions so prepared were sprayed onto young pot plants (post-emergence test) at a rate equivalent to 1000 litres per hectare.

Damage to plants was assessed 13 days after spraying by comparison with untreated plants, on a scale of O to 9 where 0 is 0% damage, 1 is 1-5% damage, 2 is 6-15% damage, 3 is 16-25% damage, 4 is 26-35% damage, 5 is 36-59% damage, 6 is 60-69% damage, 7 is 70-79% damage, 8 is 80-89% damage and 9 is 90-100% damage.

In a test carried out to detect pre-emergence herbicidal activity, crop seeds were sown at 2 cm depth (i.e. sugar beet, cotton, rape, winter wheat, maize, rice, soya) and weed seeds at 1 cm depth beneath compost and sprayed with the compositions at the rate of 1000 litres per hectare. 20 days after spraying, the seedlings in the sprayed plastic trays were compared with the seedlings in unsprayed control trays, the damage being assessed on the same scale of O to 9.

The results of the tests are given in Table III below.

TABLE III Test Plants (see Table IV) COMPOUND PRE-OR RATE OF NO. POST-EMERGENCE APPLN APPLICATION kg/ha BV BN GH GM ZM OS TA PA CA GA AR BP EH IH IL AT XT AF AM AE SH SV DS EC CR C 1 Pre 0.25 0 0 0 0 0 0 0 0 9 5 9 0 6 - 0 7 - 0 0 - 0 0 0 0 0 Post 0.0625 9 9 9 6 9 3 3 - 9 9 - 9 9 9 - 9 9 5 5 7 7 9 9 9 5 2 Pre 0.25 2 0 0 0 0 0 0 6 9 0 9 0 7 - 2 6 - 0 0 - 0 5 5 0 0 Post 0.0625 7 9 9 6 9 2 2 - 9 9 - 9 9 9 - 9 6 5 5 6 7 9 0 7 5 3 Pre 0.25 6 7 2 0 3 9 0 9 9 9 9 7 8 - 0 5 0 2 0 - 0 8 9 5 - 0 Post 0.0625 9 9 9 6 9 5 4 9 9 9 9 6 9 9 - 9 6 5 5 5 8 9 6 9 - 4 4 Pre 0.25 0 5 0 0 1 3 0 9 9 5 9 1 3 - 0 5 0 0 0 - 0 0 9 0 - 0 Post 0.0625 9 9 9 5 9 5 3 9 9 9 9 6 9 9 - 9 6 5 6 5 9 9 9 9 - 4 5 Pre 1 7 6 0 0 0 - 3 5 9 0 9 4 5 - 4 7 0 2 0 - - 3 - 0 0 Post 0.25 9 9 9 9 9 4 3 - 9 9 9 9 9 9 - 9 9 4 4 5 9 9 9 7 5 6 Pre 1 9 2 0 0 0 1 0 5 9 4 9 2 9 - 8 9 - 0 0 - 0 0 3 0 0 Post 0.0625 5 9 9 6 8 3 2 - 9 9 - 9 9 9 - 7 - 5 3 5 9 6 9 2 3 7 Pre 0.25 2 0 0 0 0 0 0 0 5 9 0 9 0 - 0 7 - 0 0 - 0 7 2 0 0 Post 0.0625 9 9 9 8 9 3 2 - 9 9 - 9 9 9 - 9 9 4 3 2 7 7 9 7 2 8 Pre 0.25 5 2 0 0 0 0 0 0 9 0 9 0 7 - 0 9 - 0 0 - 0 0 1 0 0 Post 0.0625 7 9 9 9 7 3 4 - 9 9 - 9 9 9 - 9 - 2 2 5 7 7 7 6 1 TABLE III (continued) Test Plants (see Table IV) COMPOUND PRE-OR RATE OF NO.POST-EMERGENCE APPLN APPLICATION kg/ha BV BN GH GM ZM OS TA PA CA GA AR BP EH IH IL AT XT AF AM AE SH SV DS EC CR C 9 Pre 0.25 0 0 0 0 2 2 0 0 0 - 4 2 1 - 0 2 0 0 0 - 0 0 - 0 - 0 Post 0.0625 5 8 9 5 5 3 4 6 9 9 9 5 8 9 - 8 6 4 5 2 7 7 5 3 - 4 10 Pre 0.25 0 0 0 3 4 0 0 9 0 0 9 0 7 - 0 0 0 0 0 - 0 0 0 0 - 0 Post 0.0625 9 9 9 6 6 3 4 7 9 9 9 5 9 9 - 9 5 4 5 4 6 7 5 6 - 5 11 Pre 0.25 0 0 0 0 5 0 0 0 0 0 3 0 2 - 0 0 0 0 0 - 0 0 0 0 - 0 Post 0.0625 4 7 6 6 5 3 4 6 9 9 9 5 7 9 - 9 5 3 4 0 6 7 - 6 - 2 12 Pre 0.25 0 0 0 0 2 0 0 0 0 5 0 0 0 - 0 0 0 0 0 - 0 0 0 0 - 0 Post 0.0625 4 9 7 5 7 3 3 6 9 9 9 5 6 9 - 9 6 3 4 3 6 9 9 7 - 4 13 Pre 0.25 0 0 0 0 0 2 0 0 0 3 0 0 2 - 0 2 - 3 0 - 0 0 0 0 - 0 Post 0.25 5 5 4 6 5 2 3 2 9 6 9 2 7 3 - 8 5 3 2 2 4 5 6 5 - 2 TABLE IV Abbreviations used for Test Plants BV - Sugar beet BN - Rape GH - Cotton GM - Soybean ZM - Maize OS - Rice TA - Winter wheat PA - Polygonum aviculare CA - Chenopodium album GA - Galium aparine AR - Amaranthus retroflexus BP - Bidens pilosa EH - Euphorbia heterophylla IH - Ipomoea hederacea (post-emergence) IL - Ipomoea lacunosa (pre-emergence) AT - Abutilon theophrasti XT - Xanthium strumarium AF - Avena fatua AM - Alopecurus myosuroides AE - Agropyron repens SH - Sorghum halepense SV - Setaria viridis DS - Digitaria sanguinalis EC - Echinochloa crus-galli CR - Cyperus rotundus CE - Cyperus esculentes CHEMICAL FORMULAE (in description)

CHEMICAL FORMULAE (in description)

Claims (10)

1. CLAIMS 1. A compound of formula (I)

   in which Ar is an optionally substituted aryl or heterocyclic ring system; R1 and R2 are independently selected from H, optionally substituted alkyl, alkenyl or alkynyl, halogen, NRaRb, or R1 may also be optionally substituted aryl, or R1 and R2 together with the carbon to which they are attached form an optionally substituted alkenyl or cycloalkyl or oxirane group;R3 is H, CO2R4, CN, COR4, CH2OR4, CH(OH)R4, CH(OR4)R(5), CH2OSO2R4, CH(OR4)R5, CH2OSO3R4, CH2ONR6R7, CSNH2, COSR4, CSOR4, CONHSO2R4, CONR6R7, NH2, NHCOR10, NHCO2R10,

   6 7 + 6 7 8 - - + 6 7 CONHNR@R@, CONHN+R6R7R8 V , C02 M or COON=CR6R7; M+is an agriculturally acceptable cation; V is an agriculturally acceptable anion; R4, R5 and R10 are independently selected from H or an optionally substituted alkyl, aryl, alkenyl or alkynyl group; R6, R7, R8, R9, Ra and Rb are independently selected from H or an optionally substituted alkyl, alkenyl, aryl or alkynyl group or any two of R6,R7,R8,R9,Ra and Rb together with the atom to which they are attached form a cycloalkyl or heterocyclic ring; R6 and R7 may also be a heterocyclic ring; Y is O or S; X is (CH2)m, CH=CH, CH(ORc)CH2, COCH2; where Rc is H or an optionally substituted alkyl, aryl, alkynyl or alkynyl group; m is 0, 1 or 2; and n is O or 1.
2. 2. A compound according to claim 1 where Ar is optionally substituted phenyl, optionally substituted pyridyl or optionally substituted pyrazolyl.
3. 3. A compound according to claim 1 or claim 2 where R3 is CO2R4, CN, CH2OR4, CSNH2, CONR6R7, CONHNR6R7, CONHN+R6R7R8 Y, COON=CR6R7 or CO2-M+.
4. 4. A compound according to claim 3 where R3 is CO2R4, CN, CONR6R7 or COON=CR6R7.
5. 5. A compound according to claim 4 where R3 is CO2R4.
6. 6. A compound according to any of the preceding claims where Ar is:

   where R18 is N, CH or CR20 and R19 and R20 are independently selected from halogen.
7. 7. A compound according to any of the preceding claims where R1 is H and R2 is H or CH3.
8. 8. A herbicidal composition comprising a compound of formula (I) as defined in claim 1 in combination with a carrier or diluent optionally with another herbicide not of formula (I).
9. 9. A method of killing or controlling the growth of unwanted plants which method comprises applying to the plants or to a locus thereof an effective amount of a compound of formula (I) as defined in claim 1.
10. 10. A process for preparing a compound of formula (I) as defined in claim

    1 comprising a) reacting a compound of formula (II):

    wherein n, X, Y, R1, R2 and R3 are as defined in relation to formula (I) is claim 1 with a compound of formula (III): Ar-Z (III) wherein Ar is as defined in relation to formula (I) in claim 1 and Z is a leaving group, optionally in the presence of a base; or b) where compounds are of formula (I) where n is 1, by reaction of a compound of formula (XI):

    where Ar and W are as defined in relation to formula (I) claim 1 with a compound of formula (XII):

    where X, R1, R2 and R3 are as defined in relation to formula (I) in claim 1 and Z is a leaving group in the presence of a base; and thereafter if desired carrying out one or more of the following steps: i) when R3 is alkoxycarbonyl hydrolysing to the corresponding acid; ii) when R3 is COOH esterifying or forming a salt, amide, sulphonamide, hydrazide or hydrazinium derivative; iii) when R3 is an alcohol, oxidation to the corresponding acid or aldehyde; iv) when R3 is alkoxycarbonyl, reduction to an alcohol; v) when R3 is an amide, dehydration to the corresponding nitrile; vi) where R3 is alkoxycarbonyl, m is 0 and R1 or R2 or both R1 and R2 are hydrogen, base mediated alkylation to the corresponding substituted ester; vii) when R3 is an amide, conversion to the corresponding thioamide.