GB2253846A - Herbicidal substituted naphthalenes and azanaphthalenes - Google Patents

Abstract

A compound of formula (I) <IMAGE> [in which Ar is an optionally substituted aryl or heterocyclic ring system; W is O or NR<1> (where R<1> is hydrogen or lower alkyl); A, B, D are independently selected from =N-, =CR2, NR3 or <IMAGE> E is N-CR<6>R<7>XR<8> or =C-CR<6>R<7>XR<8>, provided that A, B, D and E do not al comprise ring nitrogen atoms; X is (CH2)n, CH=CH, CH(OR<9>)CH2, COCH2 (where n is 0, 1 or 2); R<2> is H, alkyl, haloalkyl, CN, halo or CO2R<10>; R<3> is H, alkyl, haloalkyl, CN or CO2R<11>; R<4> and R<5> are independently selected from H, alkyl, haloalkyl, CN, halo or CO2R<12>, or R<4> and R<5> together with the carbon atom to which they are attached form a C=O; R<6> and R<7> are independently selected from H, optionally substituted alkyl, alkenyl or alkynyl, halogen, NR<13>R<14>, or R<6> and R<7> together with the carbon to which they are attached form an optionally substituted alkenyl or cycloalkyl group; R<8> is CO2R<15>, CN, COR<15>, CH2OR<15>, CH(OH)R<15>, CH(OR<15>)R<16>, CSNH2, COSR<15>, CSOR<15>, CONHSO2R<15>, CONR<16>R<18>, CONHNR<17>R<18>, CONHN+R<15>R<17>R<18>R<x->, CO2-R<19+> or COON=CR<5>R<6>; R<9>, R<15> and R<16> are independently selected from H or an optionally substituted alkyl, alkenyl or alkynyl group; R<13>, R<14>, R<17>, R<18>, are independently selected from H or an optionally substituted alkyl, alkenyl, aryl or alkynyl group or any two of R<13>, R<14>, R<17> and R<18> together with the atom to which they are attached form a cycloalkyl or heterocyclic ring; R<10>, R<11> and R<12> are independently selected from is H or lower alkyl; R<19+> is an agriculturally acceptable cation; and R<x-> is an agriculturally acceptable anion; provided that no more than 2 of A, B or D are C=0 groups and further provided that when A, B and D are all =CH and E is =C=CR<6>R<7>XR<8> (where R<6> and R<7> are H) then X is not (CH2)n (where n is 1 or 2)] are active as herbicides.

Description

NOVEL COMPOUNDS The present invention relates to novel substituted fused ring systems, processes for their preparation, their use as herbicides and herbicidal compositions containing them.

UK Patent Application No 2189238 A describes certain benzheterocyclyl-phenyl ether derivatives which have herbicidal activity.

EP-A-369219 describes certain (heteo)aryloxynaphthyl derivatives which also have herbicidal activity.

According to the present invention there is provided a compound of formula (I): in which Ar is an optionally substituted aryl or heterocyclic ring system; W is O or NR1; where R1 is hydogen or lower alkyl; A, B, D are independetly selected from =N-, =CF, NR or #CR4R5; E is N-CR6R7XR8 or =C-CR6R7XR8, provided that A, B, D and E do not all comprise ring nitrogen atoms; X is (CH2)n, CH=CH, CH(OR9)CH2, COCH2; where n is O, 1 or 2; R2 is H, alkyl, haloalkyl, CN, halo or CO2R1O; R is H, alkyl, haloalkyl, CN or CO2R; R4 and R5 are independently selected from H, alkyl, haloalkyl, CN, halo or CO2R, or R4 and R5 together with the carbon atom to which they are attached form a C=O; R5 and R7 are independently selected from H, optionally substituted alkyl, alkenyl or alkynyl, halogen, NR R14, or R5 and R7 together with the carbon to which they are attached form an optionally subsitituted alkenyl or cycloalkyl group; R8 is CO2R15, CN, COR15, CH2CR15, CH(OH)R15, CH(OR15)R16, CSNH2, COSR15, CSOR15, CONHSO2R15, CONR16R18, CONHNR17R18, CONHN+R15R17R18Rx-, CO2-R19+ or COON=CR17R18;; 9 15 16 R9 R15 and R16 are independently selected from H or an optionally substituted alkyl, aryl, alkenyl or alkynyl group; R13, R14, R17, R18, are independently selected from H or an optionally substituted alkyl, alkenyl, aryl or alkynyl group or any two of R , R14 R17 and R18 together with the atom to which they are attached form a cycloalkyl or heterocyclic ring; R10, R11 and R12 are independently selected from is H or lower alkyl; and R19+ is an agriculturally acceptable cation; and R is an agriculturally acceptable anion; provided that no more than 2 of A, B or D are C=O groups and further provided that when A, B and D are all =CH and E is =C-CR6R7XR8, where R6 and R7 are H, X is not (CH2)n where n is 1 or 2.

The selection of groups A, B, D and E is, of course, interelated so that the bonding of the various groups is reasonable. For instance, when one of A, B, or D is =N- or =CR-, it is essential that one adjacent group is also =N- or =CR2.

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 term "lower" used in relation to alkyl, alkenyl or alkynyl groups means that the group contains up to 3 carbon atoms. The terms "alkenyl" and 1,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 "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 Ar is phenyl.

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

Suitable optional substitutents for the aryl or heterocyclic ring systems Ar and aryl groups R9 R13 R14 R15 R16 R17 and R15 R Ar and aryl , , , , 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 thioalkyl (for example thiomethyl, sulphinylmethyl and sulphonylmethyl).

Preferred positions of substitution when the aryl ring 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.

Preferred groups Ar are groups of sub-formula (i): where R20 is hydrogen or halo; J is N or CR where R is halo or nitro.

Preferably J is a group CR.

Suitable halo groups for R20 and R are fluorine and chlorine. Most preferably one of R20 or R is fluorine and the other is chlorine.

Examples of groups of sub-formula (ii) include groups (a) - (m).

When a compound contains more than one group R2, R4 or R5, they may be the same or different.

Particularly preferred groups of sub-formula (iii) are quinoxalines of formula (p), quinazolines of formula (q), cinnolines of formula (r) and naphthalenes of formula (s).

Examples of optional substituents for alkyl, alkenyl, alkynyl groups R6, R7 R9 R 3, R14, R15 and R16 include one or more groups selected from halo such as fluoro, chloro or bromo; nitro; nitrile; aryl such as phenyl; CO2R, NHCOR, or NHCH2CO2R wherein R is hydrogen, C1-6 alkyl or an agriculturally acceptable cation and R, is hydrogen or C16 alkyl; C16 alkoxy; oxo; S(O)pR where p is O or 1 and R is alkyl (for example thiomethyl, sulphinylmethyl and sulphonylmethyl); amino; mono- or di C16 alkylamino;CONR23R24 wherein R23 and R24 are independently selected from hydrogen, C1-6 alkyl, C2-6 alkenyl or C26 alkynyl or R22 and R23 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 R19+ and R22 include sodium, potassium or calcium ions, sulphonium or sulphoxonium ions such as those of formula S(O)mR15R17R18 where m is O or 1, or ammonium or tertiary ammonium ions of formula N+R15R17R18R26 where R15, R17 and R18 are as herein before defined and R26 is a group as defined for R15.

Suitable substituents for alkyl, alkenyl or alkynyl groups in these cation R15, R17, R18 and R26 include hydroxy and aryl. Suitably where any of R15, R17 R18 and R26 are optionally substituted alkyl, they contain from 1 to 4 carbon atoms.

Particular examples of R15, R17, R18 and 26, in these cations are hydrogen, ethyl, isopropyl 2-hydroxyethyl and benzyl.

Examples of agriculturally acceptable anions Rx include halide ions such as iodide.

Suitable halo groups R6, and R7 include fluorine, chlorine and bromine.

Suitable heterocyclic rings formed from two of R13, R14, R17 and R18 and the atom to which they are attached are pyrrolidine, piperidine and morpholine.

Preferably R6 is H.

Preferably R7 is H or is C1-3 alkyl, in particular methyl.

Preferably R8 is CO2R15.

15 A preferred example of R is optionally substituted C16 alkyl, especially ethyl.

Ar is preferably optionally substituted phenyl.

W is preferably oxygen.

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

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 according to the invention are set out in Table I and II below: TABLE I The compounds in this table are of general formula IA Compound A' B' D' E' Characterising Data 1 NH C=O C=O NCH(CH3)CO2C2H5 NMR (CDCl3) 1.2(t)3H; 1.7(d)3H; 3.5(q)1H; 4.15(q)2H; 5.6(d)1H; 6.7(d)1H; 6.75(m)2H; 7.49(d)1H; 7.45(d)1H; 7.6(s)1H.

2 NH C=O CH2 NCH(CH3)CO2C2H5 NMR (CDCl3):# 1.25(t)3H; 1.55(d)3H; 4.0(s)2H; 4.15(q)2H; 6.2(dd)1H; 6.35(s)1H; 6.7(d)1H; 7.49(dd)1H; 7.6(s)1H; 9.18(s)1H.

TABLE I (Cont/d) Compound A' B' D' E' Characterising Data 3 NCH3 C=O C=O NCH(CH3)CO2C2H5 NMR (CDCl3):# 1.15(t)3H; 1.65(dd)3H; 3.65(s)3H;4.15(q)2H; 5.7(bd)1H; 6.73(m)2H; 7.2(d)1H; 7.45(m)1H; 7.62(s)1H.

4 NC2H5 C=O C=O NCH(CH3)CO2C2H5 NMR (CDCl3):# 1.14(t)3H; 1.4(t)3H; 1.65(d)3H; 4.15(q)2H; 4.25(q)2H; 6.75(m)2H; 5.7(dbroad)1H; 7.28(d)1H; 7.45(dd)1H; 7.65(S)1H.

TABLE II The compounds in this table are of general formula (IB) Compound A" B" D" E" Characterising Data 5 N CH N CCH2CO2CH2CH3 NMR (CDCl3): # 1.3(t)3H;4.2(q)2H; 5.3(s)1H; 7.11(d)1H; 7.2(dd)1H; 7.45(dd)1H; 7.55(d)1H; 7.6(s)1H; 7.75(s)1H.

6 N N CH CCH2CO2CH2CH3 NMR(CDCl3): # 1.2(t)3H; 3.9(s)2H; 4.1(q)4H; 7.15(s)1H; 7.5(d)1H; 7.65(d)1H; 7.7(s)1H; 8.6(d)1H; 9.15(s)1H.

7 CH CH CH CCH2CO2CH2CH3 m.pt 83-84 C 8 CH CH CH CCH2CO2H m.pt 163-164 C Compounds of formula (I) can be prepared by cyclisation of appropriate reactants of formula (it) wherein R and R28 are groups cyclisable to 27 groups of formula -A-B-D-E- or a precursor thereof. The nature of R27 and R28 will be apparent to the skilled chemist in the light of cyclisation techniques reported in the literature and will depend upon the nature of the group -A-B-D-E- required.

By "precursor" is meant groups convertible to a final group by standard chemical manipulations.

Examples of pairs of groups R27 and R28 are set out in Table III.

TABLE III R27 R28 Product groups of sub formula (ii) N02 COCo2R29 quinoxaline group CR6R7XR8 N02 CONHS02CH3 *quinazoline group N02 CONH2 *quinazoline group NH2 COCH3 *cinnoline group where R6 R7 R8 and X are as defined in relation to formula I and R29 is lower alkyl; * indicates that compounds require further derivatisation to prepare compound of formula (I) For example, compounds of formula (I) where the group of sub formula (i) is a quinoxaline may be prepared from compounds of formula (III): wherein Ar, W, X, R6, R7 and R8 are as defined in relation to formula (I) and R29 is lower alkyl by reaction with titanium trichloride in acetone at temperatures from -100 to 250C.

Compounds of formula (III) are prepared from compounds of formula (IV): wherein Ar, W, X, R6, R7, and R8 are as defined in relation to formula (I) by reaction with a compound of formula (V) at 120 C.

Compounds of formula (IV) are prepared from compounds of formula (VI): wherein Ar and W are as defined in relation to formula (I) by reaction with a lower alkyl ester of alanine at 15 to 5O0C, conveniently at room temperature, in a suitable solvent such as DMF in the presence of a base such as triethylamine.

Compounds of formula (V) and (VI) are known or can be prepared from known compounds by known methods.

Alternatively compounds of formula (I) can be prepared by reacting a compound of formula (VII) where Ar is as defined in relation to formula (I) and R31 is a leaving group such as halogen, with a compound of formula (VIII) wherein R32 is hydroxy and A''', B"', D " ' and E"' are equivalent to A, B, D and E respectively or a precursor thereof. The reaction is effected in the presence of a base such as alkali metal carbonates, hydroxides or hydrides.Suitably an organic solvent such as dimethylformamide (DMF), dimethylsulphoxide (DMSO) or lower alkanones such as methylethylketone (MEK) or methylisobutylketone (MIBK) is employed together with temperatures of from 500 to 12O0C. By 'precursor' is meant a group readily convertable to a group A, B, D or E by standard chemical manipulations. For example, when group E"' ios C-hal where hal is halogen, for example chlorine, it may be converted to a group CR6R7XR8 where R6 is as herein before defined, R7 is hydrogen, X is absent (i.e. n is O) and R8 15 is a group C02R by reaction with a compound of formula (IX) in the presence of a base such as potassium carbonate.The reaction is suitably effected in an organic solvent such as methylisobutylketone at elevated temperature of from 110 to 12O0C.

If desired one or more of the following steps may be carried out to convert a compound of formula (I) to another such compound.

i) when R2, R3, R4 or R5 is alkoxycarbonyl hydrolysing to the corresponding acid.

ii) whern R, R , R4 or R5 is COOH esterifying or forming a salt, amide, sulphonamide, hydrazide or hydrazinium derivative.

iii) when R2, R3, R4 or R5 is an alcohol, oxidation to COOH, CHO.

iv) when R2, R3, R4 or R5 is alkoxycarbonyl, reduction to an alcohol.

v) when R2 R3 R4 or R5 is an amide, dehydration to the corresponding nitrile.

vi) where A, B, or D are -C=O reducing one or more of such groups to a group -CR4R5; vii) where A, B or D is NH, converting the hydrogen group to another group R3.

Reaction steps i) to vii) above can all be carried out using conventional chemical conditions which will be readily apparent to the skilled chemist. Specific examples of such reactions are given hereinafter.

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, an 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 monocotyledenous and dicotyledonous species. They may show some selectivity towards certain species; they may be used as selective herbicides in rice and 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 preferbly 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 esters 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 aid.

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 cids and hexitol anhydrides, for example sorbitan monolaurate; the condensation products of the partial ester with ethylene oxide; and the lecithins; 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 di-chloride, 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 conentrate 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 homogenous 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 ingredients(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 comprises 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 suacorite. 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 0.01 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. 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 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 desmed i pham; 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, 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-methylureidosulphonyl) 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, quinchlorac and mefanacet; BB. Examples of useful contact herbicides include: bipyridylium herbicides such as those in whichthe 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 illustrates the preparation of compound 1: Step A M-nitrophenol (14.4g) was dissolved in DMSO (47 cm3) under nitrogen.

The solution was stirred, heated to 8O0C and potassium hydroxide pellets (6.83g) added. After 1Y2 hours at 800C, 5-chloro-3,4-difluorobenzotrifluoride (21.9g) was added dropwise with constant stirring. When the addition was completed, the mixture was stirred and heated at 1400C for 18 hours. After cooling, most of the solvent was removed under vacuum, and the residue partitioned between water and diethylether. The organic phase was separted and the aqueous layer extracted with two further portions of ether. The ether extracts were combined, washed three times with water, dired (MgS04) and filtered.The solvent was removed from the filtrate under vacuum to give 33g of brown oil which was purified by flash chromatography (silica; CHCl3:hexane, 2:3) to give 25.5g of 3-(2' -chloro-4'-trifluoromethyl-6' -fluorophenoxy) nitrobenzene as a yellow oil.

Step B 3-(2' -chloro-4'-trifluoromethyl-6'-fluorophenoxy) nitrobenzene (25.5g) was dissolved in ethylene dichloride (51 cm3) stirred and cooled and in a 3 salt/ice bath and concentrated sulphuric acid (81 cm ) added. The mixture was cooled to -10C and potassium nitrate (8.45g) added portionwise with vigorous stirring at -1 to OOC. When addition was complete the reaction mixture was stirred for 15 minutes at OOC and then allowed to warm to room temperature whilst stirring for a fur ther 18 hours. The mixture was poured into ice/water (400 cm ) and extracted four times with dichloromethane.

The combined dichloromethane extracts were dried (MgS04), filtered and solvent removed from the filtrate under vacuum to give a pale brown oil which was purified by flash chromatography (silica, hexane: EtOAc:85:15) to give 4-(2'-chloro-4'- trifluoromethyl-6'-fluorophenoxy)-1,2-dinitrobenzene (26.78g, 93%) as an oil.

Step C 4-(2'-chloro-4'-trifluoromethyl-6'-fluorphenoxy)-1, 2- dinitrobenzene (2g) was dissolved in dry dimethylformamide (4 cm3). Ethyl alaninate hydrochloride (0.81g) was added with stirring and dissolved over 15 minutes. Triethylamine (1.46 cm3) was then added dropwise causing the clear yellow solution to turn cloudy. The reaction mixture was stirred for 18 hours at room temperature then poured into excess water and extracted with diethyl ether. The extract was washed with water four times and then brine, dried (MgS04), filtered and evaporated at 400C to give 2g of Compound (XII) as an orange oil.

NMR (CDCl3) 1.25(t)3H; 1.6(d)3H; 4.2(q)2H; 6.18(m)2H; 7.45(dd)lH; 7.6(s)1H; 8.2(d)1H; 8.5(d)1H.

Step D The product obtained in step C (0.9g) was treated with excess ethyl oxalyl chloride (5 cm3). The mixture was stirred and heated under gentle reflux for 6 hours, cooled to room temperature, the solvent partially removed at 700C, cooled and poured into ice yielding a yellow semi-solid which was washed with water and dissolved in diethyl ether. The yellow solution was washed with water and then brine, dried (MgS04) filtered and evaporated to give a dark yellow oil which was purified by preparative TLC to give Compound No. (XIII) as a yellow oil (0.35g).

NMR (CDCl3) 1.20(t)3H; 1.22(d)3H; 3.63(s)3H; 4.18(q)2H; 5.03(q)lH; 7.05(dd)lH; 7.4(d)lH; 7.48(dd)lH; 7.65(s)1H; 8.15(d)1H.

Step E The crude product as obtained in step D (1.5g) was dissolved in Rathburn's acetone (30 cm3). The solution was stirred with ice bath cooling and titanium trichloride (30mls,30%) was added dropwise with stirring over v hour. After standing overnight, the reaction mixture was poured into excess cold water and compound 1 as a pale yellow solid filtered off (0.4g).

EXAMPLE 2 This Example illustrates the preparation of Compound 3 in Table 1.

Compound I (1.1g) prepared as described in Example 1, was dissolved in dry toluene (5Cm ) and methyl iodide (0.5g) added. The mixutre was stirred and sodium hydride added in small portions until effervescence ceased.

More methyl iodide (2cm3) was added followed by further portions of sodium hydride until effervescence stopped. The mixture was stirred and heated at reflux for 3 hours. The cooled mixture was poured into excess dilute hydrochloric acid and extracted with ether. The ethereal extract was washed with water, dried (MgS04), filtered and the solvent removed from the filtrate under reduced pressure to give a brown oil. The oil was purified by preparative plate chromatography (six2: ether) to give Compound 3 as an + off-white rigid foam (0.25g) M+ = 488.

NMR (CDC13)E 1.15(t)3H; 1.65(dd)3H; 3.65(s)3H; 4.15(q)2H; 5.7(bd)1H; 6.73(m)2H; 7.2(d)1H; 7.45(m)1H; 7.62(s)1H.

EXAMPLE 3 This Example illustrates the preparation of Compound 2 in Table I.

Compound I (3g) was dissolved in methanol and 2M hydrochloric acid (150cm ) added to produce a fine suspension. Zinc powder (30g) was added and the mixture stirred for 1 hour at room temperature and then 6 hours at 12O0C. After cooling overnight, ether was added and after stirring the mixture was filtered and the ethereal filtrate washed with water, dried (MgS04) filtered and evaporated under vacuum to give a dark oil. The oil was purified by preparative plate chromatography (SiO2: ether) and the top half of the major band R4 0.4 to 0.5 isolated to give a brown oil (0.6g).

Further preparative plate chromatography (SiO2: ether) gave Compound 2 as an oil (O.lg) M+ = 460.

NMR (CDCl3) & 1.25(t)3H; 1.55(d)3H; 4.0(s)2H; 4.15(q)2H + 6.2(dd)1H; 6.35(d)1H; 6.7(d)1H; 7.4(dd)1H; 7.6(s)lH; 9.18(s)1H.

EXAMPLE 4 This Example illustrates the preparation of Compound 5 in Table II.

Step a 5-(2-chloro-6-fluoro-4-rifluoromethylphenoxy)-N (methylsulphonyl)-2-nitrobenzamide (2.3g) was dissolved in acetone (40cm ) and stirred with ice bath cooling while titanium trichloride (40cm of a 30% solution in HC1) was added dropwise over 4 hours. The mixture was stirred at room temperature overnight. Water (150cm3) was added and the precipitate filtered off, washed with water and air dried. The solid was dissolved in sodium bicarbonate solution and extracted with ethyl acetate.

The organic phase was washed with water, dried (MgS04), filtered and the solvent removed from the filtrate under vacuum to give 5-(2-chloro-6 -fluoro-4-(triluoromethylphenoxy)-N-(methylsulphonyl)-2-amino-benzamide (1.5g).

Step b 5-(2-chloro-6-fluoro-4-trifluoromethylphenoxy)-N (methylsulphonyl)-2-aminobenzamide (lg) was stirred and heated at 12O0C with formic acid (12cm3) for 2.5 hours and left at room temperature overnight. The mixture was poured into water forming a precipitate which was filtered off, washed with water and dried to give 4-hydroxy-6 (2-chloro-6-fluoro-4-trifluoromethylphenoxy)quinazoline (0.8g).

m.pt 231-2320C M+ = 358 NMR (DMSO): 7.3(d)1H; 7.6(dd)1H; 7.7(d)1H; 8.0(m)3H; 12.3(bs)lH.

Step c 4-hydroxy-6-(2-chloro-6-fluoro-4-trifluoromethylphenoxy) quinazoline (0.25g) was stirred and heated under reflux with phosphorus oxychloride (4cm3) and phosphorus pentachloride (lug) for 4 hours. The phosphorus oxychloride was removed under vacuum, the solid residue treated with ice and the aqueous mixture extracted with ether (x2). The combined ethereal extracts were washed with water, dried (MgS04) filtered and the solvent removed from the filtrate under vacuum to give 4-chloro-6 (2-chloro-6-fluoro-4-trifluoromethylphenoxy)quinazoline (0.22g) as a pale yellow solid. M+ = 376 NMR (CDCl3) 6 7.45(d)1H; 7.5(dd)lH; 7.65(bs)1H; 7.73(dd)lH; 8.15(d)1H; 9.0(s)1H.

Step d 4-chloro-6-(2-chloro-6-fluoro-4-trifluoromethylphenoxy) quinazoline (lug), diethyl malonate (1.5g) and anhydrous potassium carbonate (5g) were stirred and heated under reflux for 7 hours, then left at room temperature for a day. The mixture was filtered and the residue washed with ethylacetate. The combined filtrate was evaporated under vacuum to give a semi solid residue. This was purified by preparative plate chromatography (six2: ether) the band at RF 0.4 giving ethyl 4-[6 (2-chloro-6-fluoro-4-trifluoromethylphenoxy)quinazolyl] acetate (O.lg as a pale yellow solid, m.pt = 147-1480C M+ = 428.

NMR (CDCl3): 6 1.3(t)3H; 4.2(q)2H; 5.3(s)1H; 7.1(d)1H; 7.2(dd)1H; 7.45(dd)1H; 7.55(d)1H; 7.6(s)1H; 7.75(s)lH.

EXAMPLE 5 This Example illustrates an alternative preparation of Compound No. 5 in Table II.

Step a 2-nitro-5-(2-chloro-6-fluoro-4-trifluoro-methylphenoxy) benzoic acid (4.4g) was stirred and heated under reflux for 2 hours with thionylchloride (50cm3). Excess thionyl chloride was removed under reduced pressure and the residue azetroped with toluene. The residue was dissolved in toluene (20ml) and added dropwise with stirring to 880 ammonia (60ml). The solid formed was filtered off, washed in the water and air dried to give 2-nitro-5-(2-chloro-6-fluoro-4-trifluoromethylphenoxy)-benzamide (3.5g) as an off white solid.

NMR (CNCl3): S 5.85(s)1H; 6.1(s)1H; 6.98(dd)1H; 7.02(d)1H; 7.45(d)lH; 7.65(s)1H; 8.15(d)1H.

Step b 2-nitro-5-(2-chloro-6-fluoro-4-trifluoromethylphenoxy)benzamide (lug) was stirred in a mixture of isopropanol (20cm3) and water (5cm3). Reduced iron powder (3g) and concentrated hydrochloric acid (5 drops) were added, the mixture heated under reflux for 3 hours and then filtered hot through hyflo. The filtrate was evaporated under reduced pressure, the residue partitioned between ether and water and the ether phase washed with water, dried (MgS04) and filtered. The filtrate was evaporated under reduced pressure to give a pale yellow solid (0.7g) which was purified by preparative plate chromatography (SiO2; ether:hexane acetic acid, 12:8:1) to give 2-amino-5-(2-chloro-6-fluoro-4-trifluoromethylphenoxy) benzamide (0.52g) as a pale yellow solid.

m.pt = 99-10O0C M+ = 348 NMR(CDCl3):S 6.l(bd)4H; 6.65(d)1H; 6.85(dd)lH; 7.0(s)1H; 7.37(dd)lH; 7.57(s)lH.

Step c 2-amino-5-(2-chloro-6-fluoro-4-trifluoromethylphenoxy)benzamide (1.25g) and formic acid (20cm ) were stirred and heated under reflux for 6 hours. The mixture was poured into water (200cm ) and the resulting pricipitate filtered off, washed with water and air dried to give 4-hydroxy-6-(2-chloro-6-fluoro-4-trifluoromethylphenoxy)quinazoline (1g).

M+ = 358 NMR(DMSO): b 7.3(d)1H: 7.6(dd)1H; 7.7(d)lH; 8.0(m)3H; 12.3(s)lH.

This compound can be converted to the compound 5 by reactions as described in Example 4 (steps (c) and (d).

EXAMPLE 6 This Example illustrates the preparation of Compound 6 in Table II.

Step a 3-hydroxyacetophenone (6g), 3-chloro-4, 5-difluorobenzotrifluoride (10g) and anhydrous potassium carbonate (10g) were stirred and heated at 110 C for 9 hours in dry DMF(40cm ), with a further addition of potassium carbonate (2g) after 5 hours. The mixture was poured into water, extracted with ether(x3) and the combined ethereal extract washed with water, dried (MgS04), and filtered. The filtrate was evaporated under reduced pressure to give 3-(2-chloro-6-fluoro-4-trifluoromethylphenoxy)acetophenone (12.5g) as a brown oil which solidified at standing.

NMR (CDCl3): b 2.6(s)3H; 7.13(dd)lH; 7.4(m)3H; 7.6(s)lH; 7.7(d)lH.

Step b 3-(2-chloro-6-fluoro-4-trifluoromethylphenoxy) acetophenone (5g) was added slowly to a stirred, ice cooled mixture of a sulphuric acid (20cm3) and 1,2-dichloromethane (1cm3) Potassium nitrate (1.6g) was then added portionwise and the mixture stirred to room temperature overnight. The mixture was poured onto crushed ice, extracted with ether and the ethereal extract washed with water, dried (MgS04) and filtered.The filtrate was evaporated under reduced pressure to give a semi solid residue (5g) a portion of which was purified by preparative plate chromatography (Si02; ether:hexane: acetic acid; 12:8:1) to give 2-nitro-5-(2-chloro-6fluoro-4-trifluoromethylphenoxy)acetophenone as a pale yellow solid m.pt 114-1150C M+ = 377 NMR (CDCl3): 6 2.53(s)3H; 6.85(d)lH; 7.0(dd)1H; 7.48(dd)lH; 7.65(d)1H; 8.18(d)lH.

Step c 2-nitro-5-(2-chloro-6-fluoro-4-trifluoromethylphenoxy)acetophenone (1.lug) crude) in acetone(20cm3) was stirred, with ice bath cooling, and titanium trichloride (20cm3 of 30% solution in hydro-chloric acid) was added dropwise over 3 hours and allowed to warm to room temperature. The mixture was poured into water (300cm ), extracted with ether and the etheral extracted washed with water, dried (MgS04) and filtered.The filtrate was evaporated under vacuum and the residue purified by preparative plate chromatography (six2; ether:hexane: acetic acid, 12:8:1) to give 2-amino-5- (2-chloro-6-fluoro-4-trifluoromethylphenoxy)acetophenone (0.5g) as an orange solid M+=347 NMR(CDCl3): a 2.5(s)3H; 6.1(s)2H; 6.6(d)1H; 6.9(dd)1H; 7.35(d)1H; 7.38(dd)lH; 7.6(s)lH.

Step d 2-amino-5-(2-choro-6-fluoro-4-trifluoromethylphenoxy) acetophenone (1.5g) crude) was stirred in acetic acid (2cm ) andconcentrated hydrochloric acid (50cm ) and cooled to 5 C with an ice bath. A cold solution of sodium nitrite (0.5g in water, 1.5cm ) was added dropwise.

Cold concentrated hydrochloric acid (20cm ) was added slowly and the mixture stirred for 1 hour, filtered and the residue air dried to give 4-hydroxy-6-(2-chloro-6-fluoro-4-trifluoromethylphenoxy) cinnoline (0.6g) as a pink solid m.pt = 212-2130C NMR(DMSO); 6 7.1(d)1H; 77(m)3H; 8.03(m)2H; 13.85(s)1H.

Step e 4-hydroxy-6-(2-chloro-6-fluoro-4-trifluoromethylphenoxy)cinnoline (0.6g) was heated under reflux for 3 hours with phosphorus oxychloride (5cm3). Excess phosphorus oxychloride was evaporated under reduced pressure and the residue dissolved in ether. The ether solution was washed with 2M sodium hydroxide, then water, dried (MgS04) and filtered. The filtrate was evaporated under reduced pressure and the residue purified by preparative plate chromatography (SiO2); ether:hexane:acetic acid, 12:8:1) to give 4-chloro-6-(2-chloro-6-fluoro-4-trifluoromethylphenoxy)cinnoline (0.22g) as a brown solid m.pt 86-870C M+ = 376 NMR (CDCl3): 6 7.26(s)1H; 7.5(dd)lH; 7.7(m)2H; 8.6(d)lH; 9.3(s)1H.

Step f 4-chloro-6-(2-chloro-6-fluoro-4-trifluoromethylphenoxy)cinnoline (lg crude), diethyl malonate (1.5g) and hydrous potassium carbonate (5g) when heated under reflux for 16 hours in methylisobutylketone. Further diethylmalonate (1cm3) was added and reflux continued for 6 hours, when additional diethyl malonate (1cm3) and potassium carbonate 1.5g) were added. Reflux was continued for another 7 hours. The mixture was poured into water, extracted with ether and the ethereal extract washed with water, dried (MgS04) and filtered. The filtrate was evaporated under reduced pressure to give a dark oil which was purified by preparative plate chromatography (SiO2 ether) to give Compound 5 ethyl 4-[6-(2-chloro-6- fluoro-4-trifluoromethylphenoxy)cinnolinyl] acetate (0.13g) as an oil.M+ = 428.

NMR (CDCl3)L 6 1.2(t)3H; 3.9(s)2H; 4.1(q)4H; 7.15(s)lH; 7.5(d)1H; 7.65(dd)1H; 7.7(s)1H; 8.6(d)lH; 9.15(s)1H.

EXAMPLE 7 This Example illustrates the preparation of Compound 7 in Table II.

Step a Ethyl 7-methoxy-naphthalene-1-acetate (2g) prepared as described in J.O.C. 5552, 50(26), 1985, was dissolved in dry dichloromethane under nitrogen and cooled to -750C. Boron tribromide (20cm3 of a 1M solution in dichloromethane) was added dropwise with stirring and the mixture was then warmed to room temperature for 3 hours. After ice bath cooling etanol (10cm ) was added dropwise and the resulting solution allowed to assume room temperature, when the solvents were removed under reduced pressure.

Ethanol (20cm3) and concentrated sulphuric acid (10 drops) were added and the mixture refluxed overnight. The solvents was removed under reduced pressure and the residue dissolved in ether, washed with water (x3) and dried (MgS04). After filtration, the solvent was evaporated from the filtrate under reduced pressure to give a brown oil (lug). A portion (0.2g) was purified by preparative plate chromatography (Si02; ether:hexane: acetic acid 12:8:1 to give ethyl 7-hydroxynaphthalene-1- acetate (0.15g) as a brown solid m.pt 76-770C.

NMR (CDCl3: b 1.2(t)3H; 3.92(s)2H; 4.12(q)2H; 6.65(bs)1H; 7.05(d)H; 7.23(t)lH; 7.32(d)lH; 7.68(d)lH; 7.7(d)1H.

Step b Ethyl 7-hydroxynaphthalene-l-acetate (0.8g crude from step 1), 3-chloro-4,5-difluorobenzotrifluoride (lug) and anhydrous potassium carbonate (3g) were added to dry MIBK (25cm3). The mixture was stirred and heated under reflux for 8 hours. After cooling, the mixture was filtered and the solids washed with ether. The combined filtrate was evaporated under vacuum to give a brown oil (1.4g) which crystallised on standing. A portion (0.5g) was purified using preparative plate chromatography (S:02; ether: hexane:acetic acid, 12:8:1) to give ethyl 7-(2-chloro6-fluoro-4-trifluoromethylphenoxy)naphthalene-1- acetate (0.4g) as a cream coloured solid. m.pt = 83-84 C M+ = 426.

NMR (CDCl3): 6 1.15(t)3H; 3.85(s)2H; 4.05(q)2H; 7.25(m)2H; 7.4(m)3H; 7.62(s)lH; 7.75(d)1H; 7.85(d)lH.

EXAMPLE 8 This Example illustrates the preparation of Compound 8 in Table II.

Compound 6 prepared as described in Example 7 (0.9g) was dissolved in isopropanol (35cm3) and 2M sodium hydroxide (5cm3) added slowly with stirring. The solution was heated under gentle the reflux for 5 hours, cooled and the solvents removed under reduced pressure. The residue was dissolved in water and the solution extracted with ether. The aqueous phase was acidified with 2M hydrochloric acid and the beige precipitate filtered off, washed with water and air dried to give 7-(2-chloro-6-fluoro-4-trifluoromethylphenoxy)naphthalene-1-acetic acid (0.6g). m.pt = 163-1640C M+ = 398.

NMR (CDCl3)a 3.87(s)2H; 7.23(d)3H; 7.4(q)1H; 7.43(m)1H; 7.5(s)1H; 7.78(d)lH; 7.85(s)lH.

EXAMPLE 9 This Example illustrates the preparation of Compound 4 in Table I.

A solution of Compound No. 1 (0.5g) in dry DMF (5cm ) was added slowly to a stirred suspension of 60% sodium hydride (O.lg) in dry DMF (5cm3) at 5-100C. After 30 minutes a solution of ethyl iodide (1cm3) in dry DMF was added slowly and the mixture stirred to room temperature overnight. The mixture was poured onto iced dilute hydrochloric acid and extracted with ether. The ethereal extracts were dried (MgS04), filtered and the filtrate evaporated to dryness under vacuum. The residue was purified by preparative plate chromatography (six2; ether) to give Compound No. 4 (0.13g) as a yellow oil. M+ 502.

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, 45cm 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 spray volume 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 a spray volume equivalent to 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 IV below.

TABLE IV Test Plants (see Table V) 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 CE 1 Post 1 4 7 9 5 6 0 0 4 8 5 9 5 9 - - 2 5 0 2 2 5 6 9 4 - 0 Pre 1 5 0 0 0 0 0 0 0 0 0 0 0 0 - 3 0 0 0 0 - 0 0 0 0 - 0 2 Post 1 0 0 0 0 0 0 0 2 0 - 0 0 0 - 0 0 0 2 0 - 0 0 0 0 0 Pre 1 3 8 8 7 6 0 2 8 8 5 9 4 6 5 - 5 5 2 2 0 6 8 2 4 0 3 Post 1 9 0 0 0 0 0 0 9 9 - 9 2 9 - 0 8 0 0 0 - 0 8 - 0 0 Pre 1 9 9 9 9 5 2 4 8 9 - 9 7 9 8 - 9 9 4 3 6 3 7 2 2 2 4 Post 1 5 7 2 0 0 0 0 - 9 0 9 5 8 - 0 9 0 2 3 - 5 8 - 3 0 Pre 1 9 9 9 9 9 3 3 - 9 7 9 9 9 9 - 9 9 4 3 5 9 7 9 5 6 5 Post 1 0 0 0 0 0 0 0 - 0 - 0 0 0 - 2 0 0 0 0 - 0 0 0 0 0 Pre 0.25 3 4 3 7 4 2 5 7 7 - 7 4 6 3 - 5 4 3 4 0 5 5 6 6 3 6 Post 1 0 7 0 0 0 0 0 8 9 - 9 0 5 - 0 4 4 5 0 - 0 0 0 0 0 Pre 0.25 0 3 7 6 0 0 4 7 9 - 9 3 8 7 - 4 4 5 4 0 4 3 3 0 0 7 Post 1 0 9 2 0 0 2 0 - - - 9 6 9 - 3 9 0 0 0 - 0 9 0 0 0 Pre 0.25 5 - 9 9 7 0 1 - 9 - 9 7 7 0 - 9 7 1 1 2 3 4 7 0 0 8 Post 1 0 7 1 0 0 0 0 - - - 9 2 9 - 0 7 0 0 0 - 0 5 0 0 0 Pre 0.25 6 - 9 5 1 0 1 - 9 - 9 5 8 7 - 9 7 1 1 0 2 3 0 0 1 - TABLE V 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 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 CE - Cyperus esculentus 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; W is O or NR where R is hydogen or lower alkyl; A, B, D are independently selected from =N-, =CR, NR or #CR4R5 E is N-CR6R7XR8 or =C-CR6R7XR8, provided that A, B, D and E do not all comprise ring nitrogen atoms; 9 X is (CH2)n, CH=CH, CH(OR )CH2, COCH2; where n is 0, 1 or 2; R is H, alkyl, haloalkyl, CN, halo or CO2R10 R3 is H, alkyl, haloalkyl, CN or C02R11; R4 and R5 are independently selected from H, alkyl, haloalkyl, CN, halo or CO2R, or R4 and R5 together with the carbon atom to which they are attached form a C=O;; R6 and R7 are independetly selected from H, optionally substituted alkyl, alkenyl or alkynyl, halogen, NR R14, or R6 and R7 together with the carbon to which they are attached form an optionally subsitituted alkenyl or cycloalkyl group; R8 is CO2R15, CN, COR15, CH2OR15, CH(OH)R15, CH(OR15)R16, CSNH2, COSR15, CSOR15, CONHSO2R15, CONR16R18, CONHNR17R18, CONHN+R15R17R18Rx-, CO2-R19+ or COON=CR5R6; R9, R15 and R16 are independently selected from H or an optionally substituted alkyl, aryl, alkenyl or alkynyl group; R13, R14, R17, R18, are independently selected from H or an optionally substituted alkyl, alkenyl, aryl or alkynyl group or any two of R13, R14, R17 and R18 together with the atom to which they are attached form a cycloalkyl or heterocyclic ring; R10 R and R12 are independetly selected from is H or lower alkyl;; and R19+ is an agriculturally acceptable cation; and Rx- is an agriculturally acceptable anion; provided that no more than

   2 of A, B or D are C=0 groups and further provided that when A, B and D are all =CH and E is =C-CR6R7XR8, where R6 and R7 are H, X is not (CH2)n where n is 1 or 2.
2. 2. A compound according to claim 1 wherein W is oxygen.
3. 3. A compound according to clain 1 or claim 2 wherein Ar is a group:

   where J is N or CR21 where R21 is halo or nitro and R20 is H or halo.
4. 4. A compound according to any of the preceeding claims wherein CR6R7XR8 is

   where 15 R7 is H or Cl-3 alkyl and R8 is C02R 15
5. 5. A compound according to claim 4 in which R is C16 alkyl.
6. 6. A compound according to any one of the preceeding claims wherein A, B, D and E together with the ring to which A and E are attached forms a quinoxaline, quinazoline, cinnoline or naphthalene ring.
7. 7. A process for preparing a compound of formula (I) by cyclisation of a compound of formula (II):

   where Ar and W are as defined in relation to formula (I) in claim 1 and R27 and R28 are groups cyclisable to groups of formula -A-B-D-E or a precursor thereof.
8. 8. A process according to claim 7 wherein R27 is N02 or NH2 and R28 is COCH3, CONH2, CONHS02CH3 or

   where R29 is lower alkyl and R6, R7, R8 and X are as defined in relation to formula (I) in claim 1.
9. 9. A herbicidal composition comprising a compound of formula (I) as defined in claim 1 in combination with a carrier or diluent.
10. 10. 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.