GB2237570A - Hydrazide and hydroxylamine herbicides - Google Patents

Abstract

A compound of the formula (I> <IMAGE> wherein R<1> and R<2> each independently stand for hydrogen, optionally substituted lower hydrocarbyl, optionally substituted lower hydrocarbyloxy, or optionally substituted lower hydrocarbylthio; <IMAGE> wherein R<5>, R<6>, and R<7> each independently stand for hydrogen, optionally substituted heterocyclyl, or acyl, or R<6> and R<7> together with the nitrogen atom to which they are attached may form a 4, 5, or 6-membered ring and R<8> and R<9> are each independently hydrogen or optionally substituted lower hydrocarbyl, or together with the carbon atom to which they are attached, form a 5- or 6- membered carbocyclic ring; R<4> stands for hydrogen, halogen, optionally substituted lower hydrocarbyl, optionally substituted lower hydrocarbyloxy, optionally substituted lower hydrocarbylthio, optionally substituted lower hydrocarbylsulphinyl, or optionally substituted lower hydrocarbylsulphonyl; n is 0, 1, 2, or 3; R<4> and each Z is independently -N= or = C-, is useful as a herbicide.a

Description

HERBICIDES This invention relates to hydrazide derivatives useful as herbicides, to processes for preparing them, and to herbicidal compositions and methods utilising them.

According to the present invention there are provided hydrazide derivatives of the formula (I)

wherein R1 and R2 each independently stand for hydrogen, optionally substituted lower hydrocarbyl, optionally substituted lower hydrocarbyloxy, or optionally substituted lower hydrocarbylthio;

wherein R5, R6, and R7 each independently stand for hydrogen, optionally substituted lower hydrocarbyl, optionally substituted heterocyclyl, or acyl, or R6 and R7 together with the nitrogen atom to which they are attached may form a 4, 5, or 6-membered ring; and R8 and R9 are each independently hydrogen or optionally substituted lower hydrocarbyl or heterocyclyl, or together with the carbon atom to which they are attached, form a 5- or 6- membered carbocyclic ring;; R4 stands for hydrogen, halogen, optionally substituted lower hydrocarbyl, optionally substituted lower hydrocarbyloxy, optionally substituted lower hydrocarbylthio, optionally substituted lower hydrocarbylsulphinyl, or optionally substituted lower hydrocarbylsulphonyl; n is 0,1,2, or 3; and each Z is independently -N or

The term lower hydrocarbyl used above, whether representing a substituent on its own or whether it is part of the definition of a larger group (e.g. as in hydrocarbyloxy, hydrocarbylthio etc) is intended to include hydrocarbyl groups having for example from 1 to 8 carbon atoms. A sub-class of such hydrocarbyl groups includes those having from 1 to 6 carbon atoms. A further subclass of such hydrocarbyl groups comprises those having from 1 to 4 carbon atoms.The term lower hydrocarbyl therefore includes for example C16 alkyl including both straight and branched chain isomers (e.g. methyl, ethyl, propyl, and hexyl); cycloalkyl of 3 to 6 carbon atoms (e.g. cyclopropyl, cyclobutyl and cyclohexyl); C2 toC6 alkenyl including for example allyl and crotyl; C2 to C6 alkynyl (e.g. propynyl); and phenyl.

When the lower hydrocarbyl moiety is substituted, there may be one or more substituents. Examples of substituents include halogen (i.e. fluorine, chlorine, bromine, and iodine); C14 alkoxy; C14 alkylthio; cyano; carboxy,. and salts, amides and esters thereof; alkanoyl of 2 to 4 carbon atoms; and phenyl optionally substituted by one or more C14 alkyl, C14 alkoxy, C14 alkylthio, nitro, fluorine, chlorine, bromine, cyano, or CF3 groups.

When the lower hydrocarbyl radical is a substituted phenyl radical, the substituents may include one or more of the substituents listed in the last foregoing paragraph, and may also include nitro and optionally substituted alkyl.

When one or more of the groups R5, R6, and R7 is a heterocyclic radical, it may for example be a pyridyl, pyrimidinyl, triazinyl, thiazolyl, furyl, or oxazolyl radical. When the heterocyclic radical is substituted, it may bear one or more of the substituents mentioned above in relation to substitution of the lower hydrocarbyl moiety. When one or more of R5, R6, and R7 is an acyl radical, it may for example be an alkanoyl radical of 2 to 6 carbon atoms (e.g. an acetyl or propionyl group), an alkanesulphonyl radical of 1 to 6 carbon atoms (e.g. a methanesulphonyl radical), or a benzoyl radical optionally substituted by one or more of the substituents listed above in relation to substitution of the lower hydrocarbyl moiety.When R6 and R7 together with the nitrogen atom to which they are attached form a heterocyclic ring, the ring may be for example an optionally substituted pyrrolidine.

piperidine, morpholine, or piperazine ring, optionally substituted for example by one, two, or more methyl groups.

The expression "salts and esters thereof" used above in relation to carboxy substitution includes for example salts formed from alkali metals (e.g. sodium, potassium and lithium), alkaline earth metals (e.g. calcium and magnesium), the ammonium ion, and substituted ammonium ions wherein one, two, three, or four of the hydrogen atoms have been replaced by optionally substituted C16 hydrocarbyl moieties as defined above, and esters wherein the esterifying group comprises an optionally substituted hydrocarbyl radical of for example 1 to 20 carbon atoms.

The esterifying group may be for example a C18 alkyl group, for example a methyl, ethyl, propyl or butyl group.

A sub-class of compounds according to the invention comprises compounds of formula (I) in which R is a group

in which one, two or three of the groups R5, R6, and R7 is a C1-4 alkyl group, and any group which is not a C1-4 alkyl group is a hydrogen atom. A further subclass of compounds according to the invention comprises compounds of formula (I) in which R3 is as defined in the last foregoing paragraph and the C1-4 alkyl group is a methyl group.

Another sub-class of compounds according to the invention comprises compounds of formula I in which z is a -CH group; R1 and R2 independently stand for C14 alkyl or C14 alkoxy groups; R3 is a group

in which each of R51 R6, and R7 is a hydrogen atom, or a methyl group, at least two of 5 6 7 R , R6, and R being methyl groups; and R4 is hydrogen.

A further sub-class of compounds according to the invention comprises compounds of formula (I) wherein: Z is a -N group in the ring bearing the -COR3 group, and is -CH= in the other ring; R1 and R2 independently stand for C14 alkyl or C14 alkoxy groups; R3 is a

group in which each of R5 R6, and R7 is a hydrogen atom or a methyl group, at least two of R5, R6, and R7 being methyl groups; and R4 is hydrogen.

Particular examples of compounds according to the invention and having the formula (II) are listed in Table I below: TABLE I

Compound R1 R2 R3 R4 Z 1 CH3O CH3O -NHN(CH3)2 H CH 2 CH3O CH3O -NHN(CH3)2 H N n 3 CH3O CH3O -NHN 0 H N 4 CH3O CH3O -NHN S H N 5 CH3O CH30 -NHNHPh H H The compounds of the invention may be prepared by a variety of processes.Thus, for example, they may be prepared by reacting an activated form of a suitably substituted benzoic or -picolinic acid of formula (III)

with a hydrazine or hydroxylamine derivative of formula HN(R5)-NR6R7, HN(R5)-N=CR8R9, or

The acid may be converted to an activated form by reaction with, for example a di-imide (e.g. dicyclohexyl carbodiimide) or carbonyl bis imidazole. Alternatively the acid may be converted to the corresponding acid chloride by treatment with a chlorinating agent, for example thionyl chloride or oxalyl chloride. The reactants are preferably used in substantially equimolar proportions, and the reaction is preferably carried out in an inert solvent or diluent for the reactants. Examples of solvents or diluents include liquid hydrocarbons, liquid chlorinated hydrocarbons, and ethers.

The reaction is preferably carried out at a temperature below the ambient temperature (i.e. below 200C) and preferably at a temperature in the range -50C to 50C. The compound (I) may be isolated by conventional methods, for example by filtering the reaction mixture to remove insoluble reaction products (e.g. N,N1 dicyclohexylurea when dicyclohexylcarbodiimide is used as the coupling agent) and evaporating the filtrate. The product so obtained may be purified further for example by recrystallisation.

Alternatively, the compound of the invention may be prepared by reaction of a compound of formula (IV) with a pyrimidine or triazine of formula (V) where X is a leaving group, for example CH3SO2, as shown in the scheme below

A number of the substituted pyrimidyloxy-benzoic and -picolinic acids of formula III required as starting materials in the above process are known in themselves.

Where particular compounds of formula III are not known, they may be prepared by the processes used for the known compounds, using appropriately substituted starting materials.

Other ways of preparing the compounds of the invention will be apparent to those skilled in the art.

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 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 as selective herbicides in maize 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). 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, whlich 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 nonylphenol (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 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 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. 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-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 (nSnA); 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 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 invention is illustrated by the following Examples. The abbreviations used in the Examples have the following meanings: nmr spectrum: nuclear magnetic resonance spectrum.

(This refers to the proton magnetic resonance spectrum unles otherwise stated). The following abbreviations are used to indicate the multiplicity of the peaks in the NMR spectrum: s (singlet); d (doublet); t (triplet); q (quartet) m (multiplet; br (broad). The nmr spectra were obtained using solutions in deuterochloroform unless otherwise stated.

IR spectrum: infra-red absorption spectum.

NS: mass spectrum GC: gas chromatography TLC: thin layer chromatography m.p.: melting point b.p: boiling point EXAMPLE 1 This Example illustrates the preparation of a compound according to the invention.

A solution of dicyclohexylcarbodiimide (0.25g) in dry dichloromethane (5 ml) was stirred and cooled in an ice bath while 1,1-dimethylhydrazine (0.lml) was added slowly.

2 [(4,6-dimethoxypyrimidin-2-yl) oxy] benzoic acid (0.3g) (known compound; see Japanese Patent application Kokai no 174059/1987) was then added and the mixture stirred with cooling in an ice bath for 2 hours and then left to stand at room temperature for 72 hours. The mixture was filtered to remove N,N1-dicyclohexylurea and the filtrate evaporated under reduced pressure. The residue was applied to a thin layer chromatographic plate (silica gel, 2mm) and developed with chloroform: ethanol (95:5) mixture. The major band was removed and extracted with ethyl acetate. This was evaporated under reduced pressure to give a white semi-solid.This was diluted with a little ether, and the white solid which separated was collected and dried to give the product, N-dimethylamino-3- (4,6-dimethoxypyrimidin-2-yl)oxy) benzamide (Compound 1 of Table I)(0.15g) with melting point 133-1340.

The H1 nmr spectrum of this compound was consistent with the structure assigned, with peaks as follows: 2.5 (s); 3.8 (s); 7.2 (d); 7.35 (t); 7.5 (m) and 8.0 (d).

EXAMPLE 2 This Example illustrates the preparation of further compounds according to the invention.

3( (4,6-dimethoxypyrimidin-2-yl)oxy]-2-picolinic acid (0.3g) was suspended in dry toluene (50ml) and oxalyl chloride (0.2ml) added. The suspension was heated to 1000C, when most of the acid had dissolved. The suspension was filtered and the filtrate evaporated to about half its volume under reduced pressure. 1,1 Dimethylhydrazine (0.2ml) was added to the solution with vigorous stirring, and the solution stirred for about 30 minutes at room temperature. The solution was pqured into water and the mixture extracted three times with ethyl acetate. The combined ethyl acetate extracts were washed twice with water and then with brine, and then dried (MgSO4) and evaporated to leave an orange oil.This was taken up in dichloromethane and applied to a preparative scale thin layer chromatographic plate (silica gel). This was developed with ethyl acetate methanol (95:5) and the product (0.03g) recovered by extraction into ethyl acetate. The product, N-dimethylamino-3[(4,6-dimethoxypyrimidin-2-yl)oxy] -2- picolinalide, Compound No. 2 of Table 1, was obtained as a colourless oil 1H nmr dati: 8 8.42(2H,m); 7.65(1H,d); 7.55(1H,q); 5.75(1H,s); 3.8(6H,s); 2.62(6H,s).

Using esentially the above procedure, the following compounds were prepared: N-(Morpholino)-3-[4,6-dimethoxypyrimidin-2-yl)oxy] -2-picolimamide. (Compound No. 3 of Table 1).

1H nmr data: a 8.55(1H, broad s); 8.45(1H, broad s); 7.65(1H,broad s); 7.55(1H,m); 5.75(1H, s); 3.80(4H,t); 3.75(6H,s); 2.9(4H,t).

N-(piperdinol-3-1(4,6-dimethoxypyrimidin-2-yl)oxy] -2-picolinalide. (Compound No. 4 of Table 1).

The mass spectrum of this product showed that it contained a proportion of another compound, probably the amide resulting from piperidine present as an inpurity in the N-aminopiperidine used as starting material.

N-(anilino)-3-[(4,6-dimethoxypyrimidin-2-yl)oxy] -2-picolinaside. (Compound No. 5 of Table 1).

1H nmr data: S 9.45(1H,broad d); 8.5(1H,broad d); 7.7(1H, broad d); 7.55(1H,m); 7.2(3H,m); 6.85(2-3H,m); 62(1H,d); 5.7(1H,s); 3.8(6H,s).

EXAMPLE 3 This Example illustrates the herbicidal properties of a compound according to the invention.

Each compound in the appropriate concentration was incorporated into a 4% emulsion of methylcyclohexanone and 0.4% blend of 3.6 parts Tween 20. 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 monolaurate. Formulation was effected by dissolving the compound in the requisite amount of solvent/surfactant blend and diluting with water to a final spray volume of 45ml.

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 0 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. Sb, Ct, Rp, Ww, Mz, Rc, Sy) 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 0 to 9.

The results of the tests are given in Table 2 below. TABLE II

COMPOUND RATE OF PRE- OR NO APPLN POST kg/ha EMERGENCE APPLN Sb Rp Ct Sy Mz Rc Vw Br Pi Ca Ga Am Bd Eh Ip Ab Xa Xs Av Al Ag Sh St Dg Ec Ce 1 0.015 Pre 8 2 2 2 0 3 0 - 0 9 - 7 0 5 0 3 - - 0 3 - 6 - 0 5 Post 6 3 3 5 4 4 5 - 6 8 5 7 5 3 3 0 - 2 5 6 7 7 5 5 3 3 2 0.0156 Pre 0 0 0 0 0 0 2 - 0 0 0 0 0 0 2 0 0 - 0 0 - 0 3 0 0 Post 5 5 4 4 0 2 3 - - 7 0 8 0 6 5 0 - 4 6 5 5 6 6 5 7 3 3 0.0156 Pre 0 0 0 - 0 3 2 - - 0 0 0 0 0 3 0 0 - 0 0 - 0 2 0 0 Post 6 5 4 0 2 2 3 - - 6 0 6 0 5 5 4 - 3 3 4 5 6 5 5 6 3 5 0.0625 Pre 0 0 0 0 0 0 0 - 0 0 0 0 0 0 0 0 0 - 0 0 - 0 5 5 0 Post 6 5 5 5 0 3 3 - - 7 3 9 2 6 5 3 - 4 6 5 5 9 6 6 6 3 Abbreviations used for Test Plants Sb - Sugar beet Rp - Rape Ct - Cotton Sy - Soybean Mz - Maize Ww - Winter wheat Rc - Rice Bd - Bidens pilosa Ip - Ipomoea lacunosa (pre-emergence) Ipomoea hederacea (post-emergence) Am - Amaranthus retroflexus Pi - Polygonum aviculare Ca - Chenopodium album Ga - Galium aparine Xa - Xanthium spinosum Xs - Xanthium strumarium Ab - Abutilon theophrasti Eh - Euphorbia heterophylla Av - Avena fatua Dg - Digitaria sanguinalis Al - Alopecurus myosuroides St - Setaria viridis Ec - Echinochloa crus-galli Sh - Sorghum halepense Ag - Agropyron repens Ce - Cyperus esculentus

Claims (9)

1. CLAIMS 1. A hydrazide derivative of the formula (I)

   wherein R1 and R2 each independently stand for hydrogen, optionally substituted lower hydrocarbyl, optionally substituted lower hydrocarbyloxy, or optionally substituted lower hydrocarbylthio; R3is a group - N

   a group N

   a group

   wherein R5, R6, and R7 each independently stand for hydrogen, optionally substituted heterocyclyl, or acyl, or R6 and R7 together with the nitrogen atom to which they are attached may form a 4, 5,or 6-membered ring and R8 and R9 are each independently hydrogen or optionally substituted lower hydrocarbyl, or together with the carbon atom to which they are attached, form a 5- or 6- membered carbocyclic ring;; R4 stands for hydrogen, halogen, optionally substituted lower hydrocarbyl, optionally substituted lower hydrocarbyloxy, optionally substituted lower hydrocarbylthio, optionally substituted lower hydrocarbylsulphinyl, or optionally substituted lower hydrocarbylsulphonyl; n is 0,1,2, or 3; and each Z is independently -N or
2. 2. A hydrazide derivative as claimed in claim 1, wherein R3 is a group of formula

   in which one, two, or three of the groups R5, R6 and R7 is a C1-4 alkyl group, and any group which is not a C1-4 alkyl group is a hydrogen atom.
3. 3. A hydrazide derivative as claimed in claim 2 wherein the C1-4 alkyl group is a methyl group.
4. 4. A hydrazide derivative as claimed in any of claims 1 to 3 wherein z is a -CH= group; R1 and R2 independently stand for C1-4 alkyl or C14 alkoxy groups R3 is a group

   in which each of R5, R6 and R7 is a hydrogen atom or a methyl group at least two of R5, R6 and R7 being methyl groups; and R4 is hydrogen.
5. 5. A hydrazide derivative as claimed in any of claims 1 to 3 wherein Z is a -N- group in the ring bearing the -COR3 group, and is -CH= in the other ring; R1 and R2 independently stand for ClA alkyl or ClA alkoxy groups; R3 is a -N(R5)

   group in which each of R5, R6 and R7 is a hydrogen atom or a methyl group, at least two of R5, R6 and R7 being methyl groups; and R4 is hydrogen.
6. 6. A process of severely damaging or killing unwanted plants, which comprises applying to the plant, or to the growth medium of the plants a herbicidally effective amount of a compound as defined in any of the foregoing claims.
7. 7. A herbicidal composition, comprising as an active ingredient a compound as defined in any of the foregoing claims in admixture with an inert carrier comprising a solid or liquid diluent.
8. 8. A herbicidal composition as claimed in claim 7 which further comprises a surface-active agent.
9. 9. A herbicidal composition as claimed in claim 7 or claim 8, which further comprises at least one other herbicide not of the formula (I).