WO2020193322A1

WO2020193322A1 - Sulfonamides and their use as herbicides

Info

Publication number: WO2020193322A1
Application number: PCT/EP2020/057498
Authority: WO
Inventors: Jeffrey Steven Wailes; Mary Bernadette Aspinall; Ian Thomas Tinmouth HOULSBY; Elizabeth Catherine FRYE; Breno Fernandes CAMPOS; Anne Mary SEVILLE
Original assignee: Syngenta Crop Protection Ag
Priority date: 2019-03-22
Filing date: 2020-03-18
Publication date: 2020-10-01
Also published as: GB201903993D0

Abstract

The present invention relates to compounds of Formula (I), wherein R¹ and R² are as defined herein. The invention further relates to herbicidal compositions which comprise a compound of Formula (I) and to the use of compounds of Formula (I) for controlling weeds, in particular in crops of useful plants.

Description

SULFONAMIDES AND THEIR USE AS HERBICIDES

The present invention relates to novel herbicidal compounds, to processes for their preparation, to herbicidal compositions which comprise the novel compounds, and to their use for controlling weeds, in particular in crops of useful plants, or for inhibiting plant growth.

Herbicidal sulfonamides are disclosed in GB2012170A. The present invention relates to novel herbicidal sulfonamide compounds which show improved properties compared to the known sulfonamide compounds. In particular, the compounds of the present invention show significantly improved activity towards Amaranthus sp, the effective control of which is an increasing problem in agriculture.

Thus, according to the present invention there is provided a compound of Formula (I):

wherein

R¹ is -CH₃ or chloro;

R² is selected from the group consisting -CH₃, -CH₂F, -CHF₂, -CF₃, -CH₂CH₂F, and -CF₂CF₂H.

Compounds of Formula (I) contain an asymmetric centre and may be present as a single enantiomer or pairs of enantiomers in any proportion. Typically one of the enantiomers has enhanced biological activity compared to the other possibilities. In the context of the present invention, the S-enantiomer is particularly preferred. Thus, in a further aspect of the present invention there is provided a compound of Formula (la):

In a preferred embodiment of the present invention there is provided a compound of Formula (I) or Formula (la) wherein R¹ is -CH₃.

In another embodiment of the present invention there is provided compound of Formula (I) or Formula (la) wherein R¹ is chloro.

In a further embodiment, there is provided a compound of Formula (I) or Formula (la) wherein R² is -CH₃.

In another embodiment of the present invention there is provided a compound of Formula (I) or Formula (la) wherein R² is selected from the group consisting of - CH₂F, -CHF₂, -CF₃, -CH₂CH₂F and -CF₂CF₂H. In a further embodiment, R² is selected from the group consisting of -CH₂F, -CHF₂ and -CF₃.

The compounds of Formula (I) according to the invention can be used as herbicides by themselves, but they are generally formulated into herbicidal compositions using formulation adjuvants, such as carriers, solvents and surface- active agents (SAA). Thus, the present invention further provides a herbicidal composition comprising a herbicidal compound according to the present invention and an agriculturally acceptable formulation adjuvant. The composition can be in the form of concentrates which are diluted prior to use, although ready-to-use compositions can also be made. The final dilution is usually made with water, but can be made instead of, or in addition to, water, with, for example, liquid fertilisers, micronutrients, biological organisms, oil or solvents.

As outlined above, the compounds of the present invention contain an asymmetric centre. As such, the compound of the present invention may be present in the composition as a racemic mixture of the two enantiomers. Alternatively, the compound of the present invention may be present in an enantiomer enriched form. For example, with regard to the Compound of Formula (I) in the composition, >50%, more preferably >60%, more preferably >70%, more preferably >80%, more preferably >85%, more preferably >90%, more preferably >95% is present as the enantiomer depicted in Formula (la).

The herbicidal compositions generally comprise from 0.1 to 99 % by weight, especially from 0.1 to 95 % by weight, compounds of Formula I and from 1 to 99.9 % by weight of a formulation adjuvant which preferably includes from 0 to 25 % by weight of a surface-active substance.

The compositions can be chosen from a number of formulation types. These include an emulsion concentrate (EC), a suspension concentrate (SC), a suspo- emulsion (SE), a capsule suspension (CS), a water dispersible granule (WG), an emulsifiable granule (EG), an emulsion, water in oil (EO), an emulsion, oil in water (EW), a micro-emulsion (ME), an oil dispersion (OD), an oil miscible flowable (OF), an oil miscible liquid (OL), a soluble concentrate (SL), an ultra-low volume suspension (SU), an ultra-low volume liquid (UL), a technical concentrate (TK), a dispersible concentrate (DC), a soluble powder (SP), a wettable powder (WP) and a soluble granule (SG). The formulation type chosen in any instance will depend upon the particular purpose envisaged and the physical, chemical and biological properties of the compound of Formula (I).

Soluble powders (SP) may be prepared by mixing a compound of Formula (I) with one or more water-soluble inorganic salts (such as sodium bicarbonate, sodium carbonate or magnesium sulphate) or one or more water-soluble organic solids (such as a polysaccharide) and, optionally, one or more wetting agents, one or more dispersing agents or a mixture of said agents to improve water dispersibility/solubility. The mixture is then ground to a fine powder. Similar compositions may also be granulated to form water soluble granules (SG).

Wettable powders (WP) may be prepared by mixing a compound of Formula (I) with one or more solid diluents or carriers, one or more wetting agents and, preferably, one or more dispersing agents and, optionally, one or more suspending agents to facilitate the dispersion in liquids. The mixture is then ground to a fine powder. Similar compositions may also be granulated to form water dispersible granules (WG).

Granules (GR) may be formed either by granulating a mixture of a compound of Formula (I) and one or more powdered solid diluents or carriers, or from pre- formed blank granules by absorbing a compound of Formula (I) (or a solution thereof, in a suitable agent) in a porous granular material (such as pumice, attapulgite clays, fuller's earth, kieselguhr, diatomaceous earths or ground corn cobs) or by adsorbing a compound of Formula (I) (or a solution thereof, in a suitable agent) on to a hard core material (such as sands, silicates, mineral carbonates, sulphates or phosphates) and drying if necessary. Agents which are commonly used to aid absorption or adsorption include solvents (such as aliphatic and aromatic petroleum solvents, alcohols, ethers, ketones and esters) and sticking agents (such as polyvinyl acetates, polyvinyl alcohols, dextrins, sugars and vegetable oils). One or more other additives may also be included in granules (for example an emulsifying agent, wetting agent or dispersing agent).

Dispersible Concentrates (DC) may be prepared by dissolving a compound of Formula (I) in water or an organic solvent, such as a ketone, alcohol or glycol ether. These solutions may contain a surface active agent (for example to improve water dilution or prevent crystallisation in a spray tank).

Emulsifiable concentrates (EC) or oil-in-water emulsions (EW) may be prepared by dissolving a compound of Formula (I) in an organic solvent (optionally containing one or more wetting agents, one or more emulsifying agents or a mixture of said agents). Suitable organic solvents for use in ECs include aromatic hydrocarbons (such as alkylbenzenes or alkylnaphthalenes, exemplified by SOLVESSO 100, SOLVESSO 150 and SOLVESSO 200; SOLVESSO is a Registered Trade Mark), ketones (such as cyclohexanone or methylcyclohexanone) and alcohols (such as benzyl alcohol, furfuryl alcohol or butanol), N-alkylpyrrolidones (such as N-methylpyrrolidone or N-octylpyrrolidone), dimethyl amides of fatty acids (such as Cs-Cio fatty acid dimethylamide) and chlorinated hydrocarbons. An EC product may spontaneously emulsify on addition to water, to produce an emulsion with sufficient stability to allow spray application through appropriate equipment.

Preparation of an EW involves obtaining a compound of Formula (I) either as a liquid (if it is not a liquid at room temperature, it may be melted at a reasonable temperature, typically below 70°C) or in solution (by dissolving it in an appropriate solvent) and then emulsifying the resultant liquid or solution into water containing one or more SAAs, under high shear, to produce an emulsion. Suitable solvents for use in EWs include vegetable oils, chlorinated hydrocarbons (such as chlorobenzenes), aromatic solvents (such as alkylbenzenes or alkylnaphthalenes) and other appropriate organic solvents which have a low solubility in water. Microemulsions (ME) may be prepared by mixing water with a blend of one or more solvents with one or more SAAs, to produce spontaneously a thermodynamically stable isotropic liquid formulation. A compound of Formula (I) is present initially in either the water or the solvent/SAA blend. Suitable solvents for use in MEs include those hereinbefore described for use in in ECs or in EWs. An ME may be either an oil-in-water or a water-in-oil system (which system is present may be determined by conductivity measurements) and may be suitable for mixing water- soluble and oil-soluble pesticides in the same formulation. An ME is suitable for dilution into water, either remaining as a microemulsion or forming a conventional oil- in-water emulsion.

Suspension concentrates (SC) may comprise aqueous or non-aqueous suspensions of finely divided insoluble solid particles of a compound of Formula (I). SCs may be prepared by ball or bead milling the solid compound of Formula (I) in a suitable medium, optionally with one or more dispersing agents, to produce a fine particle suspension of the compound. One or more wetting agents may be included in the composition and a suspending agent may be included to reduce the rate at which the particles settle. Alternatively, a compound of Formula (I) may be dry milled and added to water, containing agents hereinbefore described, to produce the desired end product.

Aerosol formulations comprise a compound of Formula (I) and a suitable propellant (for example n-butane). A compound of Formula (I) may also be dissolved or dispersed in a suitable medium (for example water or a water miscible liquid, such as n-propanol) to provide compositions for use in non-pressurised, hand-actuated spray pumps.

Capsule suspensions (CS) may be prepared in a manner similar to the preparation of EW formulations but with an additional polymerisation stage such that an aqueous dispersion of oil droplets is obtained, in which each oil droplet is encapsulated by a polymeric shell and contains a compound of Formula (I) and, optionally, a carrier or diluent therefor. The polymeric shell may be produced by either an interfacial polycondensation reaction or by a coacervation procedure. The compositions may provide for controlled release of the compound of Formula (I) and they may be used for seed treatment. A compound of Formula (I) may also be formulated in a biodegradable polymeric matrix to provide a slow, controlled release of the compound. The composition may include one or more additives to improve the biological performance of the composition, for example by improving wetting, retention or distribution on surfaces; resistance to rain on treated surfaces; or uptake or mobility of a compound of Formula (I). Such additives include surface active agents (SAAs), spray additives based on oils, for example certain mineral oils or natural plant oils (such as soy bean and rape seed oil), modified plant oils such as methylated rape seed oil (MRSO), and blends of these with other bio-enhancing adjuvants (ingredients which may aid or modify the action of a compound of Formula (I).

Wetting agents, dispersing agents and emulsifying agents may be SAAs of the cationic, anionic, amphoteric or non-ionic type.

Suitable SAAs of the cationic type include quaternary ammonium compounds (for example cetyltri methyl ammonium bromide), imidazolines and amine salts.

Suitable anionic SAAs include alkali metals salts of fatty acids, salts of aliphatic monoesters of sulphuric acid (for example sodium lauryl sulphate), salts of sulphonated aromatic compounds (for example sodium dodecylbenzenesulphonate, calcium dodecylbenzenesulphonate, butylnaphthalene sulphonate and mixtures of sodium di-/sopropyl- and tri-/sopropyl-naphthalene sulphonates), ether sulphates, alcohol ether sulphates (for example sodium laureth-3-sulphate), ether carboxylates (for example sodium laureth-3-carboxylate), phosphate esters (products from the reaction between one or more fatty alcohols and phosphoric acid (predominately mono-esters) or phosphorus pentoxide (predominately di-esters), for example the reaction between lauryl alcohol and tetraphosphoric acid; additionally these products may be ethoxylated), sulphosuccinamates, paraffin or olefine sulphonates, taurates, lignosulphonates and phosphates / sulphates of tristyrylphenols.

Suitable SAAs of the amphoteric type include betaines, propionates and glycinates.

Suitable SAAs of the non-ionic type include condensation products of alkylene oxides, such as ethylene oxide, propylene oxide, butylene oxide or mixtures thereof, with fatty alcohols (such as oleyl alcohol or cetyl alcohol) or with alkylphenols (such as octylphenol, nonylphenol or octylcresol); partial esters derived from long chain fatty acids or hexitol anhydrides; condensation products of said partial esters with ethylene oxide; block polymers (comprising ethylene oxide and propylene oxide); alkanolamides; simple esters (for example fatty acid polyethylene glycol esters); amine oxides (for example lauryl dimethyl amine oxide); lecithins and sorbitans and esters thereof, alkyl polyglycosides and tristyrylphenols. Suitable suspending agents include hydrophilic colloids (such as polysaccharides, polyvinylpyrrolidone or sodium carboxymethylcellulose) and swelling clays (such as bentonite or attapulgite).

The herbicidal compounds of present invention can also be used in mixture with one or more additional herbicides and/or plant growth regulators. Examples of such additional herbicides or plant growth regulators include acetochlor, acifluorfen (including acifluorfen-sodium), aclonifen, ametryn, amicarbazone, aminopyralid, aminotriazole, atrazine, bensulfuron (including bensulfuron-methyl), bentazone, bicyclopyrone, bilanafos, bispyribac-sodium, bixlozone, bromacil, bromoxynil, butachlor, butafenacil, carfentrazone (including carfentrazone-ethyl), cloransulam (including cloransulam-methyl), chlorimuron (including chlorimuron-ethyl), chlorotoluron, chlorsulfuron, cinmethylin, clacyfos, clethodim, clodinafop (including clodinafop-propargyl), clomazone, clopyralid, cyclopyranil, cyclopyrimorate, cyclosulfamuron, cyhalofop (including cyhalofop-butyl), 2,4-D (including the choline salt and 2-ethylhexyl ester thereof), 2,4-DB, desmedipham, dicamba (including the aluminium, aminopropyl, bis-aminopropylmethyl, choline, dichloroprop, diglycolamine, dimethylamine, dimethylammonium, potassium and sodium salts thereof) diclosulam, diflufenican, diflufenzopyr, dimethachlor, dimethenamid-P, diquat dibromide, diuron, ethalfluralin, ethofumesate, fenoxaprop (including fenoxaprop-P-ethyl), fenoxasulfone, fenquinotrione, fentrazamide, flazasulfuron, florasulam, florpyrauxifen (including florpyraxifen-benzyl), fluazifop (including fluazifop-P-butyl), flucarbazone (including flucarbazone-sodium), flufenacet, flumetsulam, flumioxazin, flupyrsulfuron (including flupyrsulfuron-methyl-sodium), fluroxypyr (including fluroxypyr-meptyl), fomesafen, foramsulfuron, glufosinate (including the ammonium salt thereof), glyphosate (including the diammonium, isopropylammonium and potassium salts thereof), halauxifen (including halauxifen-methyl), haloxyfop (including haloxyfop-methyl), hexazinone, hydantocidin, imazamox, imazapic, imazapyr, imazethapyr, indaziflam, iodosulfuron (including iodosulfuron-methyl-sodium), iofensulfuron (including iofensulfuron-sodium), ioxynil, isoproturon, isoxaflutole, lancotrione, MCPA, MCPB, mecoprop-P, mesosulfuron (including mesosulfuron-methyl), mesotrione, metamitron, metazachlor, methiozolin, metolachlor, metosulam, metribuzin, metsulfuron, napropamide, nicosulfuron, norflurazon, oxadiazon, oxasulfuron, oxyfluorfen, paraquat dichloride, pendimethalin, penoxsulam, phenmedipham, picloram, pinoxaden, pretilachlor, primisulfuron-methyl, propanil, propaquizafop, propyrisulfuron, propyzamide, prosulfocarb, prosulfuron, pyraclonil, pyraflufen (including pyraflufen-ethyl), pyrasulfotole, pyridate, pyriftalid, pyrimisulfan, pyroxasulfone, pyroxsulam, quinclorac, quinmerac, quizalofop (including quizalofop- P-ethyl and quizalofop-P-tefuryl), rimsulfuron, saflufenacil, sethoxydim, simazine, S- metalochlor, sulfentrazone, sulfosulfuron, tebuthiuron, tefuryltrione, tembotrione, terbuthylazine, terbutryn, thiencarbazone, thifensulfuron, tiafenacil, tolpyralate, topramezone, tralkoxydim, triafamone, triallate, triasulfuron, tribenuron (including tribenuron-methyl), triclopyr, trifloxysulfuron (including trifloxysulfuron-sodium), trifludimoxazin, trifluralin, triflusulfuron, 4-hydroxy- 1-methoxy-5-methyl-3-[4- (trifluoromethyl)-2-pyridyl]imidazolidin-2-one, 4-hydroxy-1 ,5-dimethyl-3-[4-

(trifluoromethyl)-2-pyridyl]imidazolidin-2-one, 5-ethoxy-4-hydroxy-1-methyl-3-[4- (trifluoromethyl)-2-pyridyl]imidazolidin-2-one, 4-hydroxy- 1-methyl-3-[4-

(trifluoromethyl)-2-pyridyl]imidazolidin-2-one, 4-hydroxy-1 ,5-dimethyl-3-[1-methyl-5- (trifluoromethyl)pyrazol-3-yl]imidazolidin-2-one, (4R)1-(5-tert-butylisoxazol-3-yl)-4- ethoxy-5-hydroxy-3-methyl-imidazolidin-2-one, 3-[2-(3,4-dimethoxyphenyl)-6-methyl- 3-oxo-pyridazine-4-carbonyl]bicyclo[3.2.1]octane-2,4-dione, 2-[2-(3,4- dimethoxyphenyl)-6-methyl-3-oxo-pyridazine-4-carbonyl]-5-methyl-cyclohexane-1 ,3- dione, 2-[2-(3,4-dimethoxyphenyl)-6-methyl-3-oxo-pyridazine-4- carbonyl]cyclohexane-1 ,3-dione, 2-[2-(3,4-dimethoxyphenyl)-6-methyl-3-oxo- pyridazine-4-carbonyl]-5,5-dimethyl-cyclohexane-1 ,3-dione, 6-[2-(3,4- dimethoxyphenyl)-6-methyl-3-oxo-pyridazine-4-carbonyl]-2,2,4,4-tetramethyl- cyclohexane-1 ,3,5-trione, 2-[2-(3,4-dimethoxyphenyl)-6-methyl-3-oxo-pyridazine-4- carbonyl]-5-ethyl-cyclohexane-1 ,3-dione, 2-[2-(3,4-dimethoxyphenyl)-6-methyl-3-oxo- pyridazine-4-carbonyl]-4,4,6,6-tetramethyl-cyclohexane-1 ,3-dione, 2-[6-cyclopropyl-2- (3,4-dimethoxyphenyl)-3-oxo-pyridazine-4-carbonyl]-5-methyl-cyclohexane-1 ,3-dione,

3-[6-cyclopropyl-2-(3,4-dimethoxyphenyl)-3-oxo-pyridazine-4- carbonyl]bicyclo[3.2.1]octane-2,4-dione, 2-[6-cyclopropyl-2-(3,4-dimethoxyphenyl)-3- oxo-pyridazine-4-carbonyl]-5,5-dimethyl-cyclohexane-1 ,3-dione, 6-[6-cyclopropyl-2- (3,4-dimethoxyphenyl)-3-oxo-pyridazine-4-carbonyl]-2,2,4,4-tetramethyl- cyclohexane-1 ,3,5-trione, 2-[6-cyclopropyl-2-(3,4-dimethoxyphenyl)-3-oxo-pyridazine-

4-carbonyl]cyclohexane-1 ,3-dione, 4-[2-(3,4-dimethoxyphenyl)-6-methyl-3-oxo- pyridazine-4-carbonyl]-2,2,6,6-tetramethyl-tetrahydropyran-3,5-dione and 4-[6- cyclopropyl-2-(3,4-dimethoxyphenyl)-3-oxo-pyridazine-4-carbonyl]-2, 2,6,6- tetramethyl-tetrahydropyran-3,5-dione.

The mixing partners of the compound of Formula (I) may also be in the form of esters or salts, as mentioned e.g. in The Pesticide Manual, Sixteenth Edition, British Crop Protection Council, 2012. The compound of Formula (I) can also be used in mixtures with other agrochemicals such as fungicides, nematicides or insecticides, examples of which are given in The Pesticide Manual.

The mixing ratio of the compound of Formula (I) to the mixing partner is preferably from 1 : 100 to 1000:1.

The mixtures can advantageously be used in the above-mentioned formulations (in which case "active ingredient" relates to the respective mixture of compound of Formula (I) with the mixing partner).

The compounds or mixtures of the present invention can also be used in combination with one or more herbicide safeners. Examples of such safeners include benoxacor, cloquintocet (including cloquintocet-mexyl), cyprosulfamide, dichlormid, fenchlorazole (including fenchlorazole-ethyl), fenclorim, fluxofenim, furilazole, isoxadifen (including isoxadifen-ethyl), mefenpyr (including mefenpyr-diethyl), metcamifen and oxabetrinil.

Particularly preferred are mixtures of a compound of Formula (I) with cyprosulfamide, isoxadifen-ethyl, cloquintocet-mexyl and/or N-(2-methoxybenzoyl)-4- [(methyl-aminocarbonyl)amino]benzenesulfonamide.

The safeners of the compound of Formula (I) may also be in the form of esters or salts, as mentioned e.g. in The Pesticide Manual, 16^th Edition (BCPC), 2012. The reference to cloquintocet-mexyl also applies to a lithium, sodium, potassium, calcium, magnesium, aluminium, iron, ammonium, quaternary ammonium, sulfonium or phosphonium salt thereof as disclosed in WO 02/34048.

Preferably the mixing ratio of compound of Formula (I) to safener is from 100: 1 to 1 : 10, especially from 20: 1 to 1 : 1.

The present invention still further provides a method of controlling weeds at a locus, said method comprising application to the locus of a weed controlling amount of a composition comprising a compound of Formula (I). Moreover, the present invention may further provide a method of selectively controlling weeds at a locus comprising crop plants and weeds, wherein the method comprises application to the locus of a weed controlling amount of a composition according to the present invention. ‘Controlling’ means killing, reducing or retarding growth or preventing or reducing germination. It is noted that the compounds of the present invention show a much improved selectivity compared to know, structurally similar compounds. Generally the plants to be controlled are unwanted plants (weeds).‘Locus’ means the area in which the plants are growing or will grow. The application may be applied to the locus pre-emergence and/or postemergence of the crop plant. Some crop plants may be inherently tolerant to herbicidal effects of compounds of Formula (I). Preferred crop plants include maize, wheat, barley and rice.

The rates of application of compounds of Formula I may vary within wide limits and depend on the nature of the soil, the method of application (pre- or post emergence; seed dressing; application to the seed furrow; no tillage application etc.), the crop plant, the weed(s) to be controlled, the prevailing climatic conditions, and other factors governed by the method of application, the time of application and the target crop. The compounds of Formula I according to the invention are generally applied at a rate of from 10 to 2500 g/ha, especially from 25 to 1000 g/ha, more especially from 25 to 250 g/ha.

The application is generally made by spraying the composition, typically by tractor mounted sprayer for large areas, but other methods such as dusting (for powders), drip or drench can also be used.

Crop plants are to be understood as also including those crop plants which have been rendered tolerant to other herbicides or classes of herbicides (e.g. ALS-, GS-, EPSPS-, PPO-, HPPD-, -PDS and ACCase-inhibitors) by conventional methods of breeding or by genetic engineering. An example of a crop that has been rendered tolerant to imidazolinones, e.g. imazamox, by conventional methods of breeding is Clearfield® summer rape (canola). Examples of crops that have been rendered tolerant to herbicides by genetic engineering methods include e.g. glyphosate- and glufosinate-resistant maize varieties commercially available under the trade names RoundupReady® and LibertyLink®.

Crop plants are also to be understood as being those which have been rendered resistant to harmful insects by genetic engineering methods, for example Bt maize (resistant to European corn borer), Bt cotton (resistant to cotton boll weevil) and also Bt potatoes (resistant to Colorado beetle). Examples of Bt maize are the Bt 176 maize hybrids of NK® (Syngenta Seeds). The Bt toxin is a protein that is formed naturally by Bacillus thuringiensis soil bacteria. Examples of toxins, or transgenic plants able to synthesise such toxins, are described in EP-A-451 878, EP-A-374 753, WO 93/07278, WO 95/34656, WO 03/052073 and EP-A-427 529. Examples of transgenic plants comprising one or more genes that code for an insecticidal resistance and express one or more toxins are KnockOut® (maize), Yield Gard® (maize), NuCOTIN33B® (cotton), Bollgard® (cotton), NewLeaf® (potatoes), NatureGard® and Protexcta®. Plant crops or seed material thereof can be both resistant to herbicides and, at the same time, resistant to insect feeding (“stacked” transgenic events). For example, seed can have the ability to express an insecticidal Cry3 protein while at the same time being tolerant to glyphosate.

Crop plants are also to be understood to include those which are obtained by conventional methods of breeding or genetic engineering and contain so-called output traits (e.g. improved storage stability, higher nutritional value and improved flavour).

The compositions can be used to control unwanted plants (collectively, ‘weeds’). The weeds to be controlled may be both monocotyledonous species, for example Agrostis, Alopecurus, Avena, Brachiaria, Bromus, Cenchrus, Cyperus, Digitaria, Echinochloa, Eleusine, Lolium, Monochoria, Rottboellia, Sagittaria, Scirpus, Setaria and Sorghum, and dicotyledonous species, for example Abutilon, Amaranthus, Ambrosia, Chenopodium, Chrysanthemum, Conyza, Galium, Ipomoea, Nasturtium, Sida, Sinapis, Solanum, Stellaria, Veronica, Viola and Xanthium.

In a further aspect of the present invention there is provided the use of a compound of Formula (I) as defined herein as a herbicide.

The compounds of the present invention can be prepared according to the following schemes.

Typical abbreviations used throughout are as follows:

Boc =‘Butoxycarbonyl

br. = broad

Bu = butyl

d = doublet

DCM = dichloromethane

DEAD = diethylazodicarboxylate

DIAD = diisopropylazodicarboxylate

DMF = A/./V-dimethylformamide

EDCI = /\/-(3-Dimethylaminopropyl)-/\/’-ethylcarbodiimide hydrochloride

EΐbN = triethylamine

Et2<D = diethyl ether

EtOAc = ethyl acetate

EtOH = ethanol

HATU = A/-[(dimethylamino)-1 H-1 ,2,3-triazolo-[4,5-b]pyridin-1-ylmethylene]-/\/- methylmethanaminium hexafluorophosphate /V-oxide HPLC = high performance liquid chromatography

LiHMDS = lithium bis(trimethylsilyl)amide

MeOH = methanol

Ms = mesylate

Ph = phenyl

q = quartet

RT = room temperature

s = singlet

t = triplet

TBAF = tetrabutylammonium fluoride

Tf = triflate

TFA = trifluoroacetic acid

THF = tetrahydrofuran

T3P = 1-propanephosphonic anhydride

Ts = tosylate

Scheme 1.

A compound of Formula I may be prepared from a compound of Formula A via a displacement reaction with a compound of Formula G (where X is a suitable leaving group such as halogen, OTs, OMs or OTf) in the presence of a suitable base, in a suitable solvent. Suitable bases may include K₂CO₃. Suitable solvents may include THF or DMF.

Alternatively a compound of Formula I may be prepared from a compound of Formula A via a Mitsunobu reaction with a compound of Formula G (where X = OH) in the presence of a suitable phosphine and a suitable azodicarboxylate reagent, in a suitable solvent. Suitable phosphines may include PheP or n-Bu3P. Suitable azodicarboxylate reagents may include DEAD, DIAD or (A/E)-/\/-(piperidine-1- carbonylimino)piperidine-1 -carboxamide. Suitable solvents may include toluene or THF. Compounds of Formula G are commercially available or may be prepared by methods well known in the literature. Scheme 2.

A compound of Formula la may be prepared from a compound of Formula A via a Mitsunobu reaction with a compound of Formula K in the presence of a suitable phosphine and a suitable azodicarboxylate reagent, in a suitable solvent. Suitable phosphines may include PheP or n-BusP. Suitable azodicarboxylate reagents may include DEAD, DIAD or (A/E)-/\/-(piperidine-1-carbonylimino)piperidine-1-carboxamide. Suitable solvents may include toluene or THF.

Scheme 3.

Alternatively, a compound of Formula la may be prepared from a compound of Formula I via methods of separating enantiomers. Such methods may include the use of chiral HPLC. Scheme 4. Formula B Formula A

A compound of Formula A may be prepared from a compound of Formula B via a deprotection reaction using a suitable reagent, in a suitable solvent. Suitable reagents may include TBAF. Suitable solvents may include THF.

Scheme 5.

Formula B

A compound of Formula B may be prepared from 2,6-dichloroaniline via reaction with a compound of Formula C (where Y is a suitable leaving group such as a halogen) in the presence of a suitable base, in a suitable solvent. Suitable bases may include LiHMDS. Suitable solvents may include THF.

Compounds of Formula C are commercially available or may be prepared by methods well known in the literature.

Scheme 6.

Formula A Alternatively, a compound of Formula A may be prepared from 2,6-dichloroaniline via reaction with a compound of Formula C (where Y is a suitable leaving group such as a halogen) in the presence of a suitable base, in a suitable solvent. Suitable bases may include LiHMDS. Suitable solvents may include THF.

Scheme 7.

Formula D

Formula A

In an alternative approach a compound of Formula A may be prepared from a compound of Formula D (where PG = a suitable protecting group such as acetyl or Boc) via a deprotection reaction using a suitable reagent, in a suitable solvent. Suitable reagents may include KOH, NaOH or TFA. Suitable solvents may include MeOH or DCM.

Scheme 8.

Formula E

Formula D

A compound of Formula D may be prepared from a compound of Formula E (where PG = a suitable protecting group such as acetyl or Boc) via reaction with a compound of Formula C (where Y = a suitable leaving group such as halogen) in the presence of a suitable base, in a suitable solvent. Suitable bases may include NaH. Suitable solvents may include THF.

Compounds of Formula C and of Formula E are commercially available or may be prepared by methods well known in the literature. Scheme 9.

R

In a further alternative method, a compound of Formula I may be prepared from a compound of Formula F via an ester forming reaction with a compound of Formula H. Suitable ester forming reactions may include via the acid chloride or by using a suitable activating reagent, in a suitable solvent. Suitable activating agents may include EDCI, HATU or T3P. Suitable solvents may include DCM or THF.

Compounds of Formula H are commercially available or may be prepared by methods well known in the literature.

Scheme 10.

Compounds of Formula F may be prepared from a compound of Formula J (where R = C1-2 alkyl) via an ester hydrolysis reaction using a suitable reagent, in a suitable solvent. Suitable reagents may include LiOH, NaOH or KOH. Suitable solvents may include MeOH, EtOH or THF. The following non-limiting examples provide specific synthesis methods for representative compounds of the present invention, as referred to in Table 1 below.

Example 1 : Synthesis of ethyl 2-(2,6-dichloro-A/-ethylsulfonylanilino)

propanoate (Compound S1)

Step 1 : Synthesis of N-(2,6-dichlorophenyl)-/\/-ethylsulfonyl-ethanesulfonamide.

To a stirred solution of 2,6-dichloroaniline (4.00 g, 24.7 mmol) in dry THF (25 ml_) at 0°C under an atmosphere of N2 was added dropwise LiHMDS (49.4 ml_ of a 1 M solution in THF, 49.4 mmol). The reaction was stirred for 30 minutes at 0°C then ethanesulfonyl chloride (4.68 ml_, 49.4 mmol) was added dropwise. The reaction was allowed to warm to room temperature and stirred overnight.

The reaction mixture was quenched with water and the volatile solvent removed under reduced pressure. The residue was then diluted with water and extracted with DCM (x3). The combined organic extracts were dried over MgSCU and evaporated to dryness under reduced pressure to give the crude product (6.71 g) as an orange solid which was used without further purification.

¹H NMR (400MHz, CDC ) d 7.47 (d, 2H), 7.31 (t, 1 H), 3.85 (q, 4H), 1.52 (t, 6H)

Step 2: Synthesis of A/-(2,6-dichlorophenyl)ethanesulfonamide.

To a stirred solution of the crude product from step 1 (6.71 g) in THF (50 ml_) was added TBAF (27.2 ml_ of a 1M solution in THF, 27.2 mmol). The reaction was stirred at room temperature for 1 hour then diluted with water and extracted with EtOAc (x3). The combined organic extracts were dried over MgSCU and evaporated to dryness under reduced pressure. The crude product was purified by flash column chromatography on silica gel using a gradient of 0-30% EtOAc/isohexane as eluent to give the desired product (2.44 g, 39%) as a white solid. ¹H NMR (400MHz, CDCh) d 7.45 (d, 2H), 7.20 (t, 1 H), 6.04 (br, 1 H), 3.43 (q, 2H), 1.52 (t, 3H).

Step 3: Synthesis of ethyl 2-(2,6-dichloro-/\/-ethylsulfonyl-anilino)propanoate.

A mixture of A/-(2,6-dichlorophenyl)ethanesulfonamide (2.00 g, 7.87 mmol), potassium carbonate (1.10 g, 7.87 mmol) and ethyl 2-bromopropanoate (1.02 ml_, 7.87 mmol) in THF (8 ml_) was heated under microwave irradiation at 140°C for 30 minutes.

The reaction mixture was cooled to room temperature, diluted with Et2<D and washed with water. The organic layer was evaporated to dryness under reduced pressure. The crude product was purified by flash column chromatography on silica gel using a gradient of 0-20% EtOAc/isohexane as eluent to give the desired product (2.24 g, 80%) as a colourless crystalline solid.

¹H NMR (400MHz, CDCh) d 7.41 (dt, 2H), 7.32 - 7.23 (m, 1 H), 4.93 (q, 1 H), 4.33 - 4.18 (m, 2H), 3.83 - 3.65 (m, 1 H), 3.39 (qd, 1 H), 1.39 (t, 3H), 1.31 (t, 3H), 1.20 (d, 3H).

Example 2: Synthesis of 2,2,2-trifluoroethyl 2-(2,6-dichloro-A/-ethylsulfonyl- anilino)propanoate (Compound S2)

Step 1 : Synthesis of 2-(2,6-dichloro-/\/-ethylsulfonyl-anilino)propanoic acid.

To a stirred solution of ethyl 2-(2,6-dichloro-/\/-ethylsulfonyl-anilino)propanoate (9.11 g, 25.71 mmol) in THF (250 ml_) and water (125 ml_) was added UOH.H2O (1.62 g, 38.57 mmol). The reaction was stirred at RT for 72 hours. The volatile solvent was removed under reduced pressure and the aqueous residue was then washed with EtOAc, acidified using 2M HCI and then extracted with EtOAc (3x). The combined organic extracts were washed with brine, dried over MgSCU, filtered and evaporated to dryness under reduced pressure to give the desired product (8.56 g, quant.) as a white solid.

¹ H NMR (400MHz, CDCh) d 7.41 (t, 2H), 7.25 (d, 1 H), 5.00 (q, 1 H), 3.75-3.65 (m, 1 H), 3.45-3.35 (m, 1 H), 1.41 (t, 3H), 1.28 (d, 3H).

Step 2: Synthesis of 2,2,2-trifluoroethyl 2-(2,6-dichloro-/\/-ethylsulfonyl- anilino)propanoate.

To a stirred solution of 2-(2,6-dichloro-/\/-ethylsulfonyl-anilino)propanoic acid (0.20 g, 0.613 mmol) in DCM (3 ml_) at RT was added oxalyl chloride (0.057 ml_, 0.644 mmol) followed by a couple of drops of DMF. The reaction was stirred at RT for 1 hour then evaporated to dryness under reduced pressure. The resulting residue was dissolved in DCM (1.5 ml_) and added dropwise to a stirred solution of 2,2,2-trifluoroethanol (0.0491 ml_, 0.674 mmol) and Et₃N (0.129 ml_, 0.920 mmol) in DCM (3 ml_). The reaction was stirred at RT overnight then partitioned between EtOAc and H2O. The aqueous layer was further extracted with EtOAc and the combined organic extracts washed with brine, dried over MgS0₄, and evaporated to dryness under reduced pressure to give a colourless gum. The crude product was purified by flash column chromatography on silica gel using a gradient of 0-30% EtOAc/isohexane as eluent to give the desired product (0.203 g, 81 %) as a colourless gum which solidified on standing.

¹ H NMR (400MHz, CDCh) d 7.41 (t, 2H), 7.32-7.22 (m, 1 H), 5.06 (q, 1 H), 4.75-4.65 (m, 1 H), 4.51-4.42 (m, 1 H), 3.70-3.60 (m, 1 H), 3.41-3.30 (m, 1 H), 1.40 (t, 3H), 1.26 (d 3H).

Example 3: Synthesis of ethyl 2-[2,6-dichloro-A/-(chloromethylsulfonyl)anilino] propanoate (Compound S6)

Step 1 : Synthesis of A/-(2,6-dichlorophenyl)acetamide.

To a stirred solution of 2,6-dichloroaniline (5.00 g, 30.9 mmol) in acetic acid (38.6 ml_) was added dropwise acetyl chloride (22.2 ml_, 309 mmol) and the reaction heated to 90°C for 20 mins. The reaction was cooled and poured into H2O at 0°C and extracted with DCM (x3). The combined organic extracts were dried over MgSCU and evaporated to dryness under reduced pressure to give the desired product (6.39 g, quant.) as a white solid which was used without further purification.

¹ H NMR (400MHz, CDCh) d 7.40 (d, 2H), 7.20 (t, 1 H), 6.90 (br, 1 H), 2.26 (s, 3H)

Step 2: Synthesis of A/-(chloromethylsulfonyl)-/\/-(2,6-dichlorophenyl)acetamide.

To a stirred suspension of A/-(2,6-dichlorophenyl)acetamide (1.005 g, 4.925 mmol) in dry THF (12.3 ml_) at 0°C under an N2 atmosphere was added dropwise LiHMDS (5.42 ml_ of a 1 M solution in THF, 5.418 mmol). To the resultant solution was added dropwise chloromethanesulfonyl chloride (0.497 ml_, 5.42 mmol) and the reaction was allowed to warm to room temperature and stirred overnight. The reaction was quenched with H2O and extracted with EtOAc (x3). The combined organic extracts were dried over MgSCU and evaporated to dryness under reduced pressure. The crude product was purified via flash column chromatography on silica gel using a gradient of 0-50% EtOAc/isohexane as eluent to give the desired compound (271 mg, 17%) as an orange solid.

¹ H NMR (400MHz, CDCh) d 7.52 (d, 2H), 7.40 (t, 1 H), 5.24 (s, 2H), 2.00 (s, 3H).

Step 3: Synthesis of 1-chloro-/\/-(2,6-dichlorophenyl)methanesulfonamide. To a stirred solution of A/-(chloromethylsulfonyl)-/\/-(2,6-dichlorophenyl)acetamide (270 mg, 0.853 mmol) in methanol (7.1 ml_) and water (3.5 ml_) was added potassium hydroxide (72 mg, 1.28 mmol). The reaction was heated at 60°C for 2 hours, allowed to cool to RT, acidified with 2M HCI and extracted with EtOAc (x3). The combined organic extracts were dried over MgSCU and evaporated to dryness under reduced pressure to give the desired product (234 mg, quant.) as a white solid. ¹H NMR (400MHz, CDCh) d 7.43 (d, 2H), 7.25 (d, 1 H), 6.38 (br s, 1 H), 4.80 (s, 2H).

Step 4: Synthesis of ethyl 2-[2,6-dichloro-/\/-(chloromethylsulfonyl)anilino]propanoate

A solution of ethyl 2-bromopropanoate (2.56 mmol, 0.33 ml_), 1 -chloro-/V-(2,6- dichlorophenyl)methanesulfonamide (234 mg, 0.85 mmol) and K₂CC>₃ (118 mg, 0.85 mmol) in THF (3 ml_) was heated at reflux overnight. The reaction was cooled to RT, diluted with H2O and extracted with EtOAc (x3). The combined organic extracts were dried over MgS0₄ and evaporated to dryness under reduced pressure. The crude product was purified via flash column chromatography on silica gel using a gradient of 0-20% EtOAc/isohexane to give the desired product (184 mg, 57.6%) as a white solid.

¹H NMR (400MHz, CDCh) d 7.44 (ddd, 2H), 7.30 (t, 1 H), 5.28 (d, 1 H), 4.97 (q, 1 H), 4.87 (d, 1 H), 4.33 - 4.21 (m, 2H), 1.32 (t, 3H), 1.21 (d, 3H)

Example 4: Synthesis of ethyl (2S)-2-[2,6-dichloro-A/-

(chloromethylsulfonyl)anilino]propanoate (Compound S9) Step 1 : Synthesis of ethyl (2S)-2-[2,6-dichloro-/V-

(chloromethylsulfonyl)anilino]propanoate.

To a stirred solution of 1-chloro-/\/-(2,6-dichlorophenyl)methanesulfonamide (957 mg, 3.49 mmol), triphenylphosphine (980mg, 3.66 mmol) and ethyl (2R)-2- hydroxypropanoate (0.42 ml_, 3.66 mmol) in dry THF (12 ml_) at 0 °C was added dropwise diisopropyl azodicarboxylate (0.74 ml_, 3.66 mmol). The reaction mixture was stirred at RT overnight, then diluted with water and extracted with Et2<D. The organic phase was washed with 2M HCI, dried over MgSCU and evaporated to dryness under reduced pressure. The crude product was purified by flash chromatography on silica gel using a gradient of 0-15% EtOAc/isohexane as eluent to give the desired product (1.04 g, 79%) as a pale yellow oil.

¹H NMR (400MHz, CDC ) d 7.44 (ddd, 2H), 7.30 (t, 1 H), 5.28 (d, 1 H), 4.97 (q, 1 H), 4.87 (d, 1 H), 4.33 - 4.21 (m, 2H), 1.32 (t, 3H), 1.21 (d, 3H)

Chiral purity measured at >99% e.e. using HPLC method EtOH_IF3. Retention time of major (S) enantiomer = 2.57 min. Retention time of minor (R) enantiomer = 2.36 min.

Example 5: Synthesis of ethyl (2S)-2-(2,6-dichloro-A/-ethylsulfonyl- anilino)propanoate (Compound S5)

Step 1 : Synthesis of ethyl (2S)-2-(2,6-dichloro-/\/-ethylsulfonyl-anilino)propanoate

To a stirred solution of A/-(2,6-dichlorophenyl)ethanesulfonamide (10.0 g, 39.3 mmol), (A/E)-/\/-(piperidine-1-carbonylimino)piperidine-1 -carboxamide (10.4 g, 41.3 mmol) and ethyl (2R)-2-hydroxypropanoate (4.72 ml_, 41.3 mmol) in dry toluene (98.4 ml_) at 0 °C under an atmosphere of N2 was added dropwise tributylphosphane (12 ml_, 47.2 mmol). The reaction mixture was stirred at RT overnight, then quenched with water and extracted with EtOAc (x 3). The combined organic extracts were washed with sodium thiosulphate solution and brine, dried over MgSCU and concentrated under reduced pressure. Once the volume had been reduced to ~30 ml_ precipitation was observed. DCM was added and the resultant solid removed by filtration. The residue was evaporated to dryness under reduced pressure and the crude product purified by flash chromatography on silica gel using a gradient of 0-30% EtOAc/cyclohexane to give the desired product (7.90 g, 57%) as a colourless oil.

¹H NMR (400MHz, CDC ) d 7.41 (dt, 2H), 7.32 - 7.23 (m, 1 H), 4.93 (q, 1 H), 4.33 - 4.18 (m, 2H), 3.83 - 3.65 (m, 1 H), 3.39 (qd, 1 H), 1.39 (t, 3H), 1.31 (t, 3H), 1.20 (d, 3H).

Chiral purity measured at 86% e.e. using HPLC method EtOH_IC3. Retention time of major (S) enantiomer = 4.23 min. Retention time of minor (R) enantiomer = 3.51 min.

Chiral HPLC methods

Determined using a Waters H-Class Acquity UPLC

Eluent is isohexane (+ 0.1 % glacial acetic acid)/EtOH (+0.1% glacial acetic acid) using the following gradient:

Method EtOH_IF3 uses a Chiralpak 3m 4.6x100mm IF-3 column.

Method EtOH_IC3 uses a Chiralpak 3m 4.6x100mm IC-3 column. Table 1 - Examples of herbicidal compounds of the present invention.

Bioloqical Examples Test 1

Seeds of a variety of test species are sown in standard soil in pots ( Lolium perenne (LOLPE), Solanum nigrum (SOLNI), Amaranthus retoflexus (AMARE) and Setaria faberi (SETFA). After cultivation for one day (pre-emergence) or after 8 days cultivation (post-emergence) under controlled conditions in a glasshouse (at 24/16°C, day/night; 14 hours light; 65 % humidity), the plants are sprayed with an aqueous spray solution derived from the formulation of the technical active ingredient in acetone / water (50:50) solution containing 0.5% Tween 20 (polyoxyethelyene sorbitan monolaurate, CAS RN 9005-64-5). Compounds are applied at 1000 g/ha unless otherwise stated. The test plants are then grown in a glasshouse under controlled conditions in a glasshouse (at 24/16°C, day/night; 14 hours light; 65 % humidity) and watered twice daily. After 13 days for pre and post-emergence, the test is evaluated for the percentage damage caused to the plant. The biological activities (% phytotoxicity) are shown in Tables B1 and B2 below. Compound A = Compound 26 from GB2012170A. Compound B = S-enantiomer of Compound 26 from GB2012170A.

Table B1. Post-emergence activity.

Table B2. Pre-emergence activity.

Claims

1. A compound of Formula (I):

wherein

R¹ is -CH₃ or chloro;

2. A compound according to claim 1 , wherein the compound of Formula (I) is a compound of Formula (la):

3. A compound according to claim 1 or claim 2, wherein R¹ is -CH₃.

4. A compound according to claim 1 or claim 2, wherein R¹ is chloro.

5. A compound according to any one of the previous claims, wherein R² is -CH₃.

6. A compound according to any one of claims 1 to 4, wherein R² is selected from the group consisting of -CH2F, -CHF2, -CF₃, -CH2CH2F and -CF2CF2H.

7. A compound according to claim 6, wherein R² is selected from the group consisting of -CH2F, -CHF2 and -CF₃.

8. A herbicidal composition comprising a compound according to any one of the previous claims and an agriculturally acceptable formulation adjuvant.

9. A herbicidal composition according to claim 8, further comprising at least one additional pesticide.

10. A herbicidal composition according to claim 9, wherein the additional pesticide is a herbicide or herbicide safener.

11. A method of controlling weeds at a locus comprising application to the locus of a weed controlling amount of a composition according to any one of claims 8 to 10.

12. Use of a compound of Formula (I) as defined in claim 1 as a herbicide.