The present invention relates to novel, herbicidally active sulfonylurea compounds, to processes for the preparation thereof, to compositions comprising those compounds and also to the use thereof in controlling weeds, especially in crops of useful plants, or in inhibiting plant growth.

The present invention relates to compounds of formula I

wherein Ri is hydrogen, methyl or trifluoromethyl, R ₂ is methyl or methoxy, A is Cι-C - haloalkyl, is an alkali metal or alkaline earth metal atom and n is 1 or 2.

The alkyl groups appearing in those substituent definitions may be straight-chained or branched and are, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, iso- butyl, tert-butyl, n-pentyl or isopentyl. Suitable haloalkyi groups may be derived from the said alkyl groups, halogen being especially chlorine and more especially fluorine. Haloalkyi includes both mono- and poly-halogenated alkyl radicals.

The sulfonylurea compounds corresponding to the salts of formula I according to the invention and having the formula II

wherein R,, R ₂ and A are as defined, are known, for example, from EP-A-103 453, WO 92/16522, WO 94/03064 and US 5 393 734.

By reaction with suitable salt-forming agents the compounds of formula II can be converted into the compounds of formula I according to the invention in a customary manner known perse. Such salt-forming agents are in principle any bases that are capable of abstracting the acid hydrogen atom in the SO ₂ -NH-CO grouping. Hydrides, hydroxides, alcoholates, hydrogen carbonates and carbonates of alkali metal and alkaline earth metals, especially of sodium, potassium, magnesium and calcium, have proved especially advantageous in that connection. Preferably, the alcoholates, hydrogen carbonates and carbonates can be represented by the formulae III, IV and V

wherein R _a is hydrogen, C^Csalkyl or phenyl, n and m are 1 or 2, the sum of n and m being 3, and M is an alkali metal or alkaline earth metal atom.

Preferred compounds of formula I are those wherein A is CrC ₃ fluoroalkyl. In a further group of preferred compounds M is an alkali metal atom, especially sodium. In another group of preferred compounds R is hydrogen.

The reaction of the compounds of formula II with the bases of formulae III, IV and V to form the compounds of formula I according to the invention is carried out in a manner known per se preferably in protic or aprotic solvents at room temperature or at elevated temperature, it being possible for crown ethers and/or phase transfer catalysts to be present, as described, for example, in J. March, Advanced Org. Chem., John Wiley and Sons, 4th Edition, 1992: Phase Transfer Catalysis, page 362. For example, the compounds of the invention can often be obtained in good yields just by simply stirring the compounds of formulae II and III, IV or V at room temperature in aqueous solution.

Suitable for the use according to the invention of the compounds of formula I or of the compositions comprising them are all application methods customary in agriculture, for example preemergence application, postemergence application and seed dressing, and also different methods and techniques, for example the controlled release of active ingredient. For that purpose the active ingredient is applied in solution to mineral granule carriers or polymerised granules (urea/formaldehyde) and dried. If required, a coating may

also be applied (coated granules) which allows the active ingredient to be released in metered amounts over a specific period of time.

The compounds of formula I may be used in unmodified form, that is to say as obtained in the synthesis, but they are preferably formulated in customary manner together with the adjuvants customarily employed in formulation technology, e.g. into emulsifiable concentrates, directly sprayable or dilutable solutions, dilute emulsions, wettable powders, soluble powders, dusts, granules or microcapsules. As with the nature of the compositions, the methods of application, such as spraying, atomising, dusting, wetting, scattering or pouring, are chosen in accordance with the intended objectives and the prevailing circumstances.

The formulations, that is to say the compositions, preparations or mixtures comprising the compound (active ingredient) of formula I or at least one compound of formula I and usually one or more solid or liquid formulation adjuvants, are prepared in known manner, e.g. by homogeneously mixing and/or grinding the active ingredients with the formulation adjuvants, for example solvents or solid carriers. It is also possible to use surface-active compounds (surfactants) in the preparation of the formulations.

Suitable solvents are: aromatic hydrocarbons, preferably the fractions containing 8 to 12 carbon atoms, for example xylene mixtures or substituted naphthalenes, phthalic acid esters, such as dibutyl ordioctyl phthalate-. aliphatic hydrocarbons, such as cyclohexane or paraffins, alcohols and glycols and their ethers and esters, such as ethanol, ethylene glycol, ethylene glycol monomethyl or monoethyl ether, ketones, such as cyclohexanone, strongly polar solvents, such as N-methyl-2-pyrrolidone, dimethyl sulfoxide or N.N-dimethyl- formamide, and vegetable oils or epoxidised vegetable oils, such as epoxidised coconut oil or soybean oil, or water.

The solid carriers used, e.g. for dusts and dispersible powders, are normally natural mineral fillers, such as calcite, talcum, kaolin, montmorillonite or attapulgite. In order to improve the physical properties of the formulation it is also possible to add highly dispersed silicic acid or highly dispersed absorbent polymers. Suitable granulated adsorptive carriers are porous types, for example pumice, broken brick, sepiolite or bentonite, and suitable non-sorbent

carriers are, for example, calcite or sand. In addition, a great number of pregranulated materials of inorganic or organic nature can be used, e.g. especially dolomite or pulverised plant residues.

Depending upon the nature of the compound of formula I to be formulated, suitable surface- active compounds are non-ionic, cationic and/or anionic surfactants and surfactant mixtures having good emulsifying, dispersing and wetting properties.

Both water-soluble soaps and water-soluble synthetic surface-active compounds are suitable anionic surfactants.

Suitable soaps are the alkali metal salts, alkaline earth metal salts or unsubstituted or substituted ammonium salts of higher fatty acids (C10-C-22), e.g. the sodium or potassium salts of oleic or stearic acid, or of natural fatty acid mixtures which can be obtained e.g. from coconut oil or tallow oil. Mention may also be made of fatty acid methyltaurine salts.

More frequently, however, so-called synthetic surfactants are used, especially fatty alcohol sulfonates, fatty alcohol sulfates, sulfonated benzimidazole derivatives or alkylaryl- sulfonates.

The fatty alcohol sulfonates or sulfates are usually in the form of alkali metal salts, alkaline earth metal salts or unsubstituted or substituted ammonium salts and contain a C8-C ₂₂ alkyl radical, the alkyl moiety of acyl radicals also being included, e.g. the sodium or calcium salt of lignosulfonic acid, of dodecyl sulfate or of a mixture of fatty alcohol sulfates obtained from natural fatty acids. These compounds also comprise the salts of sulfated and sulfonated fatty alcohol/ethylene oxide adducts. The sulfonated benzimidazole derivatives preferably contain two sulfon* cid groups and one fatty acid radical containing 8 to 22 carbon atoms. Examples of larylsulfonates are the sodium, calcium or triethanolamine salts of dodecylbenzenesulforuc acid, dibutylnaphthalenesulfonic acid, or of a condensate of naphthalenesulfonic acid and formaldehyde.

Also suitable are corresponding phosphates, e.g. salts of the phosphoric acid ester of an adduct of p-nonylphenol with 4 to 14 mol of ethylene oxide, or phospholipids.

Non-ionic surfactants are preferably polyglycol ether derivatives of aliphatic or cycloaliphatic alcohols, saturated or unsaturated fatty acids and alkylphenols, said derivatives containing 3 to 30 glycol ether groups and 8 to 20 carbon atoms in the (aliphatic) hydrocarbon moiety and 6 to 18 carbon atoms in the alkyl moiety of the alkylphenols.

Further suitable non-ionic surfactants are the water-soluble adducts of polyethylene oxide with polypropylene glycol, ethylenediaminopolypropylene glycol and alkylpolypropylene glycol containing 1 to 10 carbon atoms in the alkyl chain, which adducts contain 20 to 250 ethylene glycol ether groups and 10 to 100 propylene glycol ether groups. These compounds usually contain 1 to 5 ethylene glycol units per propylene glycol unit.

Examples of non-ionic surfactants are nonylphenolpolyethoxyethanols, castor oil polyglycol ethers, polypropylene/polyethylene oxide adducts, tributylphenoxypolyethoxyethanol, polyethylene glycol and octylphenoxypolyethoxyethanol.

Fatty acid esters of polyoxyethylene sorbitan, e.g. polyoxyethylene sorbitan trioleate, are also suitable non-ionic surfactants.

Cationic surfactants are preferably quaternary ammonium salts which contain, as N- substituent, at least one Cβ-C alkyl radical and, as further substituents, unsubstituted or halogenated lower alkyl, benzyl or hydroxy-lower alkyl radicals. The salts are preferably in the form of halides, methyl sulfates or ethyl sulfates, e.g. stearyltrimethylammonium chloride or benzyldi(2-chloroethyl)ethylammonium bromide.

The surfactants customarily employed in formulation technology, which may also be used in the compositions according to the invention, are described inter alia in "McCutcheon's Detergents and Emulsifiers Annual" MC Publishing Corp., Ridgewood New Jersey, 1981 , Stache, H., "Tensid-Taschenbuch", Carl Hanser Verlag, Munich Vienna, 1981 and M. and J. Ash, "Encyclopedia of Surfactants", Vol l-lll, Chemical Publishing Co., New York, 1980- 1981.

The herbicidal formulations usually comprise from 0.1 to 99 % by weight, preferably from 0.1 to 95 % by weight, herbicide, from 1 to 99.9 % by weight, preferably from 5 to 99.8 % by

weight, of a solid or liquid formulation adjuvant and from 0 to 25 % by weight, preferably from 0.1 to 25 % by weight, of a surfactant.

Whereas commercial products will preferably be formulated as concentrates, the end user will normally employ dilute formulations.

The compositions may also comprise further auxiliaries, such as stabilisers, e.g. vegetable oils or epoxidised vegetable oils (epoxidised coconut oil, rape oil or soybean oil), antifoams, e.g. silicone oil, preservatives, viscosity regulators, binders and tackifiers, as well as fertilisers or other active ingredients.

Preferred formulations have especially the following composition (throughout, percentages are by weight):

Dusts: active ingredient: 0.1 to 50 %, preferably 0.1 to 1 % solid carrier: 99.9 to 90 %, preferably 99.9 to 99 %

Suspension concentrates: active ingredient: 5 to 75 %, preferably 10 to 50 % water: 94 to 24 %, preferably 88 to 30 % surface-active agent: 1 to 40 %, preferably 2 to 30 %

Wettable powders: active ingredient: 0.5 to 90 %, preferably 1 to 80 % surface-active agent: 0.5 to 20 %, preferably 1 to 15 % solid carrier: 5 to 95 %, preferably 15 to 90 %

Granules: active ingredient: 0.1 to 30 %, preferably 0.1 to 15 % solid carrier: 99.5 to 70 %, preferably 97 to 85 %

The compounds of formula I according to the invention and also compositions and formulations comprising them are, surprisingly, distinguished by greater storage stability in comparison with the corresponding compounds of formula II and compositions and formulations comprising them. The present invention therefore relates also to a method of increasing the storage stability of herbicidal and plant-growth-inhibiting compositions that comprise as active ingredient a compound of formula II

wherein H is hydrogen, methyl or trifluoromethyl, R ₂ is methyl or methoxy and A is _Λ O - haloalkyi, in which method before being mixed with the formulation adjuvants the compound of formula II is converted into the corresponding compound of formula I.

The compounds of formula I are usually applied to the plants or to the locus thereof at rates of application of from 0.001 to 4 kg/ha, preferably from 0.001 to 2 kg/ha, especially from 0.005 to 1 kg/ha. The concentration required to achieve the desired effect can be determined by experiment. It is dependent on the type of action, the stage of development of the cultivated plant and of the weed, and also on the application (place, time, method) and, in dependence on those parameters, can vary within wide limits.

The compounds of formula I are distinguished by herbicidal and growth-inhibiting properties, which render them suitable for use in crops of useful plants, especially in cereals, cotton, soybeans, sugar beet, sugar cane, plantation crops, rape, maize and rice, and also for non- selective control of weeds.

Crops are to be understood as including also those which have been rendered tolerant to herbicides or classes of herbicide by conventional methods of breeding or genetic engineering. The weeds that are to be controlled may be mono- or di-cotyledonous weeds, e.g. Stellaria, Nasturtium, Agrostis, Digitaria, Avena, Setaria, Sinapis, Lolium, Solanum, Phaseolus, Echinochloa, Scirpus, Monochoria, Sagittaria, Bromus, Alopecurus, Sorghum halepense, Rottboellia, Cyperus, Abutilon, Sida, Xanthium, Amaranthus, Chenopodium, Ipomoea, Chrysanthemum, Galium, Viola and Veronica.

The Examples that follow further illustrate, but do not limit, the invention.

Preparation examples:

Example P1 :

Preparation of compound No. 5 of the formula

1.56 g of N-(3-difluoromethoxypyridin-2-yl-sulfonyl)-N'-(4-methyl-6-me thoxypyrimidin-2-yl)- urea are added at room temperature to a solution of 40 ml of aqueous 0.1 N sodium hydroxide solution. The reaction mixture is stirred at room temperature overnight. The residue obtained after concentration by evaporation at 50°C in vacuo is stirred with ether and filtered. 1.54 g of product having a melting point of 170 to 173°C are obtained.

The compounds listed in the following Table can also be prepared in analogous manner:

Table 1 :

Formulation Exam les for com ounds of formula I

The active ingredient is thoroughly mixed with the adjuvants and the mixture is thoroughly ground in a suitable mill, affording wettable powders which can be diluted with water to give suspensions of any desired concentration.

F2. Coated granules a) b) c)

compound of Table 1 highly dispersed silicic acid inorganic carrier (diameter 0.1 - 1 mm) for example CaCO ₃ or SiO ₂

The active ingredient is dissolved in methylene chloride and the solution is sprayed onto the carrier, and the solvent is subsequently evaporated off in vacuo.

F3. Coated granules a) b) c)

compound of Table 1 0.1 % polyethylene glycol mol. wt. 200 1.0 % highly dispersed silicic acid 0.9 % inorganic carrier 98.0 % (diameter 0.1 - 1 mm) for example CaCO ₃ or SiO ₂

The finely ground active ingredient is uniformly applied, in a mixer, to the carrier moistened with polyethylene glycol. Non-dusty coated granules are obtained in this manner.

F4. Extruder granules a) b) c) d)

compound of Table 1 sodium lignosulfonate carboxymethylcellulose kaolin

The active ingredient is mixed and ground with the adjuvants, and the mixture is moistened with water. The mixture is extruded and then dried in a stream of air.

Ready-for-use dusts are obtained by mixing the active ingredient with the carriers, and grinding the mixture in a suitable mill.

F6. Suspension concentrates a) b) c) d)

compound of Table 1 ethylene glycol nonylphenol polyglycol ether

(15 mol of ethylene oxide) sodium lignosulfonate carboxymethylcellulose

37% aqueous formaldehyde solution silicone oil emulsion water

The finely ground active ingredient is intimately mixed with the adjuvants, giving a suspension concentrate from which suspensions of any desired concentration can be obtained by dilution with water.

Biological Examples

Example B1 : Postemergence herbicidal action:

Under greenhouse conditions, monocotyledonous and dicotyledonous weeds are raised in plastics pots containing standard soil. Test compound No. 5 is applied to the test plants in the 3- to 6-leaf stage. The test compound is applied in an aqueous suspension

(500 litres water/ha) at rates of application of 15 to 250 g/ha active ingredient. 3 weeks after application, evaluation is made in accordance with a scale of nine ratings (1=total damage,

9 = no action). Ratings of from 1 to 4 (especially from 1 to 3) indicate good to very good herbicidal action.

Test plants Rate of application [g/ha] compound No. 5 250 125 60 30 15

Avena 1 1 1 2 2

Bromus 2 2 3 4 4

Lolium 1 1 1 1 2

Alopecurus 1 1 1 1 2

Echinochloa 1 1 1 1 1

Setaria 1 2 3 4 4

Panicum 2 2 2 2 3

Brachiaria 2 2 2 2 3

Abutilon 2 2 2 2 3

Sida 2 2 2 3 4

Amaranthus 2 2 2 2 2

Chenopodium 2 4

Sinapis 1 1

Stellaria 2 2

Polygonum 1 1

Kochia 1 2

The said weeds can also be controlled very successfully by pre-emergence application of the herbicide. Similar results are also obtained when the active ingredient is formulated in accordance with any one of Formulation Examples F1 to F6.

Example of the storage stability of the herbicidal compositions according to the invention Formulations of compounds Nos. 5 and 8 according to the invention are prepared in customary manner by mixing and grinding in a laboratory mill (Janke&Kunkel, M20 type). The composition of the formulations (percentages relate to weight) is as follows:

Composition of the formulation of compound No. 5

5.00% compound No. 5

1.00% octylphenol/8 EO (Invadin JFC 800)

2.42% disodium hydrogen phosphate

1.58% potassium dihydrogen phosphate

1.00% urea/formaldehyde polymer (Pergopak M)

89.00% sodium chloride

Composition of the formulation of compound No.8 5.00% compound No.8 2.00% sodium lignosulfonate (Attisol II) 2.00% castor oil/36-37 EO (Emulsogen EL) 1.21% disodium hydrogen phosphate 0.79% potassium dihydrogen phosphate 5.00% urea/formaldehyde polymer (Pergopak M) 20.00% kaolin (Pulver AG) 69.00% sodium chloride

10 ml portions of each of the formulations are stored at temperatures of from 35 to 54°C. After 18 days' storage, the decrease in the concentration of compounds nos. 5 and 8 is determined by means of liquid chromatography (Varian 5000 liquid chromatograph). The following results are obtained (content expressed as a percentage of the starting concentration):

Compound No. Content (%) after 18 days' storage at 35°C 54°C

5 100 94.5

8 99.3 90.6

The formulations of compounds Nos. 5 and 8 are distinguished by a high storage stability.