CS261243B2 - Herbicide and plants' growth suppression agent and method of efficient component production - Google Patents

Description

BACKGROUND OF THE INVENTION The present invention relates to a herbicidal composition and a plant growth control composition which comprises the active ingredient (R) -2 - [- (5-chloro-3-fluoropyridin-2-yloxy) phenoxy] propionic acid as an active ingredient. The compositions according to the invention are generally used as herbicides and in particular for controlling weeds in crops of useful plants such as cereals, rice, maize, soybeans and sugar beet.

The (R) -2- (4- (5-chloro-3-fluoropyridin-2-yloxy) phenoxy) propionate propynyl ester corresponding to formula I was found to be

(I), has an extremely good effect against monocotyledonous and some dicotyledonous weeds, in particular it is effective in post-emergence application to weeds and grassy weeds which are adversely present in crop crops such as cereals, corn, rice, soybean and sugar beet .

Especially valuable is the ability to control grass weeds which are otherwise difficult to control with this new active ingredient, such as deaf oats (Avena fatua), Avena sterilis, field fox (Alopecurus myosuroides), perennial rye (Lolium perenne), Phalaris spec. , brome (Bromus tectorum), various types of rind (Setaria) and millet (Panicům). The active compound according to the invention already operates under field conditions at low rates of application of less than 1 kg per ha, in which the crop plants do not damage or, if so, only to an insignificant extent.

SUMMARY OF THE INVENTION The present invention provides a herbicidal and plant growth control composition comprising as active ingredient (R) -2-Q4- (5-chloro-3-fluoropyridin-2-yloxy) phenoxy] propionic acid propynyl ester of the formula AND

(I).

Halopyridyloxy-alpha-phenoxy-propionic acid derivatives have been previously described in numerous publications (cf., for example, DE-A 2,546,251, 2,649,706, 2,714,622, 2,715,284 and EP-A 483,1473, 83,556). and 97,460). In these publications, alpha-β- (3-fluoro-halopyridyl-2-oxy) -phenoxy] -propionic acid esters are contemplated and protected in part. The optically active ester according to the invention, however, differs from the known halopyridyloxy-.alpha.-phenoxypropionic acids by a stronger effect, thus giving the possibility of using this substance in low application rates.

The application of the active ingredient can be carried out both pre-and post-emergence. The application rates can vary within wide limits, for example between 0.01 and 2 kg of active compound per ha.

Further, the compound of formula I has beneficial effects in controlling plant growth (growth inhibition). In particular, it inhibits grass growth.

The novel ester of formula (I) can be prepared by various methods.

According to the invention, the (R) -2- [β- (5-chloro-3-fluoropyridin-2-yloxy) phenoxy] propionate propynyl ester of formula I is prepared by reacting 5-chloro-2,3-difluoropyridine of formula II

(II) in an inert solvent or diluent, in the presence of an equimolar amount of a base, with a 4-hydroxyphenoxy-alpha-propionic acid ester of formula III

CHo

AND

OCH-CO-OCH ₃ ^M

C = CH (III)

Another method for preparing a compound of formula I is to convert 4- (5-chloro-3-fluoropyridin-2-yloxy) phenol of formula IV

F

(IV) acts in an inert solvent or diluent in the presence of an equimolar amount of the (S) -enantiomeric alpha-halopropionic acid propylester of formula V

CH.

I ³

Hal-CH-CO-OCH ₂ -C =CH in which

Hal represents chlorine, bromine or iodine.

Another method consists in reacting the (R) -enantiomeric halide of 2- [4- (5-chloro-3-fluoropyridin-2-yloxy) phenoxy] propionic acid VI

in which

Hal represents a chlorine, fluorine or bromine atom, acts in an inert solvent or diluent in the presence of an equimolar amount of the base by the propinol of the formula

H-CH ₂ -C ₅ CH.

Further, the ester of formula I can also be prepared by reacting the (R) -enantiomeric 2- [4- (5-chloro-3-fluoropyridin-2-yloxy) phenoxy] propionic acid of formula VII

(VII) (VIII), acts in an inert solvent or diluent, in the presence of an equimolar amount of base, with a propionyl halide of formula VIII

Hal-CH ₂ -C =CH in which

Hal represents a halogen atom.

Finally, another method for preparing an ester of formula (I) is to prepare (R) -enantiomeric 2- [4- (3-amino-5-chloro-pyridin-2-yloxy) -phenoxy] -propionic acid-propylester (IX)

is converted into a diazonium salt according to known methods and further converted to a fluorine derivative.

According to another method, the (R) -enantiomeric ester of formula I is also prepared by reacting 4- (5-chloro-3-fluoropyridin-2-yloxy) phenol of formula IV in an inert organic solvent and in the presence of a base.

F

with the (S) -enantiomeric lactic acid propynyl sulfonate of formula X ΐ ^Η 3

R-SO ₂ -OCH-CO-OCH ₂ -C =CH (X), * (S) in which

R is a straight or branched (C 1 -C 6) alkyl group optionally substituted by halogen, cyano, (C 1 -C 4) alkoxycarbonyl, or phenyl which is itself optionally substituted by halogen, C 1 -C 6 alkyl C 4 -C 4 alkoxy, C 1 -C 4 alkoxy, nitro, cyano or C 1 -C 4 alkoxycarbonyl in the alkoxy moiety, followed by isolation of the (R) -2-? 4- (5-chloro-3) propynyl ester from the reaction mixture; (Fluoropyridin-2-yloxy) phenoxy] propionic acid.

The starting compound of formula II, i.e. 5-chloro-2,3-difluoropyridine, can be obtained by fluorination of the corresponding 2,3,5-trichloropyridine in the presence of cesium fluoride. The desired product is obtained from the reaction mixture by distillation and further purified by fractional distillation. 5-chloro-2,3-difluoropyridine is also obtained from 2,5-dichloro-3-nitropyridine, which is reduced to 3-amino-2,5-dichloropyridine by hydrogen in the presence of Raney-nickel as a catalyst. The product is then converted to 2,5-dichloro-3-fluoropyridine by treatment with sodium nitrite in hydrofluoric acid. This compound can be fluorinated with good yield in the presence of potassium fluoride to 5-chloro-2,3-difluoropyridine.

4- (5-chloro-3-fluoropyridyl-2-oxy) phenol, i.e. the starting material of formula IV, is prepared by condensing 5-chloro-2,3-difluoropyridine and hydroquinone in an inert organic solvent in the presence of a base.

The starting material of formula IX can be obtained by reducing the (R) -2- [E - (5-chloro-3-nitropyridin-2-yloxy) phenoxy] propionic acid propynyl ester.

Other starting materials are either known or can be readily prepared by conventional methods. Part of these reactions are preferably carried out in an inert, organic solvent or diluent which is inert to the reactants, such as an alcohol, ester, ether, ketone, dimethylformamide, dimethylsulfoxide, acetonitrile, an aromatic hydrocarbon such as benzene, toluene, etc.

The reaction temperatures are between -10 ° C and +150 ° C, but practically between room temperature and the boiling point of the reaction mixture or the boiling point of the solvent. The reaction lasts from one hour to about one day, depending on the starting material used, the solvent used and the temperature at which the reaction proceeds.

Where a halogen atom is cleaved in the reaction, an equimolar amount of an acid binding agent should be used. In principle, any inorganic or organic base such as sodium hydroxide, potassium hydroxide, sodium bicarbonate, potassium carbonate, tert. potassium butoxide as well as amines such as trimethylamine, triethylamine, pyridine, 4-dimethylaminopyridine etc.

The new active compound of formula I is a stable compound which dissolves in conventional solvents such as alcohols, ethers, ketones, dimethylformamide, dimethylsulfoxide, etc.

The ester of the formula I is used in unchanged form or preferably together with auxiliaries which are customary in the preparation of the compositions and is processed in a known manner, for example, into emulsion concentrates, sprayable solutions or further dilutions, dilute emulsions, wettable powders, soluble powders, dusts, granules, also encapsulated in, for example, polymeric substances. Methods of application, such as spraying, fogging, dusting, scattering or potting, as well as the nature of the composition, are selected in accordance with the desired objectives and proportions. .

Compositions, i.e. compositions containing the active compound of the formula I and optionally a solid or liquid additive, concentrates or ready-to-use preparations are prepared in a known manner, for example by thoroughly mixing and / or grinding the active compound with fillers such as solvents, solid carriers and optionally surfactants (surfactants).

Suitable solvents are: aromatic hydrocarbons, preferably C8-C12 fractions, such as mixtures of xylenes or substituted naphthalenes, phthalic acid esters such as dibutyl phthalate or dioctyl phthalate, aliphatic hydrocarbons such as cyclohexane or paraffin hydrocarbons, alcohols and glycols, and their ethers and esters, such as ethanol, ethylene glycol, ethylene glycol monomethyl ether or ethylene glycol monoethyl ether, ketones such as cyclohexanone, strongly polar solvents such as N-methyl-2-pyrrolidone, dimethylsulfoxide or dimethylformamide, and optionally epoxidized vegetable oils such as epoxidized coconut oil or soybean oil, or water. ·

As solid carriers, for example for dusts and dispersible powders, natural stone flours such as limestone, talc, kaolin, montmoronite or attapulgite are generally used. High disperse silicic acid or high disperse absorbent polymers can also be added to improve physical properties. Suitable granular, adsorptive granular carriers are porous types such as pumice, brick pulp, sepiolite or bentonite, and limestone or sand are suitable as non-sorptive carrier materials. In addition, a large number of pre-granulated materials of inorganic or organic origin can be used, such as in particular dolomite or comminuted plant residues.

Depending on the type of active compound of the formula I, suitable surfactants are nonionic, cationic and / or anionic surfactants with good emulsifying, dispersing and wetting properties. Surfactants are also understood as meaning mixtures of surfactants.

Suitable anionic surfactants can be both water-soluble soaps and water-soluble synthetic surfactants.

Soaps include alkali metal, alkaline earth metal, or optionally substituted ammonium salts of higher fatty acids (C10-C20), or sodium or potassium salts of oleic acid or stearic acid, or natural mixtures of fatty acids which may be obtained, for example, from coconut oil or tallow. Fatty acid salts of methyl taurine must also be mentioned.

However, so-called synthetic surfactants, in particular fatty sulfonates, fatty sulfates, sulfonated benzimidazole derivatives or alkylarylsulfonates, are more commonly used.

Fatty sulphonates or fatty sulphates generally exist in the form of alkali metal, alkaline earth metal or optionally substituted ammonium salts and contain an alkyl radical of 8 to 22 carbon atoms, the alkyl also including the alkyl portion of the acyl radicals, for example sodium. or a calcium salt of ligninsulfonic acid, a dodecylsulfuric acid ester, or a mixture of sulfated fatty alcohols which has been made from natural fatty acids. Also included are salts of sulfuric acid esters and sulfonic acids of fatty alcohol and ethylene oxide adducts. The sulfonated benzimidazole derivatives preferably contain 2 sulfo groups and one fatty acid radical having 8 to 22 carbon atoms. Alkylarylsulfonates are, for example, the sodium, calcium or triethanolammonium salt of dodecylbenzenesulfonic acid dibutylnaphthalenesulfonic acid or the condensation product of naphthalenesulfonic acid with formaldehyde.

Also suitable are the corresponding phosphates, such as salts of the phosphoric acid ester of the p-nonylphenol adduct with 4 to 14 moles of ethylene oxide.

Suitable nonionic surfactants are, in particular, derivatives of polyglycol ethers of aliphatic or cycloaliphatic alcohols, saturated or unsaturated fatty acids and alkylphenols, which may contain 3 to 30 glycol ether groups and 8 to 20 carbon atoms in the (aliphatic) hydrocarbon radical and 6 to 18 carbon atoms in the alkyl the remainder of the alkylphenols.

Other suitable nonionic surfactants are adducts of polyethylene oxide with polypropylene glycol, ethylenediaminopolypropylene glycol and an alkylpolypropylene glycol of 1 to 10 carbon atoms in the alkyl chain containing 20 to 250 ethylene glycol ether groups and 10 to 100 propylene glycol ether groups. Said compounds usually contain 1 to 5 units of ethylene glycol per propylene glycol unit. .

Examples of nonionic surfactants include nonylphenolpolyethoxyethanols, castor oil polyglycol ethers, polypropylene and polyethylene oxide adducts, tributylphenoxypolyethoxyethanol, polyethylene glycol and octylphenoxypolyethoxyethanol.

Also suitable are polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan trioleate.

The cationic surfactants are in particular quaternary ammonium salts which contain as a substituent on the nitrogen atom at least one alkyl radical of 8 to 22 carbon atoms and, as further substituents, lower or halogenated alkyl, benzyl or lower hydroxyalkyl radicals. These salts are preferably present in the form of halides, methylsulfates or ethylsulfates, for example in the form of stearyltrimethylammonium chloride or benzyl-di- (2-chloroethyl) ethylammonium bromide.

Surfactants which can be used in the preparation of compositions are described, inter alia, in the following publications:

Mc Cutcheon ' s Detergents and Emulsifiers Annual, MC Publishing Corp., Ringwood, New Jersey, 1979; Sisley and Wood, Encyclopedia of Surface Active Agents, Chemical Publishing Co., Inc. New York, 1964.

The compositions generally contain 0.1 to 99%, in particular 0.1 to 95%, of active compound of the formula I and 1 to 99% of a solid or liquid additive and 0 to 25%, in particular 0.1 to 25% of a surfactant.

While concentrated products are more likely to be used as commercial goods, the end consumer usually uses dilute products.

The compositions according to the invention may contain other additives, such as stabilizers, anti-foaming agents, viscosity regulators, binders, adhesives, as well as fertilizers or other active substances, to achieve special effects.

The following examples describe in detail the preparation of (R) -2- (4- (5-chloro-3-fluoropyridin-2-yloxy) phenoxy] propionic acid propylester (I) as well as compositions containing the novel ester (I) as an active ingredient. However, these examples do not limit the scope of the invention in any way.

Example 1

Preparation of (R) -2- [4- (5-chloro-3-fluoropyridin-2-yloxy) phenoxy] propionic acid propynyl ester

F

A solution of 24.2 g (0.11 mol) of (R) -2- (4-hydroxyphenoxyphenoxy) propionic acid propionate in 80 ml of dimethylformamide was slowly added dropwise at 10 ° C to a stirred suspension of 4.9 g (0.11 mol) of the suspension. sodium hydride (55%) in dimethylformamide. After all the solution was added dropwise, the reaction mixture was further stirred at the same temperature for 1 hour. A further solution of 16-4 g (0.10 mol) of 5-chloro-2,3-difluoropyridine in 40 ml of dimethylformamide was added dropwise to the reaction mixture, and the mixture was stirred at room temperature for a further 24 hours. The reaction mixture was then poured onto ice-water and the organic product was extracted three times with ether. The ether phases were combined, washed with water and brine, dried over sodium sulfate and filtered through silica gel. Evaporation of the etherate filtrate left a pale oil which crystallized from ethanol. G (72% of theory) of (R) -propinylester are thus obtained. Mp 55-56 ° C.

5-chloro-2 _? The 3-difluoropyridine that is needed as a starting material can be prepared as follows:

and > 3-amino-2,5-dichloropyridine

To a solution of 129.2 g (0.69 mol) of 2,5-dichloro-3-nitropyridine in 1,300 mL of dioxane was added g of Raney nickel, which had been previously washed with ethanol. The mixture was now hydrogenated with hydrogen at 20-35 ° C at atmospheric pressure. When 20% of the theoretically consumable amount of hydrogen was consumed, 30 g of ethanol-washed Raney nickel were added again. Hydrogenation is continued for another 22 hours, then the catalyst is filtered off, the solvent is evaporated and the residue is crystallized from hexane / ethyl acetate. There was thus obtained 3-amino-2,5-dichloropyridine (84.9 g), m.p. 129-132 ° C. Yield: 78%.

b) 2,5-dichloro-3-fluoropyridine

450 ml (22.5 mol) of hydrogen fluoride are introduced in a steel autoclave. 163 g (1.0 mol) of 3-amino-2,5-dichloropyridine are then added with stirring at -1 ° C. 82.8 g (1.2 mol) of sodium nitrite are then slowly added to the solution with stirring at the same temperature. After the addition was complete, the reaction mixture was stirred for 1.5 hours at -5 ° C to -1 ° C and then the temperature of the reaction mixture was allowed to slowly rise to 60 ° C. After gas evolution had ceased, hydrogen fluoride was distilled off and the residue was taken up in methylene chloride. Ice and water were then added to the methylene chloride solution, and the mixture was neutralized with concentrated ammonia. The organic phase was separated and the aqueous phase was washed three times with methylene chloride. The combined organic phases were washed with water, dried over magnesium sulfate, filtered through silica gel and the filtrate was evaporated. 141.5 g (85% of theory) of 2,5-dichloro-3-fluoropyridine are obtained.

c) 5-chloro-2,3-difluoropyridine

64.6 g (1.1 mol) of potassium fluoride and 11.25 g (0.075 mol) of cesium fluoride in 240 ml of sulfolane, i.e. 1,1-dioxotetrahydrothiophene, are introduced. 50 ml of sulfolane are then distilled off by heating under reduced pressure. A solution of 61.4 g (0.37 mol) of 2,5-dichloro-3-fluoropyridine in 20 ml of sulfolane was added with stirring to the remaining suspension. The reaction mixture was then stirred at 140 ° C for 35 hours. After cooling, the reaction mixture was poured onto ice-water, and the organic matter was extracted with ether. The ether phase is washed with water, dried over magnesium sulphate, filtered and evaporated. 48.7 g of 5-chloro-2,3-difluoropyridine remain as a colorless liquid which boils at 65 to 69 ° C / 13 300 Pa · Yield: 88% of theory ·

Example 2

Preparation of (R) (+) - 2- (4- (5-chloro-3-fluoropyridyl-2-oxy) phenoxy) propionate propynyl ester

4.9 ml (0.035 mol) of triethylamine and 2 ml (0.035 mol) of propinol in 40 ml of toluene are introduced and the mixture is cooled with a mixture of ice and water. 10.6 g (0.030 mol) of (R) -2- [4- (5-chloro-3-fluoropyridin-2-yloxy) phenoxy] propionyl chloride in 30 ml of toluene are then added dropwise over 45 minutes. The reaction mixture was then further stirred at room temperature for 3 hours. The reaction mixture was then poured onto 150 ml of ice-water and extracted twice with ethyl acetate. The ethyl acetate extracts were washed with brine, dried (MgSO 4), filtered and concentrated. The residue is taken up in hexane / ethyl acetate (2: 1) and the solution is purified by silica gel column chromatography. After evaporation of the solvent the residue crystallized. The crystals obtained melted at 54 ° C. + 45.4 ° (2% in acetone).

The (R) -2- [4- (5-chloro-3-fluoropyridin-2-yloxy) phenoxy] propionic acid chloride used as starting material is prepared as follows:

a) 4- (5-chloro-3-fluoropyridin-2-yloxy) phenol

A mixture of 27.5 g (0.25 mol) of hydroquinone, 11.2 g (0.2 mol) of potassium hydroxide and 600 ml of dimethylsulfoxide is stirred under nitrogen atmosphere until complete dissolution. A solution of 30 g (0.2 mol) of 5-chloro-2,3-difluoropyridine in 200 ml of dimethylsulfoxide is then added dropwise with stirring to the reaction solution. The reaction solution is then heated to 70 ° C and stirred at this temperature for 4 hours. The reaction mixture is then poured onto ice-water, acidified with concentrated hydrochloric acid and then extracted with ethyl acetate. The organic phases are washed, dried over magnesium sulphate, filtered and evaporated to dryness. The residue is taken up in a mixture of hexane and ethyl acetate and then purified by chromatography on a column of silica gel. 33 g of 4- (5-chloro-3-fluoropyridin-2-yloxy) phenol are obtained in the form of white crystals, m.p. 97-98 ° C.

b) ¹ (R) -2- [4- (5-Chloro-3-fluoro-pyridin-2-yloxy) -phenoxy] -propionic acid methyl ester

To a suspension of potassium carbonate (13.8 g, 0.1 mol) in dimethylsulfoxide (50 ml) was added dropwise a solution of 4- (5-chloro-3-fluoropyridin-2-yloxy) phenol (24.0 g, 0.1 mol) in stirring. 80 ml of dimethyl sulfoxide and the mixture was stirred at room temperature for 2 hours. A solution of 25.8 g (0.1 mol) of (S) (-) - lactic acid methyl ester tosylate in 30 ml of dimethylsulfoxide is then added dropwise over 30 minutes. The reaction mixture was then stirred at 60 ° C for 20 hours. For working-up, the reaction mixture was poured into ice-water and extracted three times with ether. The extracts were washed with water and brine, dried (MgSO4), filtered and concentrated. The crude product obtained is purified by chromatography on silica gel (3: 1 hexane / ethyl acetate). 26.0 g of pure product are thus obtained in the form of an oil. [.alpha.] D @ ^{20 =} +38.8 - 0.5 DEG (in acetone).

c) (R) (+) - 2- [4- (5-chloro-3-fluoropyridin-2-yloxy) phenoxy] propionic acid

13.0 g (0.040 mol) of (R) (+) - 2- [4- (5-chloro-3-fluoro-pyridin-2-yloxy) -phenoxy] -propionic acid methyl ester are dissolved in 65 ml of dioxane. 42 ml of 1N sodium hydroxide solution are then added to this solution with stirring and the reaction solution is heated at 35 [deg.] C. for 2.5 hours. The reaction mixture was poured onto ice-water and acidified with 22 ml of 2N hydrochloric acid. The reaction mixture was extracted twice with ethyl acetate, the extracts were washed with brine, dried over magnesium sulfate, filtered and concentrated. The residue crystallized from a mixture of ethyl acetate and hexane. 10.2 g of white crystals of melting point 95 DEG-96 DEG C. are thus obtained. Yield 81.8% of theory. [Α] ²⁰ D = 1-37.7 - 0.5 ° (in acetone).

d) (R) -2-Q4- (5-Chloro-3-fluoropyridin-2-yloxy) phenoxy] propionic acid chloride

10.8 g (0.035 mol) of (R) -2- [4- (5-chloro-3-fluoropyridin-2-yloxy) phenox (E) | propionic acid is dissolved in 150 ml of toluene. 50 ml of toluene are distilled off from this solution at a bath temperature of 130 ° C. The mixture was then cooled to an internal temperature of 90 ° C and 3.8 ml of thionyl chloride was slowly added thereto with stirring. The reaction mixture was further stirred at the same temperature for 16 hours and then concentrated under reduced pressure. The acid chloride thus obtained, which melts at 47-48 ° C, is used directly.

Example 3 (% =% by weight)

The preparation of the compositions using the active compound of the formula I in the liquid state

Emulsion concentrate and) (b) C) propinylester (P.) -2-Q4- (5-chloro- -3-Fluoropyridin-2-yloxy) phenoxy] - propionic acid 20% 40% 50% calcium dodecylbenzenesulfo- new acids 5% 8% 5.8% polyethylene glycol ether castor- 4Ь- · - oil (36 moles of ethylene oxide) 5% - - tributylphenolpolyethylene glycol (30 mol ethylene oxide) - 12% 4.2% cyclohexanone - 15% 20% mixture of xylenes 70% 25% 20%

Emulsions of any desired concentration can be prepared from such concentrates by dilution with water.

Solutions: propynyl ester (as above) ethylene glycol monomethyl ether%

continued table

Solutions: and) (b) C) (d) polyethylene glycol (molecular- weight 400) - 70% - - N-methyl-2-pyrrolidone - 20% . - - epoxidized coconut oil - - 1% 5% Gasoline (with temperature range boiling point 160 to 190 ° C) - - 94% -

These solutions are suitable for use as minimal drops.

Granulate:

(R) -2-Q4- (5-chloro-3-fluoropyridin-2-yloxy) phenoxy] propionic acid kaolin high disperse silica attapulgite

a)%

%%

b)%

%

The active substance is dissolved in methylene chloride, the solution is sprayed onto the carrier and the solvent is then evaporated off under vacuum.

Dust: a) b) propynyl ester 2% 5% high disperse silica 1% 5% talc 97% kaolin - 90%

By thoroughly mixing the carrier substances with the active substance, a directly usable dust is obtained.

Examples of compositions for the active compound of the formula I in solid form (% =% by weight)

(a) Wettable powder:

a) b)

propinylester 20% 60% sodium lignin sulphonate 5% 5% sodium lauryl sulfate 3% - natriumdiisobutylnaftalen- sulfonate - 6% octylphenolpolyethylene glycol ether (7 to 8 moles of ethylene oxide) - 2% high dispersive acid siliceous 5% 27% kaolin 67% -

The active ingredient is well mixed with the ingredients and the resulting mixture is ground well in a suitable mill. A wettable powder is obtained which can be diluted with water to suspensions of any desired concentration.

Emulsion concentrate: (R) -2- [E - (5-chloro-3-fluoropyridin-2-yloxy) phenoxy] propionic acid propynyl octylphenolpolyethylene glycol ether (4-5 moles of ethylene oxide) dodecylbenzenesulfonic acid calcium salt%

%%

castor oil polyglycol ether (36 moles ethylene oxide) 4% cyclohexanone 30% xylene mixture 50%

Emulsions of any desired concentration can be prepared from this concentrate by dilution with water.

Dust: and) (b) propinylester 5% 8% talc 95% . - kaolin - 92%

By mixing the active ingredient with the carrier, a dustable powder is obtained after grinding in a suitable mill.

Granules prepared by extrusion:

propinylester. 10% sodium lignin sulphonate 2% carboxymethylcellulose 1% kaolin 87%

The active ingredient is mixed with the ingredients, the mixture is ground and moistened with water; the mixture obtained is processed on an extruder and then dried in an air stream.

Coated granulate: propynyl ester 3% polyethylene glycol (molecular weight 200) kaolin%

The finely divided active substance is uniformly applied to a kaolin moistened with polyethylene glycol in a mixer. In this way a non-dusted coated granulate is obtained.

Suspension concentrate: (R) -2- [4- (5-chloro-3-fluoro-pyridin-2-yloxy) -phenyl] -propionic acid propynyl ester ethylene glycol nonylphenolpolyethylene glycol ether (15 mol of ethylene oxide) sodium lignin sulphonate carboxymethylcellulose 37% aqueous formaldehyde solution 75% silicone oil % aqueous emulsions water%

%.

% ¹⁰ %%

0.2%

0.8%%

The finely divided active ingredient is intimately mixed with the ingredients. A suspension concentrate is obtained from which suspensions of each desired concentration can be prepared by dilution with water.

Example 5

Test for herbicidal effect (effect of herbicide in post-emergence application - effect of contact herbicide)

Various grasses such as maize (Zea mays), sorghum (Sorghum hybrids), rice (Oryza sativa), deaf oats (Avena fatua), brome (Bromus tectorům), perennial ryegrass (Lolium perenne), foxtail (Alopecurus myosuroides) , the bloodweed (Digitaria sanguinalís), the hedgehog (Echinochloa crus galii), the sorghum sorghum (Sorghum halepense) and Rottboéllia exaltata are planted in pots in a greenhouse and sprayed with water dispersion (4 to 6 leaves) the enantiomer of the invention and the racemate in various doses, expressed in g of active ingredient per ha, by spraying on the leaves of the plants; the plants are then maintained at a temperature of 24 to 26 ° C at 45 to 60% relative humidity and regularly watered. The experiment is evaluated 10 days after treatment.

Plant damage is evaluated according to the following scale;

the plant grows as an untreated control of total damage; dead plant

2-8 intermediate damage

The results of this test for each species of test plant are summarized in the following table:

Table

Herbicidal effect in controlling monocotyledonous plants after post-emergence application

Type of plant

Racemate R-enantiomer

Dose of active substance in g / ha

500 250 125 60 30 15

Zea mais

Sorghum hybrids 11

Oryza sativa

Avena fatua

Bromus tectorum 46

Lolium perenne

Alopecurus myosuroides 11

The sanguinalís 11

Echinochloa crus. galii 11

Sorghum halepense

Rottboellia exaltata 11

1 2 5 8 1 1 2 4 7 7 1 1 4 6 8 9 1 2 3 6 9 9 1 1 7 9 9 9 2 4 2 3 6 8 1 1 2 4 6 9 1. 1 1 2 2 3 1 1 1 1 1 2 1 1 1 4 6 8 1 1 1 2 3 4 1 1

1 1 1 4 1 1 2 4 4 4 6 8 1 3 5 6 6 8 9 9 1 2 3 4 2 2 4 7 1 1 1 2 1 1 1 1 1 1 5 8 1 1 1 3

The damage values and mean values found for each application rate for the experimental grass species are plotted in the graph shown in the attached drawing.

This drawing shows the average efficacy of the test active compounds against grasses after post-emergence application. As can be seen from the accompanying drawing, an amount of active ingredient of 86 g / ha, when a racemate is used, is required to obtain a grade 3 which corresponds to a good herbicidal effect. Surprisingly, the same degree of killing is achieved already at 42 g / ha when the R-enantiomer is used. This results in an unexpected increase in efficiency of more than a factor of 2.

In the accompanying drawing, the amount of active substance used (in grams / ha) is indicated on the x-axis. The χ axis indicates the mean value of plant damage.

The number 1 curve is for the racemate;

the curve of number 2 is for the R-enantiomer.

The graph showing the herbicidal effect was calculated from the following individual values. Each plant, after treatment, is scored on a scale of 1 to 9 and corresponds to the following percentages:

1 = total damage 100% 2 = very significant damage 87.5% 3 = severe damage 75% 4 = moderate damage 62.5% 5 = moderate damage 50% 6 = still tolerable damage, in which the plant, if is still at an early stage, can regenerate 37% 7 = slight damage 25% 8 = very slight damage 12.5% 9 = no damage, that is the plant grows as untreated control plant 0%

SUBJECT

Claims (2)

SUBJECT OF THE INVENTION A herbicidal and plant growth-inhibiting agent, characterized in that, as active ingredient, the (R) -2- [4- (5-chloro-3-fluoro-pyridin-2-yloxy) -phenoxy] -propionic acid propynyl ester of the formula I is present together with the active ingredient. with inert additives. 2. A process for the preparation of an active ingredient according to claim 1, i.e. (R) -2- [4- (5-chloro-3-fluoro-pyridin-2-yloxy) -phenoxy] -propionic acid propylester of the formula I, characterized in that -chloro-2,3-difluoropyridine of formula II F (II) acts in an inert solvent or diluent, in the presence of an equimolar amount of base, with a 4-hydroxyphenoxy-alpha-propionic acid ester of formula III CH ₃ AND OCH - CO - OCH ₂ C = CH (III)