DD253754A5 - HERBICIDES AND PLANT GROWTH RESTRICTING MEDIUM - Google Patents

Abstract

The invention relates to a herbicidal and plant growth inhibiting agent containing (R) -2- & 4- (5-chloro-3-fluoropyridin-2-yloxy) -phenoxy! -Propionsaeurepropinylester, which is characterized by exceptional herbicidal and the Graeserwuchs inhibiting effect , It corresponds to the formula I, and is suitable for the selective control of weeds in crops or for the inhibition of Graeserwuchses. Formula I

Description

See 1 page table

Field of application of the invention

The present invention relates to herbicidal and plant growth inhibiting agents containing novel (R) -2- [4- (5-chloro-3-fluoropyridin-2-yloxy) -phenoxy] -propionic acid propynyl ester with herbicidal activity, its preparation, and its use as a herbicide in general and especially for controlling weeds in crops such as cereals, rice, corn, soy, sugar beet.

Characteristic of the known state of the art

Halogenopyridyloxy-a-phenoxy-propionic acid derivatives have been described in numerous publications, see, for example, DE-A 2546251, 266 706, 2714622, 2715284 and EP-A 483, 1473, 83556 and 97460. Therein, a- [4- (3- Fluoro-halopyridyl-2-oxy) -phenoxy] -propionic acid ester, in part also contemplated and included in the scope.

Object of the invention

The aim of the invention is to provide a new herbicidal and plant growth-inhibiting agent which can be used as an efficient selective herbicide for crops such as cereals, corn, rice, soy and sugar beet and is effective even at low rates.

Explanation of the essence of the invention

The invention has for its object to find new compounds with the desired properties that are suitable as active ingredient in the new herbicidal and plant growth inhibitory agent. According to the invention, the (R) -2- [4- (5-chloro-3-fluoropyridin-2-yloxy) -phenoxy] -propionic acid propinyl ester of the formula I is used as active ingredient in the novel herbicidal and plant growth-inhibiting agent

Cl J / ^X "-O · ^'NN · -OCH co-OCH CHCH ₀

- N

O OCHC

applied.

The optically active ester according to the invention differs from the known halopyridyloxy-a-phenoxypropionic acids by stronger action and thus the possibility to use it in lower application rates.

The inventive (Rl ^ -W-fB-chloro-S-fluoropyridine ^ -xyl-phenoxyl-propionic acid propinyl ester is characterized by an exceptionally good action against mono- and some dicotyledonous weeds, above all it acts in the after-run process against adverse in cultures Weeds and grass weeds that are particularly common in cereals, maize, rice, soya and sugar beet, and the ability to control grass weeds that are otherwise difficult to control, such as Avena fatua, Avena sterilis, Alopecurus myosuroides, Lolium perenne, Phalaris sp., Bromus tectorum, various Setaria and Panicum species.

The effect occurs under field conditions even at low application rates of less than 1 kg per hectare, in which the cultures are not or only slightly damaged.

The optically active ester according to the invention differs from the known halopyridyloxy-a-phenoxypropionic acids by stronger action and thus the possibility to use it in lower application rates.

The application can be carried out both pre-emergence and post-emergence. The application rates can vary within wide limits, z. B. between 0.01 to 2kg of active ingredient per hectare.

Furthermore, the compound of formula I has favorable growth-regulating effects (growth inhibition). In particular, it inhibits the growth of grasses.

The preparation of the new ester of formula I is carried out by various methods.

After a first of these methods, 5-chloro-2,3-difluoropyridine of the formula II is used

egg-

in an inert solvent or diluent, in the presence of the equimolar amount of a base with the 4-hydroxyphe ^1- noxy-a-propionic acid ester of formula III,

CH ₃ β - ♦ ι

HO "" \ · -OCH-CO-OCH ₂ -C = CH

Another method is that 4- (5-chloro-3-fluoropyridin-2-yloxy) phenol of the formula IV f

a · · -o- \\. y- oh .....

in an inert solvent or diluent in the presence of the equimolar amount of a base with a (S) enantiomeric a-halopropionic propinyl ester of the formula V is reacted

CH ₃ Hal-CH-CO-OCH ₂ -CHCH

wherein shark means chlorine, bromine or iodine.

Another method consists of reacting an (R) -enantiomeric 2- [4- (5-chloro-3-fluoropyridin-2-yloxy) -phenoxy] -propionsäurehalogenid of formula Vl

· .-. / -V 9 ^H 3

_cl _ / \ _o- ^ X-OCH-COHaI

wherein Hal is fluorine, chlorine or bromine, in an inert solvent or diluent in the presence of equimolar amount of a base with propynol HOCH ₂ -C = CH.

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

..- *. _y -v CH ₃

<J <J ^om

in an inert solvent or diluent, in the presence of the equimolar amount of a base with a propynyl halide of formula VIII

Hal CH ₂ -C = CH (VIII),

wherein Hal means halogen.

Finally, another method is to react the (R) -enantiomeric 2- [4- (3-amino-5-chloropyridin-2-yloxy) -phenoxyl-propionic acid propynyl ester of formula IX

s-K y - * \ 9 ^H3

_Cl _y ^ .- O- ^ ^ -OCH-CO-OCHz-CsCH (IX),

converted by known methods into a diazonium salt and this further in the fluorine compound.

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

C ₁ -. / \ -Q -> ( full

with a (S) -enantiomeric lactic acid-propynyl ester sulfonate of formula X is reacted

CH ₃ R-SO ₂ OCH-CO-OCH ₂ -C = Ch (X),

wherein R is a straight-chain or branched C 1 -C 6 -alkyl radical or unsubstituted by halogen, cyano, C 1 -C ₄ -alkoxycarbonyl or a phenyl radical which is unsubstituted or halogen, C 1 -C ₄ -alkyl, C 1 -C ₄ -alkoxy, nitro, cyano or C 1 -C ₄ -alkyl Alkoxycarbonyl is substituted, and isolated the obtained (R) -2- [4- (5-chloro-3-fluoropyridin-2-yloxy) -phenoxy] -propionäurepropinylester from the reaction mixture.

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

4- (5-chloro-3-fluoropyridyl-2-oxy) -phenol, the starting compound of formula IV is prepared by condensation of 5-chloro-2,3-difluoropyridine with hydroquinone in an inert organic solvent in the presence of a base ,

The starting material of formula IX can be obtained by reduction of ds (R) -2- [4- (5-chloro-3-nitropyridin-2-yloxy) -phenoxy-propionic acid propinyl ester.

The remaining starting materials are either known or can be readily prepared by conventional syntheses. Some of these reactions are advantageously carried out in an inert organic solvent or diluent to the reactants, e.g. an alcohol, ester, ether, ketone, dimethylformamide, dimethyl sulfoxide, aceonitrile, an aromatic such as benzene, toluene etc.

The reaction temperatures are between -1O ⁰ C and +150 ⁰ C, but practically between the room temperature and the boiling point of the solvent. The reaction time is depending on the selected starting material, the solvent and the temperature from 1 hour to about one day.

Where a halogen atom is split off in the reaction, the equimolar amount of acid-binding agent should be used. As such, in principle, any inorganic or organic base, such as. As NaOH, KOH, NaHCO ₃ , K ₂ CO ₃ , K-tert.

Butylate, and amines such as trimethylamine, triethylamine, pyridine, 4-dimethylaminopyridine, etc.

The new active ingredient of the formula I is a stable compound which is dissolved in common organic solvents, such as alcohols,

Äthern, ketones, dimethylformamide, dimethyl sulfoxide, etc. are soluble.

The ester of the formula I is used here in unchanged form or preferably together with the auxiliaries customary in formulation technology and is therefore used, for example. to emulsion concentrates, directly sprayable or dilutable solutions, dilute emulsions, wettable powders, soluble powders, dusts, granules, also encapsulations in e.g.

processed polymeric substances in a known manner. The application methods such as spraying, atomizing, dusting, scattering or pouring are chosen in the same way as the type of means according to the desired goals and the given conditions.

The formulations, d. H. the compositions, preparations or compositions containing the active substance of the formula I and, where appropriate, a solid or liquid additive are prepared in a known manner, e.g. by intimately mixing and / or grinding the active ingredients with diluents, e.g. with solvents, solid carriers and optionally surface-active compounds (surfactants).

Suitable solvents are: Aromatic hydrocarbons, preferably the fractions C ₈ to C ₁₂ , wiez. B.

Xylene or substituted naphthalenes, phthalic acid esters such as dibutyl or Dioctylphthalat, aliphatic hydrocarbons such as cyclohexane or paraffins, alcohols and glycols and their ethers and esters such as ethanol, ethylene glycol, ethylene glycol monomethyl or -äthyläther. Ketones such as cyclohexanone, strongly polar solvents such as N-methyl-2-pyrrolidone, dimethyl sulfoxide or dimethylformamide, and optionally epoxidized vegetable oils such as epoxidized coconut oil or soybean oil; or water.

As solid carriers, for. As for dusts and dispersible powders, natural minerals are generally used, such as calcite, talc, kaolin, montmorillonite or attapulgite. To improve the physical properties, it is also possible to add highly dispersed silicic acid or highly dispersed absorbent polymers. As granular, adsorptive granules are porous types such. As pumice, broken brick, sepiolite or bentonite, as non-sorptive carrier materials such. As calcite or sand in question. In addition, a variety of pre-granulated materials of inorganic or organic nature such as in particular dolomite or crushed plant residues can be used.

Suitable surface-active compounds, depending on the nature of the active compound of the formula I to be formulated, are nonionic, cationic and / or anionic surfactants having good emulsifying, dispersing and wetting properties. Surfactants are also surfactant mixtures.

Suitable anionic surfactants may be both so-called water-soluble soaps and water-soluble synthetic surface-active compounds.

As soaps are the alkali, alkaline earth or optionally substituted ammonium salts of higher fatty acids (C ₁₀ -C ₂₀ ), such as

z. As the sodium or potassium salts of oleic or stearic acid, or of natural fatty acid mixtures z. B. can be obtained from coconut or tallow oil. Also to be mentioned are the fatty acid methyl taurine salts.

Frequently, however, so-called synthetic surfactants are used, in particular fatty sulfonates, fatty sulfates, sulfonated benzimidazole derivatives or alkylarylsulfonates.

The fatty sulfonates or sulfates are generally present as alkali, alkaline earth or optionally substituted ammonium salts and have an alkyl radical having 8 to 22 carbon atoms, wherein alkyl also includes the alkyl moiety of acyl radicals, for. As the Na or Ca salt of lignin, the Dodecylschwefelsäureesters or a fatty alcohol sulfate mixture prepared from natural fatty acids.

This subheading also covers the salts of sulfuric acid esters and sulfonic acids of fatty alcohol / ethylene oxide adducts. The sulfonated benzimidazole derivatives preferably contain 2 sulfonic acid groups and a fatty acid residue having 8-22 C atoms.

Alkylarylsulfonates are z. As the sodium, calcium or triethanolamine salts of dodecylbenzenesulfonic acid, dibutylnaphthalenesulfonic acid, or a naphthalenesulfonic acid-formaldehyde condensation product.

Furthermore, corresponding phosphates such. B. salts of the phosphoric acid ester of a p-nonylphenol (4-14) -ethylene oxide adduct in question.

Suitable nonionic surfactants are primarily polyglycol ether derivatives 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 radical of the alkylphenols.

Further suitable nonionic surfactants are the water-soluble polyethylene oxide adducts containing from 20 to 250 ethylene glycol ether groups and from 10 to 100 propylene glycol ether groups with polypropylene glycol, ethylene diaminopolypropylene glycol and alkylpolypropylene glycol having from 1 to 10 carbon atoms in the alkyl chain. The compounds mentioned usually contain 1 to 5 ethylene glycol units per propylene glycol unit.

Nonylphenol polyethoxyethanols, castor oil polyglycol ethers, polypropylene-polyethylene oxide adducts, tributylphenoxylethoxyethanol, polyethylene glycol and octylphenoxypolyethoxyethanol may be mentioned as examples of nonionic surfactants.

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

The cationic surfactants are, above all, quaternary ammonium salts which contain as N-substituents at least one alkyl radical having 8 to 22 C atoms and contain, as further substituents, lower, optionally halogenated alkyl, benzyl or lower hydroxyalkyl radicals. The salts are preferably in the form of halides, methylsulfates or ethylsulfates, e.g. As the stearyltrimethylammonium chloride or benzyldi (2-chloroethyl) ethylammonium bromide.

The surfactants commonly used in formulation technology are i.a. described in the following publications:

Mc Cutcheon's Detergents and Emulsifiers Annual

MC Publishing Corp., Ringwood, New Jersey, 1979.

Sisley and Wood, "Encyclopaedia of Surface Active Agents",

Chemical Publishing Co., Inc. New York, 1964.

These preparations generally contain 0.1 to 99%, in particular 0.1 to 95%, active ingredient of the formula 1.1 to 99% of a solid or liquid additive and 0 to 25%, in particular 0.1 to 25%, of one surfactant.

While merchandise is more likely to be concentrated, the end user typically uses diluted funds.

The compositions may also contain other additives such as stabilizers, defoamers, viscosity regulators, binders, adhesives and fertilizers or other active ingredients to achieve special effects.

embodiment

The following examples describe in detail the preparation of the inventive (R) -2- (4- [5-chloro-3-fluoro-pyridin-2-yloxy] -phenoxy) -propionic acid propinyl ester of the formula I and agents containing this ester. Temperatures are in degrees Celsius, while percentages are by weight.

Example 1: Preparation of (R) -2- (4- [5-chloro-3-fluoro-pyridin-2-yloxy] -phenoxy) -propionic acid propynyl ester F

'.-. ^CH ^

/ - \ Λ Λ I ³

Cl - // ^ rOe ^ \ · -OCH-COOCH ₀ -CsCH

β-Ν

A solution of 24.2 g (0.11 mol) of (R) -2- (4-hydroxyphenoxy-phenoxy) -propionsäuj; epropinylester in 80ml dimethylformamide is slowly added dropwise at 1O ⁰ C to a stirred suspension of 4.9 g (0, 11 mol) of sodium hydride suspension (55%) in dimethylformamide. After everything has dropped, stirring is continued for one hour at the same temperature. A further solution of 16.4 g (0.10 mol) of 5-chloro-2,3-difluoropyridine in 40 ml of dimethylformamide is then added dropwise to the reaction mixture and the mixture is stirred at room temperature for 24 hours. The reaction mixture is then poured into ice / water and the organic material extracted three times with ether. The ether phases are collected, washed with water and brine, dried over magnesium sulfate and filtered over silica gel. Evaporation of the ether filtrate leaves a pale oil which is crystallized from ethanol. This gives 25 g (72% of theory) of the (R) -Propinylesters. Melting point 55-56 ⁰ C

 The 5-chloro-2,3-difluoropyridine required as starting material is prepared as follows:

a) 3-amino-2,5-dichloropyridine

In a solution of 129.2 g (0.69 mol) of 2,5-dichloro-3-nitropyridine in 1300 ml of dioxane is added 26 g of Raney nickel, which was previously washed with ethanol. The mixture is then hydrogenated with hydrogen at 20-35 ⁰ C under atmospheric pressure. After 20% of the theoretical amount of hydrogen has been absorbed, another 30 g of ethanol-washed Raney nickel are added. The hydrogenation is continued for 22 hours, then the catalyst is filtered off, the solvent evaporated and the residue crystallized from hexane / ethyl acetate. This gives 84.9 g of 3-amino-2,5-dichloropyridine which melts at 129-132 ° C. Yield 78% of theory.

b) 2,5-dichloro-3-fluoropyridine

A steel autoclave is charged with 450 ml (22.5 mol) of hydrogen fluoride. To this is added with stirring at a temperature of - 1 ° C 163g (1.0 mol) of 3-amino-2,5-dichloropyridine. Then, at the same temperature, 82.8 g (1.2 mol) of sodium nitrite are slowly added to the solution with stirring. After everything is added, it is stirred for a further 1.5 hours at a temperature of -5 ⁰ C to -I ⁰ C, then allowed to gradually warm the reaction mixture to 60 ° C. After the gas evolution has ceased, the hydrogen fluoride is distilled off and the residue taken up in methylene chloride. Then add ice and water and neutralize the mixture with concentrated ammonia. The organic phase is separated off and the aqueous phase is washed three times with methylene chloride. The collected organic phases are washed with water, dried over magnesium sulfate filtered through silica gel and evaporated. This gives 141.5 g (85% of theory) of 2,5-dichloro-3-fluoropyridine.

c) 5-chloro-2,3-difluoropyridine

A suspension of 64.6 g (1.1 mol) of potassium fluoride and 11.25 g (0.075 mol) of cesium fluoride in 240 ml sulfolane (1,1-Dioxotetrahydrothiophen) is presented. By heating under reduced pressure, 50 ml of sulfolane are distilled off again. A solution of 61.4 g (0.37 mol) of 2,5-dichloro-3-fluoropyridine in 20 ml of sulfolane are added to the remaining suspension with stirring. The mixture is then stirred at 140 ^° C. for 35 hours. After cooling, it is poured onto ice / water and the organic material extracted with ether. The ether phase is washed with water, dried over magnesium sulfate, filtered and evaporated. There remain 48.7 g of 5-chloro-2,3-difluoropyridine as a colorless liquid which boils at 65-69 ° C / 133mbar. Yield: 88% of theory.

Example 2: Preparation of (R) (+) - 2- [4- (5-chloro-3-fluoropyridyl-2-oxy) -phenoxy] -propionic acid-propynyl ester

-1 y- \ ^CH 3

_Cl _ / \ -o- ^ ^ .- OCHCOCH ₂ -C = CH

A solution of 4.9 ml (0.035 mol) of triethylamine and 2 ml (0.035 mol) of propynol in 40 ml of toluene is introduced and cooled with ice / water. Then 10.6 g (0.030 mol) of (R 1 -W -is-chloro-S-fluoropyridine-oxy-phenoxy-1-propionyl chloride in 30 ml of toluene are added dropwise over 45 minutes, followed by stirring at room temperature for 3 hours The extracts are washed with brine, dried over magnesium sulfate, filtered and concentrated, the residue is taken up in hexane / ethyl acetate 2: 1 and chromatographed on a silica gel column for purification The crystals crystallize at 54 ° C, [α] ° + 45.4 ° (2% in acetone).

The required as starting material (Rl ^ -W-fö-chloro-S-fluoropyridin ^ -xyl-phenoxy-I-propionic acid chloride 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 dimethyl sulfoxide is stirred under nitrogen atmosphere until everything is dissolved. Then a solution of 30 g (0.2 mol) of 5-chloro-2,3-difluoropyridine in 200 ml of dimethyl sulfoxide is added dropwise with stirring. The reaction solution is then heated to 70 ⁰ C and stirred for 4 hours at this temperature. Then it is poured onto ice / water, the mixture is acidic with concentrated hydrochloric acid and extracted with ethyl acetate. The organic phases are washed, dried over magnesium sulfate, filtered and evaporated to dryness. The residue is taken up in hexane / ethyl acetate and chromatographed on a silica gel column for purification. After evaporation of the solvent, the residue crystallizes. 33 g of 4- (5-chloro-3-fluoropyridin-2-yloxy) -phenol are obtained as white crystals, which melt at 97-98 ° C.

b) (R) -2- [4- (Chloro-3-fluoropyridin-2-yloxy) -phenoxy] -propionic acid methyl ester

To a suspension of 13.8 g (0.1 mol) of potassium carbonate in 50 ml of dimethyl sulfoxide is added dropwise with stirring a solution of 24.0 g (0.1 mol) of 4- (5-chloro-3-fluoropyridin-2-yloxy). -phenol in 80ml dimethyl sulfoxide and the mixture stirred for 2 hours at room temperature. Then added dropwise within 30 minusten a solution of 25.8 g (0.1 mol) of S (-) - methyl lactate tosylate in 30 ml of dimethyl sulfoxide. Subsequently, the reaction mixture is stirred at 60 ^° C. for 20 hours. For workup, it is poured onto ice / water and extracted three times with ether. The extracts are washed with water and brine, dried over magnesium sulfate, filtered and concentrated. The crude product obtained is purified by chromatography on silica gel (solvent mixture: hexane / ethyl acetate 3: 1). This gives 26.0 g of pure product as an oil ([a] g ° = +38.8 ± 0.5 ⁰ C 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-fluoropyridin-2-yloxy) -phenoxy] -propionic acid methyl ester are dissolved in 65 ml of dioxane. 42 ml of 1N sodium hydroxide solution are then added, with stirring, and the solution is heated at 35 ^° C. for 2.5 hours. The reaction mixture is then poured onto ice / water and acidified with 22 ml of 2N hydrochloric acid.

It is then extracted twice with ethyl acetate, the extracts are washed with brine, dried over magnesium sulfate, filtered and concentrated. The residue is crystallized from ethyl acetate / hexane. This gives 10.2 g of white crystals with melting point 95-96 ⁰ C. Yield 81.8% of theory. [a] & ° +37.7 ± 0.5 ° in acetone.

d) (RI ^ -l / MS-chloro-S-fluoropyridine ^ -xylxyl-phenoxyl-propionic acid chloride

10.8 (0.035 mol) of (R) -2- [4- (5-chloro-3-fluoropyridin-2-yloxy) -phenoxy] -propionic acid are dissolved in 150 ml of toluene. With a bath of 130 ⁰ C 50 ml of toluene are distilled off. Subsequently, the mixture is cooled to an internal temperature of 90 ⁰ C and

20% 40% 50% 5% 8th% 5.8% 5% - - - 12% 4.2% - 15% 20% 70% 25% 20%

3.8 ml of thionyl chloride are slowly added dropwise with stirring. The reaction mixture is stirred for 16 hours at the same temperature and then concentrated under vacuum. The resulting acid chloride, melting point of 47-48 ° C, is used directly.

Example 3 Preparation of a Formulation with Liquid Active Ingredients of the Formula I (% by Weight)

Emulsion Concentrates a) b) c)

(R) -2- [4- (5-chloro-3-fluoropyridine

2-yloxy) -phenoxy] -propionic acid propynyl ester Ca-dodecylbenzenesulfonate

Castor oil polyethylene glycol ether (36 moles of AeO) tributylphenoyl polyethylene glycol ether (30 moles of AeO) cyclohexanone

xylenes

From such concentrates, emulsions of any desired concentration can be prepared by dilution with water.

solutions

Propinyl ester (as above) Ethylene glycol monomethyl ether Polyethylene glycol M G 400 N-methyl-2-pyrrolidone Epoxidized coconut oil Gasoline (boiling limit 160-190 ° C)

The solutions are suitable for use in the form of very small drops.

granules

(R) -2- (5-chloro-3-fluoropyridin-2-yloxy) -

phenoxy-propionsäurepropinylester

kaolin

Highly dispersed silicic acid

Attapulgite - 90%

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

dusts

propynyl

Highly dispersed silicic acid

talc

Kaolin - 90%

Intimately mixing the excipients with the active ingredient gives ready-to-use dusts.

Formulation Examples of Solid Active Ingredients of Formula I (% = Wt%)

a) b) c) d) 80% 10% 5% 95 ° / < 20% - - - - - 70% - - - 20% - - - - 1% 5 ° / < 94% - gnet. a) b) 5% 10% 94% - 1%

a) b) 2% 5 ° / c 1% 5 ° / < 97%

a) spray powder a) b) propynyl 20% 60% Na ligninsulfonate 5% 5% Na Laurylsulat 3% - Na Diisobutylnaphthalinsulfonat - 6% Octylphenolpolyethylene glycol ether (7-8 moles of AeO) - 2% Highly dispersed silicic acid 5% 27% kaolin , 67% _

The active ingredient is well mixed with the additives and ground well in a suitable mill. This gives wettable powders which can be diluted with water to give suspensions of any desired concentration.

Emulsion concentrate

(R) -2- [4- (5-chloro-3-fluoropyridin-2-yloxy) -

phenoxy] -propionic acid propinyl ester 10%

Octylphenolpolyethylene glycol ether (4-5 moles of AeO) 3%

Ca-dodecylbenzenesulfonate 3%

Ricinus polyglycol ether (36 molAeO) 4%

Cyclohexanone 30%

Xylene mixture 50%

From this concentrate emulsions of any desired concentration can be prepared by dilution with water.

Dusts a) b)

Propinyl ester. 5% 8%

Talc 95%

Kaolin - 92%

Ready-to-use dusts are obtained by mixing the active ingredient with the carrier and grinding on a suitable mill.

Extruder granules

Propinyl ester 10%

Na lignosulfonate 2%

Carboxymethylcellulose 1%

Kaolin 87%

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

Coated granules

Propinyl ester. 3%

Polyethylene glycol (M G 200) 3%

Kaolin 94%

The finely ground active substance is applied evenly in a mixer to the kaolin moistened with polyethylene glycol. In this way, dust-free coating granules are obtained.

Suspension concentrate

(R) -2- [4- (5-chloro-3-fluoropyridin-2-yloxy) -

phenoxyl-propionic acid propinyl ester 40%

Ethylene Glycol 10% Nonylphenol Polyethylene Glycol Ether (15 molAeO) 6%

Na lignosulfonate 10% carboxymethyl cellulose 1%

37% aqueous formaldehyde solution 0.2%

Silicone oil in the form of a 75% aqueous emulsion 0.8%

Water 32%

The finely ground active substance is intimately mixed with the additives. This gives a Suspensipns concentrate from which suspensions of any desired concentration can be prepared by dilution with water.

Example 5: Herbicidal action

Post-emergent herbicidal action (contact herbicide)

The grass species Zea corn, Sorghum hybridum, Oryza sativa, Avena fatua, Bromus tectorum, Lolium perenne, Alopecurus myosuro'ides, Digitaria sanguinalis, Echinochloa crus galli, Sorghum halepense and Rottboellia exaltata were grown in pots in the greenhouse and after emergence (in 4 to 6-leaf stage) with an aqueous dispersion of the (R) -enantiomer according to the invention and the racemate in various dosages, expressed in g of active ingredient per hectare sprayed on the plants and these at a temperature of 24-26 ⁰ C at 45-60 ⁰ C relative humidity and kept regular watering. The trial is evaluated 10 days after the treatment. The damage done to the plants is scored according to a scale of 9:

plant

9% thrives as untreated control plant

1% total loss, plant dead,

2-8% Intermediate stages of injury.

The rating is determined for each application rate from the tested grass types and the mean values are entered in the enclosed graph.

This shows the average post-emergence activity of the two tested active ingredients against the grasses. As can be seen from the figure, to achieve a rating of 3, which corresponds to a good herbicidal action, one

Application rate of 86 g AMS / ha is required when the racemate is used. The same level of control is surprisingly achieved with 42 g AS / ha, when the R-enantiomers is used. This results in an unexpected increase in activity by more than a factor of 2.

Claims (2)

1. A herbicidal and plant growth-inhibiting agent, characterized in that it contains as active ingredient the (R) -2- [4- (5-chloro-3-fluoropyridin-2-yloxy) -phenoxy] -propionic acid propinyl ester of the formula I. / Γ \ / -. Γ ³ Cl - * Vo- / ^ OCH-COOCH ₉ -CScH contains, along with inert ingredients. 2. The use of the (R) -2- [4- (5-chloro-3-fluoropyridin-2-yloxy) -phenoxy] propionic acid propinyl ester of the formula I, claim 1 or an agent containing it, characterized in that it selective weed agent is used in crops.