AU592804B2

AU592804B2 - (r)-2-{4-(5-chloro-3-fluoropyridin-2-yloxy)-phenoxyl}- propionic acid propynyl ester with herbicidal activity

Info

Publication number: AU592804B2
Application number: AU59491/86A
Authority: AU
Inventors: Rolf Schurter
Original assignee: Ciba Geigy AG
Current assignee: Syngenta Participations AG
Priority date: 1986-06-12
Filing date: 1986-07-02
Publication date: 1990-01-25
Anticipated expiration: 2006-07-02
Also published as: MY102085A; PL147477B1; NO168528B; PT82937A; PH21693A; YU199687A; DD253754A5; NZ216736A; JPH0529221B2; DK162216C; ES2007331A6; FI862769L; CS261243B2; NO862665L; YU117086A; FI87772B; KR880000398A; FI862769A0; TNSN86112A1; SU1567116A3

Description

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592804 FORM 10 SPRUSON FERGUSON COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE: Class Int. Class Complete Specification Lodged: Accepted:

I

raa0 0 0, o00n 0 0 0 0* 0 0oo ft 00~ 0 000 4 00 00 0 0 04 00 4t 011'0 0 0*0 04 0, I 0 Priority: Related Art: Publishod: I his douiumnt contains tIh Salienidriiis nmade utn i S:tiui 4i and is cor.ect lo, i [,rit ting. i Name of Applicant: Address of Applicant: Actual Inventor: Address for Service: CIBA-GEIGY AG Klybeckstrasse 141, 4002 Basle, Switzerlaiind ROLF SCHURTER Spruson Ferguson, Patent Attorneys, Level 33 St Martins Tower 31 Market Street, Sydney, New South Wales, 2000, Australia Complete Specification for the invention entitled: "(R)-2-[4-(5-CHLORO-3-FLUOROPYRIDIN-2-YLOXY)-P7'NOXYL]- PROPIONIC ACID PROPYNYL ESTER WITH HERBICIDAL ACTIVITY" The following statement is a full description of this invention, including the best method of performing it known to us SBR:ALB:62W

I

14 -1I (R-2-[4-(5-ChlIoro-3-flIuoropyri din-2-yoxy)-phenoxy I propionic acid- propynvl ester with -hel,'bicidal activtty The present invention relates to the novel (R)-2-C4--(5--chloro-3fluoropyridin-2--yloxy)--phenoxyj-proplonlc acid propynyl ester, substantially free of the S enantiomer, io its production, to compositions containing this derivative as active ingredient, and also to the use thereof as herbicides in general, and in particular for controlling weeds in crops of cultivated plants, such as cereals, rice, maize, soyabean and sugar beet.

The (R-2-44-(5-Chl1oro-3-fl1uoropyr id in-2-yl oxy)-phenoxy ]-prop ion i c acid propynyl ester corresponds to the formula I C* 2 0 0 o 0000 00 00 0 0000 0 000 0 4 0 00 0 0 0 000 0 2 -[4-(5-Chl oro-3-fI luoropyr id in-2-yl oxy)-phenoxy )-prop ion ic acid propynyl ester, is characterised by a good action against mono- and some dicotylidonous wqeeds; it is effective in the post emergence process against undesirable weeds and wild grasses occurring in cultivated crops, such as crops of 0000 0 0 0 .0 0 0 00 0 0a0 S 34 TLH/3188U -2 cereals, maize, rice, soyabean and sugar beet. A particularly valuable aspect is that it is possible with the novel derivative to combat wild grasses which are very difficult to control, for example Avena fatua, Avena sterilis, Alopecurus myosuroides, Lolium perenne, chalaris sp.

Bromus tectorum and various species of Setaria and.

Panicum. The actioi under field conditions is achieved even with small applied amounts of less than 1 kg per hectare, at which levels the cultivated crops are not harmed, or are to harmed to only a negligible extent.

0 oo oo Halopyridyloxy-a-phenoxy-propionic acid derivatives have been described in numerous publications (cp. for example the German Offenlegungsschriften Nos. 2,546,251, o°0 'o 2,649,706, 2,714,622 and 2,715,284, and the European Publi- 00 0 0 Oo cations Nos. 483, 1473, 83556 and 97 460). The present ester 0 0 0 000 0 is distinguished from the known halopyridyloxy-a-phenoxy-, propionic acid derivatives by a better action.

o 00 o o 00 0 000. The amounts applied can vary within wide limits, for 0 0 0 00 example between 0.01 and 2 kg of active substance per 00o :O hectare.

0 0 9 0 The novel ester of the formula X can be produced by 0o reacting 5-chloro-2,3-difluoropyridine of the formula II 0 0

F

I

I), 1--Q Cl-* *-P in an inert solvent or diluent and in the presence of the equimolar amount of a base, with the (R)-enantiomeric 4hydroxyphenoxy-a-propionic acid propyntl ester of the formula III 3 HO-* *-OCH- COOCH C:CH (II)

(R)

A second process comprises reacting 4-(5-chloro-3-fluoropyridin-2-y.oxy)-phenol of the formula IV

F

Cl- -OH (IV), in an inert solvent or diluent and in the presence of the equimolar amount of a base, with the enantiomeric a-haloproprionic acid propynyl ester of the formula V 0 0 ooo CH 3 0o 0 0o0 Hal-CH-COOCH2C CH (V)

(S)

t00g."g wherein Hal is halogen.

A further process comprises reacting a (R)-enantiomeric 2-[4-(5-chloro-3-fluoropyridin-2-yloxy)-phenoxyjpropionic acid halide of the formula VI Y CH Cl-* -OCH-COHal (V C (R) wherein Hal is halogen, ii an inert solvent or diluent and in the presence of the equimolar amount of a base, with propynol HOCH2 -CCH.

In addition, the ester of the formula I can be 9 produced by reacting the enantiomeric chloro-3-fluoropyridin-2-yloxy)-phenoxy] -propionic acid of the formula VII -4- V CH 3

OCH-COONII

(R)

in an inert solvent or diluent and in the presence of the equimolar amount of a base, with a propyny halide o4 the formula VIII Hal-CH -C=Cu (VTII) wherein Hal is halogen.

Finally, a further process comprises converting the p400 00 0 *.0402-yloxy)-phenoxy]-propionic acid propynyl ester of the 0)0 Q formula Ix 00 00 02 13 ci-. *-OCH-COOCII 2 OS 2 0600 (fl) 0 using known mthods, Into a diazonium salt, and convertirngj this further into the fluorine compound 00 The(R)-enantiomer of the ester of formula I ia also prepared by reacting in an.

inert organic solvent and in the presence of a kiase, 5-chloro-3-fluoropyridin-2-yloxy) -phenol of the formula IV Cl- 9 9-r -OH (IV),r 5 with (S)-lactic acid propynyl ester-sulfonate of the formula X CH 3 R-SO2 CH- COOCH2CECH

(S)

*co 00 0 C 00 0 0 CCC a wherein R is a C -C 6 alkyl group which is straight-chain or branched, and which is unsubstituted or substituted by halogen, cyano, C 1

-C

4 alkoxycarbonyl or is a phenyl group which is unsubstituted or substituted by Cl-C 4 alkyl, C 1

-C

4 alkoxy, halogen, nitro, cyano, C -C 4 alkoxycarbonyl and isolating the resulting (R )-2[4-(3-fluoro-5-halopyridin-2-yloxy)-phenoxy]-propionic acid propynyl ester obtained from the reaction mixture.

The starting material of formula II 5-chloro-2,3-difluoropyridine may be prepared by fluorinating the corresponding 2,3,5-trichloropyridine in the presence of cesium fluoride. The products can be distilled off the reaction mixture and have to be purified by fractionate distillation. It is also possible to obtain a 4) o to CC 0 00C C C

CC

a tC 5-chloro-2,3-difluoropyridine starting from 3-nitropyridine, which is reduced by means of hydrogen in )O the presence of e.g. Raney-nickel catalyst to 3-amino-2,5dichloropyridine. This compound is then converted with sodium nitrite in the presence of hydrofluoric acid to 2,5-dichloro-3-fluoropyridine. This latter product can then be fluorinated in a good yield by means of potassiumfluoride to 2,3-difluoro-5-chloropyridine.

-e -6- The starting material of formula IV e~g. 3 -fluoropyridin-2-yloxy) -phenol can be obtained by condensing in an inert organic solvent, in the presence of a base 5-chloro-2,3--difluoropyridine and hydroquinono The starting material of formula IX can be obtaind e.g.by reducing the corresponding (R)-2-[4-(,3-chloro 3-nitropyridin-2-yloxy) -phanoxy] -propionic acid propynyl ester.

The remaining starting material are eithcar kn'nor S can easily be prepared by conventional means.

A number of these reactions are advantageously carried out in an organic solvent or diluent inert to the reactanta, for example an alcohol, ester, ether, ketone, diamethyl formamide, dimethyl sulfoxide, acetonitrile 1,1-clioxy- -tetrahydrothiophene or an aromatic compound, such as toluene and xylene.

0 The reaction tamperatures are between -10%C andl5 0

'C,

in practice however between room temperature and the boiling point of the solvent. Depending on the chosen ~ostarting material, the solvent and the temperature, the reaction time is between I hour up to about 1 day.

Where a halogen atom is detached in the reaction, the equimolar amount of an acid-binding agent should be used.

Suitable as such is essentially any inorganic or organic base, for example NaCH, MR., NaHCO 3 K 2 C0 3 or K-tertbutylate, and amines, such af trimethylamine, triethylamine, pyridine, 4 -dime thylarninopyrid iae, and so forth, -7 The novel active substance of the formnula I 1. a tb compound which is soluble in customary organic solvents, such as alcohols, ethers, ketones, dime thylf ormamide,, dtrnethyl sulfoxide, and the like.- The compounds of the formula I are used either in an unmodified form or preferably together with auxiliaries customarily employed in formulation practice, and are thus processed in a knowni manner for example into the form~ of emulsion concentrates, directly sprayable or dilutable C solutions, diluted emulsions, wettable powders, soluble powders, dusts or granulates, and also encapsulations in for example polymeric substances. The application processes, such as spraying, atomising, dusting, scattering co or pouring, and likewise the type of composition, are selected to suit the objectivcs to be achieved and tho given conditions, The formulations, that is to say, the compositions formula I and optionally a solid or liquid additive, are tproduced in a known manner, for example by the intimate mixing and/or grinding of the active substances with extenders, such as with solvents, solid carriers and optionally surface-active compounds (tensides) 1 8 Suitable solvents are: aromatic hydrocarbons, preferably the fractions C 8 to C 1 2 such as xylene mixtures or substituted naphthalenes, phthalic esters, such as dibutylor dioctylphthalate, aliphatic hydrocarbons, such as cyclohexane or paraffins, alcohols and glycols, as well as ethers and esters thereof, such as ethanol, ethylene glycol, ethylene glycol monomethyl or -ethyl ethers, ketones such as cyclohexanone, strongly polar solvents, such as N-methyl-2-pyrrolidone, dimethyl sulfoxide or dimethylformamide, as well as optionally epoxidised vegetable oils, such as epoxidised coconut oil or soybean oil; o o or water.

°a The solid carriers used, for example for dusts and o dispersible powders, are as a rule natural mineral fillers, K such as calcite, talcum, kaolin, montmorillonite or attapulgite. In order to improve the physical properties, it is possible to add highly dispersed silicic acid or highly dispersed absorbent polymers. Suitable granulated S4," adsorptive carriers are porous types, for example pumice, SO ground brick, sepiolite or bentonite; and suitable nonsorbent carriers are materials such as calcite or sand.

There can also be used a great number of pre-granulated o materials of inorganic or organic nature, such as in particular dolomite or ground plant residues.

Suitable surface-active compounds are, depending on 1 the nature of the active substance of the formula I to be formulated, nonionic, cationic and/or anionic tensides having good emulsifying, dispersing and wetting properties.

By 'tensides' are also meant mixtures of tensides.

Suitable anionic tensid s are both so-called watersoluble soaps as well as water-soluble, synthetic, surface-active compounds.

p Soaps which are applicable are for example the alkali metal, alkaline-earth metal or optionally substituted ammonium salts of higher fatty acids (C 1 0

-C

2 0 for example the Na or K salts of oleic or stearic acid, or of natural fatty acid mixtures, which can be obtained for example from coconut oil or tallow oil. Also to b( mentioned are tho fatty acid-methyl-taurine salts.

So-called synthetic tensides are however more frequently used, particularly fatty sulfonates, fatty IO sulfates, sulfonated benzimidazole derivatives or alkylarylsulfonates. The fatty sulfonates or sulfates are as a rule in the form of ;ilkali metal, alkaline-earth metal or optionally substituted ammonium salts, and

S

a 0 contain an alkyl group having 8 to 22 C atoms, 'alkyl, o ?including also the alkyl moiety of acyl groups, for example the Na or Ca salt of licninsulfonic acid, of dodecylsulfuric acid ester or of a fatty alcohol sulfate o .mixture produced from natural fatty acid Included among these are also 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 group having 8 22 C atoms. Alkyarylsulfonates are for example the Na, Ca or triethanolamine salts of dodecylbenzenesulfonic acid, of dibutylnaphthalenesulfonic acid or of a naphthalenesulfonic acid-formald.ehyde condensation .product.

Also suitable are corresponding phosphates, for example salts of the phosphoric ester of a p-nonylphenol-(4-14)ethylene oxide adduct.

10 Suitable nonionic tensides are in particular polyglycol ether derivatives of aliphatic or cycloaliphatic alcohols, saturated or unsaturated fatty acids and alkylphenols, which can contain 3 to 30 glycol ethar groups and 8 to carbon atoms in the (aliphatic) hydrocarbon radical and 6 to 18 carbon atoms in the alkyl moiezy of the alkylphenols.

Further suitable nonionic tensides are the watersoluble polyethylene oxide adducts, which contain 20 to 250 ethylene glycol ether groups and 10 to 100 propylene S glycol ether groups, with polypropylene glycol, ethylenet ediaminopolypropylene glycol and alkylpolypropylcne glycol having 1 to 10 carbon atoms in the alkyl chain. The S compo.Lnds mentioned usually contain 1 to 5 ethylene glycol units per propylene glycol unit. Examples of nonionic tensides which may be mentioned are: nonylphenolpolyethoxyethanols, castor oil polyglycol ethers, polypropylene/polyethyleneoxy adducts, tributylphenoxypolyethoxyethanol, polyethylene glycol and octylphenoxy- O polyethoxyethanol. Suitable also are fatty acid esters of polyoxyethylenesorbitan, such as polyoxyethylenesorbitan-trioleate.

In the case of the cationic tensides, they are in particular quaternary ammonium salts which contain as N-substituents at least one alkyl group having 8 to 22 carbon atoms and, as further substituents, lower, optionally halogenated alkyl, benzyl or lower hydroxyalkyl groups.

The salts are preferably in the form of halides, methyl sulfates or ethyl sulphates, for example stearyltrimethyl- O3 ammonium chloride or benzyldi(2-chloroethyl)ethylammonium bromide.

The tensides customarily used in formulation practice are described, inter alia, in the following publications: "M Cutcheon's Detergents and Emulsifters Annual", MC Publishing Corp., Ridgewoo=d, New Jersey, 1979 Sisely and Wood, "Encylopedia of Surface Active Agents", Chemical Publishing Co., Inc. LNew York, 1964 These preparations contain as a rule 0.1 to 99Z/, particul.arly 0.1 to 95%, of active -,ubstance of the forrula 1, 1 to 99% of a solid or liquid additive, and 0 to 0 1 especially 0.1 to 25%, of a tenside.

Whereas comumercial products are preferably in the form of concentrated1 compositions, the compositions employed by the end-user are as a rule c~luted.

The compositions can also contain further additives, such as stabilisers, antifoaming agents, viscosity regulators, binders and adhesives, and also fertilisers or other active ingredients for obtaining special effects.

The following Exampl~es d'Ascribe in detail the pr~~duction of the (5-chloro-3-fluoropyridin-2-yloxy)-phenoxy1propionic acid propynyl ester, and compositions containing such esters as active ingredients.

Percentages relate to weight.

E.'amole 1.

Prep~aration of (5-chloro-3--fluoropyridin-2-yloxy)eAW phenoxv]-propionic acijd__!ropyriy1 ester OC -COOCH 2

C;C

(R)

12- A solution of 24,2 g (0.11 mol) (R)-2-[4-hydroxy-phenoxy)propionic acid propynyl ester in 80 ml of dimethylformamide is added dropwise, while stirring,at a temperature of 100 to a suspension of 4-9 g (0.11 mol) of a sodium-hydride dispersion in 30 ml of dimethylformamide. After everything has been added, stirring is continued at the same temperature for 1 hour. Then another solution of 16,4 g (0.10 mol) 5-chloro-2,3-difluoropyridine in 40 ml of dimethylformamide is added thereto dropwise over a period of 4 hours. Stirring is then continued for 24 hours at room temperature. The reaction mixture is then poured onto ice/water and extracted three times with ether. The organic layers are collected, washed with water a* and concentrated sodium-chloride-solution, then dried over 9QOQ a magnesium-sulfate and filtered over silica-gel. The etheral solution is then concentrated. The resulting clear oil is cristallized in ethanol to yield 25 g (72% of the theory) of the desired propynyl ester. Melting point 55-56C'.

on0. CO The 5-chloro-2,3-difluoropyridine necessary as stacting material is c tained as follows: a) 3-amino-2,5-dichloropyridine To a solution of 129.2 g (0.69 mol) of 2,5-dichloro-3nitropyridine in 1300 ml of dioxane is added 26.0 g of J Raney-nickel, that has previously been washed with ethanol.

theoretical amount of hydrogen, another 30 g of washed Raney-ni~kel catalyst are added, After hydrognating for o3 22 hours, the catalyst is filtered offg the S,~3l evaporated and the residue is crystallized ethyl acetate. Thus, 84.9 g of 3-amino-2,5 pyridine (78% of the theory) are obtained, 129-132 0

C.

13 4 4c~ 4 4 44 4 o 4 *n 4 44 *e b) 2,5-dichloro-3-fluoropyridine To 450 ml (22.5 mol) of hydrogen fluoride in a stainless steel reaction vessel are added at a temperature of -5 to 163 g (1.0 mol) of 3-amino-2,5-dichloropyridine.

Then there are added while stirring at the same temperature 82.8 g (1.2 mol) of sodium nitrite into the solution. The reaction mixture is stirred for 1.5 hours at.-5 to -1°,then the temperature is slowly raised to +60 0 C. After the evolution of gas has ceased, the hydrogen fluoride 'O is distilled off and the residue is taken up in methylene chloride. Ice/water is then added thereto and the cold mixture is neutralized with concentrated ammonium hydroxide solution. The organic phase separated and the water phase is extracted three times with methylene chloride. The organic phases are washed with water, dried over magnesium sulfate, filtered through silica-gel and evaporated.

Thus, 141.5 g (85% of the theory) of 2,5-dichloro-3-fluoro yridine are obtained, c) 5-chloro-2,3-difluoropyridine 5O A suspension of 64.6 g (1.1 mol) of potassium fluoride and 11.25 g (0.075 mol) of cesium-fltoride in 240 ml of sulfolane (1,1-dioxo-tetrahydrothiophene) is heated to 140 0

C.

By reducing the pressure 50 ml of sulfolane are distilled off. To the suspension a solution of 61.4 g (0.37 mol) of 2,5-dichloro-3-fluoropyridine in ml of sulfolane is added.

The reaction-mixture is then stirred for 35 hours at a temperature of 140°, cooled and poured into ice/water. The organic material is extracted with ether. The ethereal layer is washed with water dried over magnesium sulfate, filtered and evaporated to yield 48.7 g of a colourless oil (88% of the theory) which boils at 65-66° at 133 mbar.

40 04 4n04 o 00 44I 0 4 00 *4 00 0*4 00 4 44* 44 a1t 14 Example 2 Preparation of 4-(5-chloro-3-fluoropyridin-2-yloxlphenoxy]-propionic acid propinyl ester CH 3 2

(R)

cs o. 0@ u o ,oe

,O

0 0 0 0# A solution of 10.6 g (0.030mol) of (+)-2-[4-(5-chloro-3fluoropyridin-2-yloxy)-phenoxy] -propionic acid chloride in 100 ml toluene is added slowly, while stirring into a solution of 4.9 m (0.035 mol) of triethylamine and 2ml (O,035mo) of propynol in 40 mil of toluene, that is cooled in an icebath. When everything is added, the ice-bath is removed and the reaction mixture is stirred for 3 hours at room temperature. The reaction mixture is then poured into ice/ water and the organic material is extracted twice with ethyl acetate, The ethyl acetate layer is washed with a saturated salt solution, dried over magnesium sulfato, filtered and evaporated. The residue is purified by chromatography over a silicagel column with a hexano/othyl acetate solution, After evaporation of the solvent, the residue crystallizes, melti 0 ,g at 540 (C]D +45.4 2% in acot.: C The (R)-2-[4-(5-chloro-3-fluoropyridin-2-yloxy)-phonoxy] propionic acid chloride necessary as starting materiat is obtained as follows: a) 4-(5-chloro-3-fluoropyridin-2-yloxy)-phenol A mixture of 27.5 g (0.25 mol) of hydroquinone, 11.2 T mol),of potassium hydroxide in 600 ml of dimethylsulfoxide is stirred at room temperature under a nitrogen atmosphere until everything is -t -1 -F.

15 dissolved. A solution of '0 g (0.2 moll of 5-chloro-2,3difluoropyridine in 200 ml of dimethylsulfoxide is added dropwise thereto. The reaction mixture is then heated to 700 and stirred at that temperature for 4 hours. Then it is poured into ice/water and the mixture is acidified with hydrochloric acic', extracted with ethyl acetate, dried over magnesium sulfate, filtered and evaporated to dryness. The residue is taken up in a hexane/ethyl acetate 2:1 solvent and passed over a s:ilicagel column o0 for purification. After concentrating the eluate, the residue crystallizes to yield 33 g of white crystals, o o melting at 97-98°.

06 0 (+)-2-[4-(5-chloro-3-fluoropyridin-2-yloxy)-phnoxylropionic acid methyl ester ts 0O A solution of 24 g (0.1 mol) of 4-(5-chloro-3-fluoropyridin-2-yloxy)-phenol in 80 ml of dimethylsulfoxide is added dropwise to a stirred solution of 13.8 g (0.1 mol) o of potassium carbonate in 50 ml of dimethylsulfoxide.

be When everything is added, the mixture is stirred for 2(V) 2 hours at room temperature and then a solution of 25.8 g (0.1 mol) of (S)(-)-lactic acid-methylester tosylate is added dropwise over 30 minutes. The mixture is heated to 600 and stirred at that temperature for 20 hours, then poured onto ice/water and the organic material is extracj ted three times with ether. The ether-layer is washed with water and saturated salt solution, dried over magnesium sulfate, filtered and evaporated. The residue is passed for purification through a silicagel column with a hexane/ethyl acetate 3:1 solvent. After distillation of the solvent, 26 g of a clear oil of the above ester is 20 obtained ([CID +38.8 +0.50 2% in acetone)-.

D

I C: 16 c) (+)-2-[4-(5-chloro-3-.fluoropyridin-2-yloxy)-phenoxy]propionic acid To a solution of 13.0 g (0.04 mol) of 3 -fluoropyridin-2-yloxy)-methyl ester in 65 ml of dioxane are added 42 ml of IN sodium hydroxide and the mixture is stirred for 2- hours at a temperature of 350. Then it is poured onto an ice/water mixture and acidified with 22 ml of 2N hydrochloric acid. The organic material is extracted therefrom twice with ethyl acetate. The organic PQ layers are washed with a saturated salt solution and dried ooooo over magnesium sulfate, filtered and concentrated. The 0 o o 00 residue is cristallized in ethyl acetate/hexane and 00 0 o0oa yields 10.2 g (81.8% of the theory) of the above 00 o. (5-chloro-3-fluoropyridin-2-yloxy)-phenoxy]- 0 propionic acid as white crystals, which melt at 95-960 S o 20 oo 0 +37.5 0.50 2% in acetone).

0 00 0 C 0 0o o0 a cO ooaco '0oo0 d) (5-chloro-3-fluoropyridin-2-yloxy) -phenoxy]o propionic acid chloride o oo a 0 10.8 g (0.035 mol) of (R)-2-[4-(5-chloro-3-fluoropyridin-2yloxy)-phenoxy]-propionic acid are dissolved in 150 ml of toluene. Then 50 ml of toluene are distilled off in an oil-bath that has a temperature of 130°. The reaction mixture is then cooled down to 900 and 3.8 ml of thionyl chloride are added slowly thereto. The mixture is stirred for 16 hours at 90° and then evaporated under reduced pressure. The residue crystallizes and has a melting point of 47 to 480.

|1 11_ c 17 Examole 3 ProducLion of A formulation with liquid active ingredients of the formula I oer cent by weight) Emulsion concentrateS a) b) c) 000000 0 C o a 0000 a o0 0 0000 0000 Q00 o a 00 o 00 00 0 00 0 0 oOQ a 0 0 o a (5-chloro-3-fluoropyridi- 2-yloxy)-phenoxy]-propionic acid propynyl ester calcium dodecylbenzenesulfonate castor oil-polyethylene glycol ether (36 mols of ethylene oxide) tributylphenol-polyethylene glycol ether (30 rols of ethylene oxide) cyclohexanone %ylene mixture 20% 5% 40% 8% 5.8% 12% 1.5% 70% 25% 4.2% be produced water, Emuaions any required concentration can from concentrates of this type by dilution with Solutions b) C) d) 00 oc o o C (5-chloro-3-fluoropyridin-n 2' yloxy) -phenoxy I-prop ionic acid 00 propynyJ ester 807 ethylene glyco-monomethyl ether polyethylene glycol MG 400 N-methyl-2-pyrrolidone epoxidised coconut oil ligroin (boiling limites 160-190 0

C)-

The solutions are suitable for application of very fine drops 94% in the formn 18 Granulates a) b) (R)-2-[4-(5-chloro-3-fluoropyriaiin-2yloxy) -phenoxy] -propionic acid propynyl ester 5% kaolin 94% highly dispersed silicic acid 1% aetapulgite The active ingredient is dissolved in methylene chloride; the solution is subsequently sprayed onto the carrier, and the solvent is evaporated off in vacuo.

Dusts a) b) 000000 0 0 2- (5-chloro-3-fluoropyridin-2- 00 0 yloxy) -phenoxyl-propionic acid a #0 propynyl ester 2% 0 P 2%l highly dispersed silicic acid 1% talcum 9 kaolin Ready-for-use dusts are obtained by the intimate mixing together of the carriers with the active ingredient.

a@ Forr.ulation Examples for solid active ingredients of o the formula I per cent by weight) Wettable oowders a) b) (5-chloro-3-fluoropyridiin"-2yloxy)-phenoxyj-propionic acid propynyl ester 2.0 sodium lignin sulfonate 57o sodium lauryl sulfate 3% sodium diisobutylnaphthalene sulfonate 6% octylphenolpolyethylene glycol ether 3o (7-8 mols of ethylene oxide) 2% highly dispersed silicic acid 5% 27% kaolin 67% II I 19 The active ingredient is well mixed with the additives and the mixture is thoroughly ground in a suitable mill.

Wettable powders which can be diluted with water to give suspensions of the required concentration are obtained.

Emulsion concentrate (R)-2[4-(5-chloro-3-fluorpyridin-2yloxy)-phenoxy]-propionic acid propynyl ester octylphenol polyethylene glycol ether (4-5 mols of ethylene oxide) calcium dodecylbenzenesulfonate castor oil polyglycol ether (36 mols of ethylene oxide) cyclohexanone xylene mixture 3% 3% 4% 0 oo00oo0 Q 0 0oooo 00 0 0000 0 0 0 00 0 o o 0 00 00 0 000 0 0 00 0 00 0000 e c a o 0 O 00 9 0 00 0 0 B a o Emulsions of the required concentration can be from this concentrate by dilution with water.

obtained Dusts (R)-2-[4-(5-chloro-3-fluoropyridin-2yloxy)-phenoxy]-propionic acid propynyl ester talcum kaolin a) b) 5% 8% 95% 92% Dusts ready for use are obtained by mixing the 'activ substance with the carriers and grinding the mixture in a suitable mill.

Extruder granulate (R)-2-[4-(5-chloro-3-fluoropyridin-2yloxy)-phenoxy]-propionic acid propynyl ester sodium lignin sulfonate carboxymethy1cellulose kaolin 2% 1% 87% The active ingredientc is mixed and ground with the additives, and the mixture is moistened with water, This mixture is eXLruded and then dried in a stream of ai..

Coated granulate (5-chloro-3--ifluoropyridiin-2yloxy) -phenoxy] -pro~ionic acidt propynyl ester 3 polyethylene glycol (MG 200) 3 Q kaolin 9112 The finely ground active in-redient is evenly applied, in a mixer, to the kaolin moistened with polyethylene 0 glycol. Dustfree coated garanulates are obtained in tiS 0 manner.

6044 Suspension concentrate .0 C (5-chloro-3-f luoropyridin-2propynyl ester o ethylene glycol 0 nonylphenolpolyethylec gly 'col ether b C (15 mols of ethylene oxide) sodium lignin sulfonate carboxymethylcellulose 1 37% aqueous formaldehyde solutioix 0 .211 silicone oil in the form of a aqueous emulsion 0.81"/ water 32% The finely ground active ingredient is intimately mixed with the additives. There is thus obtained a suspension concentrate from which can be produced, by dilution with water, suspensions of the concentration required.

0 o 0 1100 0 4 (I P 0 o 4a V 04 4 go4 C- 00 0o 0 9 t& 4 V t 04 t 4 21 0xampj.e 4 Herbicidal action Post-emergence herbicidal action (contact herbicide) The grasses Zea mais, Sorghum hybridum, Oryza sativa, Avena fatua, Bromus tectorum, Lolium perenne, Alopecurus myosuroides, Digitaria sanguinalis, Echinochloa crus galli, Sorghum halepense 'nd Rottboellia exaltata are grown in pots in a greenhouse, and after emergence (in the 4- to 6-leaf stage) the plants are sprayed with an aqueous suspension of the compound to be tested in varying dosages, expressed in g of active compound per hectare. The treated plants are kept at a temperature of 24-26 0 C, at 45-60 relative humidity and regularly watered.

The test results are evaluated after ten days.

The condition of the plants is assessed according to the following damage ratings: 9 No damage, plant grows like untreated control plant 1 Total damage, plant dead 2-8 intermediate stage of damage.

The damage for every grass at each application rate is evaluated and the mean values for all the grasses are entered into the enclosed graphic.

44 4 4' 4, .4 44 4) Ao 4 In this graphic the mean value cf the r *tivity of the tested substances on the grasses is entered for each application rate. In order to reach a mark 3, which corresponds to a good herbicidal activity, an amount of 86 g of the racemate is needed. In order to get the same activity, surprisingly only 42 g of the (R)-enantiomere are needed. The activity of the (R)-enantiomer is unexpectedly more than double of that of the racemate on these grasses.

Claims

2. A herbicidal and plant-growth-regulating ccmposition ccnta!Mni an effective amount of (R)-2-[4-(5-Chloro-3-fluoropyridin-2-yloxy)-phenoxy propionic acid propynyl ester according to claim 1 together with Inert carrier mnaterial,
3. A method of selectively controlling weeds which comprisez' applying thereto or to the locus thereof a herbicidally effective ar.-unt 0 4 (R)-2-[4-(5-Ghloro-3-fluoropyridin-2-yloxy)-phenoxy)-propinic acid propynyl ester according to claim 1.
4. A process for producing the (R)-anantiomneric 2-.f4-(5-Chloro-3-fluoropyridin-2-yloxy)-phenoxy]-propionic p:ryrpyy ester according to claim 1, which process comprises reactinj 0 0C r -crhloro-2,3-difluoropyrid1t,, of the formula 11Z In an inert solvent or diluent and In the presence of the equimolar amount, ofa bswith the (R)-enantiomeric 4-hydroxyphenoxy-ctpopoi acid propynyl ester of the formula 11I1 I-o- OCH>'0 -COOCH 2C iC [1 (R) TLH/3188U 23 A process for producing the enantiomeric 2-C4-(5-chloro- 3-fluoropyridin-2-yloxy)-phenoxyl-propionic acid propynyl ester according to claim 1, which process comprises reacting a (R)-enantiomeric 2 -L 4 -(5-chloro-3-fluoropyridin-2-yloxy)-phenoxy -propionic acid halide of the formula VI T cii *-OCH-COHal (VI) (R) wherein Hal is halogen in an inert organic solvent or diluent and in the presence of the equilomar amount of a base, with propynyl, HO-CH 2 CCH.
6. An (R)-2-14-(5-chloro-3-fluoropyri d i n-2-yloxy)-phenoxy]-propionic acid propynyl ester, substantially free of the S enantiomer, substantially Sas hereinbefore described with reference to Example 1, or Example 2. o0 A herbicidal and plant growth regulating composition, substantially as hereinbefore described with reference to Example 3, D4. 40048, A process for producing the (R)-enantiomer of 2-[4-(5-chloro-3- 4,, fluoropyridin-2-yloxy)-phenoxyl-propionic acid propynyl ester, substantially as hereinbefore described with reference to Example 1, or Example 2. Doo DATED this NINTH day of NOVEMBER 1989 Ciba-Geigy AG 44,4 Patent Attorneys for the Applicant SPRUSON FERGUSON TLH/3188U IL