WO1981000563A1

WO1981000563A1 - Pyridinyloxyphenoxy lower alkenoic acids,esters or amides thereof as selective weed control agents

Info

Publication number: WO1981000563A1
Application number: PCT/US1979/000648
Authority: WO
Inventors: J Ting
Original assignee: Du Pont
Priority date: 1979-08-23
Filing date: 1979-08-23
Publication date: 1981-03-05

Abstract

Herbicidal pyridyloxyphenoxycrotonate esters, for example, methyl 4-(4-(5-(trifluoromethyl)-2-pyridinyloxy)phenoxy)-2-pentenoate, herbicidal compositions containing said compounds, methods of using said compounds as herbicides and processes for preparing said compounds.

Description

PYRIDINYLOXYPHENOXY LOWER ALKENOIC ACIDS, ESTERS OR AMIDES THEREOF AS

SELECTIVE WEED CONTROL AGENTS

Technical Field This invention relates to pyridyloxyphenoxycrotonate esters which are useful as selective weed control agents. The compounds are especially useful for controlling grass weeds in broadleaf crops such as soybeans. The presence of undesirable vegetation causes substantial damage to useful crops, especially agricultural products that satisfy man's basic food and fiber needs, such as cotton, rice, corn, wheat, soybean and the like. The current population explosion and concomitant world food and fiber shortage underlie the need for improvements in the efficiency of producing these crops. Preventing or minimizing the loss of a portion of such valuable crops by killing or inhibiting the growth of undesired vegetation is one way of improving this efficiency.

A wide variety of materials useful for killing or inhibiting (controlling) the growth of undesired vegetation is available; such materials are commonly referred to as herbicides. The need exists, however, for still more effective herbicides that destroy or control weeds without causing significant damage to useful crops. Background Art

Belgian Patent 871,523 to Kumiai, dated October 31, 1977, claims diphenyl ether herbicides. The following compound is representative of this disclosure:

German Patent 2,639,796, assigned to Rohm and Haas and dated September 3, 1975, claims diphenyl ether herbicides of the type represented by the following formula:

where R. is alkylene or alkenyl of up to 5 carbon atoms Unexamined Japanese Patent 3,130,672, assigned to Ishihara Industries KK and dated April 18, 1977, claims phenoxy valeric acid derivatives such as

where X H or-Cl.

German Patent 2,812,571, assigned to Ishihara Sangyo and dated July 21, 1977, claims phenoxy pyridine derivatives of the type represented by the formula:

where X = F or Cl, Y = H or Cl and n = 0, 1 or 2.

Summary of the Invention This invention relates to novel compounds of Formula I, to their agricultural compositions and to their method of use as pre— and postemergence herbicides.

where

X is H, Cl or Br; Y is CF₃ or Cl;

R_χ is H,-CH₃,-CH₂CH₃ or-CH₂OCH₃; R₂ is-OR₃,-NR₄R₅ or-SR₆; R₃ is H, C₁-C₄ alkyl, -CH₂CH₂OCH₃, -CH₂CH₂OCH₂CH₃ or -CH₂CH₂CH₂OCH₃; R₄ is H, C₁ -C₃ alkyl, or-OCH ₃; R₅ is H, or C₁-C₃ alkyl; and

R₆ is C₁-C₄ alkyl; provided that when R₄ is -OCH₃ then R₅ is CH₃.

This invention also relates to agriculturally suitable salts of the above described compound where

R₂ is-OR₃ and R₃ is hydrogen.

Detailed Description of the Invention

Preferred Comoounds

Preferred for their high activity and/or favorable cost are those compounds of Formula I wherein independently: R₁ is CH₃; or R₂ is OR₃; or X is H or Cl.

More preferred for their higher activity and/or even more favorable cost are those compounds of Formula I wherein

R₁ is CH₃ and R₂ is OR₃.

Most preferred for their even higher activity and/or even more favorable cost are those comoounds of Formula I. wherein.

R₁ is CH₃; R₂ is OR₃; and

X is H or Cl.

Specifically preferred for high activity and favorable cost are:

4-[4-[5-(trifluoromethyl)-2-pyridinyloxy]phenoxy-

2-pentenoate; and

4-[4-(3,5-dichloro-2-pyridinyloxy) phenoxy]-2- pentenoate. Methods of Preparation

The compounds of Formula I, in which R₂ is

OR₃, can be prepared, as shown in Equation A, by the reaction of a substituted phenol of the Formula II, wherein X and Y are as defined hereinbefore,

and a substituted alkenoic acid derivative of the Formula III, wherein R₁ and R₃ are as defined hereinbefore and wherein Z is Cl or Br. An approximately equimolar amount of the compound of Formula II and the compound of Formula III are contacted in the presence of a base. Suitable bases include an alkali metal or alkali earth metal hydroxide, hydride, carbonate, bicarbonate or alkoxide, for example, sodium methoxide or potassium t-butoxide. The base is present in an amount of about 1 to 2 molar times the amount of the compound of Formula II. The reaction can be carried out in an organic solvent such as methyl- ethyl ketone, tetrahydrofuran, dimethylformamide, dimethylsulfoxide, or dioxane at temperatures about 20°-100°C, preferably about 25°-80°C. In this reaction procedure (and the reaction procedures relating to compounds IV, V, VI, described below) pressure is not critical since pressures above and below atmospheric are suitable. For convenience, atmospheric pressure is preferred.

The compounds of Formula II are known in the art, for example, in the teachings of U.S. 4,046,553 and Belgian Patent 865,136, the disclosures of which are hereby incorporated by reference. The substituted alkenoic acid derivatives of Formula III are prepared according to the teachings of Justis Liebigs Annalen Per. Chemie 576, 155 (1952) and Otdel. Khim. Nauk. 1512 (1960), also hereby incorporated by reference.

The compounds of Formula IV,

in which R₂ is OR₃ and R₃ is H and where X, Y and R₁ are as defined hereinbefore, can be prepared by the acidic hydrolysis of the compounds of Formula I with hydrochloric acid or sulfuric acid, or by the basic hydrolysis of the compounds of Formula (I) with sodium hydroxide, potassium hydroxide, or barium hydroxide followed by acidification with hydrochloric acid or sulfuric acid. The preparation of the compounds of Formula IV can be carried out in a solvent such as a mixture of methanol and water, or of ethanol and water at temperatures of about 25-100°C.

The compounds of Formula V,

in which R₂ is NR₄R₅ and where X, Y, R₁, R₄ and R₅ are as defined hereinbefore, can be prepared by contacting the corresponding acid chloride with the proper amine. Typically, the amine is present in an amount of about two molar times the amount of acid chloride. The reaction can be carried out neat or in an organic solvent such as methylene chloride, chloroform, tetra- hydrofuran, or dioxane at ambient temperature. The acid chloride can be prepared by reacting the compounds of Formula IV with thionyl chloride, a method known in the art. The compounds of Formula VI,

in which R₂ is SR₆ and where X, Y, R. and R₆ are as defined hereinbefore, can be obtained by reacting the corresponding acid chloride of the compounds of Formula IV with the proper mercaptan in the presence of a base. The acid chloride, the compound of Formula IV and the base are typically present in approximately equimolar proportions . The reaction can be carried out in an organic solvent such as methylene chloride, tetrahydrofuran or toluene. The reaction can be carried out at temperatures between about 0° and 100°C, preferably between about 25° and 50°C. The base used for the preparation of the compounds of Formula VI can be a tertiary organic amine such as trimethylamine, triethylamine, N,N-dimethylaniline or pyridine, or alkali metal or alkali earth metal carbonate or bicarbonate.

Agriculturally suitable salts of compounds of Formula I are also useful herbicides and can be prepared By a number of ways known to the art. For example, metal salts can be made by treating compounds of Formula I wherein R₂ is OR₃ and R₃ is hydrogen with a solution of an alkali or alkaline earth metal salt having a sufficiently Basir anion (e.g. hydroxide, alkoxide, carbonate or hydride), Ammonium, amine, and quaternary amine salts can be made by similar techniques.

Salts of compounds of Formula I wherein R₂ is OR₃ and R₃ is hydrogen can also be prepared by exchange of one cation for another. Cationic exchange can be effected by direct treatment of an aqueous solution of a salt of a compound of Formula I (e.g. alkali metal or quaternary ammonium salt) with a solution containing the cation to be exchanged. This method is most effective when the desired salt containing the exchanged cation is insoluble in water and can be separated by filtration. Exchange may also be effected by passing an aqueous solution of salt of a compound of Formula I (e.g. an alkali metal or quaternary ammonium salt) through a column packed with a cation exchange resin containing the cation to be exchanged. In this method, the cation of the resin is exchanged for that or the original salt and the desired product is eluted from the column. This method is particularly useful when the desired salt is water soluble.

In the following examples, all parts and percentages are by weight and temperatures are in degrees centigrade unless otherwise specified.

EXAMPLE I Methyl 4-[4-[5-(trifluoromethyl)-2-pyridinyloxy] phenoxy]- 2-pentenoate

In 50 ml of methyl ethyl ketone, 2.0 g (0.0078 mole) of 4- [5- (trifluoromethyl ) -2-pyridinyloxy]phenol, 3.2 g of methyl 4-bromo-2-pentenoate, and 2.0 g of potassium carbonate were refluxed with constant stirring for 32 hours. Upon cooling to room temperature, the suspension was filtered through celite and the insoluble material washed with 75 ml of acetone. The filtrate was concentrated under reduced pressure to give an oily residue which was dissolved in 125 ml of ethyl ether and transferred to a separatory funnel. After washing with saturated sodium bicarbonate and water, the ether layer was dried over magnesium sulfate and charcoal filtered. Under reduced pressure, the solvent was evaporated and traces of volatile impurities removed at 0.4 mm Hg. (50° for 2 hours) to yield 2.4 g (84%) of product, . N_D ²⁵ 1.520.

IR (neat): 5.75 (CO₂CH₃), 5.95, 6.15 (C=C), 6.55, 6.65, 11.85 microns; NMR (CDCl₃): 6 1.50 (d, 3H, CH₃, J=7 Hz), 3.75 (s, 3H, OCH₃), 4.70-5.20 (m, 1H, allylic hydrogen), 5.90-6.30 (m, 1H, vinylic hydrogen),

6.80-7.35 (m, 5H, vinylic proton and phenol protons).

7.80-8.10 (m, 2H, pyridine protons), 8.40-8.60 (m, 1H, pyridine proton); mass spectrum: (m/e): M 367 (m.w. 367). EXAMPLE II

Methyl 4-[4-(3,5-dichloro-2-pyridinyloxy) phenoxy]-2- pentenoate

To 2.5 g (0.0098 mole) of 4-(3,5-dichloro-2-pyri- dinyloxy) phenol, and 1.5 g of potassium carbonate in 40 ml of methyl ethyl ketone, 2.5 g of methyl 4-bromo- 2-pentenoate, dissolved in 10 ml of methyl ethyl ketone, was added at room temperature with constant stirring. The mixture was heated at reflux for 20 hours. Upon cooling to room temperature, the mixture was filtered through celite and the insoluble material washed with 50 ml of ethyl ether. An oily residue which remained after concentrating the filtrate under reduced pressure was dissolved in 125 ml of ethyl ether and washed with excess water. Drying over magnesium sulfate, charcoal filtering, and removal of solvent and volatile impurities at reduced pressure (0.35 mm Hg, 1.5 hours at 75°) gave 2.5 g (69%) of product, N_D ²⁵1.5790.

IR (neat): 5.75 (CO₂CH₃), 5.95, 6.30 (C=C) , 6.60, 6.90, 11.95 microns; NMR (CDC1₃): δ 1.50 (d, 3H, CH₃, J=7Hz), 3.75 (s, 3H, 0CH₃), 4.75-5.15 (m, 1H, allylic hydrogen), 5.85-6.20 (m, 1H, vinylic proton), 6.70-7.20 (m, 5H, vinylic proton and phenol protons), 7.60-7.90 (m, 2H, pyridine protons).

EXAMPLE III Ethyl 4-[4-(3,5-dichloro-2-rpyridinyloxy) phenoxy]-2- butenoate

To 5.1 g (0.02 mole) of 4- (3,5-dichloro-2-pyridin- yloxy) phenol in 40 ml of methyl ethyl ketone is added 5.1 g of ethyl 4-bromo-2-butenoate, dissolved in 10 ml of methyl ethyl ketone, followed by the addition of 2.8 g anhydrous potassium carbonate. The mixture was refluxed 18 hours with continuous stirring. After evaporation of methyl ethyl ketone under reduced pressure, the residue was washed with water, extracted into ethyl ether, dried over magnesium sulfate, and concentrated. Purification by dry column chromatography in ethyl ether/hexane (1:1) gave 0.6 g (8%) of product. IR (neat): 5.75 (CO₂C₂H₅) microns; NMR (CDC1₃) : δ 1.30 (t, 3H, CH₃) , 4.30 (q, 2H, OCH₂), 4.80 (m, 2H, allylic protons); 8.40 (m, 2H, vinylic protons), 7.0- 8.0 (m, 6H, aromatic protons).

Following the teaching of Examples I, II and III, and by substituting an appropriate 2-pyridinyloxy- phenol and an appropriate alkenoate the compounds in Table 1 can be prepared.

4-[4-15 -(trifluoromethyl)-2- -pyridinyloxy] phenoxy]-

2-pentenoic acid

The following procedure can be employed to make the title compound. To 6.8 g of methyl 4-[4-[5-(trifluoromethyl)- 2-pyridinyloxy] phenoxy]-2-pentenoate, in 50 ml of methanol, add 0.8 g of sodium hydroxide in 5 ml of water. Reflux the mixture for 4 hours. Cool and concentrate the mixture to remove methanol. Add water to the residue and acidify the mixture with 5% hydrochloric acid. Filter the precipitate, wash with water and dry. Purify the title compound by recrystallization from solvents such as ethano1/H₂O,

By hydrolysis of an appropriate ester, employing the procedure of Example IV, the carboxylic acids listed in Table 2 can be prepared.

EXAMPLE V

Sodium 4-[4-[5-(trifluoromethyl)-2-pyridinyl]- phenoxy]-2-pentehoate

The following procedure can be employed to make the title compound.

To 6.5 g of 4- [4- [5- (trifluoromethyl)-2- pyridinyl]phenoxy]-2-pentenoic acid and 10 ml of methanol, add 1.1 g of anhydrous sodium methoxide. Stir the mixture at room temperature for 3 hours, and concentrate to remove methanol and to yield the title compound. Wash this compound with cold ether and dry.

By treatment of the appropriate carboxylic acid with a suitable base such as ammonia, an amine, quaternary ammonium hydroxide, or alkali metal or alkaline earth hydroxide, hydride, carbonate, or bicarbonate, the following carboxylic acid salts may be prepared by the method of Example V.

EXAMPLE' VI

N,N-Dimethyl-4-[4-[5-(trifluoromethyl)-2-pyridinyloxy]- phenoxy]-2-pentenamide The following procedure can be employed to make the title compound. To 6.6 g of 4-[4-[5-(trifluoromethyl)-2- pyridinyloxy]phenoxy]-2-pentenoic acid in 20 ml of methylene chloride add dropwise 2.6 g of thionyl chloride. Stir the mixture at room temperature for 5 hours and concentrate under vacuum to yield 4- [4- [5- (trifluoromethyl)- 2-ρyridinyloxy]phenoxy]-2-pentenoyl chloride.

To 6.9 g of 4-[4-[5-(trifluoromethyl)-2- pyridinyloxy] phenoxy]-2-pentenoyl chloride in 30 ml of methylene chloride, cooled in an ice-acetone bath, add dropwise 2.6 ml of liquified dimethylamine. Allow the reaction mixture to gradually warm to room temperature, and stir at room temperature for 1 hour. Wash the mixture with water and remove methylene chloride under vacuum to yield N,N-dimethyl 4-[4-[5-(trifluoromethyl)-2-pyridinyl- oxy]phenoxy]-2-pentenamide.

By treatment of an appropriate acid chloride with an appropriate amine by the procedures of Example VI, the amides listed in Table 4 are prepared.

EXAMPLE VII

Methyl 4-[4-[5-(trifluoromethyl)-2-pyridinyloxy] phenoxy]- 2-pententhioate

The following procedure can be employed to make the title compound.

To a mixture of 6.9 g of 4-[4-[5-(trifluoromethyl)-2-pyridinyloxy]phenoxy]-2-pentenoyl chloride and 2.0 g triethylamine in 30 ml of methylene chloride, cooled in an ice-acetone bath, add dropwise 1.1 ml of liquified methanethiol. Allow the. reaction mixture to warm to room temperature, stir for 1 hour, and wash with water. Remove methylene chloride under vacuum to afford methyl 4-[4-[5-(trifluoromethyl)-2- pyridinyloxy]phenoxy]-2-pententhioate. By treatment of an appropriate acid chloride with an appropriate mercaptan following the procedures of Example VII, the thiolesters listed in Table 5 can be obtained.

Formulations

Useful formulations of the compounds of Formula I can be prepared in conventional ways. They include dusts, granules, pellets, solutions, suspensions, emulsions, wettable powders, emulsions, concentrates and the like. Many of these may be applied directly. Sprayable formulations can be extended in suitable media and used at spray volumes of from a few pints to several hundred gallons per acre. High-strength compositions are primarily used as intermediates for further formulation. The formulations, broadly, contain about 1% to 99% by weight of active ingredient fsf and at least one of aj about 0.1% to 20% surfactant (s) and b) about 1% to 99% solid or liquid diluent (s). More specifically, they will contain these ingredients in the following approximate proportions:

Lower or higher levels of active ingredient can, of course, be present depending on the intended use and the physical properties of the compound. Higher ratios of surfactant to active ingredient are sometimes desirable, and are achieved by incorporation into the formulation or by tank mixing.

Typical solid diluents are described in Watkins, et al., "Handbook of Insecticide Dust Diluents and Carriers", 2nd. Edn., Dorland Books, Caldwell, N.J. The more absorptive diluents are preferred for wettable powders and the denser ones for dusts. Typical liquid diluents and solvents are described in Marsden, "Solvent Guide", 2nd. Edn., Interscience, New York., 1950. Solubility under Q.1% is preferred for suspension concentrates; solution concentrates are preferably stable against phase separation at 0°C, "McCutcheon s Detergents and

Emulsifiers Annual", MC Publishing Co., Ridgewood, N.J., as well as Sisely and Wood, "Encyclopedia of Surface

Active Agents", Chemical Publ. Co., Inc., New York, 1964, list surfactants and recommended uses. All formulations can contain minor amounts of additives to reduce foam, caking, corrosion, microbiological growth, etc. Preferably, ingredients should be approved by the U.S. Environmental Protection Agency for the use intended.

The methods of making such compositions are well known. Solutions are prepared by simply mixing the ingredients. Fine solid compositions are made by blending and, usually, grinding as in a hammer or fluid energy mill. Suspensions are prepared by wet milling (.see, for example, Littler, U.S. Patent 3,060,084). Granules and pellets may be made by spraying the active material upon preformed granular carriers or by agglomeration techniques. See J. E. Browning, "Agglomeration'", Chemical Engineering, Dec. 4, 1967, pp. 147ff. and "Perry*s Chemical Engineer's Handbook",4th Edn McGraw-Hill, N.Y., 1963, pp. 8-59ff. For further information regarding the art of formulation, see for example;

H. M. Loux, U.S. Patent 3,235,361, Feb. 15, 1966,

Col. 6, line 16 through Col. 7, line 19 and

Examples 10 through 41;

R. W. Luckenbaugh, U.S. Patent 3,309,192,

March 14, 1967, Col. 5, line 43 through Col. 7, line 62 and Ex. 8, 12, 15, 39, 41, 52, 53, 58,

132, 138-40, 162-164 , 166, 167, 169-182;

H. Gysin and E. Khüsli, U.S. Patent 2,891,855,

June 23, 1959, Col. 3, line 66 through Col. 5, line 17 and Examples 1-4;

G. C Klingman, "Weed Control as a Science",

John Wiley s Sons, mc|, New York., 1961, pp.. 81-96;

J. D, Fryer and S\ A. Evans, "Weed Control

Handbook", 5th. Edn. Balckwell Scientific

Publications, Oxford, 1968, pp. 101-103.

Wettable Powder

Methyl 4-[4-[5-(trifluoromethyl)- 35%

-2-pyridinyloxy] phenoxy]-2- pentenoate hydrous calcium silicate 61% sodium ligninsulfonate 3% sodium dioctylsulfosuccinate 1%

The ingredients are thoroughly blended, passed th-rough a hammer mill and sifted through a U.S.S. No. 50 sieve (0.3 mm openings) before packaging.

All compounds of the invention can be formulated in similar manner.

B. Solution

Methyl 4-[4-[5-(trifluoromethyl)- 50% 2-ρyridinyloxy] phenoxy]-2- pentenoate dimethylformamide 50%

The ingredients are stirred together to make a solution for direct low-volume application.

C. Granule

Solution of Example B ^10% attapulgite granules (Q.71/0.30mm) 90% The solution is sprayed upon the preformed clay granules in a double-cone blender.

D. Emulsifiable Concentrate

Methyl 4-[4-[5-(trifluoromethyl)- 30% 2-pyridinyloxy] phenoxy]-2- pentenoate blend of oil soluble sulfonates and polyoxyethylene ethers cyclohexanone 64% The ingredients are combined and stirred with gentle warming to speed mixing. A fine-screen filter is included in the packaging operation to xfemove any extraneous undissolved material. Compositions can contain, in addition to the active ingredients of this invention, other conventional agricultural chemicals such as fertilizers, plant growth modifiers or herbicides.

For example, the compounds of Formula I can be combined with ihe following herbicides:

(1) 5-tert-butyl-3-(2,4-dichloro-5-lsopropoxyphenyl)- 1,3, 4-oxadiazol-2-one;

(2) 6-methylthio-2, 4-bis (ethylamino) -s-triazine;

(.3 ) 3-isopropyl-C1H)-benzo-2, 1 , 3-thiodiazin-4-one- 2,2-dioxide;

(4) 2,4-dichlorophenoxyacetic acid and related esters and salts. (.5 ) S-(2, 2, 3-trichloroallyl)-diisopropylthiocarbamate;

(6) Methyl 2-[4-(2 , 4-dichlorophenoxy (phenoxy)]- propanoate;

(7) 1 , 2-dimethyl-3 , 5-diphenyl-lH-pyrazolium methyl sulfate; (8 ) 4-chloro-2-butynyl 3-chlorocarbanilate.

The compounds of Formula I can also be combined with other herbicides and are particularly useful in combination with bromacil [3-(sec-butyl)-5- bromo-6-methyluracil], diuron 13, (3,4-dichlorophenyl)_.- 1, 1-dimethylurea] , 3-cyclohexyl-1-methyl-6-dimethyl- amino-s-triazine-2,4 (1H,3H)-dione, paraquat

[1,1'-dimethyl-4, 4'-bipyridinum ion], m-(3, 3-dimethyl- ureidol-phenyl terjt-butylcarbamate, 2-methyl-4-chloro- phenoxyacetic acid, its salts or esters, 4-amino-6- tert-butyl-3-methylthio-as-thio-as.-.triazine-5(4H)-one bentazone [3-isopropyl-lH-2,l,3-benzothiadiazin-( 4 )- 3H-one-2,2-dioxide, and linuron [3-(3,4-dichlorophenyl)- 1-methoxy-l-methyl urea} for controlling a broad spectrum of weeds. The agricultural chemicals listed above are examplary of the compounds which can be mixed with the active compounds and are not intended to limit the invention in any way. Use The compounds of the present invention are useful when applied as pre- and/or post-emergence treatments for broad-spectrum control of a wide variety of weed and brush species growing on industrial sites, storage lots, along fences and building foundations, along railroad and utility rights-of-way, etc. In addition, the compounds of the invention have utility for weed control in certain crops, such as soybean, cotton, sugarbeets and beans.

These herbicides are particularly useful for selectivity removing and controlling grass weeds, including volunteer corn, in broadleaf crops including soybeans, cotton, sugarbeets, beans, flax, cabbage, tomatoes, potatoes, peanuts, carrots, cucurbits, endive, beets etc. Grassweeds include crabgrass, foxtail, barnyardgrass, wild oats, johnsongrass, fall panicum, cheatgrass, quackgrass, and orchardgrass. Compounds of this invention show a remarkable and unexpected degree of safety to broadleaf crops and an unusual phytotoxicity to grass weeds whether applied to the soil before weeds and crops emerge, that is, preemergence, or whether applied postemergence including spraying on the weeds and crops. In addition, the compounds are useful when applied as preemergence or postemergence treatments alone and in combination with other herbicides or surfactants for broad-spectrum control of a wide variety of weeds and brush species growing on industrial sites, on storage lots and along fences, building foundations, railroad, highway and utility rights-of-way etc.

Compounds of the present invention are considered to show an unexpected degree of safety on broadleaf crops as demonstrated by use of methyl 4-[4-[5-(tri- fluoromethyl)-2-pyridinyloxy] phenoxy]-2-pentenoate on soybean, cotton and beans.

The precise amount of the compounds of this invention to be used in any particular situation will vary widely according to the end result desired. Factors effecting the optimum rate of application include the plant species to be controlled, soil type, formulation used, prevailing weather conditions, foliage density, length of time for which residual activity is desired, etc. Broadly speaking, the compounds are used at levels at about 0.06 to 20 kilograms per hectare, preferably approximately 0.125 to 5 kilograms per hectare. In general, the higher rates of application from within this range will be selected for adverse conditions or where extended persistence in soil is desired, and the lower rates for weed control in crops.

The herbicides effectively control grass weeds as demonstrated by the examples, but they do not control broadleaf weeds at low application rates. To obtain control of a wider spectrum of both broadleaf and grass weeds, combination treatments consisting of compounds of this invention with other herbicides effective on broadleaf weeds may be used to advantage. Combination treatments may be used with the components applied simultaneously as in a tank mix or mixed formulation, or sequentially with either or both components applied preplant incorporated, preemergence, postemergence, postemergence-directed, broadcast, band or spot treatment or any combination of these methods. The following examples of combination utility are cited: Compounds of this invention with Other Herbicide Use bentazon (post-) Soybeans 2,4-DB (post-) Peanuts, Soybeans Alfalfa, Clover

Simazin (pre-) Nursery, Citrus, Peaches, Established Alfalfa pyrazon (pre-, early Sugarbeets post-) silvex Fence lines, rights-of-ways dichloroprop (post-) Brush, Release of Evergreens

MCPB (early post-) peas dicamba (pre-) flax and rape desmedipham (post-) Sugarbeets prometryn (pre-) Celery and Cotton

Phenmedipham (post-) Sugarbeets acifluorofen (Blazer®) (post) Soybeans

2-chloro-N-[(4-methoxy- 6-methyl-l,3,5-triazin- 2-yl) aminocarbonyl]- benzenesulfonamide Wheat and flax

1-methylethyl 2[[(4, 6- dimethoxy-1, 3, 5-triazin- 2-yl) aminocarbonyl] amino- sulfonyl] ]benzoate Wheat and flax

1-methylethyl 2 [ [ (4-methoxy- 6-methyl-l, 3, 5-triazin-2- yl) aminocarbonyl] amino- sulfonyl] ]benzoate Wheat and flax dinoseb (post) Soybeans lenacil (pre) Sugarbeets Example viii

Seeds of crabgrass (Digitaria spp.), barnyardgrass (Echinochloa crusgalli), wild oats (Avena fatua), Cassia tora, momingglory (Ipomoea spp.) cocklebur (Xanthium spp.), sorghum, corn, soybean, rice, wheat and nutsedge tubers were planted in a growth medium and treated preemergence with the chemicals dissolved in a nonphytotoxic solvent. At the same time, cotton having five leaves (.including cotyledonary ones), bush beans with the third trifoliate leaf expanding, crabgrass with two leaves, barnyardgrass with two leaves, wild oats with one leaf, cassia with three leaves (including cotyledonary ones), morningglory with four leaves (including the cotyledonary ones), cocklebur with four leaves C.including the cotyledonary ones), sorghum with three leaves, corn with three leaves, soybean with two cotyledonary leaves, rice with two leaves, wheat with one leaf, and nutsedge with three-five leaves were sprayed. Treated plants and controls were maintained in a greenhouse for sixteen days . All species were compared to controls and visually rated for response to treatment seven and sixteen days after treatment. The ratings are based on a numerical scale extending from 0 = no injury, to 10 = no kill. The accompanying descriptive symbols have the following meanings: B = burn; G = growth retardation; C = chlorosis/necrosis; U = unusual pigmentation; E = emergence inhibition; and H = formative effects. The ratings for the compound tested by this procedure are shown in Table 6 for

7 days after treating.

Claims

BA-8344WHAT IS CLAIMED IS :

1. A compound of the formula

where

X is H, Cl or Br ; Y is CF₃ or Cl ;

R₁ is H, CH₃ , CH₂CH₃ or CH₂OCH₃ ;

R₂ is OR₃ , NR ₄R₅ or SR₆ ;

R₃ is H, C₁-C₄ alkyl, -CH₂CH₂OCH₃, -CH₂CH₂OCH₂CH₃ or -CH₂CH₂CH₂OCH₃ ; R₄ is H or C--C₃ alkyl or OCH₃;

R₅ is H or C₁-C₃ alkyl ; and

R₆ is C₁-C₄ alkyl; provided that when R₄is -OCH₃, then R₅ is CH₃; and agriculturally suitable salts thereof when R₂ is OR₃ and R₃ is H.

2. A compound of Claim 1 wherein R₁ is CH₃.

3. A compound of Claim 1 wherein R₂ is OR₃.

4. A compound of Claim 1 wherein X is H or Cl .

5. A compound of Claim 1 wherein R₁ is CH₃ and R₂ is OR₃.

6. A compound of Claim 1 where R₁ is CH₃, R₂ is OR₃ and X is H or Cl.

7. The compound of Claim 1 which is methyl 4-[4- [5-trifluoromethyl)-2-pyridinyloxy] phenoxy]-2- pentenoate.

8. The compound of Claim 1 which is methyl 4-[4- (3 , 5-dichloro-2-pyridinyloxy) phenoxy]-2-pentenoate.

9. A composition for the control of undesirable vegetation consisting essentially of an herbicidally effective amount of a compound of any of Claims 1 to 8 and at least one of (a) a surface active agent and (b) a solid or liquid diluent.

10. A method for the control of undesirable vegetation comprising applying to the locus of such undesirable vegetation an herbicidally effective amount of a compound of any of Claims 1 to 8.

11. A composition for the control of grass weeds in broadleaf crops consisting essentially of an herbicidally effective amount of a compound of any of Claims 1 to 8 and at least one of (a) a surface active agent and (b) a solid or liquid diluent.

12. A method for the control of grass weeds in broadleaf crops comprising applying to the locus of such grass weeds an herbicidally effective amount of a compound of any of Claims 1 to 8.

13. A process for preparing a compound of Claim 1 where R₂ is OR₃ which comprises contacting, in the presence of a base, the compounds

where X, Y, R₁ and R₃ are as previously defined and where Z is Cl or Br.

14. A process for preparing a compound of Claim 1 where R₂ is -NR₄R₅ which comprises contacting

and HNR₄R₅, where

X, Y, R₁, R₄ and R₅ are as previously defined,

15. A process for preparing a compound of Claim 1 where R₂ is -SR₆ which comprises contacting the compounds

and

HSR₆, where X, Y, R₁ and R₆ are as previously defined.