CA1196644A - Substituted phenoxypropionic acid esters and intermediates thereof, processes for production thereof and herbicide - Google Patents

Abstract

SUMMARY OF THE INVENTION

Novel substituted phenoxypropionic acid esters of the formula (I) in which Ar represents a radical of the formula or

Description

~66~

Ib The invention relates to certain new substituted phenoxypropionic acid esters, to several processes for their production, and to their use as herbicides.
It has alxeady been disclosed ~hat certain

2 l4-phenoxy-phenox~7-propionic acid derivatives possess herbicidal properties (see German published specifica-tion (DE~OS) 2,617,804 and Japanese published speci~
fication No. 1311545 ~ 1977). Thus, for example, 2-dimethylamino-ethyl 2-~4-(4-~rifluoromethyl phenoxy)-phenoxy7-propionate of the formula F3C- ~ ~- ~ -O~CH-C-O-~CH ) -N~ H3 lA-l ) can be used for combating weeds, However, the activity of this substance is not always completely satisfactory.
The present invention now provides, as new com-pounds, the substi~uted phenoxy-propionic acid esters of the general formula CH3 o R R2 Ar-O~ 0-CH-- C-O-CH-(CH~m-N-CH ~
R Xa (I) Nit-159-Foreign countries ~ ~. .

6~

in which Ar represents a radical of the oxmula ~ sr ~ N

in which Y represents a halogen atom or a trifluoro-methyl group and b represents 1 or 2, R1 and R3, independently of each other, represent a ` hydrogen atom or a methyl group, R2 represents a lower alkyl group or a lower alkenyl group, X represents a hydrogen atom, a halogen atom or a lower alkoxy group, m represents 1 or 2 and a represents 1 or 2.
The invention also provides a process for the preparation of a substituted phenoxy-propionic acid ester of the formula (I~, which process comprises a) reacting a compound of the seneral formula ~r-O- ~ -OM (II~

in whic~
~r has the meanings given above and Nit-159 L~ d~

M represents a hydro~en atom or an alkali metal atom, with a compound of the general formula z1 CH - C-O-CH(CH2) -N -CH- ~ %a (III) in which Rl ~ R2 t R3, X, a and m have the meanings given above and z1 represents a halogen atom, or b) reacting a compound o the general formula CH O
Ar-O- ~ ~ 3 ~' 2 (IV) in which Ar has the meaning given above and Z represents a hydroxyl group or a halogen atom, with a compound of the general formula R1 ~2 Xa H~CHICH2)m~N~ H- ~ (V~

Nit-159 ~664~

in which R1, R2, ~3, X, A and m have the meanings gi~en above, or c) reacting a compound of the general formula A~ ~1 3VI3 in which Ar and z1 have the meanings given above, with a compound of the general formula M O- ~ -O-CH - C-O-CH(CH2) ~N ~CH- ~ Xa (VII) in which R1, R2, R3, X, M, a and m have the meanings given above.
The present invention also provides herbicidal compositions comprising as active ingredients substi-tuted phenoxypropionic acid esters of the general formula lI). In an additional aspect, the present invention provides a method of combatin~ weeds by applying a substituted phenoxypropionic acid ester of the general formula (I) to the weeds or to their habitat.
Surprisingly, the compounds according to the pre-Nit-159 6 ~9L

sent invention, which have not previously been described in the literature, show an excellent herbicidal acti-vity and are particularly useful for selectively com-bating a wide range of weeds, such as gramineous weeds, without causing subs~antial phytotoxicity on useful upland farm crops. It is particularly surprising that the compounds according to this invention also exhibit a better herbicidal activity than the 2-dimethylamino-ethyl 2 ~4-(4-trifluoromethyl-phenoxy~-phenoxy7-pro-pionate, which is an effective herbicide known fromthe prior art. It should also be pointed out that the compounds according to he present invention, even when applied in low dosages, show an excellent selecti-vity and very effectively control the regeneration of weeds, especially of perennial gramineous weeds, over a long period of time due to their excellent re-sidual effect.
The compounds according to the present invention are structurally charactexised by the fact that in an alkyl ester of a substituted phenoxypropionic acid, the alkyl group is substituted by a substituted benzyl-amino group.
Preferred compounds according to the present in-vention are those substituted phenoxypropionic acid esters of the general formula (I), in ~hich Ar represents a radical of the formula y ~ or Nit-159 6~
-in which Y represents fluorine, chlorine, bromine and/or trifluoromethyl and b is 1 or 2, R1 and R3, independently of each other, represent a hydrogen atom or a methyl group, R represents alkyl with 1 to 4 carbon atoms, such as methyl, ethyl, propyl, isopropyl, n-butyl, iso-butyl, sec. butyl or tert.-butyl, or repre-sents alkenyl with 2 or 3 carbon atoms, such as vinyl, allyl and 1-propenyl, X represents hydrogen, fluoxine, chlorine, bromine or alkoxy with 1 to 4 carbon atoms, such as methoxy, ethoxy, propoxy, isopropoxy, n-~utoxy, iso-butoxy, sec.-butoxy or tert.-butoxy, m represents 1 or 2 and a represents 1 or 2.
The course of process variant ~a) according to the present invention can be illus~rated by the following reaction scheme:
CH3 O Rl R2 . ~r-O- ~ -O~ ~ Z~ ~C-Oo~H(~H21~ N-C - ~ Xa (II) (III) ~r~ o ~GH ~ CH;2 ~ N~ a (I) Nit-159 i6'~

If specifically 4-(4-trifluoromethyl~phenoxy)-phenol and 2~(N-methylben~ylami~o)-ethyl 2-bromo-propionate are used as starting materials, the course of reaction variant (a) ~ccording to the inven~ion can be represented by the following equàtion:

ON ~ 8r~ - ( C~2 ~ 2~ 2 ~3 C ~ _O_ ~ ~O-C~-~C~ CN~32-N-~2~

Formula (II) gives an unambiguous definition of the compounds required as starting materials in process variant (a) according to the invention. In this for-mula, Ar preferably represents those radicals whichhave already been mentioned as preferred therefor in con-nection with the description o~ the substances of the formula ~I). M preferably represents hydrogen, lithium, sodium and potassium.
~he following may be mentioned as examples of compounds of the formula (II):
4-~4-trifluoromethylphenoxy3phenol, 4-(5-trifluoromethyl-2~pyridyloxy)phenol, 4-(3,5-dic}lloro-2-pyridyloxy)phenol, and 4-(3-chloro-5-trifluoromethyl-2 pyridyloxy)phenol, and the corresponding lithium, sodium and potassium salts~

66~

- 8 - 23l89-57o6 Formula (III) prov~s a general definition of the compounds required as further starting materials in pro-cess variant (a) according to the invention. I~ this for-mula, R1, R2, R3, X, a and m preferably represent those radicals and indices, which have already been mentioned as preferred therefor in connection wi~h the description of the substances of the formula (I). z1 preferably re-presents chlorine or bromine.
The following may be mentioned as examples of com-pounds of the formula (III~:
2-(N-methylbenzylamino)-ethyl-2-chloro (or bromo)-propionate, 2-~N-isopropylbenzylamino)ethyl 2-chloro(or bromo)-propionate, 2-(N-methyl- ~ -methylbenzylamino)ethyl 2-chloro(or bromo)propionate, 2-(N-methyl-2-fluorobenzylamino3ethyl ~-chloro(or bromo)propionate, 2-(N-allyl-4-chlorobenzylamino)ethyl 2-chloro(or bromo)propionate, 2-(N methyl-4-methoxybenzylamino)ethyl 2-chloro(or bromo)propionate, 2-~N isopropyl-3,4-dichlorobenzylamino)ethyl 2-chloro (or bromo)propionate, 2-~N-methyl-4-chlorobenzylamino)ethyl 2-chloro(or bromo)propionate, 1-(methyl-2-(N-methylbenzylamino)ethyl 2-chloro(or bromo)propionate, and

3-(N-methylbenzylamino)propyl 2-chloro(or bromo)-propionate.
The compounds of the formula (III) have not hitherto been described in the literature.

Nit-159 . . ~

6~
, ~

The compound of the general formula (III) may be pre-pared by a process which comprises d) reacting a compound of the yeneral formula C~l O
' 3 " (VIII) Z -CH - C-Z

in which zl and z2 have the meanings given above, with a compound of the general formula ( 2)m , ~ Xa (V) in which Rl, R , R3, X, a and m have the meanings given above.
Reaction variant (a) according to the present inven-tion is preferably carried out in the presence of a solvent or di].uent. For this purpose, any inert solvents and diluents may be employed.
Examples of such solvents and diluents include water;aliphatic, alicyclic and aromatic hydrocarbons - each of which may optlonally be chlorinated (such as hexane, cyclohexane, petroleum ether, ligroin, benzene, toluene, xylene, methylene ~hloride, chloroform, carbon tetrachloride, ethylene chloride, tri-chloroethylene, and chlorobenzene), ethers (such as diethyl ether, methyl ethyl ether, di-isopropyl ether, dibutyl ~6~

ether, propylene oxide, dioxane, and tetrahydrofuran), ketones (such as acetone, methyl ethyl ketone, methyl isopropyl ketone, and methyl isobutyl ketone)/ nitriles (such as acetonitrile, propionitrile, and acrylonitrile), alcohols (such as methanol, ethanol, iso-propanol, butanol, and ethylene glycol, esters (such as ethyl acetate and amyl acetate), acid amides (such as dime-thylformamide and dimethylacetamide) sulfones and sul~
foxides (such as dimethylsulfoxide and sulfolane) and bases (such as pyridine).
The reaction variant ~a) is pxeferably carried out in khe presence o~ acid-binding ~gent. As examples of such acid-binding agents, there may be mentioned hydroxides, carbonates, bicarbonates and alcoholates of alkali metals, and tertiary amines such as triethylamine, diethylaniline pyridine.
Reaction variant (a) can be carried out over a wide range of temperatures. Generally, it is carried out at a temperature between -20C and the boiling point of the reaction mixture, preferably between 0C and 100C.
This reaction variant ~a) is preferably carried out under ambient pressure, although it can be effected under elevated or reduced pressure.
The course of process variant (b) according to the present inven~ion can be illust~ated by the following reaction scheme:

Nit~159 e~3 o Rl ~2 X
~r-O ~ -~-C~ Z2 ~ C~2~-N-~

(IV) ( V) H3 0 ~ R2 Ar o~ CH--e-~eH~C~23 ~N-~H_ ~ ~ H,z2 .. . 1 (I) If specifically 2-~4~(3,5-dichloro-2-pyridyloxy)-phenoxy7-propionylchloride and 2-(N-isopropylbenæyl-amino)-ethanol are used as starting materials, the cour~e of reaction variant (b) accordiny to the in-vention can be represented by the following equation:
~ CN3 O c~e~332 Cl- ~ -O ~ O-~H~ hO ~-(C~2~2-N-C~2 Cl CH3 0 CH~CH332 ~ Cl~ N~-c-O~ 2)2~ ~H~ ~ + ~1 Formula ~IV) gives an unambiguous definition o~ the compounds, which are required as starting materials in process variant ~b) according to the invention. In thls ~oxmula, Ar preferably represents those radicals which have already been mentioned as preferred therefor in connection with the description of the substances of the formula ~I). z2 preferably repxesents hydroxyl, chlorlne and bromine~
The following may be mentioned a~ examples of compounds of the formula (IV):
2-L4-(4-tri~luoromethylphenoxy~phenoxy7propionyl chloride, Nit-159 ~6/~

2-~4-~5-tri~luoromethyl-2-pyridyloxy~phenoxy/pro pionyl chloride, 2-~4-~3,5-dichloro-2~pyrid~loxy~phenoxy7propionyl chloride, and 2-~4-(3-~hloro-5 trifluoromethyl-~-pyridyloxy)-phenoxy7propionyl chloride, as well as the corresponding bromides and ree propionic acids.
Formula (V) provides a general definition of the compounds, which are also required as s~arting materials in process variant (b) according to the invention. In this formula~ R~, R2, R3, X, a and m preferably repre-sent those radicals and lndices, which have already been mentioned as preferred therefor in connection with the description of the substances of the formula tI).
The following may be mentioned as examples of compounds of the formula (V~:
2-(N-methylbenzylamino)ethanol, 2-(N-isopropylbenzylamino)ethanol, 2-(N-methyl~ methylbenzylamino)ethanol, 2-(N-methyl-2-fluorobenzylamino)ethanol, 2-(N allyl--4-chloroben2ylamino)ethanol, 2-(N~methyl 4-methoxybenzylamino)ethanol, 2-(N-isopropyl-3,4-dichlorobenzylamino~e~hanol, 2-(N-methyl-4-chlorobenzylamino)ethanol, 1-lN-methylbenzylamino3-2-propanol, and 3-(N-methylbenzylamino)-1-propanol.
In carrying out reaction variant (b), any of the inert solvents or diluents as described hereinbefore for reaction variant ia), except alcohols~ are pre ferably used to obtain the nd products with high puri Nit-159 ty in high yield. Likewise, reaction variant ~b) is preferably carried out in the presence of an acid bind1ng agent as described hereinbefore for reaction variant (a).
Reaction variant (b) can be c~rried out over a wide range of temperatures. Generally, it is carried out at a temperature between -20C and the boiling point of the reac-tion mixture, preferably between 0C and 100C.
The reaction variant (b) is preferably carried out under ambient pressure, although it can be efected under elevated or reduced pressure.
The course of process variant (c) according to the present invention can be illustrated by the following reaction scheme:
~H3 ~ Rl R2 ~_8~ O~ o~ 6H2)~ N-~H- ~ X

VI~
CH3 O R~
A~ 0~ g~---C~ C~2)~ ,81 gI~

If specifically ~-bromo-5-trifluoromethylpyridine and 2-(N-methylbenzylamino)-ethyl 2-(4-hydroxyphenoxy)-propionate are used as starting materials, the course o~ reaction variant (c) according to the invention can be represented by the ~ollowing equation:

3~ ~ HO~ O-(~H2)2-N ~2 --~P3e~ e~ H2~2-N ~H~ ~ H~

Nit-159 6'~4 Formula (VI) gives an u~ambiguous definition of the com-pounds required as starting materials in process variant (c~ according to the invention. In this formula, Ar pre-ferably represents those radicals which have already been mentioned as preferred therefor in connection with the description of the substances of the formula (I3. z1 preferably represents fluorine, chlorine or bromine.
The following may be mentioned as examples of com-pounds of the formula (VI):

4-chloro(or bromo)-trifluoromethylbenzene, 2-chloro(or fluoro, or bromo)-5-trifluoromethyl-pyridine, 2,3,5-trichloropyridine, 1S 2-bromo-3,5-dichloropyridine r 2,3-dichloro-5-trifluoromethylpyridine, and ~-bromo-3 chloro-5-trifluoromethylpyridine.
Formula (VII) provides a general definition of the compounds required as further starting materials in process variant (c) according to the invention. In this formula, R1, R2, R3, X, a and m preferably represent those radicals and indices, which have already been mentioned as pre~erred therefor in connection with the description o~ the substances of the formula tI). M preferably re-presents hydrogen, lithium, sodium and potassium.
The following may be mentioned as examples ofcompounds of the formula (VII~:
2-(N-methylbenzylamino)ethyl 2-t4~hydroxyphenoxy)-propionate, Nit-159 2-(N-isopropylbenzylamino)ethyl 2-(4-hydroxyphenoxy)-propionate, 2-(N-methyl-~-methylbenzylamino)ethyl 2-(4-hydroxy-phenoxy)propionate, 2-(N-methyl-2-fluorobenzylamino)ethyl 2-(4-hydroxy-phenoxy)propionate, 2-(N-allyl-4-chlorobenzylamino)ethyl 2-(4-hydroxy-phenoxy)propiona-te, 2(N-methyl-4-methoxybenzylamino)ethyl 2-(4-hydroxy-phenoxy)propionate, 2-(N-isopropyl-3,4-dichlorobenzylamino)ethyl 2-(4-hydroxyphenoxy)propionate, 2-(N-methyl-4-chlorobenzylamino)ethyl 2-~4-hydroxy-phenoxy)propionate, l-methyl-2-(N-methylbenzylamino)ethyl 2-(4-hydroxy-phenoxy)propionate, and 3-(N-methylbenzylamino)propyl 2-(4-hydroxyphenyl)-propionate, and the correspondlng lithium, sodium and potassium salts.
~0 The compounds of the formula (VII) have not hitherto been descrihed in the literature.
The compound of the general :Eormula (VII), may be pre-pared by a process which comprises e) reacting a compound of the formula ,;~P'`i' ~6 ~ j L~ ~

CH3 R1 R3 Xa Z1-C~ - C - O ~H (CH2)~-CH- ~ (III1 in which R1, R , R3, X, z1, a and m have the meanings given 5above, with h~dxoquinone of the formula HO ~ OH (IX) and r if appropriate, reacting the resulting product with an alkali metal hydroxide, an alkali metal car-bonate or an alkali metal alcoholate, III carrying out reaction variant (c), any of theinert solvents or diluents as described hereinbefore for reaction variant (a~, except alcohols, are pre-ferably u~ed to obtain the end products with high purity in high yield. Likewi~e, reaction variant (c) is preferably carried out in the presence of an acid-binding agent as described hereinbefore for reaction ~ariant (a).
Reaction variant (c) can be carried out over a wide range of temperatures. Genera11y, it is carried out at a temperature between -20~ and the boiling poi~t of the reaction mixture, preferably between 0C
and 100C.

~it-159 r~

The reaction variant (c) is preferably carried out un-der ambient pressure, al-though it can be effected under elevated or reduced pressure.
The course of process (d) above can be illus-trated by the following reaction scheme:

Zl-CH - C-Z -~ HO-CH(CH2)m-N-CH

(VIII) (V) CH3 Rl R2 X
Z -CH - C-O-CH(CH2)m N CH ~ ~ ~ H.Z

(III) If specifically 2-bromo-propionylbromide and 2-(N-methylbenzylamino)-ethanol are used as starting materials, the course of reaction (d) above can be represented by the following equation:
CH3 0 ,CH3 Br-CH - C-Br + HO-(CH2)2-N-CH2 - ~

Br-CH ~ C-O-(CH2)2-N-CH2 - ~ + HBr , . ' Formula (VIII) gives an unambiguous definition of the compounds required as starting materials in process (d) above.
In this formula, Z preferably represents chlorine and bromine.
z2 preferably represents hydroxyl, chlorine and bromine.
Specific examples of the compounds of the formula (VIII) are 2-chloropropionic acid, 2-bromopropionic acid, as well as the corresponding chlorides and bromides.
In carrying out reaction (d), any of the inert sol-vents or diluents as described hereinbefore for reaction variant (a), except alcohols, are preferably used to obtain the inter-mediates of the formula (III) with high purity in high yield.
Likewise, reaction (d) is preferably carried out in the presence of an acid-binding agent as described hereinbefore for reaction variant (a).
Reaction (d) can be carried out over a wide range of temperatures. Generally, it is carried out at a temperature between -20C and the boiling point of the reaction mixture, preferably between 0C and 100C.
The reaction (d) is preferably carried out under am-~0 bient pressure, although it can be effected under elevated or r~duced pressure.
The course of process (e) above can be illustratedby the following reaction scheme:

- 1~ -r~.~, CH3 Rl R2 X

HO ~ ~ -OH + Z -CH C O 2 m ,3 { ~ a HO ~ O-CH--C-O-CH(CH2) -N-CH ~ +xaH,Z1 R

(VII-i) If specifically 2-(N-methylbenzylamino)-ethyl 2-bromo-propionate and hydroquinone are used as starting materials, the course of reaction (e) above can be represented by the following equakion:

HO- ~ OH + BR-CH-- C-O-(CH2)2-N-CH2 ~

HO- ~ O-CH - C-O-(CH2)2-N-CH ~ ~ -~ HBr The compounds of yeneral formula (VII) in which M is an alkali metal atom, can be produced by reacting the 2-(4-hydroxyphenoxy)propionic acid esters of general formula (VII-i) with an alkali metal hydroxide, an alkali metal carbonate, or .10 an alkali metal alcoholate.
Specific examples of such alkali metal hydroxides are lithium hydroxide, sodium hydroxide and potassium hydroxide.
Specific examples of such alkali me-tal carbonated are sodium ~,' ~~\
i6 ~

carbonate and potassium carbonate. Specific examples of such alkali metal alcoholates are sodium or potassium methylate and sodium or potassium ethylate.
In ca~rying out reaction (e), any of the inert sol-vents or diluents as described hereinbefore for reaction variant (a) are preferably used to obtain the intermediates of the for-mula (VII) with high purity in high yieldO
Reaction (e) can be carried Ollt over a wide range of temperatures. Generally, it is carried out at a temperature be-tween -20C and the boiling point of the reaction mixture, pref-erably between 0C and 100C.
The reaction (e) is preferably carried out under am-bient pressure, although it can be effected under elevated or red~ced pressure.
The active compounds of formula (I) according to the present invention show excellent selective herbicidal activity.
They can be applied either before or after emergence of the plants. They are preferably applied before emergence of the plants, that is to say by the pre-emergence method. They can also be incorporated into -the soil before sowing.
Since the active compounds according to the present lnvention show little or no to~icity towards warmblooded animals and show good selectivity for agricultural plants, that is, cause no phytotoxicity for agricultuxal plants, they can be con-veniently used as herbicides for controlling weeds, particular-ly for the ' ~
. ;~

control of gramineous ~eeds. By "weeds" in the broadest sense there are meant plants growing in places where they are not desired.
The active compounds according to the present in-vention may be used, for example, to combat the following plants: -Echinochloa cxus-galli P. Beauv., Digitaria adscendens Henr., Eleusine indica Gaertn. t Setaria viridis P. Beauv., Avena fatua, Alopecurus aequalis var. amurensis Ohwi, Setaria lutescens, Agropyron repens, and ~gropyron tsuku~hiense var. transiens Ohwi.
In addition, they also show excellent herbicidal and regrowth-control effects on, for example, perennial weeds, such as Johnson grass and Cynodon dactylon.
The active compounds according to the present in-vention may be used as selective herbicides in many cultures. As examples the following cultures may be mentioned: beanst cotton, carrot, potato, beet, cabbage, mustard, peanut, radish, tobacco, tomato and cucu~ber.
The active compounds according to the present in-vention can be converted into custo~ary formulations using agricultural acceptable adjuvants by methods generally practiced in the production of agricultural chemicals. In actual use, the herbicidal compositions in various forms are applied either directly or ater dilutin`g them with water to the desired concentrations.
Examples of the agriculturally acceptable adjuvants, as referred to herein, are diluents (solvents, extenders, carriexs), surfaceactive agents (solubilizing agents, emulsifiers, dispersants, wetting agents~, stabilizers, Nit-159 ~66~

stickers, aerosol propell~nt~, and synergists.
Examples of the solvents are wa~er, and organic solvents, for example hydrocarbons (e.g., n-hexane, petroleum ether~ naphtha, petroleum fractions (e.g.
paraffin waxes, kexosine, light oils, middle oils, heavy oils~, benzene, toluene, and xylenes~, halogenated hydro-carbons (e.g. methylene chl~ride, carbon tetrachloride, trichloroethylene, ethylene dichloride, chlorobenæene and chloroform), alcohols (e.g. methyl alcohol, ethyl alcohol9 propyl alcohol, and ethylene glycol), ethers (e.g., ethyl etherj ethylene oxide and dioxane), alcohol ethers (e.g., ethylene glycol monomethyl ether), ketones (e.g. acetone and isophorone), esters (e.g., ethyl acetate and amyl acetate), amides ~e.g. dimethylformamide and dimethylacetamide) and suifoxides (e.g , dimethyl sulfoxide).
Examples of the extenders or carriers include in-organic powders, for example slaked lime, magnesium limeJ gypsum, calcium carbonate, silica, perlite, pumice, calcite, diat~maceous e~rth, amorphous silica, alumina, zeolites, and clay minerals ~e.g., pyrophyllite, talc, montmorillonite, beidellite, vermiculite, kaolinite and mica); vegetable powders such as cereal powders, st~rches, processed starches, sugar, gluc~se and crushed stalks of plants; and powders ~f synthetic resins such ~s phenolic resins, urea resins, and vin~l chloride resins.
Exa~ples of t~e sur~ace-active a~ents include anio-nic surface active agents such as alkylsulfuric acid esters (e.g., sodium l urylsul~ate), arylsu~fonic acid Nit-15~

salts (e~g., alkylarylsulfonic acid salts and sodium alkylnaphthalenesulfcnates), succinic acid salts and salts o~ sulfuric acid esters of polyethylene glycol alkylaryl ethers; cationic surface-active agents such as alk~lamines (e.~., laurylamine, stearyl trimethyl ammonium chloride and alkyl dimethylbenzyl ammonium chloride) and polyoxyethylene alkylamines; nonionic surface-active agents such as polyoxyethylene glycol ethers ~e.~ polyoxyethylene alkylaryl ethers and the condensation products thereof) r polyoxyethylene glycol esters (e.g., polyoxyethylene fatty acid esters), and polyhydric alcohol esters (e.g. polyoxyethylene sor-bitan monolaurate); and amphoteric surface-active agents.
Examples o other adjuvants include stabilizers;
stickers (e.g. agricultural soaps, casein lime, sodium alginate, polyvinyl alcohol, vinyl acetatP-type adhe-sives and acrylic adhesives); e~fect-prolonging agents;
dispersion stabîlizers (e.g., casein, tragacanth, car-boxymethyl cellulose and polyvinyl alcohol); and syner-gists.
The active compounds according to this invention can be converted into the customary formulations, such as emulsifiable concentrates, oils, wettable powders, soluble powders, suspensions, dusts, granules and pul-verulent compositions. These formulations may be pro-duced in known manner.
~ he amount of active compound in the ready to-use preparation can vary widely according to circumstance.

Nit-159 Howe~er, it is in general from 0.001 to about 100 per cent by weight o~ active co~pound, preferably from about 0.005 to 95 per cent by weight.
In actual use~ the suitable amount of the ac~ive compound in the aforesaid compositions of various orms and ready~to-use preparations is, for example, about 0.01 to about 95 % by weight, preferably about 0.05 to about 60 % by weight.
The content of the active ingredient can be pro-perly varied depending upon the form of the preparationor composition, the method, purpose, time and locus o~
its application, the state of occurrence of weeds, etc.
If required, the compound of this invention may be used further in combination with other agricultural chemicals, for example insec~icides, fungicides, miti-cides, nematocides, antiviral agents, other herbicides, plant growth regulators and attractants ~e~g. organo-phosphorus ester compounds, carbamate compounds, dithio ~or thiol) carbamate compounds, organic chlorine com-pounds, dinitro compounds, organic sulfur or organometallic compounds, antibiotics, substituted diphenyl ether compounds, urea compounds, and triazine com-pou~ds), and~or fertilizers.
Various compositions and ready-to-use preparations ~5 con~aining the aforesaid active ingredient can be applied by ~arious methods generally practiced in the fleld oE agricultural chemical application, for example dispersing (liquid spraying, misting, atomizing, dust dispersing, granule dispexsing, water surface application and pouring); and soil application (mixing with the soil, ~it-159 and sprinkling~. They can also be used by the ~o-called ultralow volume spraying methodO ~ccording to this method, the active ingredient may be included in an amount of 100 %~
The rate of application per unit area is, ~or example, about 0.01 to about 2.0 kg, preferably a~out 0.05 to about 1.0 kg~ per hectare. In special cases, how-ever, it may, and sometimes should, be outside the specified range.
The present invention also provides a herbici~al composition containing as active ingredien~ a compound of the present inventlon in admixtura with a solid diluent or carrier or in admixture with a liquid diluent or carrier containing a sur~ace-active agent.
The present invention also pxovides a method of combating weeds which comprises appl~ing to the weeds or to a habitat thereof, a compound of the present invention alone or in the form of a composition CQn-taining as active ingredient a compound of the pre-sent invention in admixture with a d1luent or carrier.
It will be seen that the usual methods of provi-ding a harvested crop may be improved b~ the present invention.
Compositions according to this invention are lllus-trated in the following Examples.
In these Examples, the compounds according to the present invention are each identified b.y the number (given in brackets) o~ the corresponding preparative Example. References to "parts" are t.o be unders~ood as meaning parts by weight.

~it-159 6~

Preparative Examples Example 1 (intermediate) ~r-C~~~ ~CH2) 2 ~ H2-~

(Compound No. III-1~

A solution of 21.6 g of 2-bromopropionyl bromide in 30 m~ of toluene was added dropwise at -10 to 0C to a solution of 16.5 g of 2-(N-methylbenzylamino)ethanol and 10.1 g of triethylamine in 150 ml of toluen~. After the addition was completed, the mixture was stirred at room temperature for 2 hours. The mixture was then washed successively with a 1 % aqueous solution of sodium hydro-xide and water. The washed product was dried, and then the toluene was evaporated under reduced pressure to give 29 . O g o~ 2-(N~methylbenzylamino)ethyl 2-bromo-propionate as a colorless oil.

n20 = ~.5303.

In substanti~lly the same manner as described in Example 1~ thexe were ~btained the compounds of the for-mula ~III), which are shown in the following Table 1.

~it-~59 119~;G~4 _ ~ ~o ~3 S

æ ~
U
H ~ X 5: 1 1 I t :C :E
H gd ~ IP e~
H

g~
~:~ I
- IIC
z ~a o æ o E ~ t ~ I :3: 1 3 ~ ~ V 1-O`
O ~

~) Y ~o ~ æ 2 ~
~1 V
I

~3 ~? 9 1 1 ~ I I I I I
O ~ ~ 5~ ~ ~ ~ ~ ~ ~ D~4 3~ Z

~it.- 1 59 ~66~

Example 2 (intermediate) CH3 ~ gH3 C ~ 2 2 2 ~

(Compound VII-1) 12.1 g of hydroqui~one were dissolved in 60 ml of dry dimethylformamide, and while blowiny a stream of nitrogen yas into the solution, 31.7 g of potassium carbonate were added. The mixture was heated at 90C
for 1 hour whilst stirring. Then, the temperature of the mixture was lowered to 6QC, and 30 g of ~-(N-methylben-~ylamino)ethyl 2-bromopropionate were added dropwlse at this temperature. After ~he addition was completed, the mixture was stirred at 90C for 1 hour. It was cooled ,to room temperature, and poured into ice water. The mixture was adjusted to pH 7, and then extracted with 100 ml of chloroform. When the chloroform was e~aporated, 24.0 g of 2-(N-methylbenzylamino)ethyl 2-(4-hydroxy-phenoxy)propionate were obtained as a pale yellow vis-cous oil.

n25 = 1.5487 In substantially the same manner as described in Example 2, there were obtained the compounds o~ the formula lVII), which are shown in the followlng Table 2.

Nit-159 Table 2 Compound No. Compound o the invention 5VII) VII-2 2-(N-isopropylbenzylamino~ethyl 2-(4-hydroxy~
phenoxy)propionate VII-3 2-(N-methyl- ~-methylbenzylamino)ethyl 2-(4-hydroxyphenoxy)propionate YII-4 2-(N-methyl-2-æluorobenzylamino)ethyl 2-(4-hydroxyphenoxy)propionate VII-5 2-(N-allyl-4-chlorobenzylamino~ethyl 2-(4-hydroxyphenoxy)propionate VII-6 2-(N-methyl-4-methoxybenzylamino)ethyl 2-(4-hydroxyphenoxy)propionate VII-7 2-(N~isopropyl-3,4-dichlorobenzylamino)ethyl 2 (4-hydroxyphenoxy)propionate VII-8 2-(N-methyl-4-chlorobenzylamino)ethyl 2-(4-hydroxyphenoxy)propionate ~n25= 1.55137 VII-9 1-Methyl 2-(N-methylbenzylamino)ethyl 2~(4-hydroxyphenoxy)propionate VII 10 3-(N~methylbenzylamino)propyl 2-(4-hydroxy-phenoxy)propionate Example 3 c~3 ~ C~
F3C- ~ ~O~ CH~ Q-(~H2~2 ~ 2 ~Compound No. 1 Nit-1$9 ~96~

~ mixture of 25.4 g of 4-~4-trifluoromethylphenoxy)-phenol, 14.5 g of anhydrous potassium carbona~e, 30.0 g of 2-(N-methylbenzylamino~ethyl 2-bromopropionate and 150 ml of dry acetonitrile was refluxed ~or 3 hours whilst stirring vigorously. After the reaction was completed ~he acetonitrile was evaporated under reduced pressure.
~oluene (150 ml) was added to the residue, and the toluene layer wa~ washed succes~i~ely with a 10 % aqueous solution of sodium hydroxide and water~ When the toluene was evapo-rated under r~duced pressure, 41.6 g of 2 (N methyl-benzylamino~ethyl 2-~4-(4-trifluoromethylphenoxy~phenoxy7-propionate were obtained as a colorless oil.

n20 = 1.5350.

Example 4 &l ~ C~
C~ O~ ~ ~-C~-C~ 2~2~~ 2 (Compound No. 2~

A solution of 34.7 g of 2-~4-t3,5-dichl.oro-2-pyridyl oxy~phenoxy7propionyl chloxlde was added dropwise at 0 to 10C to a solution of 19.3 g of 2~N-isopropyl~enzyl-amino)ethanol and 10.1 g o triethylamlne. After the addition was completed, the mixture was stirred for 1 hour at 30 to 40C. The mlxtur~ was washed successively with a 1 ~ aqueous so~ution of sodium hydroxide and water, and then dried. When the toluene was evaporated Nit-159 ~ 31 ~

under reduced pressure, 45.8 g of 2-(N-isopropylbenzyl-amino)ethyl 2-L4-(3,5-dichloro-2-pyridyloxy)phenoxy7pro-pionat were obtained as a colorless viscous oil.

n20 = 1.5773.

Example 5 ~3 ~ ~3 F3C_ ~ o~ ~ O-C~-~c~ 2~2 (Compound No. 3) 32.9 g of 2-(N-methylbenzylamino)ethyl 2-(4-hydroxy-phenoxy)propionate were dissolved in 100 ml of dimethyl sulfoxide, and 15.2 g o potassium carbonate were added.
The mixture was heated at ~0C for 1 hour whilst stir-ring. Then~ 20.0 g of 2-chloxo-5-trifluoromethylpyridine were added dropwise at 80 to 90C. After the addition was completed the mixture was stirred at this temperature ~or 2 hours, and coaled to room temperature. The mix-ture was poured into ice watex, and extracted with chloro-form. The chloro~orm layer was dehydrated, and the chloro~orm was evaporated to give 37.5 g of 2-(N~methyl-benzylamino)ethyl 2-~4-~5-trifluoromethyl-2-pyridyloxy~-phenoxy7propionate as a pale yellow viscous oil.

n20 ~ 1.5360.

By substantially the same procedure as describedin Example 3 compounds Nos. 4, 5, 6, 7 and 8 were syn-thesized. Furthermore, compound Nos. 9 and 10 were Nit~1~9 --3 ~--prepared by substantiall~ the sa~e procedure as described in Example 4. Compound Nos. 11, 12, 13 and 14 were pre-pared by substantially the s~e procedure as described in Example 5. These compounds are shown in the following

5 Table 3.

~it-1 59

6~

~33--Tabl e 3 CH3 O ~1 ~2 X
Ar-O~ O-C~ o-CII(CH2)~ Ci1-(~ a (I~

Compound Ar R~ R3 ~ Jt Phy~ al No. ~ con~tant 4 P3C~ C ~ o ~ 1 H n2~ l.5336 ~3C ~ H -CH3 -C~3 1 H n20 l . 5364 6 F3C~ -CN3 . -CH3 12-F n~ l ~ 5292

7 F3C~ 2CH8CH2 8 1 ~ l n2~ 1~5426 f~l

8 Cl-~ H--CH3 H 1 ~ 20 l . 5793 C:l

9 Cl-~ H CH3 ~CH3 l H n20 1.5805 Cl Cl-~ t3~CH3 B 12-~ n20 1.5?43 ~1 11 Cl-~- H-CH2CH C112 li 14; Cl n20 l . S826 /Cl 12 Cl~ H -CH~ ~ 14~ 13 n20 l . 5835 Cl 13 Cl~ 3H7-iso 1~ 13,~-C:1;2n20 1.5829 14 F3C~ H3 H 1~-Cl n20 l o 5395 ~it-1 59 I~ ~ddition to the compounds shown in Table 3, the compounds shown i~ T~ble 4 below were al~o prepared in accordance with the ~oregoing Examples~

Table 4 Compound No. Compound o~ ~he invention 2~(N-methylbenz~lamino)ethyl 2-~4-(4-tri-fluoromethylphenoxy)phenoxy7propionate hydrochloride 16 2-lN-isopropylbenzylamino)ethyl 2 `L4- ( 3~5~
dichloro 2-pyridyloxy)phenoxy7propionate hydrochloride 17 1-methyl-2-(N-methylbenzylamino)ethyl 2-/4-(5-trifluoromethyl-2-pyridyloxy)phenoxy7 propionate 18 3-(N-methylbenzylamino)propyl 2-~4~(5-tri-luoromethyl-2-pyridyloxy)phenoxy7propionate 19 2-(N-methylbenzylamino~ethyl 2-/4-(3-chloro 5-trifluoromethyl-2-pyridyloxy)phenoxy7 propionate In the above Table 4, the compound Nos. 15 and 16 can be easily synthesized in a customary manner by treating Nit~159 the compound Nos. 1 and 2 of the invention with h~dro-chloric acid.
Example 6 Wettable powder:~
Fifteen parts of compound Wo. 1 of the invention, 80 parts of a 1:5 mixture of white carbon ~fine powder of hydrous amorphous silicon oxide3 and powdery clay, 2 parts of sodium alkylbenzenesulfonate, and 3 parts of a sodium alkylnaphthalene sulfonate/formaldehyde condensate were ground and mixed to form a wettable powder. The wettable powder was diluted with water before use.
Example 7 Emulsifiable concentrate:
Thirty parts of compound No. 2~ 55 parts of xylene, B parts of polyoxyethylene alkylphenyl ether and 7 parts of calcium alkylbenzenesulfonate were mixed with stir-ring to form an emulsifiable concentrate. The emulsifiable concentrate was diluted with water before use.
Example 8 Dust:
Two parts of compound No. 2 and 98 parts of powdered clay were pulverized and mixed to form a dusting agent.
Example 9 Dust:
2S 1.5 parts of compound No. 4, 0.5 part o~ isopropyl hydrogen phosphate and 98 parts of powdered clay were ground and mixed to ~orm a dusting agent.

Wit-159 6~

Example 10 Granules:
25 parts of water were added to, and thoroughly mixed with, a mixture of 10 parts of compound No. 5, 30 parts o~ bentonite (montmorillonite), 58 parts of talc and 2 parts of liqnin sulfonate. The resultant mixture was formed into granules having a size of 10 to 40 mesh by means of an extrusion-type granulator, and dried at 40 to 50C to form granules.
Example 11 Granules:
A rotary mixer was charged with 95 parts of clay mineral particles having a particle size dis~ribution .in the range of 0.2 to 2 mm, and, while rotating the mixer, 5 parts of compound No. 6 dissolved in an organic solvent were sprayed unifoxmly onto the clay mineral particles. The particles were then dried at 40 to 50C
to form granules.
The herbicidal activity of the compounds of the formula (I) is illustrated by the following biotest Examples.
The known comparison compound is identified as ~ollows:

Comparison (~

F3C ~ -O~ O-CH - C-O-(CH2)2-N ~

(known from German published specification ~DE OS) No.
26 17 804~.

Nit-159 -i6~4 ~xample 12 Pre emergence soil treatment for weeds and crops in upland fields:
Preparation of active compound:
Carrier: 5 parts by weight of acetone Emulsifier: 1 part by weight of benzyloxy polyglycol ether A preparation of the active compound was obtained as an emulsifiable concentrate by mixing 1 part by weight of the active compound with the aforesaid amounts of the carrier and the emulsifier. A predetermined amount of the preparation was obtained by dilution with water.
Testing method:
Field soils placed in 1,000 cm2 pots were respect-ively seeded with Arachis (peanut), Pisum (garden pea), Gossypium (cotton) and Glycine (soya-bean) in a gre~n-house, and covered with a soil mixed with seeds of A~ro pyron repens, Echinochloa crus-galli and Setaria lutescens in a depth of 1 cm. One day after the seeding;

10 ml of the above-prepared solution respectively con-taining 200 ppm of the active ingredient were sprayed uniformly to the soil surface layer of each test pot.
4 weeks after the treatment, the herbicidal effect and degree of phytotoxicity were evaluated on a scale of from 0 to 10 in accordance with the following stan-dards.
The herbicidal effect was evaluated as follows in comparison with an untreated control.

Nit-159 6~

Rating Weed-kill ratio based on the control 10 : 100 % (withered) 9 : at least 90 % but less than 100 %
8 : at least B0 % but less than 90 ~
7 : at leask 70 % but less than 80 %
6 : at least 60 % bu~ le55 than 70 %
5 : at least 50 % but less than 60 %
4 : at least 40 % but less than 50 %
3 : at lPast 30 ~ but less than 40 %
2 : at least 20 % but less than 30 %
1 : at least 10 % but less than 20 %
0 : less than 10 % (not effective) The phytotoxicity towards the crops was evaluated as follows in comparison with the untreated control~
15Rating Phytotoxicity rate in comparison with the control 10 : at least 90 % (fatal damage~
9 : at least ~0 ~ but less than 90 %
8 : at least 70 % but less than 80 7 ~ at least 60 % but less than 70 %
6 : at least 50 % but less than 60 %
5 : at least 40 % but less than 50 %
4 : at least 30 % but less than 40 %
3 : ~t least 20 % but less than 30 %
2 : at least 10 % but less than 20 %
25 'I : more than 0 % but less than 10 0 : 0 % (no phytotoxici.ty) The test results are given in Table 5.

Nit-159 1~6~

æ

O O ~ O g~ e ~
o t,q ~ ~ ~ O ~ O O O
.
O C
O . ~ ~
~ b O O C3 0 Ci O
s e~ ~
,~
~D O e:~ o o O O O Q O
J
V

~ ~ rC

e, ~ o o c~ o 0 J ~ a '9 ~ ~ ~ ~

~n o e~ c:P o o S
A _I ~ ~1 ~4 ._1 ~ fl~
.C ~ N
~' tr O O cg ca ID C:~
E ~1 4 1 ~_ sC O ~ .~
C

C d O ¢
~æ ~., Nit-l 59 66~

Example 13 Foliage-treating test for weeds and crops in upland fields:
Field soils placed in 2,000 cm2 pots were respect-ively seeded with Glycine (soya bean], Rephanus (radish), and Beta (beet), and covered with a soil mixed with seeds of Echinochloa crus~galli, Eleusine indica, Setaria viridis, Avena fatua and Alopecurus aequalis var.
amurensis Ohwi in a depth of 1 cm. 10 days after seeding (when weeds were on the average in a second leaf stage and when Glycine, Rephanus and Beta were in the initial stage of normal leaf-growing period), 20 ml of the solu-tions prepared as in Example 12 and respectively containing 500 ppm, of the active ingredient were uniformly sprayed to the leaves of the plants to be tested.
3 weeks after the treatment, the herbicidal effect and degree of phytotoxicity were evaluated in the same manner as in Example 12.
The test results are shown in Table 6.

~it-159 ~ o o ~ C~ o 3.~
~ ~ .~c o o ~ o ~ o V
e O C~ 13 ~ O O O
o o ~ ~ o ~.
i~ o ~ ~ c~ ~ oc~

W
~r o C:9 ~ o ~ oc~
o .
I
~ o o o ~ ,la ~ ~ ~ ~
O

c ~c ~o ~ C O O O ~1 0 ~ Q ~~1 1 a .~q a a~ ~
S: '10 r ~
,.
~, .C
a~ ~
o ~ ~ o c~~ o d O
n t~
t . ~ ~,, ~

~' _ o o o o e~ oo o c~
C ~ ~ ~ 1 U
o C~ o o o ~ c~
e ~

~ ~4 ~

Nit-1 59 6~

Example 14 Herbicidal and regrowth-control test for Cynodon dactylon Persoon Upland field where Cynodon dactylon Persoon was gregarious was divided into 1 m2 sections, and 100 ml portions of solutions prepared as in Example 12 and respectively containing 100 ppm of the active ~ngre-dient were sprayed to the foliage of Cynodon dactylon Persoon in each section. Twenty days after the treat-ment, the herbicidal effects were evaluated in the same manner as in Example 12. Further the e~ect of control-ling regrowth of Cynodsn dactylon Persoon was evaluated 40 days and 80 days after the treatment in accordance with the following standards:
15 Rating Regrowth-control ratio based on untreated section 10 : lO0 ~ ~complete control o~ regrowth) 9 : at least 90 % but less than 100 %
8 : at least 80 % but less than 90 %
7 : at least 70 % but less than 80 %
6 : at least 60 % but less than 70 %
S : ~ at least 50 ~ but less ~han 60 %
4 : at least 40 % but less than 50 %
3 : at least 30 % but less than 40 %
2 : at least 20 % but less than 30 %
1 : at least 10 ~ but less than 20 %
0 : less than 10 % ~no regrowth-control effect) The results are shown in Table 7.

Nit-159 6~9~

~ble 7 ~r~ ld2l1 Regrowth control e~f~ect Effect un'c O~ tl~
~f oclt~ 20 d~y~ 40 6!1~y~ IIO d~ay~
S:o~pound ingrsdl~lsnlt ~ P ~ f t~ar NoO ~ ~c53 /h~ ~pr~yln5~ ~pr~yir~ 3praying 2 ~ O
3 O.l 1~
0.1 . lO lû
6 O.l jl,O 1~ !!i9 a 0.1 1~
O.l 1~ lO 9 1~ 0.1 1 14 0.1 Co~p~r~r (A- 1 ) Not~: Co~p~r~on (A~ th~ at ind~t@cl ln T~bl.o 5 ~it-1 59

Claims (18)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A substituted phenoxypropionic acid ester of the formula (I) in which Ar represents a radical of the formula or in which Y represents a halogen atom or a trifluoromethyl group and b represents 1 or 2, the group Y being the same or different when b is 2, R1 and R3, independently of each other, each represent a hydrogen atom or a methyl group, R2 represents a lower alkyl group or a lower alkenyl group, X represents a hydrogen atom, a halogen atom or a lower alkoxy group, m represents 1 or 2, and a represents 1 or 2, the groups X being the same or different when a is 2.

2. A substituted phenoxypropionic acid ester according to claim 1 in which Ar represents a radical of the formula or in which Y represents fluorine, chlorine, bromine or trifluoromethyl and b is 1 or 2, the group Y being the same or different when b is 2, R1 and R3, independently of each other, each represent a hydrogen atom or a methyl group, R2 represents alkyl with 1 to 4 carbon atoms, or represents al-kenyl with 2 or 3 carbon atoms X represents hydrogen, fluorine, chlorine, bromine or alkoxy with 1 to 4 carbon atoms, m represents 1 or 2, and a represents 1 or 2, the groups X being the same or different when a is 2.

3. A substituted phenoxypropionic acid ester according to claim 2 in which R2 represents methyl, ethyl, propyl, isopropyl, n-butyl, iso-butyl, sec.-butyl, tert.-butyl, or vinyl, allyl or 1-propenyl, X represents hydrogen, fluorine, chlorine, methoxy, ethoxy, pro-poxy, isopropoxy, n-butoxy, iso-butoxy, sec.-butoxy or tert.-butoxy.

4. 2-(N-methylbenzylamino)ethyl 2-[4-(3,5-dichloro-2-pyridyloxy) phenoxy]propionate of the formula

5. 2-(N-methylbenzylamino)ethyl 2-[4-(5-trifluoromethyl-2-pyridyl-oxy)phenoxy]propionate of the formula

6. 2-(N-methyl-2-fluorobenzylamino)ethyl 2-[4-(4-trifluoromethyl-phenoxy)phenoxy]propionate of the formula

7. A process for the preparation of a substituted phenoxypropionic acid ester of the formula (I) defined in claim 1, characterised in that a) a compound of the formula ( I I ) in which Ar has the meanings given in claim 1, and M represents a hydrogen atom or an alkali metal atom, is reacted with a compound of the formula (III) in which R1, R2, R3, X, a and m have the meanings given in claim 1, and Z1 represents a halogen atom, or b) a compound of the formula (IV) in which Ar has the meaning given in claim 1, Z2 represents a hydroxyl group or a halogen atom, is reacted with a compound of the formula (V) in which R1, R2, R3, X, a and m have the meanings given in claim 1, or c) a compound of the formula Ar-Z1 (VI) in which Ar has the meaning given in claim and Z1 has the meaning given above, is reacted with a compound of the formula (VII) in which R1, R2, R3, X, a and m have the meaning given in claim 1 and M
has the meaning given above.

8. A method of combating weeds which comprises applying to the weeds or to their habitat a herbicidally effective amount of a compound accord-ing to claim 1.

9. A method according to claim 8 wherein the compound is applied in the form of a composition containing said compound as active ingredient in admixture with a suitable carrier or diluent.

10. A method according to claim 9 wherein the active ingredient concentration in said composition is between 0.005 and 95 % by weight.

11. A method according to claim 9 wherein the active ingredient con-centration in said composition is between 0.05 and 60 % by weight.

12. A method according to claim 8, 9 or 11 wherein the compound is applied as a pre-emergence herbicide.

13. A method according to claim 8, 9 or 11 wherein the compound is applied as a post-emergence herbicide.

14. A method according to claim 8, 9 or 11 wherein the compound is applied to an area of cultivation at a rate of between 0.01 and 2 kg/ha.

15. A method according to claim 8, 9 or 11 wherein the compound is applied to an area of cultivation at a rate of between 0.05 and 1 kg/ha.

16. A method according to claim 8, 9 or 11 wherein such compound is 2-(N-methylbenzylamino)ethyl 2-[4-(3,5-dichloro-2-pyridyloxy)phenoxy]propionate.

17. A method according to claim 8, 9 or 11 wherein such compound is 2-(N-methylbenzylamino)ethyl 2-[4-(5-trifluoromethyl-2-pyridyloxy)phenoxy]
propionate.

18. A method according to claim 8, 9 or 11 wherein such compound is 2-(N-methyl-2-fluorobenzylamino)ethyl 2-[4-(4-trifluoromethylphenoxy)phenoxy]
propionate.