CA1133502A - Herbicidal esters of 4-trifluoromethyl 3'-carboxy-4'nitro diphenyl ethers - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
The present invention as disclosed provides novel diphenyl ethers having the formula

Description

~133502 HERBICIDAL ESTERS OF 4-TRIFLUOROMETHYL-3'-CARBOXY-4'-NITRO` DIPHENYL ETHERS
.:
Compounds of the formula /~ ,~' `; ' y X ' - 1 ~
' ~O~ `. .' ~ CO2~(CHR ) (CHR2) ,03 R3 5wherein X is a hydrogen atom, a halogen atom, a trihalomethyl group, an alkyl group, or a cyano group, Y is a hydrogen atom or a halogen atom, :
Rl is a hydrogen atom or an alkyl group, R is a hydrogen atom or an alkyl group, -lOR3 is a hydrogen atom or an alkyl group, m is an integer of 1 to 50, and ~:~
n is an integer of 0 to 6, n' is an integer of 0 to 6, provided that the sum of : : :
n and n' is an integer of 2 to 6, .~ . :
15and compositions containing these compounds exhibit herbici-dal activity.

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The Disclosure This invention relates to novel compounds which show activity as herbicides, to novel herbicidal compositions which contain these compounds, and to new methods of con-trolling weeds with these herbicidal compositions.
Certain diphenyl ethers have been shown to be effec-tive weed control agents. However, the herbicidal effec-tiveness of a given diphenyl ether cannot be predicted from an examination of the substituent groups attached to the phenyl rings in the ether, and o~ten quite closely related compounds will have quite different weed control abilities.
Various diphenyl ethers may have overlapping or complementary areas of activity or selectivity, and can thus be useful in combination to control a variety of weeds upon application `;
of a single composition. Furthermore, the diphenyl ethers - ~
hereto~ore disclosed as herbicides are not completely effec- ~`
tive. An ideal herbicide should give selective weed control, over the full growing season, with a single admin~
istration at low rates of application. It should be able ;
to control all common weeds by killing them as the seed, the germinating seed, the seedling, and the growing plant. At the same time, the herbicide should not be phytotoxic to the crops to which it is applied and should decompose or otherwise be dissipated so as not to poison the soil perman-ently. The known diphenyl ether herbicides fall short of these ideals, and it would thus be desirable to have new herbicides which show even more selective control of. unde-sirable plants among desirabIe crop plants or which complement ~;
known herbicides in activity.
In accordance with the present invention, there 1s . . .

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~133SOZ

provided a new class of novel diphenyl ethers ha~ing the formula _ CF3 I \X ;~ ~
O (I) NO CO2[(CHRl) (CHR2)n,o]mR3 wherein X is a hydrogen atom, a halogen atom, preferably a :
fluorine atom or a chlorine atom, a trihalomethyl group, preferably a trifluoromethyl group, an alkyl group, preferably havlng 1 to 4 carbon atoms, - ~.
most preferably a methyl group, or a cyano group, Y is a hydrogen atom or a halogen atom, preferably a fluorine atom or a chlorine atom, R is a hydrogen atom or a (Cl-C4)alkyl group, prefer-ably a methyl group~
R is a hydrogen atom or a (Cl-C4)alkyl group, prefer~
ably a methyl group, R3 is a hydrogen atom or a (Cl-C4)alkyl group, pre~er-ably a methyl group, m is an integer of 1 to S0, and preferably is 1 to 2, -.
n is 0 or an integer o~ 1 to 6, .
n' is 0 or an integer o~ 1 to 6, provided that the sum ;`
o~ n and n' is an integer of 2 to 6, preferably 2. -::~
~hen the X, R , R , or R substituent is an alkyl group, it can have elther a straight- or branched-chain configuration.

..

These novel compounds have been ~ound to show unex-pected activity as weed control agents. In a preferred embod-iment of the invention, X is a halogen atom, most preferably a chlorine atom, Y is a hydrogen atom or a halogen atom, preferably a chlorine atom, and either Rl or R2 is a hydrogen atom. Most preferably both Rl and R2 are hydrogen atoms.
Examples of the compounds of the invention embraced by Formula I include:

2-Chloro-4-trifluoromethyl-3'-(2-methoxy)ethoxycarbonyl-4'-nitrodiphenyl ether 2-Chloro-4-trifluoromethyl-3'-(2-hydroxy)ethoxycarbonyl-4'-ni;trodiphenyl ether 4-Trifluoromethyl-3'-(~-methoxypentaethoxy)carbonyl-4'-nitrodiphenyl ether 2-Bromo-4-trifluoromethyl-3'-(~-hydroxypentaethoxy)carbonyl-4'- `
nitrodiphenyl ether ~ ;
2,4-Bis-trifluoromethyl-3'-(~-hydroxydecaethoxy)carbony1-4'-nitrodiphenyl ether 2,6-Dichloro-4-trifluoromethyl-3'-(~-hydroxydecaethoxy)carbon-yl-4'-nitrodiphenyl ether 2-Fluoro-6-chloro-4-trifluoromethyl-3'-(~-propoxypentadeca-ethoxy)carbonyl-4'-nitrodiphenyl ether ~`
2-~ethyl-4-trifluoromethyl-3'-(~-hydroxypentaedecaethoxy)-carbonyl-4'-nitrodiphenyl ether ~`
25 2-Cyano-4-trifluoromethyl-3'-(~-isobutoxypentadecaethoxy)- ~ ~ -carbonyl-4'-nitrodiphenyl ether ~ ;
2-Iodo-4-trifluoromethyl-3'-'w-t-butoxyeicosaethoxy)carbonyl-4'-nitrodiphenyl ether 4-Trifluoromethyl-3'-t~_hydroxyeicosaethoxy)carbonyl-4'-3o nitrodiphenyl ether 2-Chloro-4-trifluoromethyl-3'-tw-methoxypentaethoxypentato-methyl)ethoxy)carbonyl-4t-nitrodiphenyl ether 2-Chloro-4-trifluoromethyl-3'-tw-hydroxyhexamethylene)oxy-carbonyl-4'-nitrodiphenyl ether 5 4-Trifluoromethyl-3'-t2-methoxypropoxy)carbonyl-4'-nitro-diphenyl ether 2-Fluoro-6-bromo-4-trifluoromethyl-3'-t3-ethyl-4-ethoxy-butoxy)carbonyl-4'-nitrodiphenyl ether _4_ - .

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The novel diphenyl ethers of the invention are use~ul both as preemergence and as postemergence herbicides. Preemer- -gence herbicides are ordinarily used to treat the soil in WhiCh the desired crop is to be planted b~ applicatio .' / :

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either before seeding, during seeding, or, as in most appli-cations, after seeding and before the crop emerges. Post-emergence herbicides are those which are applied after the plants have emerged and during their growth period. Com-5 pounds of the invention are particularly active againstbroadleaf weeds.
Among the crops on which the diphenyl ethers of the invention can be advantageously employed are, for example, soybeans, corn, wheat, barley, rice and other cereal crops, and the like.
I~hen used in transplanted rice crops, the ethers can be applied either preemergence or postemergence to the ;
weeds -- that is, they can be applied to the growth medium of the transplanted plants either before the weed plants have emerged or while they are in their early stages of growth.
The ethers can be applied to the growth medium either be`fore ;
or after the rice has been transplanted to that medium. -~
The diphenyl ethers of the invention can be applied in any amount which will give the deslred degree of weed control. A preferred rate of application of the herbicides of the invention is from about 0.1 to about 12, and most preferably about 0.25 to 4, pounds of the diphenyl ether per ;
acre.
Under some conditions, the diphenyl ethers of the invention may be advantageously incorporated into the soil or other growth medium prior to planting a crop. This incorporation can be carried out by any convenient means, including by simple mixing with the soil, by applying the diphenyl ether to the surface of the soil and then disking or dragging into the soil to the desired depth, or by ` ~133S02 employing a liquid carrier to accomplish the necessary penetration and impregnation.
A diphenyl ether of the invention can be applied to the growth medium or to plants to be treated either by 5 itself or, as is generally done, as a component in a herbi-cidal composition or formula~ion which also comprises an agronomically acceptable carrier. By agronomically-acceptable ;
carrier is meant any substance which can be used to dissolve, disperse, or diffuse a herbicidal compound in the composition without impairing the effectiveness of the herbicidal com-pound and which by itself has no detrimental effect on the soil, equipment, crops, or agronomic environment. Mixtures of the diphenyl ethers of the invention may be used in any ol these herbicidal formulations. The herbicidal compositions of the invention can be either solid`or liquid formulations or solutions. For example, the diphenyl ethers can be formulated as wettable powders, emulsifiable concentrates, dusts, granular formulations, aerosols, or flowable emulsion concentrates. In such formulations, the compounds are exten-ded with a liquid or solid carrier and, when desired, suitable surfactants are incorporated. ~ `
It is usually desirable, particularly in postemer-gence applications, to include adjuvants, such as wetting agents, spreading agents, dispersing agents, stickers, adhes-ives, and the like, in accordance with agricultural practices.Examples of ad;uvants which are commonly used in the art can be found in the John W. McCutcheon, Inc. publication "Deter-gents and Emulsifiers Annual." ~
The diphenyl ether compounds of this lnvention can ~ :

be formulated in any appropriate solve~it. Examples of ',: ~' ' solvents which are useful in ~he practice of this invention include wa~er, alcohols, ketones, aromatic hydrocarbons, halogenated hydrocarbons, dimethylformamide, dioxane, dimethyl sulfoxide, and the like. Mixtures of these solvents can also be used. The concentration of the solution can vary from about 2~ to about 9800 with a preferred range being about 25~ `~
~o about 75%.
For the preparation of emulsifiable concentrates, ~`
the diphenyl ether can be dissolved in organic solvents, ~ ~
such as benzene, toluene, xylene, methylated naphthalene, ;
corn oil, pine oil, o-dichlorobenzene, isophorone, cyclo-hexanone, methyl oleate, and the like, or in mixtures of these solvents, together with an emulsifying agent which ~ermits dispersion in water. Suitable emulsifiers include, for example, the ethylene oxide derivatives of alkylphenols or long-chain alcohols, mercaptans, carboxylic acids, and reactive amines and partially esterified polyhydric alco- -~
hols. Solvent-soluble sulfates or sulfonates, such as the alkaline earth salts or amine salts of alkylbenzenesulfonates ~ -~
and the fatty alcohol sodium sulfates, having surface-active ;~ ~
properties can be used as emulsifierS either alone or in ; ~ -conjunction with an ethylene oxide reaction product. Flow-able emulsion concentrates are formulated similarly to the emulsifiable concentrates and include, in addition to the above components, water and a stabilizing agent such as a water-soluble cellulose derivative or a water-soluble salt of a polyacrylic acid. The concentration of the active ingredient in emulsifiable concentrates is usually about 10%
to 60~ and in flowable emulsion concentrates, this can be ~,;
3G as high as about 75%.

il3350Z

l.~ettable powders suitable for spraying, can be prepared by admixing the compound with a finely divided solid, such as clays, inorganic silicates and carbonates, and silicas and incorporating T,~etting agents, sticking agents, 5 and~or dispersing agen~s in such mixtures. The concen-tration of active ingredients in such formulations is usually in the range of about 20% to 98~, preferably about 40~ to 75%. A dispersing agent can constitute about 0.5~, to about

3% of the composition, and a wetting agent can constitute from about 0.1% to about 5% of the composition.
. Dusts can be prepared by mixing the compounds of the invention with finely divided inert solids which may be organic or inorganic in nature. Materials useful for this purpose include, ~or example, botanical flours, silicas, ':

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~3350Z
~`
carbonates and clays. One convenient method of preparing a dust is to dilute a wettable powder with a finely divided carrier.
Dust concentrates containing about 20% to 80% of the active ingredient are commonly made and are subsequently diluted to about 1% to 10~i use concentration.
Granular formulations can be prepared by impregnating a solid such as a granular fuller's earth, vermiculite, ground corn cobs, seed hulls, including bran or other grainhulls, or~ ~
similar material. A solution of one or more of the diphenyl ;
10 ethers in a volatile organic solvent is then removed by evapora~ -~
tion. The granular material can have any suitable size, with a preferable size range of 16 to 60 mesh. The diphenyl ether will usually comprise about 2 to 15% of the granular formulation. `~
The diphenyl ethers of the invention can also be mixed with fertilizers or fertilizing materials before their applica~
tion. In one type of solid fertilizing composition in which the diphenyl ethers can be used, particles of a fertilizer or ~ `
fertilizing ingredients, such as ammonium sulfate, ammonium nitrate, or ammonium phosphate, can be coated with one or more `~
of the ethers. The solid diphenyl ethers and solid fertilizing material can also be admixed in mixing or blending equipment, or they can be incorporated with fertilizers in granular formu- `~
lations. Any relative proportion of diphenyl ether and ferti-lizer can be used which is suitable for the crops and weeds to 25 be treated. The diphenyl ether will commonly be from about 5% ~ i to about 25% of the fertilizing composition. These composi-tions provide fertilizing materials which promote the rapid growth of desired plants, and at the same time control the ;
growth of ~ `
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'`': :. ' _ 9 _ ~ "' ~1335~

undesired plants.
The diphenyl ethers o~ the invention can be applied 2S herbicidal sprays by methods commonly employed, such as conventional high-gallonage hydraulic sprays, low gallonage sprays, airblast spray, aerial sprays and dusts. For low volume applications a solution of the compound is usually used. The dilution and rate o~ application will usually ~ -depend upon such factors as the type of equipment employed, the methods o~ application, the area to be treated and the type and stage of development o~ the weeds.
For some applications, it may be desirable to add one or more other herbicides along with diphenyl ethers of ` "
the invention. Examples of other herbicides which can be incorporated to provide additional advantages and e~fective-ness include:
` ~arboxyl`i`c Acid`s and Derivat`ives -2,3,6-trichlorobenzoic acid and its salts 2,3,5,6-tetrachlorobenzoic acid and its salts 2-methoxy-3,5,6-trichlorobenzoic acid and its salts 2-methoxy-3,6-dichlorobenzoic acid and its salts 2,3-dichloro-6-methylbenzoic acid and its salts 2,4-dichlorophenoxyacetic acid and its salts and esters ~ ~;
2,4,5-trichlorophenoxyacetic acid and its salts and esters 2-methyl-4-chlorophenoxyacetic acid and its salts and esters~

2-(2,4,5-trichlorophenoxy)propionic acid and its salts and esters -

4-(2,4-dichlorophenoxy)butyric acid and its salts and esters 4-(2-methyl-4-chlorophenoxy)butyric acid and its salts and esters 30 2,3,6-trichIorophenylacetic acid and its salts ~
3,6-endoxohexahydrophthalic acid ~ `
,;

: ., ~
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- . .

~ dimethyl 2,3,~,6-tetrachloroterephthalate trichloroacetic acid and its salts . .
2,2-dichloropropionic acid ancl its salts 2,3-dichloroisob`utyric acid and its salts Carbamic Acid Derivatives ethyl N,N-di(n-propyl)thiolcarbamate propyl N,N-di(n-propyl)thiolcarbamate . ;~
ethyl N-ethyl-N-(n-butyljthiolcar~amate propyl N-ethyl-N-(n-butyl)thiolcarbamate 2-chloroallyl N,N-diethyldithiocarbamate :
N-methyldithiocarbamic acid salts ~.
ethyl l-hexamethyleneiminecarbothiolate : :
isopropyl N-phenylcarbamate isopropyl N-(_-chlorophenyl)carbamate 4-chloro-2-butynyl N-(m-chlorophenyl)carbamate methyl N-(3,4-dichlorophenyl)carbamate ` ~

: ~ '` ``, Phenols dinitro-o-(sec-butyl)phenol and its salts pentachlorophenol and its salts Substituted Ureas ;
3-t3,4-dichlorophenyl)-1,1-dimethylurea 3-phenyl~ dimethylurea 3-(3,4-dichlorophenyl)-3-methoxy-1,1-dimethylurea - 3-(4-chlorophenyl)-3-methoxy-1,1-dimethylurea 3-(3,4-dichlorophenyl)-1-n-butyl-1-methylurea 3-(3,4-dlchlorophenyl)-1-methoxy-1-methylurea .`
3-(4-chlorophenyl)-1-methoxy-1-methylurea 3-(3,4-dlchlorophenyl)-1,1,3-trimethylurea :
.~

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3-(3,4-dichlorophenyl)-1,1-diethylurea dichloral urea Substitut'ed Triaz'i`nes 2-chloro-4,~-bis(ethylamino)'-s-triazine 2-chloro-4-ethylamino-6-isopropylamino)'-s-triazine 2-chloro-4,6-bis(methoxypropylamino)'-s-triazine 2-methoxy-4,6-bis(isopropylamino~'-s-triazine ' 2-chloro-4-ethylamino-6-(3-metnoxypropylamino)'-s-triazine 2-methylmercapto-4,6-bis(isopropylamino)'-s-triazine 2-methylmercapto-4,6-bis(ethylamino)'-s-triazine 2-meihylmercapto-4-ethylamino-6-isopropylamino-s-triazine 2-chloro-4,3-bis(isopropylamino)'-s-triazine ;~
2-methoxy-4l6-bis(ethylamino)-s-triazine 2-methoxy-4-ethylamino-6-isopropylamino-s-triazine 2-methylmercapto-4-~2-methoxyethylamino)-6-isopropyoamino-s- ~' triaæine .
D`iphenyl` Ether Derivat`ives 2,4-dichloro-4'-nitrodiphenyl ether 2,4,6-trichloro-4'-nitrodiphenyl ether 2,4-dichloro-6-~luoro-4'-nitrodiphenyl ether 3-methyl-4'-nitrodiphenyl ether ~-~
3,5-dimethyl-4'-nitrodiphenyl ether 2,4'-dinitro-4-tri~luoromethyldiphenyl ether 2,4-dichloro-3'-methoxy-4'-nitrodiphenyl ether 2-chloro-4-tri~luoromethyl-3'-ethoxy-4'-nitrodiphenyl ether 2-chloro-4-tri~luoromethyl-4'-nitrodiphenyl ether :
2-chloro-4-trifluoromethyl-3'-carbethoxy-4'-nitrodiphenyl ether :~
2,4-dichloro-3'-carbomethoxy-4'-nitrodiphenyl ether ' .. .. .. : :.
''Anilid'es '' : :' N-(3,4-dichlorophenyl)propionamide -12~

1~33502 N-(3,4-dichlorophenyl)methacrylamide ~ :
N-(3-chloro-4-methylphenyl)-2--methylpentanamide N-(3,4-dichlorophenyl)trlmethylacetamide N-(3,4-dichlorophenyl)-a~-dimeth.vlvaleramide N-isopropyl-N-phenylchloroacetamide :;
N-n-butoxymethyl-N-(2,6-diethylphenyl)chloroacetamide :~
N-n-methoxymethyl-N-(2,6-diethylphenyl)chloroacetamide ' Uracïls

5-bromo-3-s-butyl-6-methyluracil -~
5-bromo-3-c~ lchexyl-1,6-dimethyluracil 3-cycl'ohexyl-5,6-trimethyleneuracil :: .
5-bromo-3-isopropyl-6-methyluracil ~;
3-tert-butyl-5-chloro-6-methyluracil ' Nitriles 2,o-dichlorobenzonitrile ~.
diphenylacetonitrile ~ ;
3,5-dibromo-4-hydroxybenzonitrile ~ :
- 3,5-diiodo-4-hydroxybenzonitrile '~'~
Other OrGanic Herbicldes O
2-chloro-N,N-diallylacetamide :
N-(l,l-dimethyl-2-propynyl)-3,5-dichlorobenzamide ~
maleic hydrazide :' 3-amino-1,2,4-triazole '' monosodium methanearsonate :~
disodium methanearsonate `~
N,N-dimethyl-a,a-diphenylacetamide N,N-di(n-propyl)-2,6-dinitro-4-tri~luoromethylaniline ~ "
N,N-di'(n-propyl)-2,6-dinitro-4-methyl~niline N,N-di'(n-propyl)-2,6-dinitro-4-methylsulfonylaniline :
0-(2,4-dichlorophenyl)-0-methyl-isopropylphosphoramido-thioate :~

-13- ~': `'' il33502 4-amino-3,5,5-trichloropicolinic acid 2,3-dichloro-1,4-naphthoquinone di(methoxythiocarbonyl)disullide 3-isopropyl-lH-2,1,3-benzothiadiazin- (4)3H-one-2,2-dioxide ~. .

6,7-dihydrodipyrido[1,2-a:2~,1'-c~pyrazidinium salts 1,1'-dimethyl-4,4'-bipyridinium salts 3,4,5,6-tetrahydro-3,5-dimethyl-2-thio-2H-1,3,5-thiadiazine. :

4-~mino-6-(1,1-dimethylethyl)-3-methylthio-1,2,4-triazin-5-(4H)-one 3-Amino-2,5-dichlorobenzoic acid N3, ~3-Diethyl-2,4-dinitro-6-trifluoromethyl-1,3-phenylene- :.
diamine N-(2-chloroethyl)-2,6-dinitro-M-propyl-4-trifluoromethyl-aniline ~ .

5 N-Cyclopropylmethyl-a,~,~trifluoro-2,6-dinitro-N-propyl-_-toluidine N-(l-Ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine ~ ~ -S-(0,0-diisopropyl)phosphorodithioate ester of N-(2-mercapto- :
ethyl)benzenesulfonamide `~

20 2-(-Naphthoxy)-r~,N-diethylpropionamide ~ .

2-Chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methyl- ~:
ethyl)acetamide Methylsulfanilylcarbamate 3-(p-(p-Chlorophenoxy)phenyl)-l,l-dimethylurea .
.
Phosphonomethylglycine Methyl 2-(4-(2,4-dichlorophenoxy)phenoxy)propionate -Methyl 2-(4-(4-tri~luoromethylphenoxy)phenoxy)propionate When mixtures of herbicides are employed, the relative propor- `~
tions which are used will depend upon the crop to be treated 30 and the degree of selectivity in weed control which is .
desired.
:-The ethers of the invention can be prepared by ester- . ~
ification or transesterification of a diphenyl ether of the ~ :

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formula y I X ` ':.
o (II) ~ ~'` ~"
¦ COOR

wherein X and Y are as defined above, and R is a hydrogen ~ -atom or an alkyl group, or of the corresponding acid chloride, ; ;~
with an alcohol of the formula Ho-[(cHRl)n(cHR2)n~o]mR3 (III) wherein Rl, R2, R3, m, n and n' are as defined above. One ~
method which is commonly used for preparing the carbinols of Formula III is the polymerization or copolymerization of the ~ . ,~. .
corresponding alkyleneoxides by conventional techniques.
The esterification is generally carried out at a temperature of about 0 to about 200C, and preferably at about 100 to about ~`; ;
:;-;:: . ~ .
150C, optionally in the presence of an inert organic solvent, `

15 such as a hydrocarbon or chlorinated hydrocarbon. In the ~ `~
., .~
esterification reaction, one equivalent of the alchohol is ` ~ -generally employed, although excess alcohol can be used as a solvent in the reaction. When the acid chloride is used as the reagent, an acid scavenger may be used. Typical acid scavengers include inorganic bases, such as potassium hydrox-ide, and amines, such as 2,6-lutidine, and the like.

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.~ , ~L133502 The free acid can also be esterified using a tri-alkylorthoformate, without any additional acid catalyst.
Other conventional esterification techniques, such as trans~
esterification in the presence of an acid catalyst and the like, can also be used.
A modification of the above preparative method for preparing the esters of the invention involves the reaction . .
of a metal salt, such as the sodium salt, of an acid of Formula II with a halide of the formula ;~
Hal[(CHRl)n(CHR2)n,O]mR3 (IV) where Rl-, R2, m, n, and n' are as defined above and Hal is a halogen, preferably chlorine or bromine, atom. This reac-tion is generally carried out at a temperature of about 0 to about 200C, preferably about lO0 to about 150C, and in 15 an inert organic solvent, such as benzene or toluene. ~ `
The diphenyl ether precursors can be prepared by reacting a suitably substituted phenol, or the potassium or sodium salt of the phenol, with a suitably substituted halo- ` ;
benzene, such as a chloro- or fluorobenzene in the presence of an alkaline agent. Such precursors and their preparation are described in U.S. 3,928,416, of Bayer et al., granted December 23, 1975, Another route to the compounds of the invention involves the nitration of a diphenyl ether of the fo ~ ;
~ '~"' ,,''' .

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1~33502 - lF3 ;~

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Y X (V) .-J~ ",.

C02[(CHRl)n(CHR2) ,o~mR3 wherein X, Y, and Rl, R2, R3, m, n and n' are as defined above, -using typical nitrating agents such as potassium nitrate in sulfuric acid, acetyl nitrate, mixed sulfuric acid/nitric acid, nitrosonium tetrafluoroborate, and the like. The nitra~
tion reaction is generally carrled out at about -20 to about 100C, preferably about O to about 5C, optionally in the ~;
.. ..
presence of an inert organic solvent, such as methylene ~`
chloride or other chlorinated hydrocarbon.
Ethers of the invention can also be prepared by condensing a phenol of the formula ~ (VI) Y OH X ~

wherein X and Y are as defined above with a substituted halo- ; `
benzene of the formula ~;~
. , -17_ `

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~133502 xl _ I o I (VII) i- ~
~- "
¦ \Co2[(CHRl)n(CHR2)n,o~mR3 2 ~ ;
wherein Xl is a halogen atom, preferably a fluorine atom, `;
and Rl, R , R3, m, n and n' are as defined above. This reac- -tion is generally carried out at a temperature of about 0 to ;
about 250C, preferably about 75 to about 200C, optionally in the presence of an appropriate solvent, such as sulfolane, dimethylsulfoxide, dimethylformamide, hexamethylphosphoroustri-amide, or other inert polar organic solvent. ;~
The following examples will further illustrate this invention but are not intended to limit it in any way. `-~
In Table I, tYpical diphenyl ethers of the invention are listed with their elemental analyses. A specific illustra~
tive preparation of the compounds of Examples 2 and 4 are set forth before Table I. All temperatures are in degrees Celsius and parts and percentages are by weight unless other-wise indicated. -~
Example 2 Preparation of 2-Chloro-4-trifluoromethyl-3'-t2-methoxy)-ethoxYcarbonYI-4~-nitrodiphenyl ether a. Preparation of 2-methoxyethyl-m-fluorobenzoate A solution m-fluorobenzoyl chloride (15.8 g. 0.1 mole) and 2-methoxyethanol (8.4 g. 0.11 mole) is heated in `~
glyme (100 ml.) for 8 hours at 60C. The solvent is removed under reduced pressure and the residue distilled to give 9.3 g. f 2-methoxyethyl-_-fluorobenzoate, b.p. 70-75C/0.2 mm.

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~133502 ` b. Preparation of 2-methoxyethyl-5-fluoro-2-; nitrobenzoate 2-MethoxyethyI-_-fluorobenzoate (9.3 g. 0.047 mole) is added dropwise at 5C to concentrated sulfuric acid (100 ml). A solution of potassium nitrate (4.7 g. ;~

0.047 mole) in concentrated sulfuric acid (25 ml) is then ~ ;
added, the mixture is stirred at room temperature for two hours, and then poured onto ice. Extraction with carbon tetrachloride followed by drying and stripping of the solution yields 2-methoxyethyl-5-fluoro-2-nitrobenzoate, which on recrystallization from ligroin/benzene has a melting point of 49.~-50.5C.

c. Preparation o~ 2-chloro-4-trifluoromethyl-3'-(2-methoxy)ethoxycarbonyl-4'-nitrodiphenyl ether A mixture of 2-chloro-4-trifluoromethylphenol ;~
(3.92 g, 0.02 mole) and potassium carbonate (2.89 g. 0.02 mole) is stirred overnight in dimethyl sulfoxide (50 ml.) at ;~
room temperature. 2-Methoxyethyl-5-fluoro-2-nitrobenzoate ;
(4.86 g., 0.02 mole) is added and the mixture stirred over-night, poured onto ice, and extracted with carbon tetra- ~ `
chloride. The extract is stripped ~o give 2-chloro-4-trifluoromethyl-3'-(2-methoxy)ethoxycarbonyl-4'-nltrodiphenyl ether (7.5 g.) which solidifies on standing, and has a 1;
melting point of 60-62C. ~
. .
Example 4 a. Preparation of 2-chloro-4-trifluoromethyl-3'- ~
(~_methoxy hexadecaethoxy)carbonyl-4'- ~ `
nitrodiphenyl ether A solution of 2-chloro-4-trirluoromethyl-3'-chloro-carbonyl-4'-nitrodiphenyl ether (9.5 g, 0.025 mole) in -toluene (300 ml) is heated under reflux for 4 hours in the presence of ethylene glycol monomethyl ether, of average ~j., - 1 9- ~ ' .,0,, , ..

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- ~ ~335~)2 molecular weight 750 Ag., 0.025 mole). The toluene is then removed under reduced pressure to give 26 g of 2-chloro-4-trifluoromethyl-3'-(~-methoxy hexadecaethoxy) carbonyl-4'-nitrodiphenyl ether `~
b. Preparation of 2-chloro-4-trifluoromethyl-3'-(~-methoxy dotetracontaethoxy) carbonyl-4'-nitrodiphenyl ether A solution of 2-chloro-4-trifluoromethyl-3'-chloro-carbonyl-4'-nitrodiphenyl ether (0.48 g, 0.0013 moles) in toluene (300 ml) is heated under reflux for 4 hours in thè
presence of ethylene glycol monomethyl ether, of average molecular weight 1900 (2.5g., 0.0013 moles). The toluene ;
is then removed under reduced pressure to give 2.4 g of 2-chloro-4-trifluoromethyl-3'-(~-methoxy dotetracontaethoxy)-15 carbonyl-4'-nitrodiphenyl ether. ;~
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, The following examples show the herbicidal proper-ties of diphenyl ethers of the invention. - ~;
Example 5 This example shows the herbicidal activity of ~ ~
diphenyl ethers of the invention towards a number of common ~-.reeds. Using the procedure described below, diphenyl ethers are evaluated for control of various plant species.
The following test procedure is employed. Seeds of ~
selected crops and weeds are planted in soil in flats. For `
preemergence tests, the flats are treated with the test com-pound immediately after the planting. For postemergence ~ -tests, the seeds are allowed to germinate, and after two weeks the flats are treated with the test compound immed-iately after the planting. The compound to be evaluated is dissolved in acetone, diluted with water, and sprayed -~
over the flats using a carrier volume equivalent to 50 gallons per acre at the rate of application of two pounds per acre. About two weeks after the application of the test ~ --compound, the state of growth of the plants is observed and ;~ -the phytotoxic effect of the compound is evaluated. The results of typical tests are summarized in Table II, which `~
gives the average percent control achieved by the test compounds with 0 representing no weed control and 100 com- `
plete kill of the plant. ``~
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TABLE II
HERBIC'IDAL ACTIVITY
Compound #2 Com~ound #l Common Scientific Pre- Post Pre- ' Post :
5 Name ` Name emer- emer- emer- emer-Monocots ~~~' gence gence gence gence ''~
barnyardgrass ~chin'ochloa ` cru`sgal'li'' 100 100 99 100 downybrome Bromus tectorum100 90 90 40 green foxtail ' Setaria viridis100 100 100 100 Johnsongrass S'orghum ~ .
(seedling) `-halepense 100 100 _ _ , yellow nutsedge ' Cyperus esculentus 50 100 90 70 quackgrass Agropyron repens 0 40 0 40 ~ ';
wild oats Avena fatua 70 99 90 99 ~'~
'oermudagrass Cynodon dactylon - 60 - 0 yellow millet Panicum ' :
' miIiaceaum - - 100 100 :.. , ~' Dicot's Bindweed Convolvulus ' ~
arvensis'~~~ 0 100 50 100 " ~::',,`
Cocklebur Xanthium ' :
pensylvanicum 0 100 50 0 ~:
Coffeeweed Sesbania spp. 100 100 30 loo Morningglory Ipomoea spp. 0 100 0 100 ~' Black nightshade Solanum nigrum 100 100 100 100 velvetleaf 'Abutilon 'theophras't'i 40 100 100 100 ~ ,' 30 safflower Carthamus . ' 'tincto'ri'us 0 99 30 100 ~ ,:

Example 6 ,~
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The compounds of Examples l to 3 were also evaluated .
in conventional field tests. In one typical field test, the ,`.
compound of Example 2 was tested for control of a number of ,':',.

-23- ' ~133S02 .

annual grasses and broadlea~ weeds and for tolerance to a number of common crops. Table III summarizes these tests results, using the same scale o~ control as in Table II.

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It is to be understood that changes and variations can be made without departing from the spirit and scope of -this invention as defined by the appended claims. ;

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Claims (12)

CLAIMS:

1. A compound of the formula wherein X is a hydrogen atom, a halogen atom, a (C1-C4)alkyl group, a cyano group, or a trifluoromethyl group, Y is a hydrogen atom or a halogen atom, R1 is a hydrogen atom or a (C1-C4)alkyl group, R2 is a hydrogen atom or a (C1-C4)alkyl group, R3 is a hydrogen atom or a (C1-C4)alkyl group, m is an integer of 1 to 50, and n is 0 or an integer of 1 to 6, n' is 0 or an integer of 1 to 6, wherein the sum of n and n' is an integer of 2 to 6.

2. The compound of claim 1 wherein Y is a hydrogen atom.

3. The compound of claim 2 wherein X is a halogen atom.

4. The compound of claim 3 wherein one of R1 and R2 are hydrogen atoms.

5. The compound of claim 4 wherein R3 is a hydrogen atom or a methyl group and the sum of n and n' is 2.

6. The compound of claim 5 wherein R3 is a hydro-gen atom, X is a chlorine atom, and m is 1.

7. The compound of claim 5 wherein R3 is a methyl group, X is a chlorine atom, and m is 1.

8. The compound of claim 4 wherein R3 is an ethyl group, X is a chlorine atom, m is 2, and the sum of n and n' is 2.

9. A method of controlling weeds which comprises applying to the surface of the growth medium prior to the emergence of the weeds from the growth medium a compound of claim 1 in an amount effective to control the growth of the weeds.

10. The method of claim 9 wherein the compound is applied in an amount of about 0.1 to about 12 pounds per acre.

11. A method of controlling weeds which comprises applying to weed seedlings a compound of claim 1 in an amount sufficient to control the growth of the seedlings.

12. The method of claim 11 wherein the compound is applied in an amount of about 0.1 to about 12 pounds per acre.