CA1239643A - Herbicidal diphenyl ether hydroxylamines - Google Patents

Abstract

Herbicidal diphenyl ether hydroxylamines Abstract of the Disclosure The present invention relates to herbicidal and plant growth regulating diphenyl ether diazoamines of formula I

(I) wherein R1 is hydrogen or a C1-C6alkyl, C3-C6alkenyl or C3-C6alkynyl radical which may be unsubstituted or substituted by halogen, cyano, nitro, C1-C4alkoxy, C1-C4alkylthio or di(C1-C4)alkylamino, R2 is a C1-C6alkyl, C3-C6alkenyl or C3-C6alkynyl radical which may be unsubstituted or substituted as indicated for the alkyl radical R1, or R1 and R2, together with the nitrogen and the oxygen atom, also form a saturated or partially saturated 5- or 6-membered heterocycle which may contain a further nitrogen atom and/or may be fused to a benzene ring and may be substituted by C1-C2alkyl or halogen, X is chlorine or the trifluoromethyl group and X1 is hydrogen or chlorine.

These compounds are suitable for selectively controlling weeds in crops of useful plants such as cereals, maize, rice or soybeans.
They are effective at lower rates of application, are rapidly degraded and are particularly effective for postemergence treatment.

Description

~23~6~3 Herbicidal diphenvl ether hydroxylamines The present invention relates to novel herbicidal diphenyl ether hydroxylamines, to the preparation thereof, to compositions containing the~ as herbicide , and to the use thereof as selective herbicides in crops of useful plants.

The novel diphenyl ether hydroxylamines are of formula I

ICl ~N( Rl ) oR2 X~ --0-~ -NOz (I) wherein R1 is hydrogen or a C1-C6alkyl, C3-C6alkenyl or C3-C6alkynyl radical which may be unsubstituted or substituted by halogen, cyano, nitro, C1-C4alkoxy, C1-C4alkylthio or di(C1-C4)alkylamino, RZ i9 a C1-C6alkyl, C3-C6alkenyl or C3-C6alkynyl radical which may be unsubstituted or substituted as indicated for the alkyl radical R1, or R1 and R2, together with the nitrogen and the oxygen atom, al80 form a saturated or partlally saturated 5- or 6-membered heterocycle which may contain a further nitrogen atom and/or may be fused to a benzene ring and may be substituted by C1-Czalkyl or halogen, X is chlorine or the trifluoromethyl group and X1 is hydrogen or chlorine.
~ ' ~39643 The alkyl, alkenyl or alkynyl radicals may be branched or straight chain.

Examples of suitable heterocyclic radical3 which can be formed by the radicals R1 and oR2, together with the nitrogen atom to which they are attached, are: isoxazolin-2-yl, benz-1,2-oxazol-2-yl, 1,2-oxazan-2-yl, benz-1,2-oxazine, 1,2,3-oxadiazol-2-yl, 1,2,4-oxa-diazol-2-yl, furazan-2-yl, 1,2,3-oxadiazin-2-yl, 1,2,4-oxadiazin-

2-yl etc.

Herb~cidal 2-chloro-4'-nitro-4-~rifluoromethyldiphenyl ether~
substituted ln the 3'-position by substituted amino or imino radicals, which diphenyl ethers are suitable e.g. for controlling weeds in crops of rice, are known from US patent speclfication 4 419 124. The diphenyl ether hydroxylamines of the present invention are novel and exhibit excellent selective herbicidal activity in crops of useful plants, e.g. cereals, maize, sorghum, rice, soybeans, cotton, sugar beet etc., in which crops they also damage weeds and grasses which have only been controlled up to now with total herbicidss. They are particularly effective when applied postemergence and are rapidly degraded.

Among the compounds of formula I, those compounds are particularly effective wherein - Rl is hydrogen or a C1-C6alkyl radical and R2 is a C1-C6alkyl, C3-C6alkenyl or C3-C6alkynyl radical, whlch radicals may be unsubstituted or substituted by halogen, cyano, nitro, C1-C4alkoxy, C1-C4alkylthio or di(C1-C4jalkylamino, and X i8 the trifluoromethyl group and X1 is hydrogen;

_ Rl i8 hydrogen, R2 is a C1-C6alkyl, C3-C6alkenyl or C3-C6alkynyl radical whlch may be substituted by halogen, cyano, nitro, C1-C4alkoxy, C1-C4alkylthio or di(C~-C4~alkylamino, and X i~ the trifluoromethyl group and X1 is hydrogen;

1;~3~6~3 especially the compounds:
2-chloro-3'-methoxyamino-4-nitro-4-trifluoromethyldiphenyl ether, 2-chloro-3'-N70-dimethylhydroxylamino-4'-nitro-4-trifluoromethyl-diphenyl ether, 2-chloro-3'-N-tert-butoxyamino-4'-nitro-4-trifluoromethyldiphenyl ether, 2-chloro-3'-N-ethoxyamino-4'-nitro-4-trifluoromethyldiphenyl ether, 2-chloro-3'-N-allyloxyamino-4'-nitro-4-trifluoromethyldiphenyl ether, 2-chloro~3'-N-chloroallyloxyamino-4'-nitro-4-trifluoromethyldiphenyl ether, 2-chloro-3'-N-n-butoxyamino-4'-nitro-4-trifluoromethyldiphenyl ether, 2-chloro-3'-N-n-hexyloxyamino-4'-nitro-4-trif]uoromethyldiphenyl ether, 2-chloro-3'-N-benzyloxy-4'-nitro-4-trifluoromethyldiphenyl ether, 2-chloro-3'-N-(2'-chlorobenzyloxy)amino-4'-nitro-4-trifluoromethyl-diphenyl ether, 2-chloro-3'-N-isobutoxyamino-4'-nitro-4-trifluoromethyldiphenyl ether, 2-chloro-3'-N-tert-butoxyamino-4'-nitro-4-trifluoromethyldiphenyl ether, 2-chloro-3'-N-isopropoxyamino-4'-nitro-4-trifluoromethyldiphenyl ether, 2-~hloro-3'-N-n-propoxyamino-4'-nitro-4-trifluoromethyldiphenyl ether, 2-chloro-3-N-methallyloxyamino-4'-nitro-4-trifluoromethyldiphenyl ether.

The compounds of formula I are prepared by synthesis routes known per se.

In accordance with the process of the present invention, the diphenyl ether hydroxylamines of formula I are prepared by reacting a 5-ortho-chlorophenoxynitrobenzene of formula II

~L2396~3 X~ -0-~ NO2 (II~

wherein X and Xl are as defined for formula I and A i9 a leaving ~1 group, nitro, chlorine or X~ 0- with a hydroxylamine of ~ 1 formula III
H-N(RI)-OR2 (III) ln an inert organic solvent and in the presence of at least the equimolar amount of a base.

In accordancP with a further process of the present invention, diphenyl ether hydroxylamines of formula I, wherein Rl is not hydrogen, are obtained by reacting a diphenyl ether hydroxylamine of formula Ia ~1 ~NH-OR2 X~ -0-~ -NOz (Ia) ._~ .=.

wherein R2, X and Xl are as defined for formula I, with a reactive alkyl ester of formula IV

Rl-Y (IV) wherein Rl is as defined for formula I and Y is a halogen atom or the anion of an alkylsulfonic, haloalkylsulfonlc or arylsulfonic acld or of an alkylsulfuric, haloalkylsulfuric or arylsulfuric acid, in an inert organic solvent and in the presence of at least the equimolar amount of a base.

~;~3~643 The reactions are advantagaously carried out in a solvent which is inert to the reaction partners and in the pre3ence of the molar amount of a base as acid acceptor. The temperature of these reactions may be in the range from 0C to the boiling point of the reaction mixtu~e. It is most advantageous to carry out the reactions at room temperature.

Suitablz inert organic solvents are preferably alkanols, ethers, aromatic compounds, amides or sulfoxides. Examples of such solvents are ethanol, propanol, isopropanol, hexanol, cyclohexanol, methyl ethyl ketone, dloxane, tetrahydrofuran, benzene, toluene, dimethyl-formamide, dimethylsulfoxide, acetonitrile.

Suitable bases are tertiary amines and alkali metal and alkaline earth metal carbonates, bicarbonates and hydroxideR.

The starting products of formula II are either known diphenyl ethers or they can be prepared by condensing an ortho-chlorophenol and a para-nitrochlorobenzene or a 4-nitroresorcinol with 2 molecules of 1,2-dichlorobenzene in the presence of a base in accordance with the following reaction schemes:

X~ -oH + Cl~ -NO2 ~ X~ 0--~ ~--NOz Cl-i~/ ~t-x ICl IOH ICl /0/ \-~
2 X-t~ ~-Cl + HO--~ ~--NO2 base~ X-~ -0-~ NO2 The compounds of formula I have good herbicidal properties. In high rates of application they can be used as total herbicides. However, it is more advantageous to use them in rates of application of about ~239643 O.l to 5 kg per hectare a3 selective herbicides postemergence in crops of cultivated plants. They inhibit or hinder the occurrence of dicot weeds, but especially of many monocot species such as Lollum, Alopecuris, Rottboellia, Sorghum, Diglterla, Setarla and Panicum.
Cultivated plants such as cereals, barley, wheat, rye, maize or rice, and also cotton and soybeans, are wholly unharmed, or at least unharmed at a rate of application of 1 kglha. The compound is rapidly degraded leaving no residues.

Some of the novel compounds are also suitable for desicating and defoliating cotton or potato crops shortly before harvesting.

Depending on the actlvity of the compound employed, the nature of the soil, conditions of climate and weather, the nature and time of application and the nature of the crop and of the weeds to be controlled, usual rates of applicatlon of herbicide of the present inventlon per hectare vary in the range from 0.1 to lO.0 kg and are preferably in the range from 0.5 to 4.0 kg.

Further, the compounds of formula I have advantageous growth-regulating properties (growth lnhlbltion). The growth of both monocots and dlcots i8 inhibited. Thus, for example, the compounds of formula I selectively inhiblt the growth of leguminosae which are frequently planted as cover crcps in tropicsl regions, so that, while soil erosion between cultivated plants is prevented, the cover crops cannot compete with the cultivated plants.

The compounds of formula I are used in unmodified form or, prefer ably, as compositions together with the adjuvants conventionally employed ln the art of formulatlon, and are therefore formulated in known manner to emulsiflable concentrates, dlrectly sprayable or dllutable solutions, dilute emulsions, wettable powders, soluble powders, dusts, granulates, and also encapsulations in e.g. polymer substances. As with the nature of the compositions, the methods of ~239~43 application, such as spraying, atomising, dusting, scatterlng or pouring, are chosen ln accordance with the lntended objectives and the prevailing circumstances.

The formulations, i.e. the compositions, preparations or mixtures containing the compound ~active ingredient) of formula I and, where appropriate, a solid or liquid ad~uvant, are prepared in known manner, e.g. by homogeneously mixing and/or grinding the active ingredients with extenders, e.g. solvents, solid carriers and, where appropriate, surface-active compounds (surfactants).

Suitable s~lvents are: aromatic hydrocarbons, preferably the fractions containing 8 to 12 carbon atoms, e.g. xylene mixtures or substituted naphthalene6, phthalates such as dibutyl phthalate or dioctyl phthalate, aliphatic hydrocarbons such as cyclohexane or paraffins, alcohols and glycols and their ethers and esters, such as ethanol, ethylene glycol, ethylene glycol monomethyl or monoethyl ether, ketones such as cyclohexanone, strongly polar solvents such as N-methyl-2-pyrrolidone, dimethylsulfoxide or dimethylformamide, as well as vegetable oils, epoxidised vegetable oils such as epoxidised coconut oil or soybean oil; or water.

The solid carriers used e.g. for dusts and dispersible powders are normally natural mineral fillers such as calcite, talcum, kaolin, montmorillonite or attapulgite. In order to improve the physical properties it is also possible to add highly dispersed silicic acid or highly dispersed absorbent polymers. Suitable granulated adsorp-tive carriers are porous types, for example pumice, broken brick, sepiolite or bentonite; and suitable nonsorbent carriers are materials such as calcite or sand. In addition, a great number of pregranulated materials of inorganic or organic nature can be used, e.g. especially dolomite or pulverised plant residues.

~239~4;~

Depending OD the nature of the compound of the formula I to be formulated~ suitable surface-active compounds are nonionic, cationic and/or anionic surfactants having good emulsifying, dispersing and wetting properties. The t~rm "surfactants" will also be understood as comprislng mixtures of surfactants.

Suitable anionic surfactants can be both water-soluble soaps and water-soluble synthetic surface-active compounds.

Suitable soaps are the alkali metal salts, alkaline earth metal salts or unsubstituted or substituted ammonium salts of higher fatty acids (C1o-C22), e.g. the sodium or potassium salts of oleic or stearic acid, or of natural fatty acid mixtures which can be obtained e.g. from coconut oil or tallow oil. Mention may also be made of fatty acid methyltaurin salts.

More frequently, however, so-called synthetic surfactants are used, especially fatty sulfonates, fatty sulfates, sulfonated benzimid-azole derivatives or alkylarylsulfonates.

The fatty sulfonates or sulfates are usually in the form of alkali metal salts, alkaline earth metal salts or unsubstitued or substi-tuted ammonium salts and contain a C~-C22alkyl radical which also includes the alkyl moiety of acyl radicals, e.g. the sodium or calcium salt of lignosulfonic acid, of dodecylsulfate or of a mixture of fatty alcohol sulfates obtained from natural fatty acids.
These compouDds also comprise the salts of sulfuric acid esters and sulfonic acids of fatty alcohol/ethylene oxide adducts. The sulfona-ted benzimidazole derivatives preferably contain 2 sulfonic acid groups and one fatty acid radical containing 8 to 22 carbon atoms.
Examples of alkylarylsulfonates are the sodium, calcium or tri-ethylanolamine salts of dodecylbenzenesulfonic acid~ dibutylnaph-thalenesulfonic acid, or of a naphthalenesulfonic acid/formaldehyde condensation product. Also suitable are corresponding phosphates, e.g. salts of the phosphoric acid ester of an adduct of p-nonyl-phenol with 4 to 14 moles of ethylene oxide.

~2396~3 _ 9 _ Non-ionic surfactants are preferably polyglycol ether derivatives of aliphatic or cycloaliphatic alcohols, or saturated or unsaturated fatty acids and alkylphenols, said der-Lvatives containing 3 to 30 glycol ether groups and 8 to 20 carbon atoms in the (aliphatic) hydrocarbon moiety and 6 to 18 carbon atoms ln the alkyl moiety of the alkylphenols.

Further suitable non-ionic surfactants are the water-soluble adducts of polyethylene oxide with polypropylene glycol, ethylenediamino-propylene glycol and alkylpolypropylene glycol containing I to 10 carbon atoms in the alkyl chain, which adducts contain 20 to 2S0 ethylene glycol ether groups and 10 to 100 propylene glycol ether groups. These compounds usually contain 1 to 5 ethylene glycol units per propylene glycol unit.

Representative examples of non-ionic surfactants are nonylphenol-polyethoxyethanols, castor oil polyglycol ethers, polypropylene/-polyethylene oxide adducts, tributylphenoxypolyethoxyethanol, polyethylene glycol and octylphenoxypolyethoxyethanol. Fatty acid esters of polyoxyethylene sorbitan, such as polyoxyethylene sorbitan trioleate, are also suitable non-ionic surfactants.

Cationic surfactants are preferably quaternary ammonium salts which contain, as N-substltuent, at least one C8-C22alkyl radical and, as further substituents, unsubstituted or halogenated lower alkyl, benzyl or hydroxy-lower alkyl radicals. The salts are preferably in the form of halides, methylsulfates or ethylsulfates, e.g. stearyl-trimethylammonium chloride or benzyldi(2-chloroethyl)ethylammonium bromide.

The surfactants customarily employed in the art of formulation are described e.g. in the following publications:

~23g64~

- lo -"McCutcheon's Detergents and Emulsiflers Annual", MC Publishing Corp., Ridgewood, New Jersey, 1981; H. Stache, "Tensid-Taschenbuch'i (Handbook of Surfactants), 2nd Edition, C. Hanser Verlag, Munich & Vienna, 1981; M. and J. Ash, "Encyclopedia of Surfactants", Vol. I-III, Chemical Publishing Co., New York, 1980-81.

The herbicidal compositions usually contain 0.1 to 95 %, preferably 0.1 to 80 %, of a compound of formula I, 1 to 99.9 %, of a ~olid or liquid adjuvant, and 0 to 25 %, pre-ferably 0.1 to 25 %, of a surfactant.

Preferred formulations are composed in particular of the following constituents (~0 = percentage by weight):

Emulsifiable concentrates active ingredient:1 to 20 %, preferably 5 to 10 %
surfactant:5 to 30 %, preferably 10 to 20 %
liquid carrler:50 to 94 %, preferably 70 to 85 %

Dusts active ingredient:0.1 to 10 %, preferably 0.1 to 1 %
solid carrier:99.9 to 90 %, preferably 99.9 to 99 %

Suspension concentrates active ingredient:5 to 75 %, preferably 10 to 50 %
water:94 to 25 %, preferably 90 to 30 %
surfactant:1 to 40 %, preferably 2 to 30 %

Wettable powders active ingredient:0.5 to 90 %, preferably 1 to 80 %
surfactant:0.5 to 20 %, preferably 1 to 15 %
solid carrier:5 to 95 %, preferably 15 to 90 %

6~;~

Granulates active ingredient: 0.5 to 30 %, preferably 3 to 15 %
solid carrier: 99.5 to 70 %, preferably 97 to 85 %.

Whereas commercial products wlll be preferably formulated as concentrates, the end user will normally employ dilute formulations.
The formulations can be diluted to a concentration as low as 0.001 %
of active ingredlent.

The compositions may also contain further ingredients such as stabilisers, antifoams, viscosity regulators, binders, tackifiers, as well as fertilisers and other compounds for obtaining special effects.

Example 1: Preparation of 2-chloro-3'-methoxyamino-4'-nitro-4-trifluoromethyldiphenyl ether ICl ~ HOCH3 CF3~ -0-~ -N~2 A sulfonating flask is charged with 10 g of 4-(2'-chloro-4'-tri-fluoromethylphenoxy~-1,2-dinitrobenzene, 4.6 g of O-methylhydroxyl-amine hydrochloride and 30 ml of dimethylsulfoxide. This mixture is stirred and 5.5 ml of a 30 % aqueous solution of sodium hydroxide are added dropwise to it. When the addition is complete, the reaction mixture is stirred further for 12 hours at room temperature, then diluted with 500 ml of water and extracted with ethyl acetate. The organic phase is washed several times with water, dried over sodium sulfate and concentrated. The residue is recrystallised from hexane, affording 8 g (83 % of theory) of the above diphenyl ether with a melting point of 113C.

Example 2: Preparation of 2-chloro-3'-N-methoxy-N-methylamino-4'-nitro-4-trifluoromethyldiphenyl ether 123~643 /Cl ~ (CH3)OCH3 CF3-~ 0-~ NO2 With stirring, a sulfonating flask ls charged with 9 g of 4-(2'-chloro-4'-trifluoromethylphenoxy~-1,2-dinitrobenzene, 10 ml of O-N-dimethylhydroxylamine and 20 ml of dimethylsulfoxide. The resction mixture is stirred further for 3 days at room temperature, then diluted with 500 ml of water and extracted with ethyl acetate.
The organic phase is separated, washed first with dilute hydro-chloric acid and then with water, dried over sodium sulfate and concentrated. The residue is purified by chromatography over a column of SiOz eluted with a mixture of hexane and ethyl acetate (9:1). The solvent is evaporated off, afording the title compound as a yellowish oil. Refractive index n23-5 ~ 1.5558;
yield ~ 7.5 g (80 % of theory).

Example 3: Preparation of 2-chloro-3'-N-tert-butoxyamino-4'-nitro-4-trifluoromethyldiphenyl ether ~Cl ~ H-O-C(CH3)3 CF3-~ -0--~ ~-NO2 .~. ...
A mixture of 10 g of 4-(2'-chloro-4'-trifluoromethylphenoxy)-1,2-di-nitrobenzene, 30 ml of dimethylsulfoxide, 8 g of triethylamine and 5 g of O-tert-butylhydroxylamine hydrochloride i8 stirred for about 14 hours at room temperature in a sulfonating flask. Subsequently, the reaction mixture is diluted with 500 ml of water and extracted with ethyl acetate. The organic phase is washed with dilute hydro-chloric acid and then with water, dried over sodium sulfate and concentrated. The residue is recrystallised from hexane, affording 6 g of the crystalline title compound with a melting point of 120-122C.

~239Sf~3 The following compounds ars obtained in a manner analogous to those of these Examples:
ICl /N(RI)OR2 X~ --0~ N02 ~1 No. X Xl Rl R2 Physical data .
1 CF3 H H CH3 m.p. 113C
Example 1 2 CF3 H CH3 CH3 n23.5 1 5558 Example 2

3 CF3 H H C(CH3)3 m.p. 120-122C
Example 3

4 CF3 H H C2Hs m.p. 66-67C

5 CF3 H H CH2-CH=CH2 m.p. 49-52C

6 CF3 H H CHzCH=CHCl nD 1.5836

7 CF3 H H C4Hgn n23 1.5694

8 CF3 H H C6H13n nD 1.558S

9 CF3 H H benzyl m.p. 97-100C

10 CF3 H H 2-chlorobenzyl m.p. 108-110C

11 CF3 H H CH2CH(CH3)2 m.p. 85-89C

12 CF3 H H CH(CH3)2

13 CF3 H H C3H7n

14 CF3 H H CH2C ~ CH

15 CF3 H H CH2CClzCH2

16 CF3 H H CH2C(CH3)=CH2 m.p. 55C

17 Cl H CH3 CH3

18 CF3 Cl CH3 CH3

19 CF3 Cl CH3 C2Hs CF3 H CH3 C2Hs 21 CF3 H C2Hs CH3 23 CF3 Cl H CH3 :123'9643 Example 4: Formulation Examples for compounds of formula I
(percenta~es are by wei~ht) a) Wettable powders a) b) c) Compound of formula I 20 % 60 % 0.5 %
sodium lignosulfonate S % 5 % 5 %
sodium laurylsulfate 3 % - -sodium diisobutylnaphthalenesulfonate - 6 % 6 %
octylphenol polyethylene glycol ether - 2 % 2 %
(7-8 moles of ethylene oxide) highly dispersed silicic acid5 % 27 % 27 %
kaolin 67 %
sodium chloride - - 59.5 %

The active ingredient i8 thoroughly mixed with the adjuvants and the mixture is thorougly ground in a suitable mill, affording wettable powders which can be diluted with water to give suspensions of the desired concentration.

b) Emulsifiable concentrates a) b) Compound of formula I 10 % 1 %
octylphenol polyethylene glycol ether 3 % 3 %
(4-5 moles of ethylene oxide) calcium dodecylben~enesulfonate 3 % 3 %
castor oil polyglycol ether 4 % 4 %
(36 moles of ethylene oxide) cyclohexanone 30 % 10 %
xylens mixture 50 % 79 %

Emulsions of any required concentration can be obtained from this concentrate by dilution with water.

~2396~3 c) Dusts a) b) Compound of formula I 0.1 % 1 %
talcum 99-9 %
kaolin - 99 %

Dusts which are ready for use are obtainsd by mixing the active ingredient wlth the carrier, and grinding the mixture in a suitable mill.

d) Extruder ~ranulate a) b) Compound of formula I 10 % l %
sodium lignosulfonate 2 % 2 %
carboxymethylcellulose 1 % l %
kaolin 87 % 96 %

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

e) Coated granulate Compound of formula I 3 %
polyethylene glycol (mol.wt. 200) 3 %
kaolin 94 %

The finely ground active ingredient is uniformly applied, in a mixer, to the kaolin moistened with polyethylene glycol. Non-dusty coated granulates are obtained in this manner.

~3~1~43 - lÇ -f) Suspenslon concentratz a) b) Compound of formula I 40 % 5 %
ethylene glycol 10 % 10 %
nonylphenol polyethylene glycol ether 6 % 1 %
(15 moles of ethylene oxide) sodium llgnosulfonate 10 % 5 %
carboxymethylcellulose 1 % 1 %
37 % aqueous formaldehyde solution 0.2 % 0.2 %
silicone oil in the form of a 75 % 0.8 % 0.8 %
aqueous emulsion water 32 % 77 %

The finely ground active ingredient is intimately mixed with the adjuvants, giving a suspension concentrate from which suspensions of any desired concentratlon can be obtained by dilution with water.

g) Salt solution Compound of formula I 5 %
isopropylamine 1 %
octylphenol polyethylene glycol ether 3 %
(78 moles of ethylene oxide) water 91 %
xample 5: Biolo~ical tests to determine the actlon of compounds of formula I
Preemer~ence herbicidal action In a greenhouse, plant seeds are sown in flower pots of 12-15 cm diameter, so that per pot 10 to 25 plants can develop. Immediately after sowing, the surface of the soil i9 treated with an aqueous suspension of compound No. 2 obtained from a 10 % wettable powder. A
series of concentrations of 2 to 0.25 kg a.i./ha is employed. The pots are then kept in the greenhouse at 22 - 25C and 50 - 70 %

~2396~

relative humidity and the plants are watered regularly. The test is evaluated 3 weeks later. The state of the plants i8 assessed in accordance with the following rating:

9 ~ normal growth, as untreated controls 6 - 9 = slight damage 5 - moderate damage 2 - 4 = severe damage 1 - plant withered - = plant not tested The results obtained are as follows:

Concentration 2 1 0.5 0.25 ~ . ~
Plant wheat 7 9 9 9 maize 7 8 g 9 rice 8 9 g 9 soybean 7 8 8 9 cotton 6 7 8 9 Alopeurus myosuroides 1 1 1 2 Dlgitaria sanguinalis Echinochloa crus galli 1 1 2 4 Sorghum halepense 1 1 4 4 Abutilon 1 1 2 2 Sida spinosa 1 1 2 2 Amaranthus retroflexus Chenopodium album Solanum n~grum 1 1 2 3 Stellaria media 1 1 3 3 Chrysanthemum leucum Viola tricolor Veronica sp.

~ 23~64~

Postemer~ence herbicldal action A number of weeds and cultivated plants, both monocots and dicots, are sprayed postemergence in the 4- to 6-leaf stage with an aqueous dispersion of test compound at concentrations of 2 to 0.25 kg a.i.tha, and then kept at 24 - 26C and 45 - 60 % relative humidlty. The test is evaluated 15 days after treatment in accordance with the same rating as for the preemergence test.

The results obtained are as follows:

Compound 2 4 5 . _ .
Concentration kg/ha 210.50.25 210.50.25 210.50.25 Plant __ __ barley 78 ~ 9 78 8 8 78 8 8 wheat 78 9 9 78 8 8 78 8 8 maize 78 9 9 66 8 8 67 8 8 rice 99 9 9 67 8 9 67 9 9 soybean 56 6 7 67 8 8 78 8 8 Abutilon 11 1 1 33 3 4 33 3 4 Sida spinosa 12 2 3 22 2 2 12 2 3 Amaranthus retroflexus 22 2 2 11 1 1 11 Chenopodium album 11 1 1 22 2 2 11 1 2 Solanum nigru~n 11 1 2 22 2 4 33 4 4 Ipomoea purpurea 11 1 1 11 1 1 11 2 2 Sinapis alba 11 1 1 12 3 4 11 1 3 Chrysanthemum 11 1 1 11 1 1 11 1 Galium apanne 22 2 3 22 2 3 33 4 4 Viola tricolor 11 1 1 11 1 1 11 1 Veronica sp 11 1 1 11 1 1 11 ~396~

Selective herblcidal action on rice in postemergence application Twenty-five-day-old rice plants are transplanted into large rectangular asbestos cement containers in a greenhouse. Seeds of the weeds occuring in rice crops, namely Echinochloa crus galli, Scirpus, Monocharia and Sagittaria, are then sown between the {OW6 of rice plants. The containers are well watered and kept at a temperature of about 25C and at high humidity. Twelve days later, when the weeds have emerged and reached the 2-3 leaf stage, the soil in each of the containers is covered with a layer of water to a height of 2.5 cm. The test compound is then applied ln the form of an emulsifiable concentrate with a pipette between the rows of plants. The emulsifiable concentrate is diluted and applied such that it corresponds to a concentration of 1, 0.5 and 0.25 kg/ha respectively. The test ls evaluated 4 weeks later and the state of the plants is assessed in accordance with the above rating.

~he results obtained are as follows:

Compound 2 ¦ 4 5 1 0.5 0.25 1 0.5 0.25 1 0.5 0.25 Plant rice 6 6 8 9 9 9 8 9 9 Echinochloa crus galli 1 1 1 4 4 4 4 5 5 Scirpus 1 1 1 1 2 2 1 1 4 Monocharis 1 1 1 1 1 1 1 Sagittaria 1 2 2 4 4 4 3 3 4

Claims (20)

What is claimed is

1. A diphenyl ether hydroxylamine of formula I

(I) wherein R1 is hydrogen or a C1-C6alkyl, C3-C6alkenyl or C3-C6alkynyl radical which may be unsubstituted or substituted by halogen, cyano, nitro, C1-C4alkoxy, C1-C4alkylthio or di(C1-C4)alkylamino, R2 is a C1-C6alkyl, C3-C6alkenyl or C3-C6alkynyl radical which may be unsubstituted or substituted as indicated for the alkyl radical R1, or R1 and R2, together with the nitrogen and the oxygen atom, also form a saturated or partially saturated 5- or 6-membered heterocycle which may contain a further nitrogen atom and/or may be fused to a benzene ring and may ba substituted by C1-C2alkyl or halogen, X is chlorine or the trlfluoromethyl group and X1 is hydrogen or chlorine.

2. A diphenyl ether hydroxylamine of formula I accordlng to claim 1, wherein R1 is hydrogen.

3. A diphenyl ether hydroxylamine of formula I according to claim 1, wherein R1 is hydrogen or a C1-C6alkyl radical and R2 is a C1-C6alkyl, C3-C6alkenyl or C3-C6alkynyl radical, whlch radicals may be unsubstituted or substituted by halogen, cyano, nitro, C1-C4alkoxy, C1-C4alkylthio or di(C1-C4)alkylamino, and X is the trifluoromethyl group and X1 is hydrogen.

4. A diphenyl ether hydroxylamine of formula I according to claim 1, wherein R1 is hydrogen, R2 is 8 C1-C6alkyl, C3-C6alkenyl or C3-C6alkynyl radical which may be substituted by halogen, cyano, nitro, C1-C4alkoxy, C1-C4alkylthio or di(C1-C4)alkylamino, and X is the trifluoromethyl group and X1 is hydrogen.

5. 2-Chloro-3'-methoxyamino-4-nitro-4-trifluorommethyldiphenyl ether according to claim 1.

6. 2-Chloro-3'-N,O-dimethylhydroxylamino-4'-nitro-4-trifluoromethyl-diphenyl ether according to claim 1.

7. 2-Chloro-3'-N-tert-butoxyamino-4'-nitro-4-trifluoromethyldiphenyl ether according to claim 1.

8. 2-Chloro-3'-N-ethoxyamino-4'-nitro-4-trifluoromethyldiphenyl ether according to claim 1.

9. 2-Chloro-3'-N-allyloxyamino-4'-nitro-4-trlfluoromethyldiphenyl ether according to claim 1.

10. 2-Chloro-3'-N-chloroallyloxyamino-4'-nitro-4-trifluoromethyldi-phenyl ether according to claim 1.

11. 2-Chloro-3'-N-n-butoxyamino-4'-nitro-4-trifluoromethyldiphenyl ether according to claim 1.

12. 2-Chloro-3'-N-n-hexyloxyamino-4'-nitro-4-trifluoromethyldiphenyl ether according to claim 1.

13. 2-Chloro-3'-N-benzyloxy-4'-nitro-4-trifluoromethyldiphenyl ether according to claim 1.

14. 2-Chloro-3'-N-(2'-chlorobenzyloxy)amino-4'-nitro-4-trifluoro-methyldiphenyl ether according to claim 1.

15. 2-Chloro-3'-N-isobutoxyamino-4'-nitro-4-trifluoromethyldiphenyl ether according to claim 1.

16. 2-Chloro-3'-N-tert-butoxyamino-4'-nitro-4-trifluoromethyldi-phenyl ether according to claim 1.

17. A process for the preparation of a diphenyl ether hydroxylamine of formula I according to claim 1, which process comprises a) reacting a 5-ortho-chlorophenoxynitrobenzsne of formula II

(II) wherein X and X1 are as defined in claim 1 and A is a leaving group, nitro, chlorine or , with a hydroxylamine of formula III
H-N(R1)-OR2 (III) wherein R1 and R2 are as defined in claim 1 in an inert organic solvent and in the presence of at least the equimolar amount of a base; or b) when in the compound of formula I R1 is not hydrogen, reacting a diphenyl ether hydroxylamine of formula Ia (Ia) wherein R2, X and X1 are as defined in claim 1, with a reactive alkyl ester of formula IV

R1-Y (IV) wherein R1 is as defined in claim 1 and Y is a halogen atom or the anion of an alkylsulfonic, haloalkylsulfonic or arylsulfonic acid or of an alkylsulfuric, haloalkylsulfuric or arylsulfuric acid, in an inert organic solvent and in the presence of at least the equimolar amount of a base.

18. A method of selectively controlling weeds in crops of useful plants, which method comprises treating the crops with an effective amount of a diphenyl ether hydroxylamine according to claim 1 or of a composition containing such a diphenyl ether hydroxylamine.

19. A method according to claim 18,wherein the crops are cereals, maize, rice and soybeans.

20. A method of regulating plant growth, which method comprises treating the plants or the parts of plants whose growth it is desired to regulate with an effective amount of a diphenyl ether hydroxylamine according to claim 1 or of a composition containing such a diphenyl ether hydroxylamine.