ARYLPHENYL ETHERS HAVING HERBICIDAL ACTIVITY

Abstract: The invention relates to new diphenyl ethers of the general formula wherein Ar is a phenyl or pyridyl group, which groups are substi­ tuted with 1,2 or 3 substituents, selected from the group consisting of a halogen atom, a cyano group, a nitro group, an optionally halogenated alkyl, alkoxy and alkylthio group having 1-6 carbon atoms, an alkylsul­ phonyl group having 1-4 carbon atoms, and an alkanoyl group having 1-4 carbon atoms; n is 1 or 2; R₁ and R₂ are equal or different and represent hydrogen atoms or alkyl groups having 1-4 carbon atoms; R₃ is a hydrogen atom, an alkyl or alkenyl group having 1-4 carbon atoms and optionally substituted with an alkoxy­ carbonyl group with 2-5 carbon atoms; or R₂ and R₃ together form an alkylene group with 2-5 carbon atoms, and R₄ and R₅ are equal or different and represent alkyl groups having 1-6 carbon atoms, or R₄ and R₅ together form an alkylene group having 2 or 3 carbon atoms. The compounds have a herbicidal activity. After having been processed to compositions, the compounds may be used for controlling undesired plants or for leaf-desiccation in agricultural and horticultural crop in a dosage from 0.01 to 5 kg of active substance per hectare.

Description: New diphenyl ethers having herticida' actis:ty. The invention relates to new diphenyl ether and to a method of preparing the new compounds. The invention slo relates to herbicidal compositions and te co.,positions for leaf-desiccation on the basis of the new compounds. The invention further relates to the use of these compositions for controlling undesired plants and for leaf-desiccation in agricultural and horticultural crop. It is known that diphenyl ethers with a certain substitution pattern are suitable to control weeds in agricultural and horticultural crops. This control of weeds may take place after of before the emergence of the weeds; agents whose object it is to control the weed after the emergence thereof are termed post-emergence herbicides, the other ones are termed pre-emergence herbicides. For an unhindered growth of the crop during the whole growth period, both types of herbicides are used, if desired, but one single application is preferred, however, which, win a pre-emergence herbicide is used, usually is carried out simultaneously with or immediately after the sowing of the crop and, when a post-emergence herbicide is used, usually is carried out before the emerged weed starts hindering the growth of the crop. The advantage of the use of pre-emergence herbicides is that they can be provided in the soil destined for the crop simultaneous ly with the sowing of the crop; this is labour-saving, while damage to the standing crops upon application in a later stage is avoided. On the other hand, post-emergence herbicides are often more effectively active and can hence be used in smaller quantities to be able to effectively control the weed. It stands to reason that the selectivity cf the herbicide used is of the utmost importance. As a matter of fact, the undesired plants must be controlled, c.q. the growth of undesired plants must be suppressed, while the growth of the crop may not be detrimentally influenced by the herbicide used. An ideal herbicide must control the weed in the crop during the whole growth. season after one single appli cation in a small dosage. The herbicide should be capable not only of controlling all types of weeds, but also killing bcth the seedlings and full-grown plants of these weeds, as we as preventing the germinat an of the weed seeds. Nevertheless, the herbicide ray not be phbtotoxic with respect to the crofis on which it it provided. Of course, none of the herbicides now in use is ideal. An effective weed control is usually associated with too large a phytotoxicity with respect to the crop, while a herbicide which has not detrimental influence whatsoever on the crop in a given dosage, does usually not control all weeds effectively in the same dosage. Diphenyl ethers having herbicidal properties are known from United States Patent Specification 4,039,588. As examples of these compounds are mentioned p-nitrodiphenyl ethers which in the ortho position with respect to the nitro group bear an amino substituent, for example, 2,4-dichloro-3' -isopropylamino-4'-nitrodiphenyl ether. As will become apparent from the examples, however, the activity of this herbicidal com- pound leaves to be desired. at is the object of the invention to provide herbicides which can selectively control undesired plants in agricultural and horticultural crops and simultaneously have an improved activity as compared with the above-mentioned known compound. This object can be achieved by new diphenyl ethers of the general formula EMI2.1 wherein Ar is a phenyl or pyridyl Group, which groups are sub stituted with 1,2 or 3 substituents, selected from the group consisting of a halogen atom, a cyano group, a nitro group, an optionally halogenated alkyl, alkoxy and alkylthic group having 1-6 carbon atoms, an alkylsulphonyl group having 1-4 carbon atoms, and an alkanoyl group having 1-4 carbon atoms; n is 1 or 2; R1 and R2 are equal or different and represent hydrogen atoms or alkyl groups having 1-4 carbon atoms; ; @@@nein B and @ have the meanings given in Claim 1 J and with a trialkyl phosphite or a cyclic phosphite of the general formula EMI3.1 wherein R4 and R5 have the meanings given in Claim 1, and 6 is a hydrogen atom or an alkyl group having 1-6 car bon atoms. 6. A method of preparing new diphenyl ethers, characterized in that compounds of the general formula EMI3.2 wherein Ar, R1, R2, P.3, R4 and R5 have the meanings given in Claim 1, are prepared by reacting a compound of the general formula EMI3.3 wherein Ar and R 1 have the meanings given in Claim 1, with an aliphatic aldehyde or ketone of the general formula EMI3.4 wherein R2 and R3 have the meanings given in Claim 1, and with a trialkyl phosphite or a cyclic phosphite of the general formula EMI3.5 wherein R4 and n have the meanings given ir Claim 1, and P6 is a hydrogen atom or an alkyl group having 1-6 car bon atoms. which reaction is carried out in an inert organic solvent in the presence of a catalytic quantity of a Lexis acid. A A method as claimed in Claim 4, characterized in that compounds of the general formula EMI4.1 wherein Ar, R1, R2, R3, R4 and P5 have the meanings given in Claim 1, are prepared by reacting a compound of the general formula EMI4.2 wherein Ar has the weaning given in Claim 1, and D is a halogen atom, nitro group or an optionally substituted aryloxy group, with an amino corpound of the general formula EMI4.3 wherein R1, Fl, F , P4 ard R5 have the meanings given in Claim 1. 8. A herbicidal composition, comprising in addition to a solid or liquid inert carrier material a diphenyl ether as an active substance in a herbicidally effective amount, characterized in that the active substance is a compound of the EMI4.4 <tb> general <SEP> formula <tb> <SEP> ;9 <SEP> n <tb> <SEP> / <SEP> '\R7zo0R <tb> <SEP> At <SEP> C- <SEP> V¸\MCz <SEP> 3 <tb> <SEP> \- <SEP> --i <tb> wherein the symbols have the meanings given in Claim 1. R3 A composition for leaf-desiccation, comprising in addition to a solid or liquid inert carrier material a diphenyl ether as an active substance in an amount effective for eaf-desiccation, characterized in that the active substance is (24) diisopropyl 1-[N-{nitro-5-(2,4-dichlorophenoxy)phnyl} amino]ethane phosphonate; (25) dimethyl 1-[N-{2-nitro-5-(2,4-dichlorophenoxy)phenyl}amino] propano phosphonate; (26) dipropyl 1- [N-{2-nitro-5-(2,4-dichlorophenoxy)phenyl}amino] ethane phosphonate; (27) dimethyl 1-[N-{2-nitro-5-(2,4,6-trichlorophenoxy)phenyl} arir.olethane phosphonatc; (28) dimethyl 1-[N-{2-nitro-5-(2,4 -dichloro-5-methoxyphenoxy) phenyl}amino]ethane phosphonate; (29) dimethyl i-{:: :- {2-nitro-5-(4-methylthiophenoxy)phenyl}amino] ethane phosphonate; (30) dimethyl 1-[N-{2-nitro-5-(4-methylsulphonylphenoxy)phenyl} amino]ethane phosphonate; (31) dimethyl 1-[N-{2-nitro-5-(2-nitro-4-trifluoromethylphenoxy) phenyl}amino]ethane phosphonate; (32) diethyl 1- [N-{2-nitro-5-(2-nitro-4-trifluoromethylphenoxy) phenyl}amino]ethane phosphonate; (33) dimethyl 1-L!;-l2-nitro-5-(2-trnflsorowethyl-4-ni'rophenoxy)- phenyllarino]ethane phosphonate; (34) dimethyl 1-[N-{2-nitro-5-(2-chloro-4-nitrophenoxy)phenyl} aminojethane phosphonate; (35) dimethyl 1-[N-{2-nitro-5-(5-chloro-pyridyl-2-oxy)phenyl} amino]ethane phosphonate; (36) dimethyl 1-[N-{2-nitro-5-(3,5-dichloro-pyridyl-2-oxy)phenyl} amino]ethane phosphonate; ; (37) dimethyl 1-[N-{2-nitro-5-(2-chlorophenoxy)phenyl}amino] ethane phosphonate; (38) dimethyl 1-[N-{2-nitro-5-(2-chloro-4-acetylphenoxy)phenyl} amino]ethane phosphonate; (39) dimethyl 1-[N-{2-nitro-5-(2-nitro-4-chlorophenoxy)phenyl} aminojethane phosphonate; (40) dimethyl 1-[N-{2-nitro-5-(4-trifluoromethylphenoxy) phenyl}amino]ethane phosphonate; (41) dimethyl 1- 1-tIs -nitro-5-(2-chloro-4-61,1,2,2-tetrafluoro- ethoxy)phenoxy)phenyl}amino]ethane phosphonate; (42) dimethyl 1-[N-{2-nitro-5-(2-chloro-4-methylthiophenoxy) phenyl}amino]ethane phosphonate; (43) dimethyl 1-methyl-1-[N-{2-nitro-5-(2,4-dibromophenoxy) phenyl}amino]ether phosphonate; (44) diethyl 1- 1-[ll-(g-nitro-5-(4-chlorcphenoxy)phenyllam.ino]¯ ethane phosphonate; ; (45) dimethyl-1-[N-{2-nitro-5-(2,6-dichloro-4-nitrophenoxy)phenyl} amino]ethane phosphonate; and (46) dimethyl-1-[N-{2-nitro-5-(3-chloro-4-methoxyphenoxy)phenyl} amino]ethane phosphonate. The substances according to the invention may be used for the control of undesired plants in agricultural and horticultural crops. Although the new diphenyl ethers have an interesting pre-emergence herbicidal activity, what is most striking is their activity as post-emergence herbicides. Therefore, the compounds according to the invention may be used as post- and as pre-emergence herbicides. The new diphenyl ethers may be used for the control of nonocotyle and in particular dicotyle weeds, for example. Galinsoga parviflora (small-lowered g.), Galium ap2rine (cleavers), Chenotodiuw. album (common lambsquarters), Polvronur. convolvulus (wild buckwheat), CaDsella bursa-Dastoris (shepherd's p'rse), Stellaria media (chickweed), Senecio vulgaris (common groundsel), Veronica arvensis (corn speedwell), Matricaria Faritima (chamomile), Armanthus retroflexus (redroot pigweed), Solanum nigrum (black nightshade), Spergula arvensis (corn spurrey), Urtica dioica (stinging nettle), Polygonum aviculare (knowgrass), Silybum marianum (milk thistle), Xanthium pensylvanicum, Qatura stramonium, Ipomoea muricata, Ipomoea hederacea, Ipomoea lucunosa, Cassia obtusifolia, Sida spinosa, Anoda cristata, Abutilon theophrasti and Portulaca oleracea in various crops, such as in cereals, for eale, wheat, rice, maize, oats and barley, in leguminosae, for example, bean, pea, soya, peanut and lucerne, and in pasture-land. As a special aspect of the invention it has been found that the new substances according to the invention can be used successfully in compositions for leaf-desiccation. Desiccation of defoliation of a crop prior to harvest may have several advantages. In seed crops it hastens maturity of the seeds by wrich harvest can be carried out earlier allowing double cropping of the area or preventing harvest under unfavourable conditions e.g. frest, rains, etc. Mechanical harvest is c.ade much more efficient tN desiccating or de.r liating the crop prior to harvest. Furthermore it can be a great elp in preventirt infection of the product harvested by diseases presert on the vegetative plant parts. Desiccation or defoliating a crop before harvest therefore may have marked effects on crop yield ed quality. In potatoes as much as possbile cf the above ground plant part is eliminated by desiccation in order to prevent infection of the potato tubers Ly diseases present on the vegetative plant parts and in order to facilitate mechanical harvesting. Mecha- ideal harvest in cotton requires the complete removal or dry ing of the leaves for satisfactory results. Desiccation or defoliation furthermore accelerates drying and opening of the green cotton tells without a deleterious effect on bolls already open. Fcr practical use, the substances according to the invention are processe- to compositions. In such cope- sitions the active substance is fixed with solid carrier material, if desired in combination with auxiliary substances, for example, emulsifiers, wetting agents, dispersing agents and stabilizers. Examples of compositions according to the invention are aqueous solutions and dispersions, oily solutions and oily dispersions, solutions in organic solvents, pastes, dusting powders, dispersible powders, miscible oils, granules, pellets and aerosol compositions. Dispersible powders, pastes and miscible cils are compositions in concentrate form which are diluted prior to or during use. The solutions in organic solvents are mainly used in air application, namely when large areas are treated with a comparatively small quantity of composition. The solu tions of the active substance in organic solvents may be pro vided with a phytotoxicity-resJcing substance, for example, wool fat, wool fatty acid or wool fatty alcohol. few ferns of composition will be described in greater detail hereinafter ty way of example. Granular corrositions are prepared by taking up, for example, one active substance in a solvent or dispersing it in a diluent are impregnating the resulting solution/suspenson, if desired the -resence of a binder, on granular carrier material, for example porous granules for example pumice and attaclay), mineral non-porous granules (sand or ground marlow), organic granules (for example, dried coffes grounds, cut tobaccostems or ground corncobs). A granular composition can also be prepared by compressing the active substance together wit powdered minerals in the preserce of lubricants and binders and disintegrating the compressed product to the desired grain size and sieving it. Granular compositions can be prepared in a different manner by mixing the active substance in powder form with powdered fillers, and glomulating the mixture then to the desired particle size. Dusting powders car be obtained by intimately mixing the active substance with n inert solid powdered carrier material, for example, talcum. Dispersible powders are prepared by mixing 10 to 80 parts by weight of a solic inert carrier, for example kaolin, dolomite, gypsum, chalk, bentonite, attapulgite, colloidal SiO2 or mixtures of these and similar substances, with 10 to 80 parts by weight of the active substance, 1 to 5 parts by weight of a dispersing agent, for example the lignine sulphonates or alkylnaphthalene sulphonates known for this purpose, preferably also 0.5 to 5 parts by weight of a wetting agent, for example, fatty alcohol sulphates, alkyl aryl sulphonates, fatty acid condensation products, or polyoxyethylene compounds, and finally, if desired, other additives. For the preparation cf iscible oils the active compound is dissolved in a suitable solvent which preferably is poorly water-miscible, and one cr more emulsifisiers are added to this solution Suitable solvents are, for example, xylene, toluene, petroleum distillates which are rich in aremates, for example, solvent naphtha, distilled tar oil and mixtures of tnese liquids. As emulsifiers may be used, for example, polyoxyethylene compounds and/or alkyl arl sulphonates. The concen tration of the active common in these miscible oils is not restricted to narrow limits nd ray v2ry, for example, between 2 and 50% by weight. In addition to a miscible all may also to mentioned as a liquid and highly concentrated priha@@ composition a solution of the active substance in a reacily water-miscible liquid, for example, a glycol, a glycol ether, dimethylformamide, or N-methyl- pyrrolidone, to which solution a dispersing agent and, if desired, a surface-active substance has been added. When dilu ting with water shortly before cr during praying, an aqueous dispersion of the active substance is then obtained An aerosc' composition according to the invention is obtained in the usual manner by incorporating the active substance, if desired in a sc'vent, in a volatile liquid to be used as a propellant, for example, a mixture of chlorine-flucrine derivatives of methane and ethane, a mixture of lower hydrocarbons, dimethyl ether, or gases such as carbon dioxide, nitrogen and nitrous oxide. n addition t the above-mentioned ingredients, the agents according to the invention tray also contain other substance known for use in this type of agents, For example, a lubricant, for example, calcium stearate or nagnesiun stearate, may be added to a disperslbe powder or a mixture to be granu- lated. "Adhesibes", for example, polyvinylalcohol, cellulose derivatives or other colloidal materials, such as casein, may also be added so as to improve the adhesion of the pesticide to the crop. Furthermore, a substance may be added to reduce the phytotoxicity of the active substance, carrier material or auxiliary substance, for example, wool fat or wool fatty alcohol. Growth regulating and pesticidal compounds known per se may also be incorporated in the compositions accor ding to the invention. As a result of this the activity spec trum of the composition is widened and synergism may occur. In addition foliar fertilizers ray be present. For use in such a combination composition are to be considered, In addition. to insecticidal and acaricidal compounds known per se, the following known growth regulating and fungicidal compounds: Growth regulators, for example: 1. higher alcohols, for example, octanol and decanol; 2. lower esters of fatty acids; 3. etnylene-eneratort, for example, (2-chloroethyl)phosphcnic acid and 2-chloroethyl-tris(2-methoxyethoxy)silane; 4. nltrodiphenyleters; 5. substituted dinitroanilines, for example, 2-chloro-N-ethyl -6-fluoro-N-[2,6-dinitro-4-(trifluoromethyl)phenyl]benzene methaneamine; 6. trifluoromethylsulphonylamino compounds; 7. piperidinederivatives; 8. benzylthiocarbamtes, for example, benzyl N,N'-dipropylthio carbamate; ; 9. phosphorthioncamidates and amidothionphosphonic acid esters; 10. benzoxazoles; and furthermore: maleic hydrazide; 2,3:4-di-O-isopropylidene -&alpha;-xylo-2-hexulo-furanosonic acid-sodium; N,N-dimethylqaminosucci nic acid; &alpha;-cyclopropyl-4-methoxy-&alpha;-(pyrimidin-5-yl)benzyl alcohol; 2-chloroethyltrimethyl ammonium; N,N-di(phosphonomethyl) glycine; 9-hydroxyfluorene-9-carbonic acid (or ester); 2-chloro 9-hyzroxitiuorene-9-carbonic acid tor ester) ; N-1-naphthylphtha- laminic acid; 2,3-dihydro-5,6-diphenyl-1,4-oxathiine; N-!3,4 dimethyl-3-cyclohexenyl)butylamine; and 3,5-dinitro-2,6-di methyl-L-tert.-butylacetophenone; or mixtures cf these compounds. Fungicides, for example: 1. organic tin compounds, for example, triphenyl tin hydroxide and trlphenyl tin acetate; 2. alkylene bisdithiocarbamates, for example, zinc ethylenebis dithiocarbamate and manganese ethylene bisdithiocarbamate; 3. 1-acyl- or 1-carbamoyl-N-benzimidazole (-2) carbamates and 1,2-bis (3-alkoxycarbonyl-2-thiureido)benzene; ; and furthermore 2,4-dinitro-6-(2-octylphenylcrotonate), 1-[bis (dimethylamino)phosphoryl]-3-phenyl-5-amino-1,2,4-triazole, N-trichloromethylthiophthalimide, N-trichloromethylthiotetra hydrophthalimide, N-(1,1,2,2-tetrachloroethylthio)-tetrahydroph thalimide, N-dichlorofluoromethylthio-N-phenyl-N,N'-dimethylsul phamide, tetrachloroisophthalonitrile, 2-(4'-thiazolyl)-benzimi dazole, 5-butyl-2-ethylamino-6-methylpyrimidine-4-yl-dimethyl sulphamate, 1-di-chlorethenoxy-3,3-dimethyl-1,1,2,4-triazole -1-yl)-2-butanate, &alpha;-(2-chlorophenyl)-&alpha; ;-(4-chlorophenyl)-5-pyri midinemethanol, 1-(isopropylcarbamoyl)-3-(3,5-dichlorophenyl) hydantoin, N-(1,1,2,2-tetrachloroethylthio)-4-cyclohexene-1,2carboximide, N-trichloromethylmercapto-4-cyclohexene-1,2-dicarboximide, N-tridecyl-2,6-dimethylmorpholine, metal salts of ethylphosphite, and N-(2,6-dimethylphenyl-N-methoxyacetyl)alanine methylester, or mixtures of these compounds. The dosage cf the composition according to the invent cn desired for practical application will, of course, depend on varicus factos, for example, field of application, active substance chosen, form of composition, nature and size cf the weed and te crops, arc the weather conditions. n general it holds that for herbicidal appli- cation favourable results are reached with a dosage which corresponds with Q.C1 to 5 r:g of active substance per hectare, preferably 0.1 to 3 kg per hectare. For leaf-desiccation good result are obtained with a dosage corresonding with C.1 tc 5 kg of active substance per hectare, preferably 1 to 5 leg per hectare. It has Deer. found that the herbicidal activity, as well as the effectivity for leaf-desiccation of the compositions according to the invention may increase considerably by using suitable adjuvants, for example, mineral oils and/or polyoxyethylene compounds, such as the mineral oils and surface-active substances stated in Metherlands Patent Application 7613453. Dependent or. the application, the quantity of the adjuvant to be used may vary within wide limits and usually is between 10 and 10,000 ml per hectare. The compounds according to the invention are new substances which can be prepared in a manner known per se for the synthesis of related Compounds. So the new compounds of the general formula EMI11.1 where of the symbol have the slive methanols, can be prepared by metalls a composes for the @@oral formula EMI12.1 Ar and R1 have the above meanings with an aliphatic aldehyde or ketone of the general formula EMI12.2 wherein R2 and R3 h-ve the above meanings, and with a trialkyl phosphite or a cyclic phosphite of the general formula EMI12.3 wherein R4 and R5 have the above meanings, and R6 is a hydrogen atom or an alkyl group having 1-6 carion atms. Instead of the above aliphatic aldehyde a polymerized aldehyde such as paraldehyde can be used. A further surprising aspect of the invention is, that it Fas bee found that the above reaction with aliphatic aldehyde and phosphite can best be carried out in an order organic solvent, for example, an aromatic hydrocarbon, for example, toluene, ir. the presence of a catalytic quantity a a Lexis acid, preferably anbydrous ferric chloride or borontrifluoride, the latter for example in the form of an ether complex, e.g. torentrifluoride etherate. The reaction is generally carried out at a temperature between room temperature and the boling-point of the solvent used, preferably at the boi ing-point cf the solvent. The above reaction proceeds in a better yield than with an organic base, e.g. a tertiary amine, as the catalyst instead o' a Lewis acid. New compounds of the general formula EMI12.4 wherein the symbols have the meanings gives before, can be prepared by reacting a compound of the general formula EMI13.1 wherein D is a halogen atom, a nitro group or an optionally substituted aryloxy group, with an amino compound of the general formula EMI13.2 The above reaction is preferably carried out in an inert organic solvent, e.g. dimethyl formamide or an ether such as dioxane, at a reaction temperature between 0 0C and the boiling -point of the solvent used. The invention will now be described in greater detail with reference to the following specific examples. EXAMPLE I Preparation of diethyl 1-[N-{2-nitro-5-(2-chloro-4-trifluoro methylphenoxy)phenylamino]ethane phosphonate (2) 35.6 g (37 ml) of triethyl phosphite, 13.3 g (17 ml) of acetaldehyde and 4 ml of borontrifluorideetherate were successively added to a solution of 23.4 g of 2-nitro-5 (2-chloro-4-trifluoromethylphenoxy)aniline in 300 ml of toluene. After refluxing for 2 hours, the reaction mixture was cooled, after which another 7.8 g (10 ml) of acetaldehyde were added. The reaction mixture was then refluxed again for 2 hours, cooled and washed successively with 200 ml of 2 N hydrochloric acid and three times with water. After drying, filtering, distilling off the volatile constituents under reduced pressure and column chromatography of the residue over silica as a carrier and with ethyl acetate as an eluent, 26.8 g of the desired product were obtained as a yellow syrupy liquid. Elementary analysis: 45.82% C (calculated 45.93), 4.25% H (calculated 4.26), 5.57% N (calculated 5.64) and 6.28% P (calculated 6.23). The following compounds were prepared in a corresponding manner: Solid compounds were purified by means of a recrystallization. The compounds are identified by the compound numbers used in the specification before. (1) ; melting-point 105 C; Elementary analysis: 43.82% C (Calculated 44.15), 3.82X (calculated 3.94), 16.22% Cl (calculated 16.29), 6.42% N (calculated 6.44) and 7.22% P (calculated 7.13); the last compound could be prepared in substantially the same yield by using anhydrous FeCl3 instead of BF3, and by using paraldehyde instead of acetaldehyde; (5) ; melting-point 82-83 C; Elementary analysis: 43.02% C (calculated 43.44), 4.08% (calculated 4.05), 21.07% Cl (calculated 21.37), 5.56% N (calculated 5.63), and 6.14% P (calculated 6.22); (6) ; identified by means of NMR spectrum; syrupy liquid; (4) ; syrupy liquid; Elementary analysis: found 46.62% C (calculated 46.66), found 5.01% H (calculated 4.57), found 14.94% Cl (calcu lated 15.31), found 5.93% N (calculated 6.04) and found 6.61% P (calculated 6.69); l3) ; syrup; IR: # (cm 1) 3350, 1630, 1340, 1320, 1260, 1230, 1170, 1130, 1080, 1050, 1030, 750; (7) ; melting-point 91 C; (8) ; melting-point 93 C; (9) ; melting-point 122 C; (10); syrup; IR: #(cm-1) 3340, 1630, 1338, 1260, 1220, 1050, 1030, 752; (11) ; syrup; IR: # (cm 1) 3335, 1630, 1342, 1260, 1225, 1050, 1030, 752; (12) ; melting-point 78 C (14); syrup; IR: #(cm-1) 3340, 1630, 1340, 1320, 1255, 1220, 1170, 1133, 1113, 1050, 1030, 750; (15); melting-point 133 C; (16); melting-point 131 0C; (17); syrup; IR: Y (cm-1 3335, 1625, 1338, 1260, 1230, 1050, 1030, 965, 750; (18) ; melting-point 77 C; (19) ; melting-point 95 C; (20); syrup; PMR (CDC13) # 8.61 (NH,t), 8.19 (d), 1,53 (d), 7.3, (g), 7.09 (d), 6.26 (q), 6.12 (d), 5.55 (2, m), 4.20 (5, m), 1.70 (3,m), 1.30 (6,m); (21); syrup; IR: r (cm-1) 3360, 1628, 1340, 1250, 1230, 1050, 1020, 970, 752; (22) ; melting-point 111 C; (23); syrup; IR: # (cm 1) 3320, 1733, 1620, 1332, 1260, 1230, 1040, 755; (24); syrup; IR: 8 (cm ) 3340, 1628, 1340, 1255, 1225, 990, 753; (25); syrup; PMR (CDCl3) 8.30(NH,q), 8.18 (d), 7.53 (d), 7.32 (q), 7.12 (d), 6.33 (d), 6.20 (q), 3.55-3.80 (7,m) 1.65-2.12 (2,m) 1.04 (3,t); (26); syrup; IR: 8 (cm ) 3340, 1630, 1340, 1255, 1225, 1000, 754; (27); melting-point 1760C; (28); syrup; IR: # (cm ) 3340, 1630, 1340, 1260, 1210, 1050, 1030, 750; (29) ; melting-point 75 C; (30) ; melting-point 145 C; (31); syrup; PMR (CDCl3) # 8.31 (NH), 8.26 (d), 8.22 (d), 7.95 (q), 7.42 (d), 6.68 (d), 6.36 (q), 3.70-4.20 (7, m), 1.58 (3,q); (32); syrup; PMR (CDCl3) i8.25(NH,q), 8.20 (d), 8.14 (d), 7.88 (q) 7.35 (d), 6.30 (d), 6.22 (d), 4.16 (2,m), 3.88 (m), 1.54 (q), 1.32 (3,t); (33); melting-point 1400C; (34) ; melting-point 99 C; (35) ; melting-point 151 C; (36); syrup; IR: # (cm ) 3350, 1630, 1342, 1260, 1220, 1050, 1030, 750; (37); syrup; IR: # (cm ) 3350, 1635, 1344, 1260, 1220, 1050, 1030, 750; (38); syrup; IR: # (cm ) 3340, 1690, 1630, 1338, 1250, 1220, 1050, 1030, 750; (39) ; melting-point 110 C; (40); melting-point 630C; (41); syrup; CMR for F2C1H-CêF2-O-C6H3(Cl)OC6H3(NO2)-NHC H(C4H3) -P(O)(OC5H3)OC6H3; chemical shift (ppm) (coupling-Hz) C1 107.5 (252.5; 40.7), Cê 116.5 (273.5; 28.7), C 45.6 (160.0), C4 16.1, C5 53.5 (7.4), C6 53.4 (6.5); (42); syrup; IR: 2 (cm-1) 3340, 1630, 1340, 1260, 1220, 1050, 1030, 752; (43); melting-point 101 0C; (44) ; melting-point 62 C; (45) ; melting-point 130 C; and (46); melting-point 1030C. EXAMPLE II Preparation of diethyl 1- N-12-nitro-5-(2,4-dichlorophenoxy) phenylbaminogethane phosphonate. A mixture of 27.6 g of diethyl phosphite, 4.4 g of acetaldehyde and 2 g of triethylamine was heated on 60-700C for 45 minutes. After adding another 4.4 g of acetaldehyde the mixture was heated again for 1 hour. Again a portion of acetaldehyde (2.4 g) was added and the reaction mixture was kept at room temperature overnight. A solution of 15 g of 2.4-dichloro-3'-amino-4'-nitro-diphenyl- ether in 200 ml of toluene was added to the above reaction mixture. The reaction mixture obtained was refluxed for 4 hours. After washing with water, diluted hydrochloric acid and water again the organic solvent was evaporated, yielding the crude product as a red oil. The oil was chromatographed over silica (ether as a eluent) producing 11.5 g of the desired product. The product, a syrupy liquid, was identificalwith compound no. (14) prepared according to Example I. EXAMPLE III Preparation of diethyl 2-0N-{2-nitro-5-(2-chloro-4-trifluoro- methylpbenoxy)phenyljaminoJethane phosphonate. A solution of 3.63 g of 2-chloro-4-trifluoromethyl-3',4'-dinitro-diphenylether and 5,85 g of O,O'-diethyl (2-aminoethane)phosphonate in 10 ml of dioxane was stirred at 50 0C for 3 hours, After cooling down to room temperature and adding water the aqueous phase was extracted with methylene chloride. After washing and drying the organic phase was reduced under diminished pressure, yielding an oily substance. The product obtained was chromatographed over silica (ethyl acetate as the eluent). The desired product was obtained as an orange syrup in a yield of 4.03 g; IR: Y (cm ) 3360, 1630, 1342, 1325, 1260, t240, 1170, 1130, 1080, 1050, 1030, 960, 750. The above product could be prepared in substantially the same yield under exactly the same reaction conditions, but now starting from 2,4-bis(2,4-dichlorophenoxy) nitrobenzene as the diphenyl ether compound. EXAMPLE IV (a) Preparation of a solution of an active substance, namely diethyl 1-[N-{2-nitro-5-(2-chloro-4-trifluoromethylphenoxy) phenyl}aminojethane phosphonate, in a water-miscible liquid t"liquid"). 10. g of the above active substance were dis solved in a mixture of 10 ml of isoforon and approximately 70 ml of dimethylformamide, after which polyoxyethylene gly col ricinyl ether as an emulsifier was added in a quantity of 10 g. In a corresponding manner the other active sub stances were processed to 10% to 20% "liquids". In a corresponding manner, "liquids" were ob tained in N-methyl pyrrolidone, dimethylformamide, and a mixture of N-methyl pyrrolidone and isoforon as solvents. (b) Preparation of a solution of the active substance in an organic solvent. 200 mg of the active substance to be examined were dissolved in 1,000 ml of acetone in the presence of 1.6 g of nonylphenolpolyoxyethylene. This solution was used as a spraying liquid. (c) Preparation of an emulsifiable concentrate of the active substance. 10 g of the active substance to be examined were dissolved in a mixture of 15 ml of isoforon and 70 ml of xylene; 5 g of a mixture of a polyoxyethylene sorbitan ester and an alkyl benzene sulphonate were added to this solution as an emulsifier. (d) Preparation of a dispersible powder (W.P.) of the active substance. 25 g of the active substance to be examined were mixed with 68 g of kaolin in the presence of 2 g of sodium butylnaphthalene sulphonate and 5 g of lignine sul phonate. (e) Preparation of a suspension concentrate (flowable) of the active substance. A mixture of 10 g of active substance, 2 g of lignine sulphonate and 0.8 g of a sodium alkyl sulphate was replenished with water up to a total quantity of 100 ml. (f) Preparation of a granule of the active substance 7.5 g of active substance, 5 g of sulphite lye and 87.5 g of ground dolomite were mixed, after which the resulting mixture was processed to a granular composition by means of the so-called compacting method. EXAMPLE V Selective control of weeds ("post-emergence") in agricultural and horticultural crops; open-air experiment (field screening). Compounds according to the invention were used in a formulation obtained according to Example IV (a) in a quantity of 0.1 kg per hectare in a trial plot comprising the following weeds: Galinsoga parviflpra (small-flowered g.,Gp), Valium aParine (cleavers, Ga), Chenopodium album (common lambsquarters, Ca), and Polygonum convolvulus (wild buckwheat, Pc); the following crops were present in the trial plot: Triticum aestivum (wheat, Ta) and Pisum sativum (pea, Ps). The weeds and crops were sown simultaneously After coming-up they were sprayed with a "liquid" poured-out in water, obtained according to Example IV (a), by means of a Teejet nozzle mounted on a spraying boom of a tractor. The spray liquid was sprayed in a quantity of 500 litres per hectare. After 14 days the herbicidal activity was evaluated. The results are recorded in Table A The meanings of the symbols recorded in the Table are as follows: - = no or hardly any observable damage + = obvious damage + = serious damage ++ = the plants are dead. TABLE A Results of open-air experiment in post-emergence application; 0.1 kg of active substance per hectare. 2,4-dichloro-3'-isopropylamino-4'-nitrodiphenyl ether = known EMI19.1 <tb> <SEP> Activity <SEP> on <tb> compound <SEP> no. <SEP> Ta <SEP> Ps <SEP> Gp <SEP> Ga <SEP> Ca <SEP> Pc <tb> <SEP> (2) <SEP> + <SEP> + <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> <SEP> (4) <SEP> + <SEP> - <SEP> ++ <SEP> + <SEP> ++ <SEP> ++ <tb> <SEP> (5) <SEP> + <SEP> + <SEP> ++ <SEP> ++ <SEP> ++ <SEP> + <tb> <SEP> known <SEP> + <SEP> + <SEP> jj <SEP> + <SEP> + <SEP> ++ <SEP> ++ <tb> EXAMPLE VI Selective control of weeds ("pre-emergence") in agricultural and horticultural crops; open-air experiment (field screening). Compounds according to the invention were used in a formulation obtained according to Example IV (a) in a quantity of 3 kg per hectare against the weeds mentioned in Example V; in the trial plot the following crops were sown: Triticum aestivum (wheat, Ta), Pisum sativum (pea, Ps) and Glvcine max (soya, Cm) The weeds and crops were sown simultaneously. Before coming-up they were sprayed with a "liquid", obtained according to Example IV (a) poured-out in water, by means of the spraying device described in Example V. The spray liquid was sprayed in a quantity of 500 litres per hectare. After 21 days the herbicidal activity was evaluated. The results are recorded in Table B; the meanings of the symbols are the same as in Example V. TABLE B Results open-air experiment in pre-emergence application; 3 kg of active substance per hectare. EMI19.2 <tb> <SEP> Activity <SEP> on <SEP> ¯¯¯¯ <tb> compound <SEP> no. <SEP> Ta <SEP> Ps <SEP> Gm <SEP> Gp <SEP> Ga <SEP> Ca <SEP> Pc <tb> <SEP> (2) <SEP> - <SEP> <SEP> + <SEP> + <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> <SEP> (5) <SEP> - <SEP> - <SEP> - <SEP> ++ <SEP> ++ <SEP> + <SEP> EXAMPLE VII Selective control of weeds ("post-emergence") in agricultural and horticultural crops; glasshouse experiments. Compounds according to the invention were used in a formulation obtained according to Example (b) in the dosages indicated in Table C below against the following weeds: Galinsoga parviflora (small-flowered g., Gp), Galium aparine (cleavers, Ga), Chenopodiurn album (common lambsquarters, Ca), and Polygonum convolvulus (wild buckwheat, Pc); the following crops were present: Tritium aestivum (wheat, Ta), Orvza sativa (rice, Os) and Glycine max (soya, Gm). The weeds and crops were sown simultaneously. After coming-up they were sprayed with a spraying liquid, obtained according to Example IV (b), by means of a Sata sprayer. The herbicidal activity was determined after 2 weeks. The results are recorded in Table C; the meanings of the symbols are the same as in Example V. TABLE C Results glasshouse experiments in post-emergence application 2,4-dichloro-3'-isopropylamino-4'-nitrodiphenyl ether = known EMI20.1 <tb> compound <SEP> dosage <SEP> in <SEP> g <SEP> act. <SEP> Activity <SEP> on <tb> no. <SEP> ; <SEP> subst. <SEP> per <SEP> ha. <SEP> Ta <SEP> Os <SEP> Gm <SEP> Gp <SEP> Ga <SEP> Ca <SEP> Pc <tb> <SEP> (1) <SEP> ) <SEP> 100 <SEP> # <SEP> + <SEP> + <SEP> + <SEP> i <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> <SEP> 50 <SEP> + <SEP> ++ <SEP> + <SEP> ++ <SEP> ++ <SEP> <tb> <SEP> 30 <SEP> <SEP> <SEP> + <SEP> ++ <SEP> + <SEP> ++ <SEP> ++ <tb> <SEP> (4) <SEP> 100 <SEP> 1 <SEP> + <SEP> + <SEP> + <SEP> @ <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> <SEP> 50 <SEP> + <SEP> + <SEP> + <SEP> + <SEP> .++ <SEP> + <SEP> ++ <SEP> ++ <tb> <SEP> 30 <SEP> ! <SEP> <SEP> + <SEP> + <SEP> + <SEP> ++ <SEP> + <SEP> ++ <SEP> ++ <tb> <SEP> (5) <SEP> 100 <SEP> # <SEP> <SEP> # <SEP> <SEP> + <SEP> ++ <SEP> + <SEP> ++ <SEP> ++ <tb> <SEP> (6) <SEP> 100 <SEP> - <SEP> # <SEP> <SEP> ++ <SEP> + <SEP> + <SEP> ++ <tb> <SEP> known <SEP> 100 <SEP> <SEP> <SEP> + <SEP> + <SEP> + <SEP> + <SEP> ++ <SEP> ++ <tb> EXAMPLE VIII Exactly as described in Example VII compounds according to the invention were tested in the glasshouse with regard to their herbicidal activity against the weeds defined in Example VII. ThS results are recorded in Table D; the meanings of the symbols are the same as in Example V. All compounds were tested in a dosage of 100 g of active substance per hectare. TABLE D EMI21.1 <tb> <SEP> Activity <SEP> on <tb> compound <SEP> no. <SEP> Gp <SEP> Ga <SEP> Ca <SEP> Pc <tb> <SEP> (1) <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> <SEP> (2) <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> <SEP> (3) <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> <SEP> (4) <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> <SEP> (7) <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> <SEP> (8) <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> <SEP> (9) <SEP> ++ <SEP> + <SEP> ++ <SEP> ++ <tb> <SEP> (10) <SEP> ++ <SEP> + <SEP> ++ <SEP> ++ <tb> <SEP> 11 <SEP> ) <SEP> ++ <SEP> + <SEP> ++ <SEP> ++ <tb> <SEP> (12) <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> <SEP> (13) <SEP> + <SEP> + <SEP> ++ <SEP> ++ <tb> <SEP> 1 <SEP> 4) <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> <SEP> (15) <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> <SEP> (16) <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> <SEP> (17) <SEP> i <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> <SEP> (18) <SEP> ! <SEP> ++ <SEP> <SEP> ++ <SEP> ++ <SEP> ++ <SEP> <tb> <SEP> (19) <SEP> ++ <SEP> + <SEP> ++ <SEP> ++ <tb> <SEP> (20) <SEP> t <SEP> ++ <SEP> ++ <SEP> + <SEP> ++ <SEP> ++ <tb> <SEP> (21) <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> <SEP> (22) <SEP> 1 <SEP> ++ <SEP> + <SEP> <SEP> ++ <SEP> ++ <SEP> <tb> <SEP> (23) <SEP> i <SEP> + <SEP> + <SEP> ++ <SEP> ++ <tb> <SEP> (24) <SEP> 2 <SEP> <SEP> + <SEP> + <SEP> ++ <SEP> ++ <tb> <SEP> (25) <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> <SEP> (26) <SEP> , <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> <SEP> (27) <SEP> i <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> <SEP> (28) <SEP> ++ <SEP> + <SEP> ++ <SEP> ++ <tb> <SEP> (29) <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> <SEP> (30) <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> <SEP> (31) <SEP> ++ <SEP> + <SEP> ++ <SEP> ++ <tb> <SEP> (32) <SEP> ) <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> <SEP> (33) <SEP> ++ <SEP> + <SEP> ++ <SEP> ++ <tb> (continuation table D) EMI22.1 <tb> <SEP> Activity <SEP> on <tb> compound <SEP> no. <SEP> Gp <SEP> Ga <SEP> Ca <SEP> Pc <tb> (34) <SEP> ++ <SEP> + <SEP> ++ <SEP> + <tb> (35) <SEP> . <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> (36) <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> (37) <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> (38) <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> (39) <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> (40) <SEP> + <SEP> + <SEP> ++ <SEP> ++ <tb> (41) <SEP> ++ <SEP> ++ <SEP> ++ <SEP> ++ <tb> (43) <SEP> + <SEP> + <SEP> ++ <SEP> ++ <tb> (44) <SEP> ++ <SEP> + <SEP> ++ <SEP> ++ <tb> (45) <SEP> ++ <SEP> + <SEP> ++ <SEP> ++ <tb> EXAMPLE IX Potato and cotton desiccation. Compounds according to the invention were used in a composition obtained according to Example IV (b) The plants were sprayed with these liquids in the quantities tabu lated below. After 2 weeks the activity of leaf desiccation, and, for cotton, of leaf abscission was evaluated. The results are recorded in Table E. The meanings of the symbols are as follows: - = no or hardly any desiccation effect + = obvious effect + = strong desiccation ++ = complete dieing back or abscission of the leaves. TABLE E Leaf desiccation EMI22.2 <tb> <SEP> compound <SEP> act. <SEP> on <SEP> potato <SEP> activity <SEP> on <SEP> cotton <SEP> <SEP> ¯¯¯¯¯¯¯¯¯ <SEP> <tb> no. <SEP> dosage <SEP> (kgIha) <SEP> leaves <SEP> stem <SEP> leaves <SEP> stem <SEP> leaf <SEP> abscission <tb> (1) <SEP> 3 <SEP> ++ <SEP> X <SEP> + <tb> <SEP> 1 <SEP> . <SEP> ++ <SEP> + <tb> (4) <SEP> 5 <SEP> ++ <SEP> + <SEP> ++ <tb> <SEP> 3 <SEP> ++ <SEP> ++ <tb> <SEP> 1 <SEP> <SEP> + <SEP> + <SEP> + <SEP> + <SEP> <tb> (5) <SEP> 3 <SEP> + <SEP> + <SEP> + <SEP> + <SEP> + <tb> <SEP> 1 <SEP> <SEP> + <SEP> - <SEP> + <SEP> ?-+ <SEP> + <SEP> <tb>

Claims: CLAIMS: 1. A diphenyl ether of the general formula EMI23.1 wherein Ar is a phenyl or pyridyl group, which groups are sub stituted with 1,2 or 3 substituents, selected from the group consisting of a halogen atom, a cyano group, a nitro group, an optionally halogenated alkyl, alkoxy and alkylthio group having 1-6 carbon atoms, an alkylsulphonyl group having 1-4 carbon atoms, and an alkanoyl group having 1-4 carbon atoms; n is 1 or 2; R1 and R2 are equal or different and represent hydrogen atoms or alkyl groups having 1-4 carbon atoms; R3 is a hydrogen atom, an alkyl or alkenyl group having 1-4 carbon atoms and optionally substituted with an alkoxycarbonyl group with 2-5 carbon atoms; or R2 and R3 together form an alkylene group with 2-5 car bon atoms; and R4 and R5 are equal or different and represent alkyl groups having 1-6 carbon atoms; or R4 and R5 together form an alkylene group having 2 or 3 carbon atoms. 2. A compound as claimed in Claim 1, of the general formula EMI23.2 wherein Ar' is a phenyl group, substituted in the 2,4- or 2,4,6 -positions with substituents selected from the group consisting of a halogen atom, a nitro group and a trifluoromethyl group, with the proviso tat one of the substituents at most represents a nitro group or a trifluoromethyl group, R3' is an alkyl or alkenyl group having 1 or 2 carbon atoms, and R4 and R5 have the meanings given in Claim 1. 3. A compound as claimed in Claim 2, selected from the group consisting of diethyl and diethyl esters of 1-[N-{2-nitro-5-(2,4-dichlorophenoxy)phenyl}amino]ethane phosphonic acid and of 1-[N-{2-nitro-5-(2-chloro-4-trifluoromethyl- phenoxy)phenylamino] ethane phosphonic acid. 4. A method of preparing new diphenyl ethers, characterized in that compounds of the general formula EMI24.1 wherein Ar, n, R1, R2, R3, R4 and R5 have the meanings given in Claim 1, are prepared in a manner known per se for the preparation of related compounds. 5. A method as claimed in Claim 4, characterized in that compounds of the general formula EMI24.2 wherein Ar, R1, R2, R3, R4 and R5 have the meanings given in Claim 1, are prepared by reacting a compound of the general formula EMI24.3 wherein Ar and R1 have the meanings given in Claim 1, with an aliphatic aldehyde or ketone of the general formula EMI24.4 P 3 is Z hydrogen atom, an alkyl or alkenyl group having 1-4 carbon atoc and optionally substituted with an alkoxycarbonyl group with 2-5 carbon atoms; or R2 and R3 together form an alkylene group with 2-5 car bon atoms; and R4 and R5 are equal or different and represent alkyl groups having 1-6 carbon atoms; cr P 4 and P5 together form an alkylene group having 2 or 3 carbon atoms. Particularly suitable havc proved ne; copounds of the general formula EMI25.1 wherein Ar' is a phenyl group, substituted in the 2,4- or 2,4,6 -positions with substituents selected from the group consisting of a halogen atom, a nitro group and a trifluoromethyl group, with the proviso that one of the substituents at most represents a nitro group or a trifluoromethyl group, R3' is an alkyl or alkenyl group having 1 or 2 carbon atoms, and R4 and R5 have the above meanings. Dimethyl and diethyl esters of 1-[N-{2-nitro-5 (2,4-dichlorophenoxy)phenyl}amino]ethane phosphonic acid and of 1-[N-{2-nitro-5-(2-chloro-4-trifluoromethylphenoxy)phenyl}amino] ethane phosphonic acid have proved to be excellently suitatle for use as active substances in compositions having selective herbicidal activity, such as dimethyl 1-[!-(2-nitro-5-(2,4-di chlorophenoxy)phenyl}amino]ethane phosphonate (1), diethyl 1 [N-{2-nitro-5-(2-chloro-4-trifluoromethylphenoxy)phenyl}amino] ethane phosphonate (2), dimethyl 1-[N-{2-nitro-5-(2-chloro-4 trifluoromethylphenoxy)phenyl}amino]ethane phosphonate (3), and diethyl 1-[N-{2-nitro-5-(2,4-dichlorophenoxy)phenyl}amino]ethane phosphonate. Other examples of new diphenyl ethers according to the invention which. may Lf used as elective herbicide , are: (5) diethyl 1-[N-{2-nitro-5-(2,4,6-trichlorophenoxy)phenyl}amino] ethane phosphonate; (6) dibutyl 1-[N-{2-nitro-5-(2,4,6-trichlorophenoxy)phenyl}amino] ethane phosphonate; (7) dimethyl 1-[N-{2-nitro-5-(4-methylphenoxy)phenyl}amino]ethane phosphonate; (8) dimethyl 1-[N-{2-nitro-5-(4-trifluoromethylphenoxy)phenyl} aminozethane phosphonate; (9) dimethyl 1-[N-{2-nitro-5-(4-cyanophenoxy)phenyl}amino]ethane phosphonate; (10) dimethyl 1-[N-{2-nitro-5-(4-n-propylphenoxy)phenyl}amino] ethane phosphonate; (11) dimethyl 1-[N-{2-nitro-5-(4-tert.-butylphenoxy)phenyl}amino] ethane phosphonate; (12) dimethyl 1-[N-{2-nitro-5-(2-methyl-4-chlorophenoxy)phenyl} amino]ethane phosphonate; ; (13) diethyl 1-[N-{2-nitro-5-(2-chloro-4-trifluoromethylphenoxy) phenyl}amino]ethane phosphonate; (14) dimethyl 1-rle-L2-nitro-5-(2,6-dichloro-4-trifluoromethylphe- noxy)phenyl}amino]ethane phosphonate; (15) dimethyl 1-[N-{2-nitro-5-(4-bromophenoxy)phenyl}amino]ethane phosphonate; (16) dimethyl 1-[N-{2-nitro-5-(2,4-dibromophenoxy)phenyl}amino] ethane phosphonate; (17) diethyl 1-[N-{2-nitro-5-(2,4-dibromophenoxy)phenyllaminol¯ ethane phosphonate; (18) dimethyl 1-[N-{2-nitro-5-(4-chlorophenoxy)phenyl}amino] ethane phosphonate; (19) diethyl 1-[N-{2-nitro-5-(2,4-dichlorophenoxy)phenyl} amino]ethane phosphonate; (20) diethyl 1-[N-{2-nitro-5-(2,4-dichlorophenoxy)phenyl}amino] butene-2 phosphonate; (21) diethyl N-[2-nitro-5-(2,4-dichlorophenoxy)phenylJaminomethane phosphonate; ; (22) dimethyl 1-methyl-[N-{2-nitro-5-(2,4-dichlorophenoxy)phenyl} amino propane phosphonate; (23) dimethyl 1-ethoxycarbonylmethyl-1-[N - /2-nitro-5-(2,-dicloro- phenoxy)phenyl}amino]ethane phosphonate; a compound of the general formula EMI27.1 wherein the symbols have the meanings given in Claim 1. 10. A composition as claimed in Claim 8 or 9, characterized in that the composition comprises as an active substance a compound of the general formula EMI27.2 wherein Ar' and R 3, have the meanings given in Claim 2, and R4 and R5 have the meanings given in Claim 1. 11. A composition as claimed in Claims 8 or 9, characterized in that the composition comprises as an active substance a compound selected from the group consisting of dimethyl and diethyl esters of 1-[N-{2-nitro-5-(2,4-dichloro- phenoxy)phenyl}amino]ethane phosphonic acid and of 1-EN-(2- -nitro-5-(2-chloro-4-trifluoromethylphenoxy)phenylgarino]ethane phosphonic acid. 12. A method of preparing a herbicidal composition or a composition for leaf-desiccation as claimed in any of claims 8-11, characterized in that, in addition to a solid or liquid inert carrier material, a compound of the general formula EMI27.3 wherein the symbols have the meanings given in Claim 1, is incorporated in the composition, if desired while adding other herbicidal and/or pesticidal compounds, artificial manures and/or auxiliary substances such as surface-active substances and stabilizers. 13. A method of controlling undesired plants in agricultural and horticultural crop, characterized in that the crop or the soil destined for the plants is treated with a composition as claimed in any of the claims 8, 10 and 11 in a dosage from 0,01 to 5 kg of active substance per hectare, preferably from 0.1 to 3 kg per hectare. 14. A method of leaf-desiccation in agricultural and horticultural crop, characterized in that the crop is treated with a composition as claimed in any of the claims 9-11 in a dosage from 0.1 to 5 kg of active substance per hectare, preferably from 1 to 5 kg per hectare.

Inventors: PAERELS, GERARD BERNARD, RAVEN, CORNELIS WOUTER
Applicants: DUPHAR INTERNATIONAL RESEARCH B.V
Application year: 1982
Main classification: C07F9
IPC codes: C07F9, A01N57