NL8300084A - HETEROCYCLIC ESTERS OF PHENOXYBENZOIC ACIDS. - Google Patents

Description

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Heterocyclic esters of phenoxybenzoic acids.

The invention relates to new products and more particularly to new chemical compounds of the formula 1, wherein X represents halogen or trifluoromethyl, Y is selected from hydrogen, halogen, nitro 5 and cyano, R is selected from nitro, alkylthio, halogen and cyano and n is the integers 1 or 2.

The compounds of the invention are surprisingly useful as selective herbicides.

According to a preferred embodiment of the invention, X is chlorine, bromine or trifluoromethyl, Y is hydrogen, chlorine, bromine, nitro or cyano and R is nitro, methylthio, chlorine, bromine or cyano.

The compounds of the invention may be prepared by reacting an acid chloride of the formula II, wherein X, Y and R have the meanings indicated above, with an alcohol of the formula 3, in which one of the integers 1 or 2 in the presence of an acid acceptor such as a tertiary amine. This reaction can be carried out by combining approximately equimolar amounts of the acid chloride and the alcohol in an inert organic reaction medium, such as toluene. Preferably, excess molar amounts of acid acceptor are used to ensure removal of the hydrogen chloride formed. The reaction is typically conducted at room temperature with stirring. After the completion of the reaction, the desired product can be recovered by first removing the acid acceptor salt and then evaporating the solvent used as reaction medium. This product can then be used as such or further purified using conventional techniques.

The acid chloride of the formula 2, which is 8300084 * t

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K - v - 2 - can be used in the preparation of the compounds of this invention, can be easily prepared from the corresponding acids by reaction with thionyl chloride.

Examples of precursor acids for the acid chlorides of the formula II are 2-nitro-5- (2-chloro-4-trifluoromethylphenoxy) benzoic acid, 2-nitro-5- (2-bromo-4-trifluoromethylphenoxy) benzoic acid, 2-nitro-5- (2,4-dichlorophenoxy) benzoic acid, 2-nitro-5- (2-nitro-4-chlorophenoxy) benzoic acid, 2-nitro-5- (2-cyano-4-trifluoromethylphenoxy) benzoic acid, 2 -nitro-5- (4-tri-10 fluoromethylphenoxy) benzoic acid, 2-methylthio-5- (2-chloro-4-trifluoromethylphenoxy) benzoic acid, 2-chloro-5- ('2-chloro-4-trifluoro -methylphenoxy) benzoic acid, 2-bromo-5- (2-chloro-4-trifluoromethyl-phenoxy) benzoic acid, 2-ethylthio-5- (2-chloro-4-trifluoromethyl-phenoxy) benzoic acid, 2-propylthio-5- ( 2-chloro-4-trifluoromethyl-15-phenoxy) benzoic acid, 2-eyano-5 - ((2-chloro-4-trifluoromethyl-phenoxy) -benzoic acid and the like.

Examples of alcohols of the formula III which can be used in. the preparation of the compounds of the invention are 3-hydroxytetrahydrofuran, 3-hydroxytetrahydropyran, 4-hydroxytetrahydropyran and the like.

The compounds of the invention in which the tetrahydrofuranr or tetrahydropyran moieties are attached to the carboxylic acid group in the 2-position are preferably prepared by reacting the acid corresponding to formula 2 with dihydrofuran or 3,4-dihydfopyran. . This reaction can be carried out by combining the acid and the. dihydrofuran or dihydropyran at room temperature in the presence of a catalytic amount of p-toluenesulfonic acid. The use of an excess of pyran or furan is preferred. After the reaction is complete, the mixture can be washed and stripped to remove excess starting material to yield the desired product.

The manner in which the compounds of the invention can be prepared is more particularly illustrated in the following examples.

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Example I

Preparation of 2-nitro-5- (2-chloro-4-trifluoromethylphenoxy) benzoyl chloride.

2-Nitro-5- (2-chloro-4-trifluoromethyl-5-phenoxy) -benzoic acid (80 grams) and toluene (80 ml) were placed in a reaction vessel equipped with a mechanical stirrer, thermometer and reflux condenser. Thionyl chloride (80 ml) was slowly added at room temperature with stirring. After the addition was complete, the mixture was refluxed with continued stirring for a period of 1 hour.

Stirring was then continued at room temperature overnight. The reaction mixture was then stripped to remove toluene to give the desired product as an oil.

Example II

Preparation of 3-Tetrahydro-uryl-2-nitrile-5- (2-chloro-4-trifluoro-methylphenoxy) benzoate.

3-hydroxytetrahydrofuran (1.76 grams; 0.02 mol), toluene (50 ml) and triethylamine (2.0 grams; 0.02 mol) were placed in a glass reaction vessel equipped with a mechanical stirrer and addition funnel . A solution of 2-nitro-5- (2-chloro-4-trifluoromethyl-enoxy) benzoyl chloride (7.60 g; 0.02 mol) in toluene (10 ml) was added slowly with stirring . After the addition was complete, stirring was continued overnight. The reaction mixture was then washed with water and dried over anhydrous sodium sulfate. The dried solution was then stripped under reduced pressure to remove the solvent to leave a brown oil. This oil was purified by silica gel chromatography using toluene and ethyl acetate / toluene mixtures as the eluent. The purified oil was triturated in ethanol to give the desired product, namely 3-tetrahydro-furyl-2-nitro-5- (2-chloro-4-trifluoromethylphenoxy) benzoate, as a white solid, mp 55 °. C.

35 8300084 * *

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Example III

Preparation of 3-Tetrahydrofurryl-2-nitro-5- (2-bromo-4-trifluoromethylphenoxy) benzoate.

3-hydrotetrahydrofuran (0.04 mol), 5 toluene, (50 ml) and triethylamine (0.04 mol) are placed in a glass reaction vessel equipped with a mechanical stirrer and addition funnel. A solution of 2-nitro-5- (2-bromo-4-trifluoromethylphenoxy) benzoyl chloride (0.04 mol) in toluene (20 ml) is slowly added at room temperature with stirring. After the addition is complete, stirring is continued for a period of about 8 hours. The reaction mixture is then washed with water and dried over anhydrous magnesium sulfate. The dried solution is stripped under reduced pressure to remove the solvent leaving a residue. This residue is purified by silica gel chromatography using toluene and ethyl acetate / toluene mixtures as an eluent to yield the desired product, namely 3-tetrahydrofuryl-2-nitro-5- (2-bromo-4-trifluoromethylphenoicy) benzoate .

Example IV

Preparation of 3-tetrahydrofofuryl-2-nitro-5- (2-nitro-4-trifluoromethylphenoxy) benzoate.

3-Hydroxytetrahydrofuran (0.04 mol), toluene (50ml) and triethylamine (0.04 mol) are placed in a glass reaction vessel equipped with a mechanical stirrer and addition funnel. A solution of 2-nitro-5- (2-nitro-4-trifluoromethylphenoxy) benzoyl chloride (0.04 mol) in toluene (20 ml) is slowly added at room temperature with stirring. After the addition is complete, stirring is continued for a period of about 8 hours. The reaction mixture is then washed with water and dried over anhydrous magnesium sulfate. The dried solution is stripped under reduced pressure to remove the solvent to leave a residue. This residue is purified by silica gel chromatography using toluene and ethyl acetate / toluene mixtures as the eluent to yield the desired product 8300084-5.

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3-tetrahydrofuryl-2-nitro-5- (2-nitro-4-trifluoromethylphenoxy) benzoate.

Example V

Preparation of 3-tetrahydrofuryl-2-nitro-5- (2-cyano-4-trifluoro-5 methylphenoxy) benzoate.

3-hydroxytetrahydrofuran (0.04 mol), toluene (50 ml) and triethylamine (0.04 mol) are placed in a glass reaction vessel equipped with a mechanical stirrer and addition funnel. A solution of 2-nitro-5- (2-cyano-4-trifluoro-10 methylphenoxy) benzoyl chloride (0.04 mol) in toluene (20 ml) is slowly added at room temperature with stirring.

After the addition is complete, stirring is continued for a period of about 8 hours. The reaction mixture is then washed with water and dried over anhydrous magnesium sulfate. The dried solution is then stripped under reduced pressure to remove solvent to leave a residue. This residue is purified by silica gel chromatography using toluene and ethyl acetate / toluene mixtures as an eluent to yield the desired product, namely 3-tetrahydrofnryl-2-nitro-5- (2-cyano-4-trifluoromethylph. enoxy) benzoate.

Example VI

Preparation of 3-Tetrahydrofuryl-2-methylthio-5- (4-trifluoromethyl-phenoxy) benzoate.

3-hydroxytetrahydrofuran (0.04 mol), toluene & 50 ml) and triethylamine (0.04 mol) are placed in a glass reaction vessel equipped with a mechanical stirrer and addition funnel. A solution of 2-methylthio-5- (4-trifluoromethylphenoxy) benzoyl chloride (0.04 mol) in toluene (20 ml) is slowly added at room temperature with stirring.

After the addition is complete, stirring is continued for a period of about 8 hours. The reaction mixture is then washed with water and dried over anhydrous magnesium sulfate. The dried solution is then stripped under reduced pressure to remove the solvent to leave a residue. This residue is purified by 8300084 * 6-6 silica gel chromatography using toluene and ethyl acetate / toluene mixtures as eluent to yield the desired product, namely 3-tetrahydrofuryl-2-methylthio-5- (4- trifluoromethylphenoxy) benzoate.

Example VII

Preparation of 3-tetrahydrofuryl-2-chloro-5- (2-bromo-4-trifluoromethylphenoxy) benzoate. 3-Hydroxytetrahydrofuran (0.04 mol), toluene (50ml) and triethylamine (0.04 mol) are placed in a glass reaction vessel equipped with a mechanical stirrer and addition funnel. A solution of 2-chloro-5- (2-bromo-4-trifluoromethylphenoxy) benzoyl chloride (0.04 mol) in toluene (20 ml) is slowly added at room temperature with stirring. After the addition is complete, stirring is continued for a period of about 8 hours. The reaction mixture is then washed with water and dried over anhydrous magnesium sulfate. The dried solution is stripped under reduced pressure to remove solvent to leave a residue. This residue is purified by silica gel chromatography using toluene and ethyl acetate / toluene mixtures as eluent to give the desired product, namely 3-tetrahydrofuryl-2-chloro-5- (2-bromo-4-trifluoromethylphenoxy) benzoate .

Example VIII

Preparation of 3-tetrahydrofuryl-2-bromo-5- (2-chloro-4-tri-25-fluoromethylphenoxy) benzoate.

3-Hydroxytetrahydrofuran (0.04 mol), toluene (50 ml) and triethylamine (0.04 mol) are placed in a glass reaction vessel equipped with a mechanical stirrer and an addition funnel. A solution of 2-bromo-5- (2-chloro-3.0 4-trifluoromethylphenoxy) benzoyl chloride (0.04 mol) in toluene (20 ml) is slowly added at room temperature with stirring. After the addition is complete, stirring is continued for a period of about 8 hours. The reaction mixture is then washed with water and dried over anhydrous magnesium sulfate. The dried solution is then stripped under reduced pressure to remove solvent to leave a residue. This residue is purified by silica gel chromatography using toluene and ethyl acetate / toluene mixtures as an eluent to yield the desired product, namely 3-tetrahydrofuryl-2-5 bromo-5- (2-chloro-4-trifluoromethylphenoxy) benzoate .

Example IX

Preparation of 3-tetrahydrofuryl-2-cyano-5- (2,4-dichlorophenoxy) benzoate.

3-Hydroxytetrahydrofuran (0.04 mol), 10 toluene (50ml) and triethylamine (0.04 mol) are placed in a glass reaction vessel equipped with a mechanical stirrer and addition funnel. A solution of 2-cyano-5- (2,4-dichloro-phenoxy) benzoyl chloride (0.04 mol) in toluene (20 ml) is slowly added at room temperature with stirring. After the addition is complete, stirring is continued for a period of about 8 hours. The reaction mixture is then washed with water and dried over anhydrous magnesium sulfate.

The dried solution is then stripped under reduced pressure to remove solvent leaving a residue. This residue is purified by silica gel chromatography using toluene and ethyl acetate / tduene mixtures as eluent to give the desired product, namely 3-tetrahydro uryl-2-cyano-5- (2,4-dichloro-phenoxy) benzoate. .

Example X

Preparation of 3-Tetrahydrofuryl-2-ethylthio-5- (2-chloro-4-bromophenoxy) benzoate.

3-Hydroxytetrahydrofuran (0.04 mol), toluene (50ml) and triethylamine (0.04 mol) are placed in a glass reaction vessel equipped with a mechanical stirrer and addition funnel. A solution of 2-ethylthio-5- (2-chloro-4-bromophenoxy) benzoyl chloride (0.04 mol) in toluene (20 ml) is slowly added at room temperature with stirring.

After this addition is complete, stirring is continued for about 8 hours. The reaction mixture is then washed with water and dried over anhydrous magnesium sulfate 88300084. The dried solution is then stripped under reduced pressure to remove solvent to leave a residue. This residue is purified by silica gel chromatography using toluene and 5 ethyl acetate / toluene mixtures as eluent to yield the desired product, namely 3-tetrahydrofuryl-2-ethyl thio-5- (2-chloro-4-bromophenoxy). benzoate.

Example XI

Preparation of 3-tetrahydropyranyl-2-nitro-5- (2-chloro-4-tri-10 fluoromethylphenoxy) benzoate, 3-hydroxytetrahydropyran (0.04 mol), toluene (50 ml) and triethylamine (0.04 mol) are placed in a glass reaction vessel equipped with a mechanical stirrer and addition funnel. A solution of 2-nitro-5- (2-chloro-4-trifluoromethylphenoxy) benzoyl chloride (0.04 mol) in toluene (20 ml) is slowly added at room temperature with stirring. After the addition is complete, stirring is continued for a period of about 8 hours. The reaction mixture is then washed with water and dried over anhydrous magnesium sulfate. The dried solution is then stripped under reduced pressure to remove solvent to leave a residue. This residue is purified by silica gel chromatography using toluene and ethyl acetate / toluene mixtures as the eluant to yield the desired product, namely 3-tetrahydropyranyl-2-nitro-5- (2-chloro-4-trifluoromethylphenoxy). -benzoate.

Example XII

Preparation of 4-tetrahydropyranyl-2-nitro-5- (2-chloro-4-tri-30-fluoromethylphenoxy) benzoate.

4-Hydroxytetrahydropyran (0.04 mol), toluene (50ml) and triethyphamine (0.04 mol) are placed in a glass reaction vessel equipped with a mechanical stirrer and addition funnel. One solution of 2-nitro-5- (2-chloro-4-trifluoromethylphenoxy) benzoyl chloride (0.04 mol) in toluene (20 ml) is slowly added at room temperature with stirring.

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After the addition is complete, stirring is continued for a period of about 8 hours. The reaction mixture is then washed with water and dried over anhydrous magnesium sulfate. The dried solution is then stripped under reduced pressure to remove solvent to leave a residue. This residue is purified by silica gel chromatography using toluene and ethyl acetate / toluene mixtures as an eluent to yield the desired product, namely 4-tetrahydropyranyl-2-1 o nitro-5- (2-chloro-4-tr if fluoromethylphenoxy) benzoate.

Example XIII

Preparation of 3-tetrahydropyranyl -2- (methylthio-5- (2-chloro-4-trifluoromethylphenoxy) benzoate.

3-Hydroxytetrahydropyran (0.04 mol), toluene (50ml) and triethylamine (0.04 mol) are placed in a glass reaction vessel equipped with a mechanical stirrer and addition funnel. A solution of 2-nitro-5- (2-chloro-4-trifluoromethylphenoxy) benzoyl chloride (0.04 mol) in toluene (20 ml) is slowly added at room temperature with stirring.

After the addition is complete, stirring is continued for a period of about 8 hours. The reaction mixture is then washed with water and dried over anhydrous magnesium sulfate. The dried solution is then stripped under reduced pressure to remove solvent leaving a residue. This residue is purified by silica gel chromatography using toluene and ethyl acetate / toluene mixtures as an eluent to yield the desired product, namely 3-tetrahydropyranyl-2-methylthio-5- (2-chloro-4-trifluoromethylphenoxy) ) benzoate.

Example XIV

Preparation of 2-Tetrahydropyranyl-2-nitro-5- (2-chloro-4-trifluoromethylphenoxy) benzoate.

2,3-dihydropyran (20 ml), 2-nitro-5- (2-chloro-4-trifluoromethylphenoxy) benzoic acid (0.05 mol) and para-35 toluenesulfonic acid (1 spatula tip) are placed in a glass reaction vessel equipped with a mechanical stirrer. The mixture 8300084 - «-

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- no - is added. room temperature stirred until the carboxylic acid group, as determined by infrared spectroscopy, is no longer detectable in the mixture. The mixture is then dissolved in methylene chloride, washed with dilute aqueous sodium carbonate and dried over anhydrous magnesium sulfate. The dried solution is then stripped under reduced pressure to remove solvent and excess dihydropyran, leaving the. desired product is obtained, namely 2-tetrahydropyranyl-2-nitro-5- (2-chloro-14-trifluoromethyl-enoxy) benzoate.

Example XV

Preparation of 2-Tetrahydrofuryl-2-nitro-5- (2-chloro-4-trifluoromethylpheno & y) benzoate.

Dihydrofuran (0.03 mol), 2-nitro-5- (2-chloro-4-trifluoromethylphenoxy) benzoic acid (0.025 mol), 15 methylene chloride (25 ml) and p-toluenesulfonic acid (1 spatula tip) are placed in a glass reaction vessel, equipped with a magnetic stirrer »The reaction mixture is stirred at room temperature until the carboxylic acid group can no longer be detected in the mixture by IR» Then the reaction mixture is washed with dilute aqueous sodium carbonate and with water. The washed solution is dried and stripped from solvent and unreacted starting material to give the desired product, 2-tetrahydrofuryl-2-nitro-5- (2-chloro-4-trifluoromethylphenoxy) benzoate.

For practical use as herbicides, the compounds of the invention are generally included in herbicidal compositions containing an inert carrier and a herbicidally toxic amount of such a compound. Such herbicidal preparations, which may also be referred to as formulations, allow the active compound to be suitably applied in any desired amount at the site of the weed infestation. These preparations can be solids, such as dust, granules or wettable powders, or can be liquids, such as solutions, aerosols or emulsifiable concentrates.

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Pollen products can be prepared, for example, by grinding and mixing the active compound with a solid inert carrier, such as talc, clays, silicas, pyrophyllite and the like. Granular preparations can be prepared by impregnating the compound, usually dissolved in a suitable solvent, on and in granulated carriers, such as the attapulgites or the vermiculites, usually with a particle size of about 0.3-1.5 mm. Wettable powders, which can be dispersed in water or oil to any desired concentration of the active compound, can be prepared by incorporating wetting agents into concentrated puff formulations.

In some cases, the active compounds are sufficiently soluble in conventional organic solvents, such as kerosene or xylene, so that they can be used directly as solutions in these solvents. Often solutions of herbicides can be dispersed as aerosols under superatmospheric pressure. The preferred liquid herbicidal preparations, however, are emulsifiable concentrates which contain an active compound of the invention and as an inert carrier a solvent and an emulsifying agent. Such emulsifiable concentrates can be cut with water and / or oil to any desired active compound concentration for use as sprays at the site of the weed infestation. The emulsifiers most commonly used in these concentrates are nonionic or mixtures of nonionic with anionic surfactants. By using some emulsifying systems, a reverse emulsion (water in oil) can be prepared for direct application to weed infestations.

A typical herbicidal composition according to the invention is illustrated by the following example, in which the amounts are indicated in parts by weight.

Example XVE

35 Preparation of a pollen product.

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Product of example II 10

Powdered talc 90

The above ingredients are mixed in a mechanical milling mixer and milled until a homogeneous, free-flowing pollen product of the desired particle size is obtained. This pollen product is suitable for direct application to the weed infestation site.

The compounds of the invention can be used as herbicides in any manner accepted in the art. One method of controlling weeds involves contacting the site of these weeds with a herbicidal composition containing an inert carrier and as essential active ingredient, in an amount herbicidically toxic to these weeds, a compound according to the invention ». The concentration of the new compounds of the invention in the herbicidal compositions will vary widely with the type of composition and the purpose for which it is intended, but generally, the herbicidal compositions will be from about 0.05 to about 95 % by weight of the active compounds of the invention. In a preferred embodiment of the invention, the herbicidal compositions will contain about 5 to about 75% by weight of the active compound. The compositions may also contain further substances such as other pesticides, eg insecticides, nematocides, fungicides and the like, stabilizers, dispersants, deactivators, adhesives, adhesives ("stickers"), fertilizers, activators, synergetics and the like.

The compounds of the invention are also useful when combined with other herbicides and / or defoliants, desiccants, growth inhibitors and the like in the herbicidal compositions described above. These other materials can comprise from about 5% to about 95% of the active ingredients in the herbicidal compositions. The use of combinations of 8300084 - 13% * of these other herbicides and / or defoliators, desiccants, etc., with the compounds of the invention provides herbicidal compositions which are more effective in controlling weeds, and often become results obtained which are not attainable with separate preparations of the individual herbicides. The other herbicides, defoliators, desiccants, and the plant growth inhibitory agents with which the compounds of this invention can be used in the herbicidal weed control compositions may include chlorphenoxy-. herbicides, such as 2.4-D, 2.4.5-T, MCPA, MCPB, 4 (2.4-DB), 2.4-DEB, 4-CPB, 4-CPP, 2.4.5-TB, 2.4.5-TES, 3.4- DA, silvex and the like, carbamate herbicides, such as IPC, CIPG, "swep", barban, BCPC, CEPG, GPPC and the like, thiocarbamate and dithiocarbamate herbicides, such as DCEC, methane sodium, EPTX, diallate, PEBC, perbulate, vernolate and the like, substituted urea herbicides, such as norea, siduron, dichloral urea, chloroxuron, cycluron, fenuron, monuron, monuron TGA, diuron, linuron, monolinuron, neburon, buturon, trimeturon and the like herbicides, such as simazine, chlorazine, atraone ,. desmetryne, norazine, ipazine, pro-metryn, atrazine, triazine, simetone, prometone, propazine, ametryne and the like, chloroacetamide herbicides, such as alpha-chloro-NN-dimethylacetamide, CDEA, CDAA, alpha-chloro-N-isopropyl acetamide, 2-chloro-N-isopropylacetanilide, 4- (chloroacetyl) morpholine, 1- (chloroacetyl) piperidine, and the like; chlorinated aliphatic acid herbicides, such as TGA, dalapon, 2.3-dichloropropionic acid, 2.2.3-TPA and the like, chlorinated benzoic acid and the phenylacetic acid herbicides, such as 2.3.6-TBA, 2.3.5.6-TBA, dicamba, tricamba, amiben, phenac, PBA, 2-methoxy-3,6-dichlorophenylacetic acid, 3-methoxy-2,6-dichlorophenylacetic acid, 2-methoxy-3,4,6-trichloarphenylacetic acid, 2,4-dichloro-3-nitrobenzoic acid and the like, and compounds such as aminotriazole , maleic hydrazide, phenyl mercuric acetate, endothal, biuret, technical chlordane, dimethyl-2.3.5.6-tetrachloroterephthalate, diquat, erbón, DNG, DNBP, dichlorobenil, DPA, 8300084 - J4 - * diphenamide, dipropaline, trifluraline, sol , merphos, DMPA, DSM, MSM, potassium azide, aerolexes, benefin, bensulide, AMS, bromacil, 2- (3,4-dichlorophenyl) -4-methyl-1,2,4-oxadxazolidine, 3.5-dione, bromoxynil, cacodylic acid, DMA, DPMF, cypromide, 5 DCB, DCPA, dichlgne, diphenatrile, DMTT, DNAP, EBEP, EXD, HCA, ioxynil, IPX, isoeyil, potassium cyanate, MAA, M AMA, MCPES, MCPP, MH, molinate, NPA, OCH, paraquat, PCP, picloram, DPA, PCA, pyrichlor, sesone, terbacil, terbutol, TCBA ,. brominil, CP-50144, H-176-1, H-732, M-2091, planavin, sodium tetraborate, calcium cyanamide, DEE, ephyl xanthogen disulfide, sindone, sindone B, propanil and the like.

Such herbicides may also be used in the methods and in the composition of this invention in the form of their salts, esters, amides and other derivatives if this is possible in combination with the special parent compounds.

Weeds are undesirable plants that grow in places where they are undesirable, which have no economic value and which have a disruptive influence on the production of cultivated harvest plants (harvest crops), on the growth of ornamental plants or on the well-being of the livestock (livestock). Many types of weeds are known, including annuals, such as red goosefoot, loosestrife, foxtail, blood millet, wild mustard, field cherry, English ryegrass, sticky herb, hornflower, wild oats, mallow, purslane, cepa, water pepper, bird knotweed, burdock, wild buckwheat, kochia, caterpillar, corn bilberry, ragwort, milk thistle, coffee-spice, croton, euphea, ragwort, hen's fever, ragwort, hemp-nettle, "knowel", spurge, spurrie, emex, jungle rice, fountain-30 herb, dog fennel, carpet herb, day flower, woodruff, duckweed (duck lettuce) and water nymph, biennial plants, such as wild carrot (carrot), matricaria, wild barley, silene, chamomile, burdock (burdock), royal candle, round-leaved mallow (mallow), bull thistle, canine -tongue, moth-king candle and red star thistle, or perennial plants, such as white bollard (hawk), perennial ryegrass, cultivated grass, Johnson grass, Canadian thistle, hagwort, Kermuda grass, sehapezurittg, curled sorrel, nut grass, field horn nflower, 8300084 * «- 15 - dandelion, campanula, field bindweed, russet buttonwort, screw bean, flax snapdragon, yarrow, aster, pearl seed, horsetail, verbena, sesbania, rush, bulrush and winter cherry.

Such weeds can also be classified as broadleaf or grassy weeds. It is economically desirable to control the growth of such weeds without harming beneficial plants or livestock.

The new compounds of the invention are especially valuable for weed control because they are toxic to many species and weed groups, while relatively non-toxic to many beneficial plants. The exact amount of compound required will depend on a variety of factors, including the hardness of the special weed species, the weather conditions, the type of soil, the method of application, the nature of the beneficial plants in the same area, and the like. While thus applying up to only about 28 g or 56 g of active compound per 4047 m may suffice for good control of light infestation with weeds growing under adverse conditions. the application of 4540 g or more of 2 active compounds per 4047 m may be necessary for good control of dense infestation with hard perennial weeds growing under favorable conditions.

The herbicidal toxicity of the new compounds of the invention can be illustrated by many of the established art-known research techniques, such as pre- and post-emergence research.

The herbicidal activity of the compounds of the invention has been demonstrated by tests conducted to control a variety of weeds before plant emergence. In these experiments, small plastic greenhouse pots filled with dry soil were sown with the different weed seeds. The pots became 24 8300084

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v - 16 hours or less after sowing, sprayed with water until the soil was wet and the compounds to be tested, formulated as aqueous emulsions of acetone solutions containing emulsifiers, were applied to the surface area of the concentrations indicated at the indicated concentrations. sprayed on the ground.

. After the spraying, the soil holders were placed in the greenhouse and, if necessary, provided with additional heat and watered daily or more frequently. The plants were kept under these conditions for a period of 15-21 days, after which time the condition of the plants and the degree of damage. the plants were rated on a scale from 0 to 10 in the following manner: 0 = no damage ?; 1.2 = slight damage; 3, 4 = fairly damaged; 5, 6 = fairly serious damage; 7, 8, 9 = serious damage; 10 = dead and NE = did not occur. The effectiveness of these compounds is demonstrated by the data below, which are listed in Table A. The numbers with decimal places result from the averaging of two or more scores obtained from replicate experiments.

The herbicidal activity of the compounds of the invention has also been demonstrated by tests conducted to control a variety of weeds after the emergence of the plants. In these tests, the compounds to be tested were formulated with aqueous emulsions and sprayed at the indicated dose onto the leaves of the different weed species, which have reached a predetermined size. After spraying, the plants were placed in a greenhouse and watered daily or more frequently. The water was not applied to the leaves of the treated plants. Damage severity was determined 10-35 days after treatment and was rated on the 0-10 scale as described above. The effectiveness of these compounds is demonstrated by the data below, indicated in Table B. The values with decimal places are again the result of the averaging of replicate experiments.

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Table B

Taste after the plants emerge.

5 Connection; Prodnkt.van.VQorbeeld.il. Damage valuation

Weed species #Acre 1 0.5 0.25 0.125 ......... (4047 m ^) _ '' ___________ WMSD 10 10 10 10 BDWD 10 10 10 10 10 PIGW 10 10 10 10 JMWD 10 10 10 10 VTLF 3.0 10 10 10 MNGY 10 10 10 10 YLFX 10 10 10 3 15 BNGS 1.0 10 10 10 JNGS 30 10 10 10 OKGS 10 10 9 3 WOAT 1.0 10 5 2 CBGS 10 10 10 10 20 SPGT 10 '10 10 10 CÏGS 8 2 3 0 SUBT 10 30 30 30 COTN 3.0 '30 30 30 SOYB 30 7 6 4 25 PTBN 30 .5 7 6 ALFA 3.0 10 30 30 SORG 30 30 9 4 WHITE 1¾ 10 1 1 RICE 5 1 0 0 30 CORN 15 9 0 OAT 30 30 2 0 8300084% ~ 19 - «rf« «*. ~

Abbreviations for the plants (weeds). Yellow foxtail PTBN = Pinto bean BNGS = Hanepoot ALFA = Alfalfa 10 JNGS = Johnson grass SORG = Sorghum OKGS = Cultivated grass WHT = Wheat WOAT = Wild oats 15 8300084

Claims (11)

1. A compound of the formula I, wherein X represents halogen or trifluoromethyl, Y is selected from hydrogen, halogen, nitro and cyano, R is selected from nitro, alkylthio, halogen and cyano and n is the integer 1 or 2. 2. A compound according to claim 1, characterized in that this compound is 3-tetrahydrofuryl-2-nitro-5- (2-chloro-4-trifluoromethylphenoxy) benzoate. Compound according to claim 1, characterized in that this compound is 3-1etrahydrofury1-2-nitro-5- (2-bromo-4-trifluoromethylphenoxy) benzoate. 4. A compound according to claim 1, characterized in that this compound is 3-tetrahydrofuryl-2-nitro-5- (2-nitro-4-trifluoromethylphenoxy) benzoate. Compound according to claim 1, characterized in that this compound is 3-tetrahydrofuryl-2-nitro-5- (2-cyano-4-trifluoromethylphenoxy) benzoate. A compound according to claim 3, characterized in that this compound is 3-tetrahydrofuryl-2-methyl-thio-5- (4-trifluoromethylphenoxy) benzoate. . 7. A compound according to claim 1, characterized in that this compound is 2-tetrahydropyranyl-2- 25 'nitro-5- (2-chloro-4-trifluoromethylphenoxy) benzoate. A compound according to claim 1, characterized in that this compound is 2-tetrahydrofuryl-2-nitro-5- (2-chloro-4-trifluoromethylphenoxy) benzoate. 9. A herbicidal composition containing an inert carrier and a herbicidically toxic amount of a compound according to claim 3. 10. A method of controlling weeds, characterized in that these weeds or the location of these weeds are contacted with a toxic amount of a herbicidal preoarate according to claim 9. 11. Compounds, preparations and methods as described in the description and / or examples. 8300084 m- * Y ¢ = 0-11 1, r-l s- <XqW x- / n-o-Ay-R 2 ho ^ „a 3 VELSICOL. CHEMICAL CORPORATION, Chicago, Illinois, USA St. 8300084