CS204020B2 - Herbicide and process for preparing effective compound - Google Patents

Description

The present invention relates to herbicidal compositions which contain as active ingredient novel derivatives of substituted 3-phenoxy-.alpha.-phenoxyalkanecarboxylic acid having a substituent in the .beta.-phenoxy group in the para position to the 3-phenoxy group. The invention furthermore relates to a process for the production of these novel herbicidally active novel compounds, as well as to the use of the active compounds or compositions containing them for the selective control of weeds in crops.

The new active substances correspond to the general formula I

—SRj or - NRsRe,

I-Ial is a halogen atom, n is an integer from 0 to 3,

Z represents a halogen atom or a cyano group,

R1 is hydrogen or (C1-C4) -alkyl,

Rc is methyl,

R 5 represents hydrogen or a base cation

whereas

M represents an alkali metal cation, an alkaline earth metal cation or an iron, copper, zinc, manganese, nickel,

R.- N V \

We-rv

and n represents an integer of 1, 2 or 3 and expressing the valency of the cation, while

R _a , R b, R _c ^and R d are each independently hydrogen, benzyl or optionally hydroxy or C 1 -C 4 alkoxy substituted C 1 -C 4 alkyl;

R 5 and R 4 further denote a C 1 -C 18 alkyl radical optionally substituted by halogen, cyano, C 1 -C 4 alkoxy, C 2 -C 8 alkoxyalkoxy, bis- (alkyl) amino wherein the alkyl contains up to 4 C 3 -C 8 -cycloalkenyl, optionally also morpholino, C 3 -C 18 -alkenyl, C 3 -C 8 -alkynyl, C 3 -C 12 -cycloalkyl, phenyl or benzyl which is unsubstituted or substituted at least once by halogen, C1-C4alkyl, C1-C4alkoxy, nitro, trifluoromethyl or cyano,

R 5 is hydrogen or optionally C 1 -C 4 alkoxy substituted alkyl,

R6 has the same meaning as R5, is furthermore C1-C4alkoxy, or R5 together with the nitrogen atom to which it is attached also forms a piperidine, morpholine or pyrrolidine residue.

In this formula, the alkyl radicals have both straight and branched chains and contain the indicated number of carbon atoms. The radicals R 5 and R 6 are preferably hydrogen or C 1 -C 4 alkyl radicals.

'FROM DOS. 2,136,828, 2,223,894, 2,433,067 and

No. 531,643, similar phenoxyalkanecarboxylic acid derivatives are known but contain an alkanecarboxylic acid residue in the para position.

These known compounds have a special activity against grasses and are suitable for the selective control of grass weeds in monocotyledonous and dicotyledonous crop plants. However, these compounds are not effective at all or only in very high application rates against dicotyledonous weeds.

Surprisingly, it has now been found that the novel phenoxy-.alpha.-alkanecarboxylic acid derivatives of formula I having an alkanecarboxylic acid residue in the meta-position are surprisingly suitable for controlling dicotyledonous weeds in predominantly monocotyledonous crops such as cereals (wheat, barley, sorghum), maize as well as rosehip (Sagittaria) and lupine (Cyperus) species in rice and also to selectively control weeds in dicotyledonous crops such as sugar beet, scja, cotton.

It has been found to be particularly well tolerated against rice, both rice grown under dry conditions and rice under irrigation conditions.

The compounds of formula I have proved to be most effective against the following dicotyledonous weeds:

arrowhead (Sagitaria pygmea), white mustard (Sinapis alba],

Sida spinosa,

Sesbania exaltata, Ipomoea purpurea, Galium aparine, Chrysanthemum leucum,

Abutildn, eggplant (Solanum nigrum),

Ammania indica,

Rotala Indica, Cyperus difformis,

E latine triandra,

Linda, rnia procunibčns etc.

Although the novel compounds are also effective in pre-emergence administration, post-emergence administration has proven to be particularly effective and useful.

Some of the new active ingredients are also suitable for desiccating and defoliating cotton or potatoes shortly before harvesting.

The amount of herbicide used according to the invention per hectare depends on the effectiveness of the active compound used, the soil properties, the climatic and weather conditions, the method of application and the time of application and the type of crop and weeds to be controlled. kg and preferably is 0.5 to 4.0 kg.

The compounds of formula Ia have proved to be particularly suitable according to the invention

in which

B, Hal and Z are as defined in Formula I

R1 * is hydrogen or methyl.

In formula Ia, n is 1, 2 or 3. Of particular interest in the group of compounds of formula I are compounds of formula Id

and in particular the compounds of formulas Ie, If, Ig and Ih

CiO-CH ^COS-sz (If)

wherein • B, Hal and Z are as defined in formula I, n is 0 or 1 and

R 1 is hydrogen or methyl.

Typical representatives of the compounds of formulas Id, Ie, If, Ig and Ih are

Table 5

Table 55 Table 54

The novel compounds of formula I are prepared by methods known per se for such syntheses.

The last step of the synthesis always consists of the following step and represents the process according to the invention:

o (III)

Thus, for example, to react 2-methoxy-4-chloronitrobenzene of formula OCH ₃ C-O- ^N0 and with a phenol of formula IV wherein

Hal, n, Z, R 1 and B have the above meanings.

Thus, in the process according to the invention, the 3-hydroxy diphenyl ether of formula II, which is reacted with the α-haloalkanoic acid derivative or nitrile of formula III in the presence of a base, is used as the starting material.

When carboxylic acids (B = OH) are used as starting materials of formula III, this group can additionally be converted to another of the groups defined in formula I, either directly or via the corresponding acid chloride.

Using an ester of formula III, the compound can be saponified to the free carboxylic acid, its salt and then to the amide.

In formulas II and III, n and B and Z have the meanings given in formula I and Hal is a halogen atom such as chlorine, bromine, etc.

Said reaction may be carried out in the presence or absence of inert solvents or diluents which are inert to the reactants.

Preferred solvents are polar organic solvents such as methyl ethyl ketone, dimethylformamide, dimethyl sulfoxide, etc. The reaction temperatures are between 0 and 200 degrees Celsius, preferably between 20 and 100 ° C, and the reaction time depends on the starting material used, the reaction temperature and solvent chosen. between 1 hour and several days. The process is generally carried out at atmospheric pressure. Suitable bases (condensing agents) for the reaction are customary bases, such as potassium hydroxide, sodium methoxide, sodium bicarbonate, potassium carbonate, potassium tert-butoxide, etc., but also organic bases such as triethylamine, etc.

The starting materials of formula III are zinc or can be readily prepared by conventional methods. The starting phenols of the formula II are also known.

The hitherto not described phenoxyphenols of formula II can readily be prepared according to conventional methods and conventional techniques, as described, for example, in DOS 2,433,066 and DOS 2,433,067.

(IV) in which:

Hal and n have the meanings given above, in an alkaline medium to form a nitro compound of formula V

in which

Hal and n have the meanings given above, for example according to the teachings of DOS 2 304 006.

The same nitro compound of formula V is also obtained by reacting 2 moles of phenol of formula IV with 2,4-dichloronitrobenzene to form a compound of formula IV as an intermediate.

which is then 're-etherified' by heating with methanol and potassium hydroxide in dioxane to the methoxy derivative of formula V (the method is described in DOS No. 2 533 172 j.

The nitrated substituted intermediate of formula (V) thus obtained is then reacted by conventional reduction of the nitro group to the corresponding amine, which is then converted to a diazonium salt (e.g., diazonium chloride). Finally, the diazo group of the diazonium salt was 204020

if it is replaced by a cyano or halogen atom by conventional methods.

The reduction of the nitro group in the compound of formula V is carried out either catalytically with hydrogen (e.g. in the presence of Ranev nickel) in solution in an inert solvent, or by slowly adding the compound of formula V to a mixture of iron powder and dilute hydrochloric acid at elevated temperature.

The diazotization of the amine obtained in the usual manner dissolved in dilute hydrochloric acid dropwise addition of aqueous sodium nitrite at a temperature below 5 ° C ^Q

The exchange of the diazo group with a cyano group is accomplished by dropping the diazonium salt to an aqueous solution of K [Cu (CN) 4 | or by adding powdered copper and cuprous cyanide to the diazonium salt solution. These reactions leading to p-cyanediphenyl ethers using substituted p-nitrodiphenyl ethers as starting materials are already described in DOS No. 1,912,600.

The exchange of the diazo group with chlorine is accomplished by the addition of cuprous chloride and finely dispersed copper powder to the diazonium chloride solution.

The replacement of the diazo group with bromine is best accomplished by the addition of potassium bromide and cuprous bromide to the diazonium salt solution, while the iodine replacement can already be carried out by the action of potassium iodide on the diazonium salt.

A halogen atom in the meaning of the symbol Z may also be introduced by halogenation of diphenyl ether, which is not substituted in the 4 poloze position.

Finally, in order to obtain the corresponding free phenol of formula (II) which is used as the starting material, the ether protecting group in the meta-position (-O-CH3) is cleaved, for example by treatment with hydrogen bromide in glacial acetic acid.

The following examples illustrate the preparation of several phenoxyphenoxyalkanecarboxylic acid derivatives of the formula I. Further appropriately produced active ingredients are listed in the following table. Temperatures are given in degrees Celsius.

Example 1

3- (2 ', 4'-Dichlorophenoxy) -α- (6-chlorophenoxy) propionic acid methyl ester and 128.5 g of 2,4-dichloro-3'-methoxy-4'-aminodiphenyl ether obtained by reduction of 2, 4-Dichloro-3'-methoxy-4'-nitrodiphenyl ether was dissolved in 1250 ml of glacial acetic acid and 115 ml of concentrated hydrochloric acid with heating. With good stirring, the reaction mixture is cooled to 0-5 ° C, whereupon the hydrochloride precipitates as a fine crystalline precipitate. The suspension obtained is diazotized with 113 ml of a 4 N sodium nitrite solution to give a clear solution. Excess nitrite was removed after 2 hours by addition of sulfamic acid. The diazo solution thus obtained was added dropwise at 70-75 ° C to a solution of 88 g of cuprous chloride in 750 ml of concentrated hydrochloric acid, then the mixture was heated at 85 to 90 ° C for 20 minutes and 1900 ml of water were added. After cooling, the crude product was extracted with toluene. The yield of 2,4,4‘-trichloro-3‘-methoxydiphenyl ether is 124 g or 93.8% of theory.

(b) 124 g of the crude product obtained in (a) are dissolved in 1500 ml of glacial acetic acid and, after the addition of 450 ml of 48% hydrobromic acid, the reaction mixture is refluxed for 19 hours. The solvent is distilled off on a rotary evaporator and the oily product thus obtained is extracted with toluene. After drying over sodium sulfate, the organic solvent was distilled off. High vacuum distillation yielded 91.6 g of 2,4,4‘-trichloro-3‘-hydroxydiphenyl ether having a boiling point of 157 degrees Celsius at 4 Pa.

15 g of 2,4,4‘-trichloro-3‘-hydroxydiphenyl ether were stirred overnight at 80 ° C after addition of 50 ml of 2-bromopropionic acid methyl ester, 27 g of potassium carbonate and a tip of a potassium iodide spatula. The reaction product is diluted with 100 ml of acetone and filtered. After distilling off the solvent, the residue was distilled under high vacuum to give 14 g of 3- (2 ', 4'-dichlorophenoxy) -α- (6-chlorophenoxy) propionic acid methyl ester, b.p. 171-172 ° C at 16 Pa. .

Example 2

3- (2 ‘, 4‘-Dichlorophenoxy) -α- (6-chlorophenoxy) propionic acid

37.6 g (0.1 mol) of 3- (2 ', 4'-dichlorophenoxy) -α- (6-chlorophenoxy) propionic acid methyl ester are dissolved in 150 ml of methanol and 20 ml of 45% hydroxide solution are added to this solution. sodium. The reaction mixture was stirred for half an hour at 50 ° C, the solvent was distilled off and the residue was dissolved in water. After acidification with concentrated hydrochloric acid, the reaction product precipitates in crystalline form.

Yield 25.5 g. M.p. 106-109 ° C. Example 3

3- (2 ‘, 4‘-Dichlorophenoxy) -α- (6-chlorophenoxy) propionic acid allyl ester

(a) 85.5 g of 3- (2 ', 4'-dichlorophenoxy) -α- (6-chlorophenoxy) propionic acid obtained in accordance with Example 2 are added to 360 ml of benzene and, after addition of 2 ml of pyridine and 62 ml of The reaction mixture was stirred at 70 [deg.] C. for 3 hours, then the solvent was evaporated on a rotary evaporator and the oil thus obtained was further processed directly.

(b) 30 g of the acid chloride thus obtained and 5.8 g of allyl alcohol are introduced into 120 ml of toluene and 13.2 g of triethylamine are added dropwise with good stirring at 10 to 20 ° C. After stirring the reaction mixture at room temperature overnight, 50 ml of water are added, the organic phase is separated and dried over sodium sulphate. After distilling off the solvent, 29.8 g of 3- (2 2, 4‘-dichlorophenoxy) -1- (6-chlorophenoxy) propionic acid allyl ester were obtained as a viscous oil.

Analysis:

calculated:

53.83 ° C, 3.76% H, found:

54.1% C, 3.9% H.

Example 4 Phenoxy-.alpha .- (6-chlorophenoxy) propionic acid

13 g of Ο, dl-dlmethylhydroxylamine in 100 ml of toluene are introduced and 30 g of the acid chloride obtained in 2) which is dissolved in 140 ml of toluene are added dropwise at a temperature of 5 to 20 ° C. The reaction mixture is further stirred at room temperature for 2 hours, 50 ml of water are added to the reaction mixture and the organic phase is separated. After distilling off the solvent, 30.2 g of an oil is obtained which is distilled under high vacuum. Boiling point 205 ° C / 6.7 Pa. Yield 22.2 g of the title compound.

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The novel active compounds of the formula I are stable compounds which are soluble in conventional organic solvents such as alcohols, ethers, ketones, dimethylformamide, dimethylsulfoxide, etc.

The compositions according to the invention are prepared in a manner known per se by thoroughly mixing and grinding the active compounds of the formula I with suitable carriers and / or diluents, optionally with the addition of antifoams, wetting agents, dispersants and / or solvents inert to the active compounds. The active substances can be present in the following processing forms and in the same forms, solid forms of processing can be applied:

dusting, spreading, granulate, coated granulate and homogeneous granulate;

water-dispersible concentrates of the active substance:

wettable powder, pastes, emulsions, emulsion concentrates;

liquid forms of processing: solutions.

The concentration of active ingredient in the compositions of the invention is from 1 to 80% by weight, and these concentrations may optionally be between about 0.05 to 1% when applied at low concentrations.

Other biocidal active ingredients or compositions may be admixed with the compositions of the present invention. Thus, the novel compositions may contain, for example, insecticides, fungicides, bactericides, fungistatics, bacteriostats, nematicides or other herbicides in addition to the compounds of the formula I in order to broaden the spectrum of action.

Granulate:

The following ingredients are used to prepare the 5% granulate:

.5 parts of the active substance of formula I,

0.25 parts of epichlorohydrin,

0.25 parts of cetyl polyglycol ether,

3.50 parts of polyethylene glycol, parts of kaolin (particle size 0.3 to 0.8 millimeters)

The active ingredient is mixed with epichlorohydrin and the mixture is dissolved in 6 parts of acetone, after which polyethylene glycol and cetyl polyglycol ether are added. The resulting solution is sprayed onto kaolin and then the solvent is evaporated off under vacuum.

Wettable powder:

The following ingredients are used to prepare a) 70% and b) 10% wettable powder:

a) parts of 3- (2 ', 4'-dichlorophenoxy) -a- (6-chlorophenoxy) propionic acid methyl ester, parts of sodium dibutylnaphthylsulfonate, parts of the naphthalenesulfonic acid condensation product, phenolsulfonic acids and formaldehyde (3: 2: 1), parts of kaolin , parts of chalk (prov. Champagne);

6) parts of 3- (2 2, 4‘-dichlorophenoxy) (6-chlorophenoxy) propionic acid methyl ester, parts of a mixture of sodium salts of saturated sulfated fatty alcohols, parts of a naphthalenesulfonic acid-formaldehyde condensation product, parts of kaolin.

The active ingredient is applied to the appropriate carriers (kaolin and chalk) and then the other ingredients are admixed and the mixture is ground. A wettable powder of excellent wettability and suspensibility is obtained. From such wettable powders, suspensions containing from 0.1 to 80% of the active ingredient which are suitable for controlling weeds in crop plants can be obtained by dilution with water.

Paste:

The following substances are used to prepare 45% paste:

parts of 3- (2 ', 4'-dichlorophenoxy) - (6-chlorophenoxy) -propionic acid methyl ester or other active ingredient of the formula I, parts of sodium silicate, parts of cetyl glycol ether with 8 moles of ethylene oxide, parts of oleyl polyglycol ether with 5 moles parts of spindle oil, parts of polyethylene glycol, parts of water.

The active ingredient is intimately mixed with the ingredients in equipment suitable for this purpose and the mixture is ground. A paste is obtained from which suspensions of any desired concentration can be prepared by dilution with water.

Emulsion concentrate:

To prepare 25% of the emulsion concentrate, they are mixed together

parts of 3- (4‘-chlorophenoxy) -α- (6-chlorophenoxy) propionic acid methyl ester or other active ingredient of the formula I, parts of a mixture of nonylphenol polyoxyethylene and dodecylbenzenesulfuric acid calcium salt, parts of xylene.

1S

This concentrate may be diluted with water to emulsions of suitable concentrations, for example from 0.1 to 10%. Such emulsions are suitable for controlling weeds in crop plants.

The novel 3-phenoxy-.alpha.-phenoxyalkanecarboxylic acid derivatives of the formula I, as well as the compositions containing them, have an excellent selective herbicidal activity against weeds in various crops of crops and furthermore have a regulating effect on plant growth.

A particularly preferred field of application is the selective control of, in particular, dicotyledonous weeds in cereal crops and, moreover, of rosehip (Sagittaria) and broadflower (Cyperus) in rice. The most effective derivatives of dihalophenoxyphenoxyalkanecarboxylic acid, in particular the dihalogenophenoxypropionic acid derivatives of the formula I, have proved to be the most effective.

While the novel active compounds of formula I are effective in pre-emergence and post-emergence application, post-emergence application as contact herbicides seems to be advantageous, although pre-emergence use is also important.

Preferably, the new active ingredients are formulated, for example, as 25% wettable powders or, for example, as 20% emulsifiable concentrates, which are diluted with water and then applied post-emergence to the crop plants.

Herbicidal effect after application of active substances after emergence of plants (postemergence)

Various crops and weeds are grown from potted seeds in a greenhouse until they reach the 4-6 leaf stage. Thereafter the plants are sprayed with aqueous emulsions of the active ingredient (which were obtained from 20% emulsifiable concentrate) in various doses, and the treated plants are then maintained under optimum conditions of light, irrigation, heat (22-25 ° C) and air humidity (50-70%). relative humidity) 15 days after treatment, the experiment is evaluated.

The condition of the plants shall be assessed and expressed on the following scale:

= normal condition = dead plants

8- ~ 2 = imesistup

The results of this experiment are summarized in the following table:

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In this experiment, almost all of the compounds that were tested strongly damaged dicotyledonous plants and weeds, while monocotyledonous plants largely tolerate and only slightly to moderately damage weeds.

Selective herbicidal effect on rice in post-emergence application

The 25-day-old rice plants are planted in large rectangular bowls of eternit in a greenhouse. Between the rows of rice plants are sown seeds of weeds that occur in rice, such as hedgehogs (Echinochloa crus galii), arrowhead (Sagittaria pygm.), Broadleaf (Cyperus diisformis), Ammanis indica, Rotala indioa, Elantine triandra and Lindernia procumbens. The dishes are well watered and kept in a greenhouse at a temperature of about 25 ° C and at high relative humidity. After 12 days, when the weeds have emerged and reach the 2-3 leaf stage, the soil is covered with a 2.5 cm layer of water in the bowl. The active substance is then applied in the form of an emulsion concentrate by pipette or in the form of granules between rows of plants, the emulsion concentrate being diluted and applied such that the application rate in the field corresponds to 4, 2, 1 and 0.5 kg of active substance per ha . The experiment is evaluated 4 weeks after treatment.

In this test, Compound No. 1 noticeably damages the weeds: Ammania indica, Rotala indica, Lindernia, Elatine, Cyperus, and Sagittaria. Echinochloa crus galii has only minor damage to the hedgehog. The rice remains undamaged.

Claims (11)

A herbicidal composition, characterized in that it contains at least one 3-phenoxy-α-phenoxyalkanecarboxylic acid derivative of the general formula I (HaV _and OCH-COB) in which: B is -O-N = C (R 2) 2, -OR 3, -SR 4 or-NR 5 R 6, Hal is halogen, n is 1, 2 or 3, Z represents a halogen atom or a cyano group, R 1 is hydrogen or C 1 -C 4 alkyl, R2 is methyl, R 5 represents hydrogen or a base cation M represents an alkali metal or alkaline earth metal cation or an iron, copper, manganese, nickel or ammonium cation of the formula. and R _a , R _b , R _c and R _rt are hydrogen, benzyl or unsubstituted C 1 -C 4 -alkyl or C 1 -C 4 -alkyl; R 3 and R 4 represent an alkyl radical which is unsubstituted or optionally substituted by halogen, cyano, C 1 -C 4 alkoxy, C 2 -C 8 alkoxyalkoxy, C 1 -C 4 -alkylamino, 3-cycloalkenyl up to 8 carbon atoms or morpholino, - alkenyl or alkynyl radical of 3 to 8 carbon atoms each, - cycloalkyl radical of 3 to 12 carbon atoms, C 4 -C 4 alkoxy, C 1 -C 4 alkoxy, nitro, trifluoromethyl, cyano, R 5 is hydrogen or an alkyl radical optionally substituted by C 1 -C 4 alkoxy, R 6 has the same meaning as R 5, furthermore denotes C 1 -C 4 alkoxy or together with R 5 and the nitrogen atom to which they are attached also means piperidino, morpholino or pyrrolidino. 2. A composition according to claim 1, characterized in that it contains at least one compound of the formula Ie as active ingredient in which B, R 1 and Z are as defined in formula I in point 1. 3. A composition according to claim 1, wherein the active ingredient comprises at least one compound of the formula If B, R 1 and Z are as defined in formula I in point 1. 4. A composition according to claim 1, characterized in that it contains at least one compound of the formula Ig as active ingredient B, R 1 and Z have the meaning given in Formula I in Part 1. 5. A composition according to claim 1, wherein the active ingredient comprises at least one compound of formula Ih OCH-COB Br in which B, R 1 and Z are as defined in formula I in point 1. 6. A composition according to claim 1, wherein the active ingredient is 3- (2,4,4-diichlorophenoxy) -α- (6-chlorophenoxy) propionic acid methyl ester. 7. A composition according to claim 1, wherein the active ingredient is 3- (2 &apos;, 4 &apos; -dichlorophenoxy) - [alpha] - (6-cyanophenoxy) propionic acid methyl ester. 8. A composition according to claim 1, wherein the active ingredient is 3- (2 &apos;, 4 &apos; -dichlorophenoxy) - [alpha] - (6-chlorophenoxy) propionic acid allyl ester. 9. A composition according to claim 1, wherein the active ingredient is 3- (2 &apos; -chloro-4 &apos; -brobphenoxy) -N- (6-chlorophenoxy) propionic acid methyl ester. 10. A composition according to claim 1, wherein the active ingredient comprises 3- (2 ' -bromo-4 &apos; -chlorophenoxy) - [beta] - (6-chlorophenoxy) propionic acid. 11. A process for the preparation of an active ingredient according to claim 1, characterized in that to a substituted 3-hydroxy diphenyl ether of the formula II in which: Hal, n and Z have the meaning given in formula (I) (1), act in the presence of a base with a halocarboxylic acid ester of formula (III) Ri Hal — CH — COB (III) wherein B, Hal and R are as defined in formula I in point 1.