US 5,207,820 AGrant
Crop Protection Agents Based on 1-Aryl- Or 1-Hetarylimidazose Carboxylic Esters
Issue Date:1993-05-04
•10 Claims
Abstract
1-Aryl- and 1-hetarylimidazolecarboxylic esters of the general formulae Ia and Ib ##STR1## where R.sup.1 is halogen or substituted or unsubstituted C.sub.1 -C.sub.4 -alkyl; processes for their manufacture, and agents containing them. R.sup.2 is substituted or unsubstituted C.sub.1 -C.sub.6 -alkyl; C.sub.3 -C.sub.6 -alkenyl, C.sub.3 -C.sub.6 -alkynyl or C.sub.3 -C.sub.6 -cycloalkyl; R.sup.3 is hydrogen or C.sub.1 -C.sub.4 -alkyl; R.sup.4 is substituted or unsubstituted phenyl or 5- or 6-membered heteroaromatic,
Metadata
Assignee
- BASF Aktiengesellschaft
Inventors
- Ulrich Wriede
- Gerhard Hamprecht
- Hermann Koehler
- Bruno Wuerzer
Application Information
Application Number:US 7014023
Filing Date:1991-05-03
Priority Date:1989-01-27
Art Unit:129
Classifications
IPC:
A01N 4350A01N 4308A01N 4310A01N 4316
Field of Search:
7192;98;123;90;88;113;106;91
Patent Drawings
This patent does not have any drawings.
Description
The present invention relates to 1-aryl- and 1-hetarylimidazolecarboxylic esters of the general formulae Ia and Ib ##STR2## where R.sup.1 is halogen or C.sub.1 -C.sub.4 -alkyl which may carry from one to three chlorine atoms,
R.sup.2 is C.sub.1 -C.sub.6 -alkyl which may carry from one to three of the radicals halogen, C.sub.1 -C.sub.4 -alkoxy and/or C.sub.1 -C.sub.4 -alkoxy-C.sub.1 -C.sub.4 -alkoxy, or is C.sub.3 -C.sub.6 -alkenyl, C.sub.3 -C.sub.6 -alkynyl or C.sub.3 -C.sub.6 -cycloalkyl,
R.sup.3 is hydrogen or C.sub.1 -C.sub.4 -alkyl and
R.sup.4 is a phenyl ring or a 5-membered or 6-membered heteroaromatic containing as heteroatoms one or two nitrogen atoms and/or an oxygen or a sulfur atom in the ring, and these aromatic rings may carry from one to three of the following groups: halogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -haloalkyl, C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -haloalkoxy, C.sub.1 -C.sub.4 -alkylthio, C.sub.1 -C.sub.4 -haloalkylthio, C.sub.1 -C.sub.4 -alkylsulfinyl, C.sub.1 -C.sub.4 -alkylsulfonyl, C.sub.1 -C.sub.4 -alkylcarbonyl, C.sub.1 -C.sub.4 -alkoxycarbonyl, carboxyl, nitro and/or cyano.
The present invention furthermore relates to a process for the preparation of the compounds Ia and Ib and herbicides which contain the 2-(4-hetaryloxy)- or 2-(4-aryloxy)-phenoxyacetic or -propionic acid derivatives and/or cyclohexenone derivatives as herbicidal active ingredients and aryl- or hetarylimidazolecarboxylic acid derivatives as antidotes, and methods for selectively controlling undesirable plant growth with these herbicides.
EP-A 174 562 disclosed 1-aryltriazolecarboxylic acid derivatives having crop-protecting activity. 1-Arylimidazolecarboxylic esters having growth-regulating properties (EP-A 243 615, EP-A 264 577) and 2-haloimidazolecarboxylic esters having a herbicidal action are also described (EP-A 127 446; EP-A 180 787; U.S. Pat. Nos. 4,711,962; 4,591,377 and 4,578,106).
Herbicidal active ingredients from the group consisting of the 2-(4-hetaryloxy)- or 2-(4-aryloxy)phenoxyacetic acid derivatives of the formula IV ##STR3## where R.sup.a is phenyl, pyridyl, benzoxazyl, benzothiazyl or benzopyrazinyl, and these aromatic ring systems may carry up to two of the following radicals: halogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -haloalkyl and/or C.sub.1 -C.sub.4 -halophenoxy,
R.sup.b is hydrogen, C.sub.1 -C.sub.5 -alkyl, C.sub.3 -C.sub.5 -alkylideneimino, C.sub.3 -C.sub.5 -alkylideneiminooxy-C.sub.2 or -C.sub.3 -alkyl or one equivalent of a plant-tolerated cation and
R.sup.c is hydrogen or methyl,
are used for controlling undesirable plants from the family of the framineae (for example DE-A 22 23 894, DE-A 24 33 067, DE-A 2576 251, DE-A 30 04 770, BE-A 868 875 and BE-A 858 618). However, the toleration of these substances by crops varies from commercially acceptable to non-tolerated, depending on the substituents and application rate.
The same situation is encountered with the cyclohexenone derivatives of the formula V ##STR4## where R.sup.d is C.sub.1 -C.sub.4 -alkyl,
R.sup.e is C.sub.1 -C.sub.4 -alkyl; C.sub.3 - or C.sub.4 -alkenyl, C.sub.3 - or C.sub.4 -alkynyl, C.sub.3 - or C.sub.4 -haloalkenyl or thenyl which may carry a halogen atom;
R.sup.f is C.sub.1 -C.sub.4 -alkyl which may be monosubstituted by C.sub.1 -C.sub.4 -alkylthio or C.sub.1 -C.sub.4 -alkoxy;
a 5-membered or 6-membered saturated or monounsaturated ring system which may contain, in addition to carbon members, an oxygen or sulfur atom or a sulfoxyl or sulfonyl group, and this ring may carry up to three of the following radicals: hydroxyl, halogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -haloalkyl, C.sub.1 -C.sub.4 -alkoxy and/or C.sub.1 -C.sub.4 -alkylthio;
a 10-membered saturated or monounsaturated heterocyclic structure which contains two oxygen atoms or sulfur atoms and may be substituted by up to three C.sub.1 -C.sub.4 -alkyl groups and/or methoxy groups;
phenyl, pyridyl or isoxazolyl, where these groups may carry up to three of the following radicals: C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -haloalkyl, C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -alkylthio, C.sub.3 -C.sub.6 -alkenyloxy, C.sub.3 -C.sub.6 -alkynyloxy, C.sub.1 -C.sub.4 -alkoxy-C.sub.1 -C.sub.3 -alkyl, C.sub.1 -C.sub.4 -dialkoxy-C.sub.1 -C.sub.3 -alkyl, formyl, halogen and/or benzoylamino;
R.sup.g is hydrogen or hydroxyl or, when R.sup.f is C.sub.1 -C.sub.6 -alkyl, is C.sub.1 -C.sub.6 -alkyl;
R.sup.h is hydrogen, cyano, halogen or C.sub.1 -C.sub.4 -alkoxycarbonyl and
R.sup.i is hydrogen or one equivalent of an environmentally compatible cation.
They are also described in the literature as herbicides (e.g. EP-A 228 598, EP-A 230 235, EP-A 238 021, U.S. Pat. No. 4,432,786, DE-A 24 39 104) and serve predominantly for controlling undesirable grasses in dicotyledon crops and in grasses which do not belong to the gramineae family. Depending on the structure of the substituents and the dose used, compounds from this group can also be employed for selectively controlling undesirable grasses in gramineous crops, such as wheat and rice.
It is an object of the present invention to provide compounds which overcome or greatly reduce the disadvantages encountered when using the abovementioned herbicides of the formulae IV and V. Such compounds are also referred to as antidotes or safeners.
We have found that this object is achieved by the 1-aryl- and 1-hetarylimidazonecarboxylic esters Ia and Ib defined at the outset. We have furthermore found processes for the preparation of these compounds Ia and Ib and methods for using these compounds together with the herbicides IV and V for influencing undesirable plant growth. The present invention furthermore relates to agents which contain the compounds Ia and Ib and/or herbicides of type IV or V, it being immaterial whether the herbicidal active ingredient and the antidote are formulated and applied together or separately or, if they are applied separately, which is applied first.
The novel compounds of the formulae Ia and Ib are obtainable by various methods.
Thus, the compounds Ia are obtained, for example, by reacting an imidazolecarboxylic ester of the formula II with an aryl or hetaryl derivative III in a conventional manner in an inert organic solvent in the presence of a base to give Ia. ##STR5##
In formula III, X is halogen, such as fluorine, chlorine or bromine, preferably fluorine or chlorine.
The reaction can be carried out continuously or batchwise, under atmospheric pressure or pressures up to 30, preferably from 1 to 10, bar and at from 20.degree. C. to 200.degree. C., preferably from 50.degree. C. to 170.degree. C.
Examples of suitable solvents are n-hexane, decalin, toluene, xylene, chlorobenzene, tetrahydrofuran, dioxane, dimethylformamide, diethylformamide, dimethyl sulfoxide, acetone and ethanol. Toluene and dimethylformamide are preferred.
Suitable bases are sodium bicarbonate, sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, sodium hydride, sodium methylate, sodium ethylate, potassium tert-butylate, triethylamine, diisopropylethylamine, N,N-dimethylaniline, pyridine, isoquinoline, N-methylpyrrolidine, N,N,N',N'-tetramethylethylenediamine and 1,8-diazabicyclo[5.4.0]undec-7-ene. However, sodium hydride, sodium methylate and triethylamine are preferred bases.
The preparation of the imidazolecarboxylic esters required for this purpose is described in, inter alia, ES-A 512 649 and EP-A 127 446.
The compounds Ib can be prepared from aryl- or hetarylimidazolecarboxylic esters Ia, in which R.sup.3 is hydrogen, in a conventional manner by reaction with a chlorinating agent. ##STR6##
Examples of suitable chlorinating agents are phosphorus oxytrichloride, sulfuryl chloride, thionyl chloride, phosgene, phosphorus pentachloride, phosphorus trichloride and sulfur tetrachloride, sulfuryl chloride being preferred.
The reaction is usually carried out in the presence or absence of an inert organic solvent, such as chlorobenzene or dichlorobenzene, continuously or batchwise at from 20.degree. C. to 200.degree. C., preferably from 80.degree. C. to 150.degree. C., under atmospheric or slightly superatmospheric pressure (1-5 bar).
If the reaction is carried out in the presence of one of the abovementioned solvents, it is advisable also to use a free radical initiator, such as dibenzoyl peroxide or azobisisobutyronitrile, to accelerate the reaction.
In view of the intended use of the compounds Ia and Ib as crop protection agents, suitable substituents are the following radicals:
R.sup.1 is alkyl, such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl, preferably methyl or ethyl;
haloalkyl, such as chloromethyl, dichloromethyl, trichloromethyl, 1,1-dichloroethyl or 1-chloroethyl, preferably chloromethyl, dichloromethyl or trichloromethyl; halogen, such as fluorine, chlorine, bromine or iodine, preferably chlorine or bromine;
R.sup.2 is alkyl as stated under R.sup.1, and n-pentyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, n-hexyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 2,3-dimethylbutyl or 2-ethylbutyl, preferably methyl or ethyl;
alkenyl, such as allyl, 2-butenyl, 3-butenyl, 1-methyl2-propenyl, 2-methyl-2-propenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-methyl-2-butenyl, 2-methyl-2-butenyl, 3-methyl-2-butenyl, 1,2-dimethyl-2-propenyl, 1,1-dimethyl-2-propenyl, 1-methyl-3-butenyl, 1-ethyl-2-propenyl, 2-hexenyl, 1-methyl-2-pentenyl, 1-ethyl-2-butenyl and 2-ethyl-2-butenyl, preferably allyl, 2-butenyl or 1-methyl-2-propenyl;
alkynyl, such as 2-propynyl, 2-butynyl, 3-butynyl, 1-methyl-2-propynyl, 1-methyl-2-butynyl, 1-ethyl-2-propynyl, 2-pentynyl, 3-pentynyl, 4-pentynyl or 1-methyl-2-pentynyl, preferably 2-propynyl, 1-methyl-2-propynyl or 2-butynyl;
cycloalkyl, such as cyclopropane, cycobutane, cyclopentane or cyclohexane, preferably cyclopropane, cyclopentane or cyclohexane;
haloalkyl as stated under R.sup.1, and fluoromethyl, difluoromethyl, trifluoromethyl, 2-fluoroethyl, 2,2-difluoroethyl or 2,2,2-trifluoroethyl, preferably difluoromethyl, trifluoromethyl, chloromethyl, dichloromethyl, trichloromethyl or 2-chloroethyl;
alkoxyalkyl, such as 2-methoxyethyl, 2-ethoxyethyl, 2-propoxyethyl, 3-methoxypropyl or 3-ethoxypropyl, preferably methoxyethyl or 2-ethoxyethyl;
alkoxyalkoxyalkyl, such as 2-methoxymethoxyethyl, 2-ethoxymethoxyethyl or 2-ethoxyethoxyethyl;
R.sup.3 is hydrogen or alkyl as stated under R.sup.1, preferably hydrogen, methyl or ethyl;
R.sup.4 is a phenyl ring or a 5-membered or 6-membered heteroaromatic, such as pyrrole, pyrazole, imidazole, furan, thiophene, oxazole, thiazole, isoxazole, isothiazole, pyridine, pyridazine, pyrimidine or pyrazine, preferably pyridine or pyrimidine.
Preferred substituents of R.sup.4 are alkyl as stated under R.sup.1, in particular methyl, ethyl or isopropyl; haloalkyl as stated under R.sup.2, in particular trifluoromethyl or difluoromethyl; alkoxy, such as methoxy, ethoxy propoxy, 1-methylethoxy, butoxy, 1-methoxy, 2-methoxy or 1,1-dimethylethoxy, in particular methoxy, ethoxy or 2-propoxy; haloalkoxy, such as trifluoromethoxy, trichloromethoxy, fluoromethoxy, 2,2,2-trifluoroethoxy, 1,2,2-trifluoromethoxy or 1,1,2,2-tetrafluoroethoxy, in particular trifluoromethoxy or 2,2,2-trifluoroethoxy; alkylthio, such as methylthio, ethylthio, propylthio, 2-propylthio, butylthio, 1-methylpropylthio, 2-methylpropylthio or 1,1-dimethylethylthio, in particular methylthio or ethylthio; haloalkylthio, such as trifluoromethylthio or trichloromethylthio; alkylsulfinyl, such as methylsulfinyl or ethylsulfinyl; alkylsulfonyl, such as methylsulfonyl or ethylsulfonyl; alkylcarbonyl, such as acetyl, ethylcarbonyl, propylcarbonyl, 1-methylethylcarbonyl, butylcarbonyl, 1-methylpropylcarbonyl, 2-methylpropylcarbonyl or 1,1-dimethylethylcarbonyl, in particular acetyl, 1-methylpropylcarbonyl or 1,1-dimethylethylcarbonyl; alkoxycarbonyl, such as methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl or 1-methylethoxycarbonyl; halogen, such as fluorine, chlorine or bromine, in particular fluorine or chlorine, or carboxyl, nitro or cyano.
Particularly preferred compounds Ia and Ib are those in which R.sup.4 is unsubstituted or monosubstituted or disubstituted.
Specific examples of herbicidal (hetaryloxy)- or aryloxyphenoxyacetic acid derivatives of the formula IV whose toleration by crops can be improved by aryl- or hetarylimidazolecarboxylic esters of the formulae Ia and Ib are listed in Table A below:
The herbicidal active ingredients and antidotes may be applied together or separately to the leaves and shoots of the crop plants and unwanted plants. Preferably, the antidote is applied together with the herbicidal active ingredient. If the components are applied separately, the antidote is applied first to the field and then the herbicidal active ingredient. The herbicidal active ingredient and antidote may be formulated together or separately as spray agents in the form of suspensions, emulsions or solutions.
Treatment of the crop plant seed with the antidote prior to sowing is also feasible. The herbicidal active ingredient is then applied to the field on its own in conventional manner.
For herbicidal (heteroaryloxy)-phenoxyacetic or -propionic acid derivatives of the formula IV, the amount of antidotaly active compound varies, depending on the crop. The ratios may vary over a wide range, and are also dependent on the structure of the (heteroaryloxy)phenoxyacetic or -propionic acid derivatives IV and on the crop involved. Suitable ratios of herbicidal active ingredient to antidote are from 1:4 to 1:0.01, and preferably from 1:4 to 1:0.1, parts by weight.
For the same cyclohexenone derivative V, the amount of antidote varies, depending on the crop. The ratios in which a cyclohexenone derivative V and an aryl- or heteroarylimidazolecarboxylate of the formula Ia and/or Ib are used may vary over a wide range, and are dependent on the structure of the cyclohexenone derivative, the aryl- or heteroarylimidazolecarboxylate of the formula Ia and/or Ib and the crop involved. Suitable ratios of herbicidal active ingredient to safener are from 1:4 to 1:0.01, and preferably from 1:4 to 1:0.25, parts by weight.
The novel herbicidal agents may contain, in addition to the aryl- or heteroarylimidazolecarboxylate of the formula Ia and/or Ib as safener and the herbicide from the group of the (heteroaryloxy)phenoxyacetic acids IV or cyclohexenones V, other herbicidal or growth-regulating active ingredients and inert additives without the safening effect being impaired.
The agents according to the invention, or--when applied separately--the herbicidal active ingredients and the safener, are applied for instance in the form of directly sprayable solutions, powders, suspensions (including high-percentage aqueous, oily or others), dispersions, emulsions, oil dispersions, pastes, dusts, broadcasting agents or granules by spraying, atomizing, dusting, broadcasting or pouring. The forms of application depend entirely on the purpose for which the active ingredients are to be used.
For the preparation of solutions, emulsions, pastes and oil dispersions to be sprayed direct, mineral oil fractions of medium to high boiling point, such as kerosene or diesel oil, further coal-tar oils, and oils of vegetable or animal origin, aliphatic, cyclic and aromatic hydrocarbons such as benzene, toluene, xylene, paraffin, tetrahydronaphthalene, alkylated naphthalenes and their derivatives such as methanol, ethanol, propanol, butanol, cyclohexanol, cyclohexanone, chlorobenzene, isophorone, etc., and strongly polar solvents such as N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, water, etc. are suitable.
Aqueous formulations may be prepared from emulsion concentrates, pastes, oil dispersions or wettable powders by adding water. To prepare emulsions, pastes and oil dispersions the ingredients as such or dissolved in an oil or solvent may e homogenized in water by means of wetting or dispersing agents, adherent or emulsifiers. Concentrates which are suitable for dilution with water may be prepared from active ingredient, wetting agent, adherent, emulsifying or dispersing agent and possibly solvent or oil.
Examples of surfactants are: alkali metal, alkaline earth metal and ammonium salts of aromatic sulfonic acids, e.g., ligninsulfonic acid, phenolsulfonic acid, naphthalenesulfonic acid and dibutylnaphthalenesulfonic acid, and of fatty acids, alkyl and alkylaryl sulfonates, and alkyl, lauryl ether and fatty alcohol sulfates, alkali metal and alkaline earth metal salts, of dibutylnaphthalenesulfonic acid, lauryl ether sulfate, fatty alcohol sulfates, and salts of sulfated hexadecanols, heptadecanols, and octadecanols, salts of fatty alcohol glycol ethers, condensation products of sulfonated napththalene and naphthalene derivatives with formaldehyde, condensation products of naphthalene or naphthalenesulfonic acids with phenol and formaldehyde, polyoxyethylene octylphenol ethers, ethoxylated isooctylphenol, ethoxylated octylphenol and ethoxylated nonylphenol, alkylphenol polyglycol ethers, tributylphenyl polyglycol ethers, alkylaryl polyether alcohols, isotridecyl alcohol, fatty alcohol ethylene oxide condensates, ethoxylated castor oil, polyoxyethylene alkyl ethers, ethoxylated polyoxypropylene, lauryl alcohol polyglycol ether acetal, sorbitol esters, lignin-sulfite waste liquors and methyl cellulose.
Powders, dusts and broadcasting agents may be prepared by mixing or grinding the active ingredients with a solid carrier.
Granules, e.g., coated, impregnated or homogeneous granules, may be prepared by bonding the active ingredients to solid carriers. Examples of solid carriers are mineral earths such as silicic acid, silica gels, silicates, talc, kaolin, attapulgus clay, limestone, lime, chalk, bole, loess, clay, dolomite, diatomaceous earth, calcium sulfate, magnesium sulfate, magnesium oxide, ground plastics, fertilizers such as ammonium sulfate, ammonium phosphate, ammonium nitrate, and ureas, and vegetable products such as grain meals, bark meal, wood meal, and nutshell meal, cellulosic powders, etc.
MANUFACTURING EXAMPLES
The directions given in the examples below may be used, after appropriate modifications of the starting materials, to obtain further compounds of the formula Ia and Ib. The compounds obtained are listed with their physical data in the tables below; compounds without these data may be prepared from the appropriate materials in analogous manner. In view of their close structural relationship to the compounds which have been manufactured and investigated, they are expected to have a similar action.
EXAMPLE 1
Ethyl 1-(2,4-dinitrophenyl)-2-methylimidazole-4-carboxylate
16 ml of triethylamine was added to 14.5 g (0.078 mol) of 2,4-dinitrofluorobenzene, 12 g (0.078 mol) of ethyl 2-methylimidazole-4-carboxylate and 500 ml of toluene, and the mixture was refluxed for 18 hours. The solvent was then distilled off under reduced pressure and the residue was chromatographed using pentane/ethyl acetate as mobile phase.
Yield: 19.5 g (81% of theory); m.p.: 150.degree.-152.degree. C. (Active ingredient example 1.015).
EXAMPLE 2
Isopropyl 1-(2,4-dinitrophenyl)-2-bromo-5-methyl-54-imidazolecarboxylate
4.2 ml of triethylamine was added dropwise to 5 g (0.02 mol) of isopropyl 2-bromo-5-methyl-4-imidazolecarboxylate, 3.9 g of 1-fluoro-2,4-dinitrobenzene and 200 ml of toluene, and the mixture was refluxed for 16 hours. The toluene solution was then washed with water, dried and concentrated. The residue was stirred with diethyl ether and the solid obtained in this manner was isolated.
Yield: 5.7 g (69%); m.p.: 161.degree.-162.degree. C. (Active ingredient example 1.025).
EXAMPLE 3
Methyl 1-(2,4-dibromophenyl)-2-methylimidazole-4-carboxylate
14.1 g of 30% strength sodium methylate solution was added to 10.9 g (0.078 mol) of methyl 2-methylimidazole-4-carboxylate in 100 ml of dimethylformamide; the methanol which formed was removed completely. 38.1 g (0.15 mol) of 1-fluoro-2,4-dibromobenzene was added to the dimethylformamide solution remaining, and the mixture was refluxed for 2 hours. Water was then added, extraction carried out with ethyl acetate and the ethyl acetate phase was washed with water. After removal of the solvent from the organic phase, there was obtained a residue which crystallized on trituration with diisopropyl ether.
Yield: 10.8 g (36.7%); m.p.: 162.degree.-163.degree. C. (Active ingredient example 1.059).
EXAMPLE 4
Ethyl 1-(2,4-dinitrophenyl)-2-methyl-5-chloroimidazole-4-carboxylate and ethyl 1-(2,4-dinitrophenyl)-2-trichloromethyl-5-chloroimidazole-4-carboxylate
16.5 g (0.1225 mol) of sulfuryl chloride and 0.2 g of dibenzoyl peroxide were added to 9.8 g (0.03 mol) of ethyl 1-(2,4-dinitrophenyl)-2-methylimidazole-4-carboxylate in 200 ml of chlorobenzene, and the mixture was heated at 100.degree. C. for 90 minutes. When gas evolution had ceased, the mixture was concentrated to dryness, the residue was adjusted to a pH of 7 with dilute aqueous ammonia and extracted with methylene chloride, and the organic phase was dried with sodium sulfate, concentrated and chromatographed.
Yield: 4.7 g (43% of theory); m.p.: 181.degree.-182.degree. C. (Active ingredient example 2.001).
USE EXAMPLE
The influence of various representatives of the herbicidal agents, or combinations of agent and antidote, according to the invention on the growth of unwanted and crop plants compared with that of the herbicidal active ingredient alone is demonstrated in the following greenhouse experiments.
The vessels employed were plastic flowerpots having a volume of 300 cm.sup.3 and filled with a sandy loam containing about 3.0% humus. The seeds of the test plants were sown separately, according to species, and the soil was moistened. Transparent plastic covers were then placed on the vessels to ensure uniform germination and plant growth.
For the postemergence treatment, the plants were grown, depending on growth form, to a height of 3 to 15 cm before being treated with the active ingredients, which were suspended or emulsified in water and sprayed through finely distributing nozzles.
In the biological experiments, compound V.2 was used as cyclohexenone derivative V: ##STR39##
The formulations contain from 0.1 to 95, and preferably 0.5 to 90, % by weight of active ingredient and safener. The amounts of herbicidal active ingredient applied range from 0.001 to 0.5 kg/ha.
The herbicidal active ingredient V.2 was used (on its own and together with the safener) in the spray liquor as a commercially formulated product (184 g/l EC) together with the same amounts of solvent system XXII given in the table for the safener.
All the safeners were formulated in a mixture consisting of 80% of cyclohexenones and 20% of Emulphor EL (formulaton XXII) with 10 wt % of active ingredient.
The vessels were set up in the greenhouse--heat-loving species at from 18.degree. to 35.degree. C., and those from more moderate climates at from 10.degree. to 25.degree. C.
The experiment was run for from 3 to 5 weeks. During this period, the plants were tended and their reaction to the various treatments was assessed. Damage caused by the chemical agents was evaluated on a 0 to 100 scale, compared with untreated control plants. 0 denotes no damage, and 100 denotes complete destruction (Triticum aestivum, wheat).
The table below demonstrates the safening action of compounds nos. 1.038 and 1.039; the tolerance of the cyclohexenone derivative V.2 by the crop plant was improved considerably.
Claims
We claim:
1. A herbicidal composition containing at least one compound selected from the compounds of the formulae Ia and Ib ##STR40## where R.sup.1 is halogen or C.sub.1 -C.sub.4 -alkyl which may bear from one to three chlorine atoms, R.sup.2 is C.sub.1 -C.sub.6 -alkyl which may bear from one to three of the radicals halogen, C.sub.1 -C.sub.4 -alkoxy and/or C.sub.1 -C.sub.4 -alkoxy-C.sub.1 -C.sub.4 -alkoxy, or is C.sub.3 -C.sub.6 -alkenyl, C.sub.3 -C.sub.6 -alkynyl or C.sub.3 -C.sub.6 -cycloalkyl, R.sup.3 is hydrogen or C.sub.1 -C.sub.4 -alkyl, R.sup.4 is a phenyl ring or a 5- or 6 membered heteroaromatic ring selected from the group consisting of pyrrole, pyrazole, imidazole, furan, thiozole, isoxazole, isothiazole, pyridine, pyridazine, pyrimidine or pyrazine, and these aromatic rings may bear from one to three of the following groups: halogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -haloalkyl, C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -haloalkoxy, C.sub.1 -C.sub.4 -alkylthio, C.sub.1 -C.sub.4 -alkylsulfinyl, C.sub.1 -C.sub.4 -alkylsulfonyl, C.sub.1 -C.sub.4 -alkylcarbonyl, C.sub.1 -C.sub.4 -alkoxycarbonyl, carboxyl, nitro and/ cyano and at least one herbicidally active ingredient selected from the group consisting of a) 2-(4-heteroaryloxy)- or 2-(4-aryloxy)phenoxyacetic acid derivatives of the formula IV ##STR41## where R.sup.a is phenyl, pyridyl, benzoxazyl, benzothiazyl or benzopyrazinyl, and these aromatic ring systems may bear up to two of the following radicals: halogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -haloalkyl and/or C.sub.1 -C.sub.4 -haloalkoxy, R.sup.b is hydrogen, C.sub.1 -C.sub.5 -alkyl, C.sub.3 -C.sub.5 -alkylideneimino, C.sub.3 -C.sub.5 -alkylideneiminooxy-C.sub.2 -C.sub.3 -alkyl, or one equivalent of a plant-tolerated cation, and R.sup.c is hydrogen or methyl, and b) cyclohexenone derivatives of the formula V ##STR42## where R.sup.d is C.sub.1 -C.sub.4 -alkyl; R.sup.e is C.sub.1 -C.sub.4 -alkyl, C.sub.3 -C.sub.4 -alkenyl, C.sub.3 -C.sub.4 -alkynyl, C.sub.3 -C.sub.4 -haloalkenyl or thenyl which may carry a halogen atom; R.sup.f is C.sub.1 -C.sub.4 -alkyl which is unsubstituted or monosubstituted by C.sub.1 -C.sub.4 -alkylthio or C.sub.1 -C.sub.4 -alkoxy; a 5- or 6-membered saturated or monounsaturated ring system, which in addition to carbon members may contain an oxygen or a sulfur atom or a sulfoxyl or sulfonyl group, and this ring may bear from one to three of the following radicals: hydroxyl, halogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -haloalkyl, C.sub.1 -C.sub.4 -alkoxy and/or C.sub.1 -C.sub.4 -alkylthio; a 10-membered saturated or monounsaturated heterocyclic structure containing two oxygen or sulfur atoms and which is unsubstituted or mono- to trisubstituted by C.sub.1 -C.sub.4 -alkyls and/or methoxy groups; phenyl, pyridyl or isoxazolyl, and these groups may bear up to three of the following groups: C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -haloalkyl, C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -alkylthio, C.sub.3 -C.sub.6 -alkenyloxy, C.sub.3 -C.sub.6 -alkynyloxy, C.sub.1 -C.sub.4 -alkoxy-C.sub.1 -C.sub.3 -alkyl, C.sub.1 -C.sub.4 -dialkoxy-C.sub.1 -C.sub.3 -alkyl, formyl, halogen and/or benzolyamino; R.sup.g is hydrogen, hydroxy or, when R.sup.f is C.sub.1 -C.sub.6 -alkyl, C.sub.1 -C.sub.6 -alkyl; R.sup.h is hydrogen, cyano, halogen or C.sub.1 -C.sub.4 -alkoxycarbonyl and R.sup.i is hydrogen or one equivalent of an environmental compatible cation.
2. A herbicidal composition as set forth in claim 1, containing a compound Ia and/or Ib and a herbicide a) or a herbicide b) in a weight ratio of from 4:1 to 0.01:1.
3. A process for the selective control of unwanted plants, wherein a compound of the formula Ia and/or Ib as set forth in claim 1 and a 2-(4-heteroaryloxy)- or 2-(4-aryloxy)-phenoxyacetic acid derivative of the formula IV as set forth in claim 1 or a cyclohexenone derivative of the formula V as set forth in claim 1 are applied simultaneously or one after the other during or after sowing of the crop plants or prior to or during emergence of the crop plants.
4. A process for preventing damage to crop plants by herbicidal 2-(4-heteroaryloxy)- or 2-(4-aryloxy)-phenoxyacetic acid derivatives of the formula IV as set forth in claim 1 or by herbicidal cyclohexenone derivatives of the formula V as set forth in claim 1, wherein the seed of the crop plants is treated with an antagonistically effective amount of a compound of the formula Ia and/or Ib as set forth in claim 1.
5. A process for the selective control of unwanted plants, wherein the leaves of the crop plants and unwanted plants are treated postemergence and either simultaneously or one after the other with a compound of the formula Ia and/or Ib as set forth in claim 1 and with a 2-(4-heteroaryloxy)- or 2-(4-aryloxy)-phenoxyacetic acid derivative of the formula IV as set forth in claim 1 or with a cyclohexenone derivative of the formula V as set forth in claim 1.
6. A process as set forth in claim 3, where the crop plants are barley, wheat, Indian corn, sorghum or rice.
7. A process as set forth in claim 4, where the crop plants are barley, wheat, Indian corn, sorghum or rice.
8. A process as forth in claim 5, where the crop plants are barley, wheat, Indian corn, sorghum or rice.
9. A composition as defined in claim 1, which comprises a compound of the formula Ia in which R.sup.1 is methyl, R.sup.2 is ethyl, R.sup.3 is hydrogen and R.sup.4 is 2-4-dichlorophenyl and a cyclohexenone derivative of the formula V which is ##STR43##
10. A herbicidal composition as defined in claim 1, wherein R.sup.4 of the compounds Ia and Ib is unsubstituted or substituted phenyl.