IE47388B1 - N-(imidazolylmethyl)-acetanilides,their use as herbicides and process for combating unwanted plant growth - Google Patents

Abstract

1. Acetanilides of the formula see diagramm : EP0001751,P10,F1 where R and R**1 each denotes alkyl of a maximum of 5 carbon atoms, R**2 denotes hydrogen, X denotes chlorine, and A denotes imidazole, or a salt thereof, which is attached via a ring nitrogen atom and may be mono- or polysubstituted by halogen or alkyl radicals or halogen and alkyl radicals each of a maximum of 4 carbon atoms.

Description

The present invention relates to acetanilides, herbicides containing these compounds, and a process for combating unwanted plant growth with these compounds.

Haloacetanilides with herbicidal or growth-regulating 5 properties are known, N-methoxymethyl-a-chloroaceto-2,6diethylanilide (U.S. Patent 3,547,620) is of considerable economic significance. An active ingredient bearing a 1,3dioxolan-2-yl-methyl group is also known (German Laid-Open Application DOS 2,405,510). The strength of known acet10 anilides is their herbicidal action on numerous grasses from seed. A few dicotyledonous species are also combated by the first-named compound. However, there is a need for active ingredients which in addition to exhibiting a herbicidal action on grasses also have an improved action on broadleaved species and in particular are much better tolerated by crop plants damaged by known active ingredients.

It has been found that acetanilides of the formula R where R and R1 denote alkyl of a maximum of 5 carbon atoms, R2 denotes hydrogen, X denotes chlorine and A denotes imidazole, or a salt thereof, which is attached via a ring nitrogen atom and may be mono- or polysubstituted by halogen or alkyl radicals or halogen and alkyl radicals each of a maximum of 4 carbon atoms, have, in addition to a good herbicidal action, excellent selectivity in important crops.

In view of the art it was surprising that precisely the imidazole-substituted acetanilides according to the invention are distinguished by this high level of toleration by crop plants.

Depending on the object to be achieved and the dosage rate, the new active ingredients are suitable for selectively combating unwanted plants in certain crops consisting of herbaceous or woody species, for growth regulation by inhibiting plant growth, or, at appropriately high application rates, for totally combating plant growth.

At lower dosage rates, the compounds according to the invention of the formula I in which R and R1 are substituents in the 2- and 6-positions on the phenyl nucleus and each denotes alkyl of a maximum of 5 carbon atoms have a particularly pronounced selectivity in crop plants. 2 Examples of 8, S , R , X and Y (sic) in formula I are as follows: R and R1: alkyl of a maximum of 5 carbon atoms, 10 such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, linear and branched pentyl; X: chlorine; A: an imidazole attached via a ring nitrogen atom, e.g. imdazole, 2-methylimidazole, 4(5)-chloroimidazole, 2-chloroimidazole, 4,5-dichloroimidazole, trichloroimidazole, 2-methyl5 -4,5-dichloroimidazole, 2-ethyl-4,5-dichloroimidazole, 2-isopropyl-4,5-dichloroimidazole, 4(5)-bromoimidazole, 4,5-dibromoimidazole, tribromoimidazole, 2-methyl-4,5-dibromoimidazole, and 2-bromo-4,5-dichloroimidazole.

Furthermore, the radical A may also be attached to one of 10 the conventional strong inorganic or organic acids, e.g. hydrochloric acid, hydrobromic acid, nitric acid, sulfuric acid, tetrafluoboric acid, fluosulfonic acid, formic acid, a halogenated carboxylic acid, e.g. trichloroacetic acid, an alkanesulfonic acid, e.g. methanesulfonic acid, a halogenated alkanesulfonic acid, e.g. trifluoromethanesulfonic acid, perfluorohexanesulfonic acid, or an arylsulfonic acid, e.g. dodecylbenzenesulfonic acid, to form a salt.

The new acetanilides of the formula I may be prepared by the following processes: The acetanilides of the formula I are obtained by reaction of 2-halo-N-halomethylacetanilides of the formula II with an imidazole of the formula H-A in accordance with the following equation: R I R CH--A ά + HX CO-CH2-X • II 2 The substituents R, R , R , A and X have the above meanings.

Some of the 2-halo-N-halomethylacetanilides of the formula II are disclosed in German Printed Application DAS 1,542,950; others may be prepared analogously by reaction of the corresponding azomethines with a haloacetyl halide.

The imidazole is advantageously used in at least equimolar amount, with reference to 2-halo-N-halomethylacetanilide.

The hydrogen halide liberated during the reaction is advan tageously intercepted by suitable binding agents, such as organic bases, e.g. tertiary amines, or inorganic bases, e.g. alkali metal or alkaline earth metal carbonates or bicarbonates The binding agent is added in at least equimolar amount, with reference to imidazole used.

It is advantageous to carry out the reaction in_a solvent inert to 2-halo-N-halomethylacetanilides. Suitable solvents are 20 hydrocarbons, e.g. petroleum ether, ligroin, cyclohexane, toluene and xylene; ethers, e.g. diethyl ether, diisopropyl ether, dimethoxyethane, tetrahydrofuran, dioxane, and anisole; halogenated hydrocarbons, e.g. iichloromethane, chloroform, 473 1,2-dichloroethane, carbon tetrachloride and chlorobenzene; ketones, e.g. acetone, and methyl ethyl ketone; esters, e.g. ethyl acetate and butyl acetate; and sulfones, e.g. dimethyl sulfoxide and tetrahydrothiophene-1,1-dioxide. Mixtures of these solvents may also be used.

The reaction may be carried at from 0°C upwards. To accelerate the reaction it is advantageously carried out at the boiling point of the solvent or solvent mixture, but not above 200°C. The preferred temperature range is from 50° to 150°C.

Upon completion of the reaction, the mixture is filtered and the product is, if desired after having been washed, isolated from the filtrate in a conventional manner. If a water-miscible solvent is used, it is usually advantageous to remove it by evaporation after filtration and replace it by a water-immiscible 15 solvent.

The new acetanilides of the formula I may also be prepared by reaction of 2-halo-N-halomethylacetanilides of the formula II with a salt of an imidazole of the formula M*Ae in accordance with the following equation: R‘ R ,2 R II R R .1 2 The substituents R, R , R , A and X have the above meanings, and M* denotes the silver ion, an alkali metal ion, or one equiva lent of an alkaline earth metal ion. 7 388 The alkali metal, alkaline earth metal or silver imidazoles are prepared in known manner by reaction of the imidazole H-A with alkali metals or strong bases, such as alkali metal hydroxide, alcoholate, amide or hydride, or silver hydroxide, with the liberation of hydrogen, alcohol or ammonia.

The salts M*Ae are advantageously reacted with the 2-halo-N-halomethylacetanilides of the formula II in polar aprotic solvents such as nitriles, e.g. acetonitrile, amides, e.g. dimethylformamide, polyethers, e.g. diethylene glycol dimethyl 10 ether and triethylene glycol dimethyl ether, sulfones, e.g. tetrahydrothiophene-1,1-dioxide, sulfoxides, e.g. dimethyl sulfoxide, and ketones, e.g. acetone, methyl ethyl ketone, and diisopropyl ketone, at from -30° to +50°C, preferably at room temperature. The starting materials are advantageously employed 15 in equimolar amounts. The reaction products are isolated in conventional manner, if desired after.separation of the inorganic salts M*X® which have formed and if desired after replacement of the polar aprotic solvent by a water-immiscible solvent.

The salts of the acetanilides of the formula I may be 20 obtained in known manner from the acetanilides of the formula X prepared by one of the processes described above - by addition of at least equimolar amounts of strong inorganic or organic acids, such as hydrochloric acid, hydrobromic acid, nitric acid, sulfuric acid, tetrafluroboric acid, fluosulfonic acid, formic acid, halogenated carboxylic acids, e.g. trichloroacetic acid, alkanesulfonic acids, e.g. methanesulfonic acid, halogenated alkanesulfonic acids, e.g. trifluoromethanesulfonic acid, perfluorohexanesulfonic acid, and arylsulfonic acids, e.g. dodecylbenzenesulfonic acid.

The following example illustrates the preparation of the new acetanilides and their salts. In the examples, parts by weight bear the same relationship to parts by volume as the kilogram to the liter.

EXAMPLE 1 .2 parts by weight of 2-methyI-1*,5-dichloroimidazole and 60 parts by volume of methanol are dissolved in 3^.0 parts by weight of 30* strength methanolic sodium methylate solution, and the mixture is evaporated to dryness in vaeuo at 3C°C. The crystalline residue is suspended in 200 part3 by volume of anhydrous acetonitrile. At 10°C and while 3tirring, up.2 parts by weight of 2-chloro-2'jfi’-dimethyl-H-chloromethylacetanilide is introduced in portions and the mixture is stirred at room temperature for 16 hours. After the solvent has been evaporated in vacuo, the residue is partitioned between chloroform and water, 50.0 parts by weight of 2-chloro-’’-dimethy 1--1-(2-methyl -H^-dichloroimidazol-l-yl-methyD-acetanilide (m.p. 170°C; compound no. 8) is isolated from the chloroform phase after washing 3 times with water, drying and reerystallization from toluene.

The following compounds are obtained similarly: R 2' ch2-a 'CO-CHj-X R R1 R2 X A m.p. (' 2-CHj 6-CHj H Cl υ 127 2-CH- 6-C^H- H Cl I n 106 2-CHj 6-CHj H Cl cb/Q J 1 116 2-CHj 6-CHj H Cl a: t 95 2-CHj 6-C2Hg H Cl n 88 2-C2H5 6rC2Hg H Cl n 104 2-CHj 6-C2H5 H Cl rf ClSr Cl I 162 2-CHj 6-CHj H Cl ,./X 1 170 2-CHj 6-C2Hg H Cl tl 165 No. R R1 R2 X m.p. (°C) 2-CHj 6-CHj 2-CHj 6-C2H5 2-CHj 6-CHj 2-CHj 6-C2H5 2-CHj 6-CHj 2-CHj 6-C2H5 2-CHj 6-CHj 2-CHj 6-CH5 Application of the active ingredients according to the invention may be effected for instance in the form of directly sprayable solutions, powders, suspensions (including high-percentage aqueous, oily or other suspensions), dispersions, emulsions, oil dispersions, pastes, dusts, broadcasting agents, or granules by spraying, atomizing, dusting, broadcasting or -_-——— watering. The forms of application depend entirely on the purpose for which the agents are being used; in any case they should ensure the finest possible distribution of the active ingredient according to the invention.

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, chloroform, carbon tetrachloride, cyclohexanol, cyclohexanone, chlorobenzene and isophorone, and strongly polar solvents such as dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone and water, are suitable.

Aqueous formulations may be prepared from emulsion concentrates, pastes, wettable powders (spray powders) or oil dispersions by adding water. To prepare emulsions, pastes and oil dispersions the ingredients as such or dissolved in an oil or solvent may be homogenized in water by means of wetting agents, adherents, dispersing agents 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 ligninsulfonic acid, naphthalenesulfonic acids, phenolsulfonic acids, alkylaryl sulfonates, alkyl sulfates, and alkyl sulfonates, alkali metal and alkaline earth metal salts of dibutylnaphthalenesulfonic acid, lauryl ether sulfate, fatty alcohol sulfates, alkali metal and alkaline earth metal salts of fatty acids, salts of sulfated hexadecanols, heptadecanols, and octadecanols, salts of sulfated fatty alcohol glycol ethers, condensation products of sulfonated naphthalene and naphthalene derivatives with formaldehyde, condensation products of naphthalene or naphthalenesulfonic acids with phenol and formaldehyde, polyoxyethylene octylphenol ethers, ethoxylated isooctylphenol, ethoxylated octylohenol and ethoxylated nonylphenol, alkylphenol polyglycol ethere, tributylphenol polyglycol ethers, alkylaryl polyester 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 silicagel, silicic acids, silicates, talc, kaolin, Attaclay, limestone, lime, chalk, bole, loess, clay, dolomite, diatomaceous earth, calcium and magnesium sulfate, magnesium oxide, ground plastics, fertilizers such as ammonium sulfate, ammonium nitrate, and ureas, and vegetable products such as grain flours, bark meal, wood meal, and nutshell meal, cellulosic powders, and other solid carriers. „ 47388 Ths formulations contain from 0.1 to 95, and preferably 0.5 to 90, % by weight of active ingredient. Application rates are from 0.1 to 10 kg of active ingredient per hectare.

The new herbicidal anilides according to the invention may 5 be mixed and applied together with numerous representatives of other herbicidal or growth-regulating active ingredient groups. Examples of suitable mixture components are diazines, benzothiadiazinones, 2,6-dinitroanilines, N-phenylcarbamates, dicarbamates, thiolcarbamates, halocarboxylic acids, triazine3, 10 amides, ureas, diphenyl ethers, triazinones, uracils and benzofuran derivatives.

It is also useful to apply the new compounds according to the invention, alone or in combination with other herbicides, in admixture with further crop protection agents, e.g. agents for combating pests or phytopathogenic fungi or bacteria. Of interest is also the fact that the new compounds may also be mixed with mineral solutions used to eliminate nutritional or trace element deficiencies.

The influence of various representatives of the compounds according to the invention on the growth of unwanted and wanted jq plants in comparison with chemically similar known compounds is demonstrated in the following experiments. The series of experiments were carried out in the greenhouse.

The culture vessels were plastic flowerpots having a volume of 300 cnP and the substrate was a sandy loam containing about ^55 humus. The seeds of the test plants given in Table 1 were sown shallow, and separated according to species. The active ingredients were then applied immediately to the surface of the soil. They were suspended or emulsified in water as vehicle and sprayed through finely distributing nozzles. After treatment, 2Q the vessels were lightly sprinkler-irrigated to Induce germination and growth and simultaneously to activate the chemical agents.

The vessels were then covered with transparent plastic hoods until the plants had taken root. These hoods ensured uniform germination of the test plants - to the extent that this was 25 not impaired by the chemicals - and prevented readily volatile substances from evaporating.

The pots were placed in either cooler (15° to JO°C) or warmer (25° to 40°C) parts of the greenhouse, depending on the temperature requirements of the plants. The experiments were run for from t to 6 weeks, during which period the plants were tended and their reaction to the individual treatments was* assessed. Table 2 gives the compounds examined, the application rates in kg/ha of active ingredient, and the species of teet plants. For assessment, the 0 to 100 scale was used, 0 denoting no damage or normal emergence, and 100 denoting no emergence or complete destruction of at least the visible plant parts. Results Table 2 contains some figures biologically characterizing the new compounds. What is particularly apparent from them is that the new compounds are tolerated much better by certain crop plants than the prior art compounds.

The results were obtained from preemergence treatments. The new active ingredients may of course also be used postemergence. Depending on the application rate employed, all plants are eliminated or, at lower rates, is achieved.

Table 1 - List of test plants Botanical name_ Alopecurus myo3uroide3 Beta vulgaris Echinochloa crus galli Glycine max Gossypium hirsutum Setaria spp.

Sorghum bicolor Zea mays merely a growth-inhibiting action Common name slender foxtail sugarbeet barnyardgrass soybean cotton foxtail spp. Sorghum Indian corn 100 φ w o Λ c Φ 1) fc to ft) x: P υ· bO s a χ> fc Λ · •n a ft) o. ea η rt on rt rt JZ ·-< o rt o tfl c •rt 03 £ 3 a fc ω o 03 4) 3 XJ fc »H 3 O O fc ft) 3 Λ 99 O O rH >i < E 0) rt >» Φ rt N 6 O in CM CM O O a· in ooo ooo o ooo ooo o ri ri rl ri ri ri rt OOO OOO ri ri ri ο O < oo< oo oomooi cj o Ci CM GOOD OV OO c*· Ch oo oom oom ι e: o •rt AJ a o o. a, <3 ft) ϋ C 1) bO fc ft) c δ 1) fc Q. \2/ w Ε I K tr s o fi E fc rt 3 0 J=rt 03 bO O P fc V 2 Ο ·Η rt ca £3 I—+ a E rt 3 S O P •rt 3 Cl ca Q.P 23 ο > 3 O «3 03 1 03 fc Ο 0 rt o Ο Λ ft) C •rt o >»X rt rt Ο E ι ι ooo ooo o co ο ο o mm ooo o rl 1-t CM *T oo oom ooo o c P a CC fc rt rt bO P rt ft) 3 ffl > oo oom oom o vo CC Ό rt £ oo moo moo ο o • * · · · · · · φ · rt CJ O ** CJ ο ή CM CJ CJ ca CJ Φ rt X) cc E-« Basic incleeule P ΰ φ Ρ Ρ A ca σ c § Ω, E o o in X CJ o m s CJ o Ό Φ , 03 · oca »—4 · '00 w rt C Ort (ϋ •rC fc es • fil Φ CX co n (ti ο ·Η £ ΓΗ α d ο ω c η ύ fc ο (contd. Φ ω <3 ε φ Ό Ό C 3} ΰ) 4-3 C ΐν α 4-3 Μ ύ) ε» η 03 O 3 Ό fc •H 3 0 υ fc Φ 3 fi. 0) o 0 rH >» < ε m (ti ss Φ 0 04 ε fc Ο Μ ο fc ο Ο ·Η CO Λ ε •Η 3 £Χ«Ρ >» 3 η co ιο fc Ο ·Η Ο Λ ο C •Η Ο >5 Μ «Μ (ti σ ε fc (β «, to i9 Ή Φ 3 £0 > Λ co ιη σ\ ο rl I ο σ\ Ο CU ο ο * * CM CM CM s ο CM X ο OXO \u/ I ΗΛ H'S O X Ό Ό C Ci 5 α 'V O C W - Qi IP 3 Ofc o ·. 0 <-4 ϋ ι · ’V Q. οφ -( ox s so « ή a«r O Q •H C d ’Ο. * o c Ό H J = no damage 100 = non-ermegence or complete destruction EXAMPLE 2 parts by weight of compound 1 is mixed with 10 parts by weight of N-methyl-,*-pyrrolidone. A solution is obtained which is suitable for application in the form of very fine drops.

EXAMPLE 3 parts by weight of compound 2 is dissolved in a mixture consisting of 80 parts by weight of xylene, 10 parts by weight of the adduct of 8 to 10 moles of ethylene oxide to 1 mole of oleic acid-N-monoethanolamide, 5 parts by weight of the calcium salt of dodeeylbenzenesulfonie acid, and 5 parts by weight of the adduct of 40 moles of ethylene oxide to 1 mole of castor oil.

By pouring the solution into 100,000 parts by weight of water and uniformly distributing it therein, an aqueous dispersion is obtained containing 0.02% by weight of the active ingredient.

EXAMPLE 4 parts by weight of compound 3 is dissolved i‘n a mixture consisting of 40 parts by weight of cyclohexanone, 30 parts by weight of isobutanol, 20 parts by weight of the adduct of 7 moles of ethylene oxide to 1 mole of isooctyl20 phenol, and 10 parts by weight of the adduct of 40 moles of ethylene oxide to 1 mole of castor oil. By pouring the solution into 100,000 parts by weight of water and finely distributing it therein, an aqueous dispersion is obtained containing 0.02Ϊ by weight of the active ingredient.

EXAMPLE 5 parts by weight of compound 1 13 dissolved in a mixture consisting of 25 parts by weight of cyclohexanol, 65 parts by weight of a mineral oil fraction having a boiling point between 210° and 28O°C, and 10 parts by weight of the adduct of 40 moles of ethylene oxide to 1 mole of castor oil.

By pouring the solution into 100,000 parts by weight of water and uniformly distributing it therein, an aqueous dispersion is obtained containing 0.02Ϊ by weight of the active ingredient .

EXAMPLE 6 parts by weight of compound 2 ie well mixed with 3 parts by weight of the sodium salt of diisobutylnaphthalene- a sulfonic acid, 17 parts by weight of the sodium salt of a lignin-sulfonic acid obtained from a sulfite waste liquor, and 60 parts by weight of powdered 3ilica gel, and triturated in a hammer mill. By uniformly distributing the mixture in 20,000 parts by weight of water, a spray liquid is obtained 15 containing Ο.ΐ,ί by weight of the active ingredient.

EXAMPLE 7 parts by weight of compound 3 is intimately mixed with 97 parts by weight of particulate kaolin. A dust is obtained containing 3* by weight of the active ingredient.

EXAMPLE 3 parts by weight of compound 4 is intimately mixed with a mixture consisting of 92 parts by weight of powdered silica gel and 8 parts by weight of paraffin oil which has been sprayed onto the surface of this silica gel. A formulation 25 of the active ingredient is obtained having good adherence. EXAMPLE 9 parts by weight of compound 1 is intimately mixed with 10 parts of the sodium salt of a phenolsulfonic acid-urea-formaldehyde condensate, 2 parts of silica gel and 48 parte 738 8 of water to give a stable aqueous dispersion. Dilution in 100,000 parts by weight of water gives an aqueous dispersion containing O.Ohwti of active ingredient.

EXAMPLE 10 parts of compound 2 is intimately mixed with 2 parts of the calcium salt of dodecylbenzenesulfonic acid, 8 parts of a fatty alcohol polyglyeol ether, 2 parts of the sodium salt of a phenolsulfonic acid-urea-formaldehyde condensate and 68 parts of a paraffinic mineral oil. A stable oily dispersion is obtained.

Claims (5)

1. CLAIM S:Acetanilides of the formula where R and each denotes alkyl of a maximum of 5 carbon 2 5 atoms, R denotes hydrogen, X denotes chlorine, and A denotes imidazole, or a salt thereof, which is attached via a ring nitrogen atom and may be mono- or polysubstitut ed by halogen or alkyl radicals or halogen and alkyl radicals each of a maximum of 4 carbon atoms. 10 2. 2-Chloro-2'6'-dimethyl-N-(4,5-dichloroimidazoI-l-ylmethyl)-acetanilide.

2. -chloro-2'-methyl-6 1 -ethy1-N-(2-ethyl)-4,5-dichloro imidazol-1-y1-methyl)-acetanilide. 8. A process for controlling unwanted plant growth, characterized in that the soil or the plants are treated 2-chloro-2',6 1 -diethyl-N-(4,5-dichloroimidazol-l-ylmethyl)-acetanilide, and 22 47388 2-chloro-2'-methyl-6'-ethyl-N-(4,5-dichloroimidazol25 1-yl-methyl)-acetanilide, 2-chloro-2',6'-dimethyl-N-(4,5-dichloroimidazol-lyl-methyl)-acetanilide,

3. 2-Chloro-2'-methyl-6'-ethyl-N-(4,5-dichloroimidaz ol1-y1-methyl)-acetanilide.

4. 2-Chloro-2',6’-diethyl-N-(4,5-dichloroimidazol-l-yl15 methyl)-acetanilide. 5. 2-Chloro-2 1 -methyl-6 1 -ethyl-N-(2-ethyl-4,5-dichloroimidazol-l-y1-methyl)-acetanilide 6. A herbicide containing as active ingredient an acetanilide as claimed in claim 1. 20 7. A herbicide as claimed in claim 6 wherein the acetanilide has been seleeted from the group consisting of

5. With an acetanilide as claimed in claim 1.