NO131656B - - Google Patents

Description

The present invention relates to herbicidal agents thereof

species specified in claim l's preamble suitable for the control of plant systems, including germinating grains, cuttings and fully developed plants using preparations containing these.

The term "herbicide agent" is used to denote agents that have a modifying effect on the growth or development of plants. Such a modifying effect includes e.g. killing, inhibition, defoliation, drying out, regulation, stunting, treatment of shoots, stimulation, dwarfing and other deviations from natural development. In the same way, "phytotoxic" and "phytotoxicity" are used to identify the nature and activity of the mixtures according to the present invention.

According to the present invention, herbicidal agents have been provided, which are characterized by what is stated in the preamble of the claim, containing at least one 2-halogenacetanilide with the formula

1 2

where R and R denote primary or secondary alkyl with from 1 to 3 carbon atoms,

X is chlorine, bromine or iodine, and

Z denotes alkyl, alkenyl or alkynyl, which is optionally substituted with halogen, hydroxy or keto groups, or with an alkoxy group with 1-8 carbon atoms.

Representative active compounds used in the agents according to the present invention include those in which the groups in the preceding formula are as follows: R 1 and R 2 — methyl, ethyl, propyl and isopropyl;

Z — methyl, ethyl, propyl, isopropyl, n-butyl, primary isobutyl, secondary isobutyl, tertiary butyl, the normal and branched amyl, hexyl, heptyl and octyl groups, chloromethyl, bromopropyl, iodobutyl, f fluorohexyl,, hydroxyethyl, di-hydroxypropyl, 5-alkoxyalkyl, alkenyl and alkynyl groups

corresponding to the aforementioned alkyl groups.

It is previously known that certain N-substituted 2-haloacetanilides exhibit herbicidal activity, for example in U.S. patent no. 2,863,752 2-haloacetanilides with the general formula are disclosed:

in which the substituent X may be a halogen, a nitro or C 1-4 alkyl group, Y is a halogen atom and R may be an alkyl, alkenyl, alkynyl group, which groups may be halogenated, or may be an alkoxyalkyl group such as alkoxyethyl, alkoxypropyl and alkoxybutyl, such as 2-methoxyethyl, 2-ethoxyethyl, methoxybutyl, 3-methoxypropyl, etc... From Dutch patents 64.09490 and 64.14212, 2-haloacetanilides with herbicidal action are known, which are substituted in the 2'-position with a tertiary alkyl group. Dutch patent no. 64.14212 shows compounds in which the anilide nitrogen atom is substituted with halogenated ethyl or alkenyl groups. Examples of active compounds according to the aforementioned Dutch patent are 2-chloro-2<1->tert-butyl-6-ethyl-N-chloromethylacetanilide, 2-bromo-21-tert-butyl-6'-ethyl- N-bromomethylacetanilide and 2-chloro-2'-tert-butyl-6'-methyl-N-(1-chloro-2-butenyl)acetanilide. The connections in

according to Dutch patent 64.14212 can also be used in the preparation of the herbicidal compounds disclosed in Dutch patent 64.09490, which compounds can be exemplified by 2-chloro-2'-tert-butyl-6'-methyl-N-methoxymethylacetanilide,

and its N-isopropoxymethyl and N-butoxymethyl analogs and its 2-bromo analog.

It has surprisingly been found that the herbicidal agents containing as active ingredient one or more compounds of formula I exhibit excellent herbicidal properties with regard to selectivity towards useful plants and weeds. The herbicidal mixtures according to the present invention have been shown to exhibit greater safety with regard to beneficial plants and at the same time exhibit a better effect against weeds compared to known 2-haloacetanilides.

The new compounds included in the new herbicides are produced by alcoholysis according to the equation:

1 2

where R , R , X and Z are as defined above, and X"*" is halogen. The reaction is preferably carried out in the presence of an acid-binding agent. The acyl halide adducts used in the preparation are conveniently obtained by adding a halo acyl halide to N-methylene amines, as described in patent no. 116,302. The surprising chemical activity of the X"<*>" - halogen in comparison with the lack of chemical activity with regard to the X - halogen, allows the production in high yield of the new 2-haloacetanilides. Normally, for obtaining maximum yields, it is desirable that the alcohol is present in at least an equimolar amount to the acyl halide adduct and preferably in excess. The reaction is suitably carried out at room temperature, i.e. about. 20-25°C, however, higher or lower temperatures can be used, and the temperature is not critical. The acid-binding agent is preferably used in an amount at least equimolar to the amount of the hydrogen halide, which is formed in the reaction, and can be any acid-binding agent, such as a tertiary amine, e.g. trimethylamine, triethylamine, pyridine, quaternary ammonium hydroxides and alcoholates, metal alcoholates and the like

IN

hydroxide and the like, sodium carbonate, etc. The reaction product is insoluble in water, but soluble in hydrocarbon solutions, such as benzene, toluene, xylene, hexane or the like, and can be purified by recrystallization or by vacuum distillation.

The following examples illustrate the preparation of the active compounds.

o

EXAMPLE 1

Preparation of 21. 61-dimethyl-N-(tertiary butoxymethyl)-2-chloroacetanilide.

About. 115 g (0.2 mol) of 2',6'-dimethyl-N-chloromethyl-2-chloroacetanilide dissolved in chlorobenzene was mixed with approx. 50 ml tertiary butyl alcohol and approx. 20g (0.2 mol) triethylamine in a suitable reaction vessel. The mixture was allowed to stand for 8 days at room temperature. At the end of this period, hexane was added and the mixture washed twice with water, then heated and stirred with 10% aqueous potassium carbonate solution. The mixture was cooled and separated from the potassium carbonate and the resulting oil washed twice with water, dried over magnesium sulfate and evaporated under vacuum. The product obtained was a cream colored solid melting at 75-76°C.

EXAMPLE 2

Preparation of 2', 6'-diethyl-N-(2-propynyloxymethyl)-2-chloroacetanilide.

About. 56 g of chloroacetyl chloride and 300 ml of hexane were placed in a liter bottle. While the mixture was stirred, approx. 81 g of 2,6-diethyl-N-methylaniline added dropwise over a period of 20 minutes, which resulted in a temperature rise to approx. 70°C. The mixture was cooled to approx. 50°C and approx. 89 g of 2-propynol was added over a 10 minute period. During the addition of the alcohol, the temperature fell to approx. 40°C. About. 56 g of triethylamine was then added over the course of 15 minutes, which resulted in a temperature rise to approx. 68°C. The reaction mixture was refluxed for 10 minutes and then 200 ml of cold water was added. The mixture was transferred to a separatory funnel and further 300 ml portions of water were added. The mixture separated into an aqueous phase and an oily phase. The oily phase was separated, added to benzene and washed twice with water and vacuum distilled. The product obtained was a dark amber oil having a refractive index of

1.5393, and a boiling point of 145-155°C at 0.6 mm Hg.

EXAMPLE 3

Preparation of 2', 6'-diisopropyl-N-allyloxymethyl-2-chloroacetanilide.

About. 5 g of 2,6-diisopropyl-N-methylaniline was added to a stirred solution of 3.2 g of chloroacetyl chloride in approx. 12.5 g of carbon tetrachloride. The addition rate was adjusted so that the temperature was maintained at approx. 55°C. The mixture was stirred for a further 15 minutes at 55°C and then added to 16.5 g of allyl alcohol with stirring. Sufficient carbon tetrachloride was then added to give a clear solution which was allowed to stand overnight. The solution was then diluted with carbon tetrachloride to a total volume of 75 ml and approx. 3.2 g of triethylamine was added while cooling. The reaction mixture was then extracted five times with 125 mL portions of water and dried with potassium carbonate and concentrated under vacuum to give a white solid with a melting point of 66-70°C.

EXAMPLE 4

Preparation of 2'-methyl-6'-ethyl-N-alloxymethyl-2-bromoacetanilide.

About. 9 g of 2-ethyl-6-methyl-N-methylaniline was added over 30 minutes to a stirred solution of 13 g of bromoacetyl bromide

in 25 g of carbon tetrachloride at 50°C. The mixture was stirred for approx.

15 minutes and cooled. This mixture was added to approx.

33 g of allyl alcohol and then approx. 7 g triethylamine. The mixture was extracted 6 times with 125 ml portions of water, dried

with potassium carbonate, filtered and concentrated under vacuum.

The product obtained was a brown oil

EXAMPLE 5

Preparation of 2'-methyl-6'-isopropyl-N-methoxymethyl-2-bromoacetanilide.

About. 5 g of 2-isopropyl-6-methyl-N-methylaniline was added to approx. 6.5 g of bromoacetyl bromide and dissolved in 20 g of carbon tetrachloride. During the addition, the reaction mixture was stirred and the temperature maintained at approx. 55°C. Stirring was continued for another 15 minutes after completion of the reaction. 9.6 g of methanol was added to the reaction mixture and the reaction mixture was allowed to stand overnight. The mixture was then diluted with 100 ml of carbon tetrachloride and added approx. 4 g of triethylamine. The mixture was filtered and concentrated under vacuum to give a white solid melting at 39-41°C.

EXAMPLE 6

Preparation of 2',61-diethyl-N-(methoxymethyl)-2-chloroacetanilide.

182 mol (206 g) of chloroacetyl chloride and 210 g of benzene were charged to a 2-liter, 4-necked flask, and 293 g (1.82 mol) of 2,6-diethyl-N-methylaniline was gradually added with stirring over the course of

25 minutes. The exothermic reaction raised the temperature of the reaction mixture to approx. 90°C. After cooling the mixture to approx. 35°C, 250 ml of dry methanol was added. The reaction mixture was refluxed and an excess (ca. 190

g) triethylamine was added dropwise, during this addition the temperature of the mixture rose to approx. 70°C. This temperature

was held for approx. 10 minutes and then lowered to approx. 30°C. After cooling, the mixture was washed with two 500 ml<1>s portions of water. The product was a heavy oily liquid, from which the solvent was removed by vacuum distillation at a temperature of approx. 95°C. The distillation residue was then dissolved in 500 ml of trimethylpentane and recrystallized from there by cooling with dry ice. The product obtained had a melting point (corrected) of 38.5 - 39.5°C and the following composition:

In the subsequent tables 1 and 2, compounds which can be used in the herbicidal mixtures according to the invention are given, together with their physical data (table 2). In addition to the compounds whose preparation is shown in the preceding examples 1-6, compounds (examples 7-88) prepared according to the method illustrated in examples 1-6 are also reproduced. The physical properties of these compounds appear in table 2. With the refractive index of the crystals determined at 25°C. To illustrate the advantages of the present invention, the preventive phytotoxic and herbicidal action of representative 2-halogenacetanilides was determined in greenhouse experiments, in which a particular number of seeds of several different plants, each representing a major botanical type, were planted in greenhouse beds.

A top soil layer of good quality was placed in aluminum pans

and pressed together to a depth of 1 - 1.5 cm from the top of the pan. A certain number of seeds of different plants were placed on top of the soil layer. For the surface additions, the seeds were covered by filling the pan with soil and leveling it evenly. A measured amount of the test compound in a suitable solvent or as a wettable powder was applied to this surface, in the soil incorporation treatments, the soil required to fill the pans evenly after sowing was weighed into a pan, and a known amount of the active compound was added in a solvent or as a wettable powder, and the soil carefully mixed and used as a covering layer in sown pans. After treatment, the pans were placed in a greenhouse bed, where they were watered from below as needed, to provide the right humidity for germination and growth.

Approximately 14 days after sowing and treatment, the plants were observed and the results recorded. The phytotoxic activity was determined using a fixed scale based on average germination percentage for each seed portion. The grades are defined as follows:

Preventive herbicidal activity of the 2-haloacetanilides is recorded in table 3, for different addition amounts for both surface application and incorporation into soil. In table 3, the different fro are denoted by letters as follows:

The individual degrees of damage for each plant type are indicated. The total degree of damage for all grass plants and the total degree of damage for all broad-leaved plants are also indicated. In the column labeled "Comments," indicate (1) surface application of the herbicide and (2) indicate its incorporation into soil. The data shown in Table 3 illustrate the excellent general and selective herbicidal activity of the present herbicidal compositions containing the 2-haloacetanilides. The following table 4 shows comparative results between herbicidal agents according to the invention and the herbicidal agents according to the previously mentioned Dutch patents no. 64.14212 and no. 64.09490 as well as U.S. patent No. 2,863,752.

In table 4, the same gradation for phytotoxicity is used as that used in table 3. As can be seen from the results, the herbicidal agents according to the invention combine an advantageous combination of compatibility with useful plants with high activity against weeds, and in this respect the compounds which are marked with "A", "C" and "D" particularly favorable and therefore particularly preferred. The herbicidal agents according to the invention are either particulate solids or liquid concentrate mixtures, which consist of the active component and either a particulate solid or a liquid aid, which is a composition aid or condensing agent, which allows the mixture to mix easily with a suitable solid or liquid carrier for use in a form which enables rapid uptake into the plant systems. Thus, the mixtures according to the present invention include not only the concentrated mixtures, which consist of the active component and the auxiliary agent, but

j

also phytotoxic mixtures, which are applied to the field, and which consist of the concentrated mixture, (i.e. active component plus aid) and carrier.

As indicated above, completely different effects can be achieved by modifying the application method for the agents according to the present invention. Thus, exceptional specificity towards grass can be achieved with smaller application quantities, while with larger application quantities a more general phytotoxic effect or soil sterilization takes place.

Suitable auxiliaries, which are applicable in the preparation of the concentrated mixtures, include particulate solids or liquid diluents, such as solvents or diluents, in which the active component is dissolved, suspended or distributed, and wetting or emulsifying agents, which serve to to provide uniform dispersions or solutions of the active component in the wetting agents, and adhesives or spreading agents, which improve the contact of the active component with soil or plant surfaces. All mixtures according to the present invention comprise at least one of the auxiliaries mentioned above and usually comprise a wetting agent and a wetting or emulsifying agent, due to the nature of the phytotoxic properties of the 2-haloacetanilides.

In general, the 2-haloacetanilides are insoluble in water and in many organic solvents. The active component does not need to be dissolved in the anesthetic, but can be dispersed or suspended. Examples of suitable organic solvents, which are used as anesthetics, include hexane, benzene, toluene, acetone, cyclohexanone, methyl ethyl ketone, isopropanol, butanediol, methanol, diacetone alcohol, xylene, dioxane, isopropyl ether, ethylene dichloride, tetrachloroethane, hydrogenated naphthalene, naphtha , petroleum fractions (e.g. kerosene, etc.) and the like. Real solutions can be prepared by using mixtures of organic solvents, e.g. 1 : 1 and 1 : 2 mixtures of xylene and cyclohexanone.

Solid, particulate anesthetics are also very useful. The active component is absorbed or dispersed either on or in finely divided solid material. Suitable solid dredging agents include natural clays, such as china clay, bentonites and attapulgites, other minerals in their natural state, such as talc, pyrophyllite, quartz, diatomaceous earth, Fuller's earth, lime, phosphate, kaolin, kieselguhr, volcanic ash, salt and sulfur, and the chemically modified minerals, such as acid-washed bentonite, precipitated calcium phosphate, precipitated calcium carbonate, calcined magnesium oxide and colloidal silicon oxide, and other solid materials, such as powdered cork, powdered wood, and powdered pecan or walnut shells. These materials are used in finely divided form, at least in a size ratio of 20 - 40

mesh (Tyler) and preferably of a much finer size.

The particulate, solid concentrate mixtures are added to the soil in a mixture with a particulate, solid carrier material or as a wettable powder using a liquid carrier material. When the latter method is used, add

a wetting agent or surface-active agent to the concentrate mixture, to make the particulate, solid drying agent wettable with water and to provide a stable aqueous dispersion or suspension, which is suitable for use as a spray liquid.

The surfactant used in the compositions according to the present invention to serve to provide uniform dispersions of all composition components of both liquid and solid types in both the concentrate mixtures and the toxic mixtures added may be anionic, cationic or non-ionic types , including mixtures of these. Suitable surfactants for the preparation of both solid and liquid mixtures include the usual soaps, such as salts of long-chain carboxylic acids, sulphonated animal, vegetable and mineral oils, quaternary salts of high molecular weight acids, colofolium soaps, such as salts of abietic acid, sulfuric acid salts of organic compounds with a high molecular weight, algin soaps, ethylene oxide condensed with fatty acids, alkylphenols and mercaptans and other simple and polymeric mixtures

gers that have both hydrophilic and hydrophobic functions.

The liquid concentrate mixtures preferably contain from approx. 5 to 95% by weight of the active component and the remainder auxiliary agent, which may be exclusively liquid softening agent or surfactant (which includes adhesive), but is preferably a combination of liquid softening agent and surfactant. However, it is preferred that the herbicidal aid is the largest component in the mixture. Preferably, the surfactant is from approx. 0.1 to approx. 15% by weight of the total concentrate mixture, and the rest of the mixture is a liquid laxative.

Since the 2-haloacetanilides are very active and are usually added in small amounts to achieve selectivity, the concentration of the active component in the dust mixtures can be as low as 1% by weight or less. When the powder mixtures are to be used for soil sterilisation, it is desired to have a very high concentration, and the active component can make up as much as 5 to 98% by weight of the total mixture. The rest of the mixtures consist of auxiliaries.

The carrier material, which is used for uniform distribution of the 2-haloacetanilides in effective amounts, can either be a liquid or a particulate, solid material. Normally, the carrier material is the main component of the mixture that is applied, forming more than 50% by weight of the mixture. For economic reasons, water is preferred as the liquid carrier, both for the liquid concentrate mixture and the wettable powder concentrate. Suitable solid carriers include the particulate fertilizers listed above, also solid fertilisers, such as ammonium nitrate, urea and superphosphate as well as other materials in which plant organisms take root and grow, such as compost, manure, humus, sand and such.

The herbicidal mixtures according to the invention may also contain other additives, such as fertilizers and pesticides, used as, or in connection with, the carrier materials.

For example, phytotoxic agents, which can be used in connection with the aforementioned compounds, include 2,4-dichlorophenoxyacetic acid, 2,4,5-trichlorophenoxyacetic acid, 2-methyl-4-chlorophenoxyacetic acid and their salts, esters and amides; triazine derivatives, such as 2,4-bis(3-methoxypropylamino)-6-methyl-thio-S-triazine; 2-chloro-4-ethylamino-6-isopropylamino-S-triazine and 2-ethylamino-4-isopropylamino-6-methylmercapto-S-triazine; urea derivatives, such as 3-(3,4-dichlorophenyl)-1,1-dimethylurea and 3-(p)=»chlorophenyl)-1,1-dimethylurea; acetanilides such as N-isopropyl-cc-chloroacetanilide and N-ethyl-cc-chloro-2-methylacetanilide and 2-tert-butyl-2'-chloro-6-methylacetanilide, and acetamides such as N,N-diallyl-a- chloroacetamide-N-(α-chloroacetyl)hexamethyleneimine and N,N-diethyl-α-bromoacetamide and the like.

The herbicidal mixtures can be added to the legislation on growing plants using dust spreaders, other hand spreaders and aerosol spreaders by adding to sprinkler water and other common means.

The dose to be administered to the plant system depends not only on the specific 2-halogenacetanilide, but also on the particular plant species being treated, as well as their growth stage as well as the part of the plant that is to be brought into contact with the active agent. In non-selective legal treatments, the agents according to the invention are usually administered in an amount of 0.5 - 6 kg/day, but smaller or larger amounts are suitable in some cases. In the case of non-selective preventive treatments, these agents are usually administered in a somewhat smaller amount, e.g. 0.1 - 3 kg/day. Due to the exceptionally high unit activity of the agents, soil sterilization is usually achieved at a rate of 100 - 1100 g/day. In selective preventive applications, a dose of the active compound of 5 to 550 g/day is usually useful, but smaller or larger amounts may be necessary in some cases.

Claims (4)

1. Herbicidal agent which is a further development of the agent according to patent no. 112,656 and which contains 2-haloacetanilides, characterized in that it contains as an active ingredient one or more compounds of the formula in 2 where each of the symbols R"" and R denotes a primary or secondary alkyl group with 1-3 carbon atoms, X is chlorine, bromine or iodine, and Z is alkyl, alkenyl or alkynyl with 1-8 carbon atoms, which is optionally substituted with halogen, hydroxy or keto groups, or with an alkoxy group with 1-8 carbon atoms. 2. Means according to claim 1, k a r a k •>-. s r i s e r t in that it contains 2',6'-diethyl-N-(methoxymethyl)-2-chloro-acetanilide as an active ingredient. 3. Agent according to claim 1, characterized in that it contains 2',6'-dimethyl-N-(isopropoxymethyl)-2-chloro-acetanilide as active ingredient. 4. Agent according to claim 1, characterized in that it contains 2',6'-diethyl-N-n-butoxy-methyl-2-chloro-acetanilide as active ingredient.