DE3045770C2 - - Google Patents

Description

In US-PS 26 55 447 and DE-OS 19 05 599 is one extraordinarily wide class of urea derivatives with herbicidal properties described. Over the period 25 years since the connections were made according to the US PS a lot of research has been done on the use of ureas as herbicides. Probably the most important urea derivative is the compound 3- (4-isopropylphenyl) -1,1-dimethylurea, which sold under the trade name "Isoproturon" becomes. This connection is widely used in Europe Control of weeds applied in winter crops. your The main advantage is that it is extremely effective is against a variety of weeds and both as Pre-emergence and post-emergence herbicides, both in Fall as well as spring, can be applied. your The main disadvantage is that some are economically important Weeds, especially perennial broad-leaved Weeds, perennial weeds, weed and weed, cannot be fought.

It has now been shown that a certain phenylurea derivative, that neither in US-PS 26 55 447 nor in the DE-OS 19 05 599 is expressly mentioned, in which the phenyl ring possesses two special substituents, particularly favorable ones has herbicidal properties.  

The invention therefore relates to 3- (3-methyl-4-isopropylphenyl) -1,1-dimethylurea of formula I.

This compound is particularly suitable for combating or after weeds emerge in crops like corn, barley or especially wheat. Like from the data shown in Examples 4 and 5 this connection has clear advantages over that in Commercially available herbicide to combat isoproturon Weeds in wheat.

The invention also relates to a method of manufacture the compound of formula I, which is characterized in that the aniline of the formula II

or a hydrohalide thereof with either

• a) a dimethyl carbomoyl halide in the presence of a dehydrohalogenating agent or
• b) phosgene and the resulting isocyanate of the formula III:

reacted with dimethylamine.  

Process variant (a) can be carried out with or without solvent. Suitable solvents include hydrocarbons and halogenated hydrocarbons, e.g. B. benzene, Toluene or carbon tetrachloride. This is preferred Process variant carried out under essentially anhydrous Conditions. Because the reaction is a condensation reaction where hydrogen halide is eliminated them in the presence of a dehydrohalogenating agent carried out; organic or inorganic bases are suitable; Sodium acetate has proven to be particularly suitable proven when working without using a solvent and organic bases such as triethylamine or pyridine are suitable if a solvent is used. The Reaction is preferably at a temperature in the range of 0 to 80 ° C, conveniently carried out at room temperature and the reaction mixture can be worked up by customary methods will.

Variant (b) is advantageously used in the presence of a solvent, e.g. B. a hydrocarbon such as toluene a temperature in the range of 80 to 120 ° C; the reaction can easily be carried out at the reflux temperature of the solvent used. Possibly can the resulting isocyanate of formula III from the Reaction mixture can be isolated, but it is preferred implemented in situ with dimethylamine. This reaction will be cheaper Manner at a temperature in the range of 0 to 30 ° C, simply carried out at room temperature. The wished Product can be isolated in any suitable manner.

The invention further relates to a herbicidal composition which Compound of formula I together with a suitable carrier  contains. In a method to combat unwanted Planting at one point becomes the compound or a Agent according to the invention applied to the site.

In some cases it may be beneficial to use the invention Compound with one or more herbicidal compounds Mix effectiveness, e.g. B. to the spectrum of activity change. The compound according to the invention can thus be mixed are used with other broad-spectrum herbicides such as 2- (4-chloro-6-ethylamino-s-triazin-2-ylamino) -2-methyl-propionitrile (Trade name "Cyanazine") or with more specific Herbicides with a narrower spectrum of activity than herbicides against Aniline-type flying oats as described in GB-PS 11 64 160 are, e.g. B. Ethyl N-benzyl-N- (3,4-dichlorophenyl) -2-aminopropionate (Trade name "Benzoylpropäthyl") and the racemic Mixture or (-) isomer of isopropyl or methyl-N-benzoyl-N- (3-chloro-4-fluorophenyl) -2-aminopropionate (Trade names "Flampropisopropyl" and "Flampropmethyl").

A carrier in an agent according to the invention is any Substance with which the active ingredient is prepared in order to apply it on the area to be treated, e.g. B. a plant, Seeds or soil, or its storage, transportation or the To facilitate handling. A carrier can be a solid or be a liquid including substances that Usually gaseous, however, are compressed into a liquid have been, and it can be any normal Way to prepare herbicidal agents applied Carrier can be used.

Suitable solid carriers include natural and synthetic Clays and silicates, e.g. B. natural silica such as Diatomaceous earth; Magnesium silicates, e.g. B. Talke; Magnesium aluminum silicates, e.g. B. Attapulgite and Vermiculite; Aluminum silicates, e.g. B. kaolinites, montmorillonites and mica, Calcium carbonate, calcium sulfate; synthetic hydrated  Silicon oxides and synthetic calcium or aluminum silicates; Elements, e.g. B. carbon and sulfur; natural and synthetic resins, e.g. B. coumarone resin, polyvinyl chloride and Styrene polymers and copolymers, solid polychlorophenols, bitumens, Waxes, e.g. B. beeswax, paraffin wax and chlorinated Mineral waxes, and solid fertilizers, e.g. B. Superphosphates.

Suitable liquid carriers include water, alcohols, e.g. B. isopropanol and glycols; Ketones, e.g. B. acetone, methyl ethyl ketone, Methyl isobutyl ketone and cyclohexanone; Ether; aromatic or aliphatic hydrocarbons, e.g. B. benzene, toluene and xylene; Petroleum fractions, e.g. B. kerosene and light mineral oils; chlorinated hydrocarbons, e.g. B. carbon tetrachloride, Perchlorethylene and trichloroethane. Mixtures of different ones Liquids are often suitable.

Agricultural funds are often concentrated Form, which is then made by the consumer before Application is diluted. The presence of small amounts of a carrier which is a surfactant this process of dilution. So is preferably at least a carrier in the agent according to the invention a surface-active Medium. For example, the remedy can at least contain two carriers, at least one of which is a surface-active Is medium.

A surfactant can be an emulsifier Be a dispersant or a wetting agent; it can be non-ionic or be ionic. Examples of suitable surfactants Agents include the sodium or calcium salts of polyacrylic acids and lignin sulfonic acids, the condensation products of fatty acids or aliphatic amines or amides, contain at least 12 carbon atoms in the molecule, with ethylene oxide and / or propylene oxide; Fatty acid esters of glycerin, Sorbitol, sucrose or pentaerythritol; Condensates of these substances with ethylene oxide and / or propylene oxide; Condensation products of fatty alcohols or alkylphenols, e.g. B. p-Octylphenol  or p-octyl cresol with ethylene oxide and / or propylene oxide; Sulfates or sulfonates of these condensation products; Alkali or alkaline earth metal salts, preferably sodium salts, of Sulfuric or sulfonic acid esters containing at least 10 Carbon atoms in the molecule, e.g. B. sodium lauryl sulfate, sodium sec-alkyl sulfates, Sodium salts of sulfonated castor oil and sodium alkylarylsulfonates such as sodium dodecylbenzenesulfonate and polymers of ethylene oxide and copolymers of Ethylene oxide and propylene oxide.

The agents according to the invention can, for. B. as wettable powder, Dusts, granules, solutions, emulsifiable concentrates, Emulsions, suspension concentrates and aerosols are produced will. Wettable powders usually contain 25, 50 and 75% by weight of active ingredient and customarily in addition to the solid inert Carrier 3 to 10 wt .-% of a dispersant and if necessary 0 to 10 wt .-% stabilizer (s) and / or other additives like penetrants or tackifiers. Become dusts usually produced as a dust concentrate with a similar Composition like that of a wettable powder but without dispersant and are in the field with more solid carrier diluted to an agent, the usual way Contains 0.5 to 10 wt .-% active ingredient. Granules are becoming more common Made so that they have a grain size between 0.152 and 1.676 mm and can by agglomeration or impregnation getting produced. Generally included Granules 0.5 to 25% by weight of active ingredient and 0 to 10% by weight Additives such as stabilizers, slow release modifiers of the active ingredient and binder. Emulsifiable concentrates usually contain in addition to a solvent and if necessary cosolvent, 10 to 50% (w / v) active ingredient 2 to 20% (w / v) emulsifiers and 0 to 20% w / v. other additives such as stabilizers, penetrants and corrosion inhibitors. Suspension concentrates are usually composed in such a way that you have a stable non-settling flowable Product usually receives and contains 10 to 75% by weight Active ingredient, 0.5 to 15% by weight of dispersing agent, 0.1 to 10% by weight  Suspending agents such as protective colloids and thixotropic agents, 0 to 10% by weight of other additives such as anti-foaming agents, corrosion inhibitors, Stabilizers, penetrants and tackifiers and water or an organic liquid in which the active ingredient is essentially insoluble; certain organic Solids or inorganic salts can be dissolved in the agent to help prevent weaning or as an antifreeze for water.

Aqueous dispersions and emulsions e.g. B. Means that receive by diluting a wettable powder or a concentrate according to the invention with water are also within the scope of the invention. The emulsions can be in the form a water-in-oil or an oil-in-water emulsion and have a thick mayonnaise-like consistency.

The agents according to the invention can contain other ingredients e.g. B. other compounds with insecticidal or fungicidal properties contain.

The invention is illustrated by the following examples.

example 1 Preparation of 3- (3-methyl-4-isopropylphenyl) -1,1-dimethylurea

7.4 g of 3-methyl-4-isopropylaniline and 0.5 g of anhydrous sodium acetate were stirred together as a solid mixture and 5.4 g of dimethylcarbamoyl chloride were added within 15 minutes. The mixture was left at room temperature overnight left, then treated with water and then with methylene chloride extracted. After drying over magnesium sulfate the solvent was evaporated and the resulting solid recrystallized from a mixture of hexane and toluene.  

3.5 g of the desired product, mp 153 to 154 ° C.

analysis
calculated for C₁₃H₂₀N₂O C 70.9, H 9.1, N 12.7
found C 69.9, H 9.1, N 12.1

Example 2 Alternative process for the preparation of the invention connection

5 g of 3-methyl-4-isopropylaniline (80% pure) in 150 ml of toluene were heated to reflux temperature while COCl₂ gas was passed through the solution for about 1.5 hours and then dry nitrogen gas to remove excess COCl₂. After cooling to room temperature, 5 g Dimethylamine in 20 ml of toluene was added to the reaction mixture. The toluene was evaporated, and hexane was added to the residue and the precipitate, 5.5 g of the desired product, is filtered off. After recrystallization from a mixture of hexane and toluene the desired product had a melting point of 154 ° C.

Example 3 This example shows the production of the starting substance 3-methyl-4-isopropylaniline.

186 g of 3-methylaniline were dissolved in 600 ml of sulfuric acid (85% by weight) solved. The mixture was heated to 80 ° C and 120 g isopropyl alcohol admitted. The mixture was stirred at 80 ° C for 6 hours. After this time the mixture was poured onto ice and ammonium hydroxide added until the mixture was neutral. Then was Diethyl ether added and the ether extract evaporated. The The residue was distilled, giving 110 g of the desired  Product received, bp 100 ° C at a pressure of 3.25 mbar.

Example 4 Selective herbicidal activity of the compound according to the invention Comparative experiment a)

In this trial, the selective herbicidal activity of 3- (3-methyl-4-isopropylphenyl) -1,1-dimethylurea in Wheat compared to that of the commercial wheat herbicide Isoproturon, 3- (4-isopropylphenyl) -1,1-dimethylurea. The experiments before emergence were on wheat, Triticum vulgar variety Sappo, and the trials after emergence performed at the Maris Huntsman variety. The examined Weed species were: common grasshopper, agropyron repens (Co); Airport oats, Avena fatua / ludoviciana (Wo); Raygrass, Lolium multiflorum (Rg); Annual panicle grass, Poa annua (Pa); Ostrich grass, Agrostis tenuis (Bt); Bulrush, Alopecurus myosuroides (At the); Windstalk, Apera spica venti (Wg); Chickweed, Stellaria media (St); Honorary Award, Veronica persica (Sw); Sticky herb Galium aparine (Gg); Knotweed, polygonum lapathifolium (pp); red deadnettle, Lamium purpureum (Dn); Field mustard, Sinapis arvensis (Ck); Chamomile, Matricaria spp (Mw); Shepherd's purse, Capsella bursa pastoris (Sp); Poppy, Papaver rhoeas (Po).

The active substances to be examined were emulsifiable concentrates containing 20% by weight of active ingredient, 10% by weight of mineral oil, Emulsifiers and xylene prepared as a solvent. Each Concentrate was diluted with water and the test plants were with quantities of 6.0, 2.0, 0.6, 0.2, 0.06 and 0.02 kg / ha Active ingredient sprayed. There were four repetitions for each dose performed and both attempts before emergence as well as after emergence. When trying before the emergence was not treated soil in which the Seeds were found, and untreated in the post-emergence trials  Soil in which seedlings were found for comparison used. After 21 days, when trying to the emergence and 28 days trying before the emergence, the effect of the active ingredients was visually corresponding rated on a 0 to 9 scale; a rating of 0 shows growth as in the untreated comparison and a rating of 9 indicates plant death. At this rating corresponds to an increase of one unit on the linear scale an approximately 10% increase in Effect.

The results obtained were subjected to probit analysis where a computer calculates the parameters a and b in a relationship of form:

Probit (percentural response) = a + b log (dose).

With the help of the resulting curve, the respective doses can can be calculated for a particular response. In this example was a GID₅₀ value, i.e. H. the dose that is required is to produce a 50% response to the active substance calculated for each type.

A selectivity factor for calculated each weed compared to wheat:

The greater the selectivity factor, the more selective the herbicide works.

Finally, the ratio of selectivity factor for the compound of the invention to the selectivity factor for Isoproturon calculated. A value greater than 1 indicates that the compound of the invention acts more selectively than Isoproturon. The results are given in Table I where the compound of the invention as A and isoproturon as I. referred to as.  

Table I

Table I shows the following:

• 1. The connection according to the invention is compared to 9 of the 12th examined before emergence and compared to 11 of the 15 weeds examined more strongly after emergence selectively.
• 2. The compound of the invention is much more effective as isoproturon against commercially important weeds, like couch grass (a perennial grass weed), sticky weed and honorary award.
• 3. The compound of the invention is 1.8 times on average selective like isoproturon when applied before emergence and 2.5 as selective as isoproturon in Apply after emergence.

Comparative experiment b)

A second experiment was carried out in which the selective herbicidal activity of 3- (3-methyl-4-isopropylphenyl) -1,1-dimethylurea with two other commercial urea herbicides was compared, namely 3- (3-chloro-4-methoxyphenyl) -1,1-dimethylurea (Trade name "Chlorotoluron") and 3- (3-chloro-4-methylphenyl) -1,1-dimethylurea (Trade name "Metoxuron"). That at the procedure used for this pre-emergence test was the same as in comparative experiment a) for the pre-emergence experiment described with the modifications given below. The Weed species examined were: Common couch grass, Agropyron repens (Co); Airport oats, Avenafatura / Ludoviciana (Wo); Raygrass, Lolium multiflorum (Rg); annual panicle grass, Poa annua (Pa); woolly Honey grass, Holcus lanatus (Yo); Bulrush, Alopecurus myossuroides (At the); Sugar beet, Beta vulgaris (Sb); Chickweed, Stellaria media (St); Honorary Award, Veronica persica (Sw); Field winch, Convolvulus arvensis (Cv); Knotweed, Polygonum lapathifolium (Pd); Field mustard, Sinapis arvenis (Ck). In this attempt  the results of the treatment were assessed visually after 20 days and these experimental results were as above Comparative experiment a) stated in the selectivity factors converted, except that in this case chlorotoluron was used as the standard. That is the selectivity factor, like he did for the two compounds under investigation was obtained for the individual weed species each by the selectivity factor for chlorotoluron divided, the ratio for chlorotoluron then became 1 set. The results are given in Table II where the compound of the invention again as A, chlorotoluron is designated as C and metoxuron as M.  

Table II

As can be seen from Table II, the invention is Connection on average more than 2 times as selective as either Chlorotoluron or Metoxuron if they are before emergence to be applied in wheat.

Example 5 Field evaluation of 3- (3-methyl-4-isopropylphenyl) -1,1-dimethylurea

The effectiveness and spectrum of action of 3- (3-methyl-4-isopropylphenyl) -1,1-dimethylurea after emergence was compared with that of 3- (4-isopropylphenyl) -1,1-dimethylurea (Isoproturon) in a total of 7 field trials in winter cereals compared in the UK. The trials were in fields with normal commercial winter wheat and winter barley, in which naturally occurring weeds and / or broad-leaved weeds were present.

The preparations of the compound according to the invention in the form a suspension concentrate containing 500 g / l and isoproturon containing 50 g / l S.C. (Hytan 500 L) were washed with water diluted and each in a comparable amount of four Cans applied for every attempt. There were doses of 1.58, 2.10, 2.63 and 4.2 g of active ingredient per hectare corresponding to the ¾, 1, 1¼ or 2 times the commercially recommended dose of 2.1 kg / am / ha isoproturon as a post-herbicide on winter cereals applied in spring. In three attempts (5, 6, and 7) was the compound of the invention with the addition of a Spraying agent applied to the properties of the agent to improve. The spray aid was in the form of a mixture with the compound of the invention in a tank in one Ratio of 2 parts of compound (a.m.) to 1 part of spraying aid based on w / v applied.

Areas of 10 by 3 m were applied and each treatment was 3 times in different statistically distributed blocks carried out. The funds were put to each area with the help  a gas pressure sprayer for small areas, the sprayed a volume of 417 l / ha, applied. details regarding the state of development of crops and the application conditions for each attempt are in Table III indicated.

Assessment of crop health and effectiveness chemical treatments for grasses and broad-leaved weeds were one to three months after treatment. The effects on crops were carried out visually according to the EWRC 1-9 scale, where the value 0 has no effect and the value 9 a Dying of crops means. Weed evaluation includes the estimate of the percentage coverage of broad-leaved weeds in general and of types of predominant weeds, which are found in all test pieces found. The grass weeds were rated by counting panicles in 6 or 8 equal areas of 0.5 m + and converting these values into numbers for the single flowers 0.5 m in each area. The weed species examined were: a) broad-leaved weeds - honorary award, Veronica persica (Sw); Chickweed, Stellaria media (St); Chamomile, Matricaria spp. (Mw); Sticky herb, Galium aparine (Gg); red deadnettle, Laminium purpurea (Dn) and b) grass weeds - bulrush, alopecrus myrosuroides (Am); Airport oats, Avena spp. (Where). Depending on the Climatic conditions were the crops 138 to 169 days after treatment using a combination harvester harvested and the grain weight of the crops determined.

The results of the field trials are shown in Table IV below specified. The values given are mean values for the at the effects examined in the various field tests, d. H. from the results for the various field trials in any case the average is calculated. The specified effect for crops, the mean is on the EWRC scale  by visual evaluation in 7 attempts. The for effectiveness values given against weeds refer to the percentage reduction in weed growth versus the comparison ranges according to the procedures given above. The effectiveness values against all broad-leaved weed species in the experiment are also specified and this The mean for all weed species in this experiment is given under the heading "Total dicotylidons" as percentage reduction in plant growth compared to Comparison. The weight of the crop is given as percentage value of the harvest weight of comparison fields, the was set at 100%.  

Table I

Table I

Claims (3)

1. 3- (3-methyl-4-isopropylphenyl) 1,1-dimethylurea. 2. A process for the preparation of the compound according to claim 1, characterized in that the aniline of the formula II: or a hydrohalide thereof with either

• a) a dimethyl carbomoyl halide in the presence of a dehydrohalogenating agent or
• b) phosgene and the resulting isocyanate of the formula III: reacted with dimethylamine.

3. herbicidal agent, characterized in that it as active ingredient the compound of claim 1 together with one or more, optionally surface-active carriers, contains.