CS208185B2 - Herbicide means and method of making the active ingredients - Google Patents

Abstract

Novel compounds of the formula <IMAGE> in which R1 and R2 have the meanings given in Claim 1, are prepared by reacting a compound of the formula <IMAGE> in which R1 and R2 have the abovementioned meanings, with the compound of the formula CH3-NCO III. The compounds are used for the selective treatment of weeds in crop plants.

Description

BACKGROUND OF THE INVENTION The present invention relates to herbicidal compositions for the selective control of weeds in crops of useful plants containing phenylurea derivatives as active ingredients, to a process for the preparation of these active ingredients and to a method for their use for the above-mentioned purposes.

Accordingly, it is the subject. A herbicidal composition for the selective control of weeds in crops of useful plants, characterized in that it contains a compound of the formula I as active ingredient.

CHO h N-CO-N-CH * * 1 (1) wherein each of the symbols R 1 and R 2, which may be the same or different, represents an alkyl group having 1 to 4 carbon atoms, a fluorine atom, a chlorine or bromine atom - in which at most one of R1 and R2 is an alkyl group having from 1 to 4 carbon atoms and, when R2 represents a chlorine atom, R1 represents a methyl group , in combination with a carrier or diluent.

The compounds of formula (I) are novel and the process of their preparation is also within the scope of the invention.

In accordance with the invention, the compounds described above are produced by condensing a compound of the general formula. II

in which

R1 and R2 are as defined above, with the compound of formula III

CH 3 CN, (III) at a temperature ranging from 15 to -100 ° C.

The above reaction can be carried out, for example, in an organic; a solvent such as a hydrocarbon, for example toluene, preferably under anhydrous conditions, at a temperature in the range of -15 ^° C to -100 ^° C.

The compounds of formula I exhibit a broad spectrum of herbicidal activity against both monocotyledonous and dicotyledonous weeds such as ipsaras (Alopecurus s ₍ pp.), Kindly bent (Amaranthus retroflexus), palsy capsule (Capisella bursa pajstoris), white chiropody (Chenopodium album), chickweed (Stellaria media), old man (Senecio vulgaris), hedgehog (Echinocíhloa crus-galli), annual meadow-grass (Poa ainnua), bentgrass (Agroistosa alba), Sida Setaria geniculata), the creeping tree frog (Digitaria sanguinališ), the guinea fowl (Sisymibriuím irio) and the flatsedge (Cyperia rotunda).

In addition, the doses of the compounds of the formula I required for weed control do not cause any substantial damage to crops such as cereals, in particular barley and wheat, in particular wheat, rose, corn, sugar cane, cotton, pulses, peanuts, soy, alfalfa, cane, carrots, potatoes and flax.

It should be noted that some of the compounds of formula (I) show some dependence of their selective action in wheat on wheat varieties. The susceptibility of any variety of ina: compound, however, can be readily determined by simple greenhouse tests.

Of course, the amount of the compound of the invention to be applied to the crop to be cultivated for the aforementioned purposes depends on the crop, the compound used, the method of application, the environmental conditions and the type of weed weed. In general, however, satisfactory results are obtained with the application of the compounds according to the invention at rates of from 0.5 to 5 kg / ha, preferably from 1 to 3.5 kg / ha.

The compounds of the invention may be used as herbicidal compositions in combination with appropriate carriers or diluents. These compositions are the subject of the invention.

The herbicidal compositions may be used in either solid or liquid dosage forms. Solid dosage forms, for example, dusts and granules, can be prepared by mixing solid carriers with the compounds of the invention or impregnating the solid carriers with the compounds. Examples of solids include diatomaceous earth, kaolin, talc, chalk, limestone and powdered cellulose.

Various additives may be used to prepare the iherbicidal compositions. Typical additives of this kind are wetting and dispersing agents, for example the formaldehyde condensation product with naphthalene sulfonate and alkylbepzene sulfonates, adhesion promoters, for example dextrin, and emulsion stabilizers, for example ammonium cassate. These. additives ⁽ conveniently added, for example, to wettable powder formulations or used together with suitable solvents such as hydrocarbons such as benzene, toluene, xylene, tetrahydro-naphthalene, alkylated naphthalenes, kerosein, aromatic petroleum fractions of petroleum, ketones such as isophorone, acetone , cyclohexanone, diisobutyl ketone and methyl ethyl ketone, alcohols such as isopropanol, ethanol and methylcyclohexanol, and with chlorinated hydrocarbons such as tetrachlorethylene, ethylene chloride or trichlorethylene, to prepare emulsion concentrates.

The herbicidal compositions according to the invention may contain, in addition to the compound of formula (I) as active ingredient, other active ingredients such as herbicides, for example herbicides from the group of ureas, halobenzonitriles, carbamates and triazines.

The formulations according to the invention generally comprise between 20 and 80% by weight, preferably between 2 and 50% by weight, of the compound of the formula I as active ingredient.

The dosage forms of the compositions according to the invention generally contain between 0.01 and 10% by weight of the compound of the formula I as active ingredient.

The following are specific examples of herbicidal compositions of the present invention.

Example A

A. Wettable powder of parts of a compound of formula I, for example 1-methyl-3-formyl-3- (3-chloro-4-isopropylphenyl) urea, 5 parts of the condensation product of formialdehyde and naphthalene sulfonate, 2 parts of alkylbenzene disulfonate, 5 parts of dextrin, 1 part of ammonium caseinate and 62 parts of diatomaceous earth are / mixed until a homogeneous mixture is obtained, which is then ground until the individual particles are substantially smaller than 45 μ on average;

Example В

An emulsion concentrate of parts of the compound of formula I, 65 parts of xylene and 10 parts of a mixture of the reaction products of alkylphenol with ethylene oxide and calcium dodecylbenzenesulfonate: is stirred vigorously until a homogeneous solution is obtained. The emulsion concentrate obtained is diluted with water before use.

Example C

The granules of kg of the compound of formula I, for example 1-methyl-3-foyl-3- (3-chloro-4-isopropylphenyl) urea, are dissolved in 25 liters of methylene chloride. The solution is. then add to 95 kg of granulated attapulgite (24/48 mesh particle size) and mix thoroughly. The solvent is then evaporated under heating under reduced pressure.

The compounds of the invention may be applied both before and after emergence of weeds or crop plants. Preferably, the disclosed compounds are applied in a conventional manner before or after emergence of crop plants, especially before emergence.

Preferred compounds of the invention are compounds of formula Ia

CHO R 1 (~ 4 N - CO - NHCHb

Cl ^(1a - ⁾ in which

R 11 represents an alkyl group having 2 to 4 carbon atoms, in particular 2 or 3 carbon atoms, for example an isopropyl group.

The invention is illustrated by the following non-limiting examples. By percentages and parts are meant percentages and parts by weight.

EXAMPLE 1 1-Methyl-3-formic acid 3- (3-methyl-4-chlorophenyl) urea

To a solution of 0.1 mole of 3-methyl-4-chloroformanilide in 150 mL of absolute toluene was added 11.4 g (0.2 mole) of methyl isocyanate and 1.5 mL of triethylamine, the reaction vessel was sealed and allowed to stand for 4 to 7 days. at room temperature. The precipitate formed is filtered off and washed with petroleum ether * to give the title compound, m.p. upon crystallization from ether at 108-110 ° C.

The compounds of the general formula I are summarized in the following Table 1 in an analogous manner.

If no precipitate forms after 7 days, the solvent a and excess methyl isocyanate are evaporated under vacuum, the product is dried under high vacuum and recrystallized.

TABLE 1

Example number Rz Ri Melting point (crystallization solvent) 2 СНз Br Mp 115-117 ° C (eithanol) 3 i-СзНг Cl Mp 84-85 ° C (ether / petroleum ether) . 4 Cl C2H5 65 to 67 ° C- (ether / petroleum ether) 5 Cl I-C3H7 Mp 99-101 ° C (ether) 6 Cl seik.-C4H9 oil Rf 0,4 *) 7 Cl t-C4H9 Mp 112-114 ° C (ether) 8 Br I-C3H7 110-112 ° C (ethanol)

Legend:

*) measured by silica gel chromatography using a 9: 1 mixture of chloroform and acetone as the solvent system.

Example 1 a d 9

Selective weed control - pre-emergence treatment

The sieve pans are filled to a height of 6 cm with a mixture of peat cultivation substrate No. 1 (Toirfetreuverband G. m. 'Bh, 29 Olden-beirig, Federal Republic of Germany) and sand. The surface of the peat substrate / sand mixture is sprayed with 50 ml of an aqueous solution of the compound of formula (I) prepared as described in Example VI) and the various seeds listed below are sown in each dish. After sowing the seeds the treated surface is covered with a thin layer (0, 5 ^l CIM) irašelinného complete, the mixture of substrate and sand. The plates are then kept at room temperature for 14 days to 14 hours illumination per day.

As described above, the compounds of Examples 1 to 8 were applied at rates of 1.5 kg / ha and 2.5 kg / ha.

The following plant species are used to try:

Alipecurus spp., Amaranthuis retroflexus, Capsella bursa pastoriš, White m-coon (Chenopodium album), Stellairia media, Sene »cio vulgaris, Hedgehog ' corn leg (Echinochl-oa crus-galli), annual meadow-grass (Poa annua), bentgrass (Agro-stís alba), wheat. ce (Triticum vulgaire - variety Probuls), barley (Ho-rdeum), soya (Glycine soya), flax (Li-nuim usitatisisium), bramiboir (Solanum tuberosum) and cotton (Gossypium · hirsutum).

In any case, there is a selective herbicidal effect, i.e. the weeds are significantly damaged without significant damage to the crop plants.

Example 10

Selective weed control - post-emergence treatment

The procedure is analogous to Example 9, except that the herbicide is applied only when the plants are in the 2 to 4 leaf state. Sowing of the plant seeds is regulated so that the plants reach the stage of 2-4 liters at about the same time.

The compounds of Examples 1 to 8 were also applied by the above procedures at rates corresponding to 1.5 kg / ha and 2.5 kg / ha.

The following plant species are used in the experiment:

Chenopodium album, Stella.ria media, Senecio vulgaris, Echinoichloa cruis-galli, Poa annua, Agrostis alba and cultivated plants in Example 9.

In all cases, a selective herbicidal effect occurs.

Claims (5)

OBJECT OF THE INVENTION CLAIMS 1. A herbicidal composition for the selective control of weeds in crops of useful plants, characterized in that it contains, as an active ingredient, a compound of the formula (I). N-CO-N-CH _b dl in which! each of R 1 and R 2, which may be the same or different, represents a C 1 -C 4 alkyl, fluorine, chlorine or bromine atom, with at most one of R 1 and R 2 being a chlorine atom or an alkyl group having 1 to 4 carbon atoms, and when R 2 represents a chlorine atom, then R 1 is not a methyl group, in an icomibination with a carrier or diluent. 2. A composition according to claim 1, wherein the active ingredient is a compound of formula (Ia ⁾ in which: R 11 is C 2 -C 4 alkyl. 3. A composition according to claim 2, wherein the active ingredient is a compound of formula (Ia) in which Ru is an isopropyl group. 4. A composition according to claim 2, wherein the active ingredient is an ishorium compound of formula (Ia) wherein Ru is tert-butyl. 5. A process according to claim 1, wherein the compound of formula II is condensed R 1, (t 1) wherein R 1 and R 2 are as in point 1, with a compound of formula III Ct CHO N-CO-NHCH _b (I &.) CH3NCO, at a temperature ranging from 15 to 100 ^° C. (III)