DE3701666A1 - Imidazopyridinone derivatives, processes for their preparation, and their use as herbicides - Google Patents

Abstract

The invention relates to novel imidazopyridinone derivatives of the general formula I <IMAGE> in which X represents a hydrogen or halogen atom, Y represents a hydrogen or halogen atom, but where at least X or Y is a halogen atom, or one of the groups -O-R2, -S-R2 or N(R2)2, R1 represents a hydrogen atom, a hydroxycarbonyl or a C1-C4-alkoxycarbonyl radical and R2 represents a hydrogen atom, a C1-C14-alkyl, C3-C8-cycloalkyl, C2-C8-alkenyl or C2-C8-alkynyl radical which is optionally substituted by one or more halogen atoms, a hydroxycarbonyl-C1-C8-alkyl or C1-C4-alkoxycarbonyl-C1-C8-alkyl radical, a C1-C8-alkoxy-C1-C 8-alkyl radical, a C1-C4-alkyl radical which is substituted by a saturated heterocycle, or a phenyl or phenyl-C1-C4-alkyl radical which is optionally monosubstituted or polysubstituted by identical or different substituents from the series comprising halogen, C1-C4-alkyl, halo-C1-C4-alkyl, nitro or C1-C4-alkoxy, to processes for their preparation and to their use as herbicides.

Description

The invention relates to new imidazopyridinone derivatives, processes for their Production and their use as herbicidal agents.

It is already known that certain tetrahydroindazoles and tetrahydrophthalimides have herbicidal properties (EP applications 00 61 741 and 01 05 721). The effectiveness of these substances can be described as good, however selectivity problems occur in certain crops with a corresponding herbicidal action on.

It has now been found that imidazopyridinone derivatives of the general formula I

in the

X is a hydrogen or a halogen atom, Y is a hydrogen or a halogen atom,
however, at least X or Y is a halogen atom, zein is hydrogen or a halogen atom, a trihalomethyl group or one of the groups -O-R₂, -S-R₂ or -N (R₂) ₂, R₁ is a hydrogen atom, a hydroxycarbonyl or a C₁- C₄-alkoxycarbonyl radical and R₂ is a hydrogen atom, a C₁-C₁₄-alkyl, C₃-C₈-cycloalkyl, C₂-C₈-alkenyl or C₂-C₈-alkynyl radical optionally substituted by one or more halogen atoms, a hydroxycarbonyl-C₁-C₈-alkyl - Or C₁-C₄-alkoxycarbonyl-C₁-C₈-alkyl radical, a C₁-C₈-alkoxy-C₁-C₈-alkyl radical, a substituted by a saturated heterocycle C₁-C₄-alkyl radical or an optionally one or more, the same or different by Halogen, C₁-C₄-alkyl, halogen-C₁-C₄-alkyl, nitro or C₁-C₄-alkoxy substituted phenyl or phenyl-C₁-C₄-alkyl radical, surprisingly show better compatibility in main agricultural crops than the known compounds.

The term "halogen" includes fluorine, chlorine, bromine and iodine.

The term "haloalkyl" means that one or more hydrogen atoms of the alkyl radical are replaced by halogen.

A saturated heterocycle means, for example, tetrahydrofuran, Tetrahydrothiophene, pyrolidine, dioxane, tetrahydropyran and Piperidine.

The compounds of general formula I according to the invention can for example be made by

• A) Compounds of the general formula II in which R₁, X, Y and Z have the meanings given under the general formula I, hydrogenated by reaction with hydrogen, or
• B) esters of the general formula III in which X, Y and Z have the meanings given under the general formula I and R is C₁-C₄-alkyl, saponified to the corresponding acids and, if desired, the acids decarboxylated by heating, or
• C) Compounds of the general formula IV in which R₁, X and Y have the meanings given under the general formula I, with a compound of the general formula VR₂-A (V) in which R₂ has the meanings given under the general formula I but does not represent a hydrogen atom, and A represents fluorine, chlorine, bromine, iodine or a tosyl radical.

The implementation according to method A) is advantageously carried out with the help of a Catalyst in a polar, organic solvent, such as methanol or Ethanol, but also dimethylformamide or dimethyl sulfoxide and optionally with the addition of water at temperatures between 0 and 80 ° C, preferably at 20 to 30 ° C carried out.

All known hydrogenation catalysts can be used as catalysts, preferably are solid catalysts such as Raney nickel, palladium and platinum, too mounted on a solid inert carrier such as activated carbon.

The saponification according to method B) is advantageously carried out with the help of Alkalis such as sodium hydroxide or potassium hydroxide in the same solvents as in method A) at temperatures around 80 ° C. The decarboxylation is done by heating the substances above the melting points out.

The implementation according to method C) is expedient with the aid of a Acid acceptors at a temperature between 0 and 150 ° C, especially between Room temperature and reflux temperature of the solution carried out. The usual basic agents, in particular aliphatic ones, are the acid acceptors Amines, such as triethylamine or diisopropylamine, but also Alkali carbonates and their aqueous solutions are suitable.  

The etherification can also be used in a two-phase system a catalyst and optionally carried out in the presence of solvents will. Alkali hydroxides or alkali carbonates, solid, serve as bases or in aqueous solution.

The reactants themselves are suitable as solvents if they are liquid are. Otherwise, they become immiscible with water and compared to the bases inert substances, such as aliphatic or aromatic hydrocarbons, such as Example hexane, benzene or toluene used. Preferred catalysts are Crown ether and quaternary ammonium salt in question as in Dehmlow et al. Dehmlow: Phase Transfer Catalysis, Weinheim 1980 are.

Usually, the starting materials are used in a stoichiometric ratio a. A surplus of one or the other can in individual cases be beneficial.

The compounds according to the invention produced by the abovementioned processes can be isolated from the reaction mixture by the customary methods be, for example by distilling off the solvent used at normal or reduced pressure or by extraction.

An increased degree of purity can usually be determined by column chromatography Purification and obtained by fractional crystallization.

The compounds of the invention are generally crystalline or viscous substances, some of which are readily soluble in halogenated hydrocarbons, such as chloroform, sulfoxides such as dimethyl sulfoxide, or Are esters, like ethyl acetate.  

The compounds according to the invention can be one or more asymmetrical Contain carbon atoms. The present invention includes the optically active forms and mixtures thereof. Unless otherwise stated in the examples, receive the racemates.

So far, hydrogenated imidazopyridinones and their preparation are hardly known. Individual representatives have Palazzo and Picconi in Il Farmaco, Ed. Sci. vintage 1975 Volume 30, page 197 ff., But they do not mention any possible uses in crop protection.

The starting materials for the preparation of the hydrogenated imidazopyridinones can be obtained by methods known per se.

When used in pre-sowing, pre-emergence, but especially in post-emergence applications against economically important ones mono- and dicotyledon weeds have excellent herbicidal activity. The compounds are characterized by selectivity in agricultural Main crops, such as soybeans, sugar beets and cereals.

The active compounds according to the invention can be used, for example, against the following Plant genera are used:

Dicot weeds of the genera Abutilon, Chrysanthemum, Brassica, Helianthus, Mentha, Sinapis, Lepidium, Galium, Stellaria, Anthemis, Chenopodium, Atriplex, Senecio, Portulaca, Ipomoea, Matricaria, Galinsoga, Urtica, Amaranthus, Polygonum, Sesbania, Ambrosia, Sonchus, Solanum, Lamium, Veronica, Datura, Viola, Centaurea, Galeopsis.  

Monocot weeds of the genera Echinochloa, Setaria, Panicum, Digitaria, Phleum, Poa, Festuca, Eleusine, Brachiaria, Lolium, Bromus, Avena, Cyperus, Sorghum, Agropyron, Cynodon, Monochoria, Fimbristylis, Sagittaria, Eleocharis, Scirpus, Paspalum, Ischaemum, Agrostis, Alopercurus, Apera, Rottboellia, Triticum and Hordeum.

The use of the active compounds according to the invention is by no means limited to those mentioned Weed genera and crops limited, but extends affect other plants in the same way.

The compounds are also suitable for weed control on industrial and Track systems, on paths and squares with and without tree cover, in forestry, Ornamental trees, berries and hops as well as in plantation crops, as well as for the defoliation of agricultural crops.

The amount of active ingredient used can vary over a wide range. they depends essentially on the type of effect you want. In general the application rates are between 0.01 and 5 kg of active ingredient per hectare of soil, preferably for example in weed control between 0.1 and 0.5 kg of active ingredient per hectare.

The compounds according to the invention can either be used alone or in a mixture with one another or with other active ingredients. If necessary, you can other crop protection or pesticides depending on the desired Purpose to be added. If a broadening of the spectrum of activity other herbicides may also be added. For example, those suitable as herbicidally active mixture partners Active ingredients described in Weed Abstracts, Vol. 35, No. 5, 1986, under the title "List of common names and abbreviations employed for currently used herbicides and plant growth regulators in Weed Abstracts ".

A promotion of the intensity and speed of action can Example by adding additives, such as organic solvents, Wetting agents and oils can be achieved. Such additives may therefore be left out a reduction in drug dosage.  

Phospholipids can also be used as mixing partners to Example those from the group phosphatidylcholine, the hydrogenated phosphatidylcholines, Phosphatidylethanolamine, the N-acylphosphatidylethanolamines, Phosphatidylinositol, Phosphatidylserine, Lysolecithin and Phosphatidylglycerol.

The labeled active ingredients or their mixtures are expediently in Form of preparations such as powders, sprinkling agents, granules, solutions, Emulsions or suspensions, with the addition of liquid and / or solid Carriers or diluents and, if necessary, adhesives, Wetting, emulsifying and / or dispersing aids applied.

Suitable liquid carriers are, for example, aliphatic and aromatic Hydrocarbons, such as benzene, toluene, xylene, cyclohexanone, isophorone, Dimethyl sulfoxide, dimethylformamide, mineral oil fractions and vegetable oils.

Minerals are suitable as solid carriers, for example bentonite, silica gel, Talc, kaolin, attapulgite, limestone, and herbal products, for Example flour.

Examples of surface-active substances include calcium lignin sulfonate, Polyethylene alkylphenyl ether, naphthalenesulfonic acids and their salts, Phenolsulfonic acids and their salts, formaldehyde condensates, fatty alcohol sulfates as well as substituted benzenesulfonic acids and their salts.

The proportion of the active ingredient (s) in the different preparations can vary widely. For example, the Average about 10 to 90 percent by weight of active ingredient, about 90 to 10 percent by weight liquid or solid carriers and optionally up to 20 percent by weight surfactants.

The funds can be applied in the customary manner, for example with Water as a carrier in spray liquor quantities about 100 to 1000 liters / ha. An application  of the means in the so-called low-volume and ultra-low-volume method is just as possible as their application in the form of so-called microgranules.

These preparations can be prepared in a manner known per se, for example by grinding or mixing processes. If desired can prepare preparations of the individual components just before their use can be mixed, such as in the so-called tank mix process is carried out in practice.

For example, the following are used to prepare the various preparations Components used:

A) wettable powder
20 percent by weight active ingredient 35 percent by weight bentonite 35 percent by weight silica 8 percent by weight calcium salt of lignosulfonic acid 2 percent by weight sodium salt of N-methyl-N-oleyl-taurine

B) paste
45 percent by weight active ingredient 5 percent by weight sodium aluminum silicate 15 percent by weight cetyl polyglycol ether with 8 moles of ethylene oxide 2 percent by weight spindle oil 10 percent by weight polyethylene glycol 23 percent by weight water

C) Emulsion concentrate
20% by weight of active ingredient 75% by weight of isophorone 5% by weight of a mixture of the calcium salt of dodecylbenzenesulfonic acid and nonylphenyl polyoxyethylene

The following examples describe the preparation of the invention Links:

Example 1 1-carbomethoxy-2- (2,4,5-trichlorophenyl) -5,6,7,8-tetrahydroimidazo [1, -5-a] pyridine- 3 (2H) -on

19.8 g (0.053 mol) of 1-carbomethoxy-2- (2,4,5-trichlorophenyl-imidazo [1,5-a] pyridin-3 (2H) -one are dissolved in 50 ml of methanol + 50 ml of methylene chloride, 0.5 g of 10% palladium on activated carbon is added and under a hydrogen atmosphere at room temperature and normal pressure until the solution is decolorized hydrated. The catalyst is then filtered off and the solution is concentrated and the residue was recrystallized from ethyl acetate.

Yield: 18 g = 90.4% of theory Mp: 199 ° C

Elemental analysis
calculated: C 47.96% H 3.49% Cl 28.32% N 7.46% found: C 47.97% H 3.7% Cl 27.41% N 7.55%

Preparation of the starting materials for Example 1. a) N- (2-pyridylmethylene) -2,4,5-trichloroaniline

53.6 g (0.5 mol) 2-pyridinecarboxaldehyde, 117.9 g (0.6 mol) 2,4,5-trichloroaniline and 1 g of p-toluenesulfonic acid are dissolved in 150 ml of toluene and on the water separator until the end of water formation to reflux heated. The reaction product crystallizes on cooling. It will suction filtered and recrystallized from ethyl acetate.

Yield: 115 g = 80.7% of theory Mp .: 133-135 ° C.  

b) N- (2-pyridylmethyl) -2,4,5-trichloroaniline

115 g of N- (2-pyridylmethylene) -2,4,5-trichloroaniline are dissolved in 250 ml of toluene dissolved, 1 g of Raney nickel added and at room temperature and normal pressure treated with hydrogen.

After the hydrogen uptake has ended, the catalyst is filtered off and evaporated the solution. The residue is recrystallized from ethyl acetate.

Yield: 63 g = 54.8% of theory Mp: 80-81 ° C

c) 1-Carbomethoxy-2- (2,4,5-trichlorophenyl) imidazo [1,5-a] pyridin-3 (2H) - one

8.4 g (0.03 mol) of N- (2-pyridylmethyl) -2,4,5-trichloroaniline is dissolved in 100 ml Toluene submitted and mixed with 4 g (0.033 mol) of N, N-dimethylaniline. At 0 ° C 63 ml of a 20% toluene solution of phosgene (corresponds to 0.12 Mol) added dropwise. The mixture is stirred at 0 ° C for 1 hour, then for 1/2 Warmed to room temperature for one hour. Finally, 1 hour at 50 ° C warmed up. Then it is cooled again and 50 ml of methanol are added, thereby the solution warms to 40 ° C. The mixture is left to stand at room temperature for 16 hours. Then the reaction mixture with potassium hydrogen carbonate solution and washed thoroughly with water, over magnesium sulfate dried and concentrated. The residue is recrystallized from ethyl acetate.

Yield: 5.8 g = 52% of theory Mp .: 160-163 ° C  

Example 2 2- (2,4,5-trichlorophenyl) -5,6,7,8-tetrahydro-imidazo [1,5-a] pyridin-3 (-2H) -one- 1-carboxylic acid

10 g (0.027 mol) of 1-carbomethoxy-2- (2,4,5-trichlorophenyl) -5,6,7,8-tetrahydroimidazo [1, -5-a] pyridin-3 (2H) -one are dissolved in 150 ml of ethanol, with 4.3 g (0.11 mol) of sodium hydroxide in 60 ml of water and added for 1 hour heated to 80 ° C. The reaction solution is concentrated, the residue in 100 ml of water are taken up and acidified with cooling with dilute hydrochloric acid. The precipitate is filtered off, washed with water and dried.

Yield: 9.1 g = 93% of theory Mp: 128 ° C (decomposition)

Elemental analysis:
calculated: C 46.05% H 3.07% Cl 29.41% N 7.75% found: C 46.41% H 3.42% Cl 28.21% N 7.61%

Example 3 2- (2,4,5-trichlorophenyl) -5,6,7,8-tetrahydro-imidazo [1,5-a] pyridin-3 (-2H) -one

4.7 g (0.013 mol) of 2- (2,4,5-trichlorophenyl) -5,6,7,8-tetrahydro-imidazo [1,5-a] pyridine- 3- (2H) -one-1-carboxylic acid are rapidly heated to 200 to 210 ° C and melt with decarboxylation. After gas evolution has ended, Suspended hexane and dissolved in the heat by adding ethyl acetate.

When cooling, 2.7 g of white needles crystallize. By repeating the Procedure, another 0.4 g can be obtained.

Overall yield: 3.1 g = 75% of theory Mp: 170-171 ° C

Elemental analysis
calculated: C 49.16% H 3.49% Cl 33.49% N 8.82% found: C 49.22% H 3.41% Cl 32.26% N 8.77%

Example 4 2- [4-chloro-2-fluoro-5- (tetrahydrofuran-2-yl-methoxy) phenyl] -5,6,7,8 - tetrahydro- imidazon [1,5-a] pyridin-3 (2H) -one

1.3 g (4.6 mmol) of 2- (4-chloro-2-fluoro-5-hydroxyphenyl) -5,6,7,8-tetrahydroimidazo [1,5-a] pyridin-3 (2H) -one are dissolved in 40 ml of dimethylformamide and mixed with 0.6 g (4.6 mmol) of potassium carbonate. 30 minutes is at room temperature stirred. Then 1.2 g (4.6 mmol) of tetrahydrofurfuryl tosylate added and stirred at 80 ° C for 3 hours. 16 hours is at room temperature left standing and then mixed with water. The product comes with Extracted ethyl acetate and dried the organic phase over magnesium sulfate. After the concentration, an oil remains, which over silica gel with a Hexane-ethyl acetate mixture is purified chromatographically.

Yield: 1.2 g = 71.1% of theory Mp: 88-90 ° C

Elemental analysis:
calculated:
found:

Preparation of the starting materials for Example 4. a) 4-Chloro-2-fluoro-5-methoxycarbonyloxy-aniline

82 g (0.33 mol) of 4-chloro-2-fluoro-5-methoxycarbonyloxy-nitrobenzene dissolved in 800 ml of ethanol, mixed with 20 g of 10% Pd / activated carbon and at  Room temperature and normal pressure up to the absorption of 22.4 liters of hydrogen hydrated. The catalyst is filtered off, the reaction mixture concentrated and the residue recrystallized from toluene-cyclohexane.

Yield: 65.9 g = 91% of theory Mp: 86 ° C

b) N- (2-Pydridylmethylene) -4-chloro-2-fluoro-5-methoxycarbonyloxy-aniline

45 g (0.205 mol) of 4-chloro-2-fluoro-5-methoxycarbonyloxy-aniline were added to 400 ml of methylene chloride dissolved, 22 g (0.205 mol) of 2-pyridinecarboxaldehyde and 1 g of p-toluenesulfonic acid were added and under a nitrogen atmosphere heated to reflux at the water separator. After 4.5 hours the cooled reaction mixture was washed twice with water and over Magnesium sulfate dried. After concentration, the residue can pass through Trituration can be crystallized with diisopropyl ether.

Yield: 56.7 g = 90% of theory Mp. 10:9:00 C

c) N- (2-pyridylmethyl) -4-chloro-2-fluoro-5-methoxycarbonyloxy-aniline

87.9 g (0.28 mol) of N- (2-pyridylmethylene) -4-chloro-2-fluoro-5-methoxycarbonyloxy- aniline are dissolved in 400 ml ethanol and 80 ml methylene chloride, 10 g of Raney nickel washed three times with ethanol were added and the mixture hydrogenated at room temperature and normal pressure. After 3.5 hours another 10 g of catalyst were added and hydrogenated for a further 4 hours. The catalyst is filtered off and the mother liquor is concentrated. The residue is about  Chromatographed silica gel with hexane-ethyl acetate 1: 1. For further purification can be recrystallized from ethanol.

Yield: 69.2 g = 78% of theory Mp .: 120-125 ° C.

d) 1-carbomethoxy-2- (4-chloro-2-fluoro-5-methoxycarbonyloxy-phenyl) -imida-zo [1,5-a] pyridin-3 (2H) -one

69.2 g (0.22 mol) of N- (2-pyridylmethyl) -4-chloro-2-fluoro-5-methoxycarbonyloxy- aniline and 30.8 g (0.26 mol) of dimethylaniline are dissolved in 427 ml of toluene dissolved, cooled to 0 ° C and 471 ml of a 20% toluene solution of phosgene (= 0.91 mol) was added dropwise. Then 1 hour at 0 ° C, then 0.5 Stirred at room temperature and 1 hour at 50 ° C. Then it will be 427 ml of methanol were added dropwise at room temperature, the temperature rising 35 ° C rises, and the mixture was left to stand for 14 hours. Then it is washed twice with potassium hydrogen carbonate solution and once with water, with Magnesium sulfate dried and concentrated. The residue is over silica gel chromatographed with ethyl acetate.

Yield: 80 g = 91% of theory
Oily product

e) 1-carbomethoxy-2- (4-chloro-2-fluoro-5-methoxycarbonyloxy-phenyl) -5,6,7-, 8- tetrahydro-imidazo [1,5-a] pyridin-3 (2H) -one

11.3 g (0.029 mol) of 1-carbomethoxy-2- (4-chloro-2-fluoro-5-methoxycarbonyloxy- phenyl) imidazo [1,5-a] pyridin-3 (2H) -one are in 200 ml of ethanol + 200 ml Dissolved methylene chloride, mixed with 0.2 g of 10% Pd / activated carbon and until decolorization with hydrogen at room temperature and normal pressure treated. The catalyst is then filtered off, the mother liquor concentrated and the residue recrystallized from heptane-ethyl acetate.

Yield: 9.2 g = 79.6% of theory Mp .: 127 ° C  

f) 2- (4-chloro-2-fluoro-5-hydroxy-phenyl) -5,6,7,8-tetrahydro-imidazo [1,5 - a] pyridine-3- (2H) -one-1-carboxylic acid

9.2 g (0.023 mol) of 1-carbomethoxy-2- [4-chloro-2-fluoro-5-methoxycarbonyloxy- phenyl] -5,6,7,8-tetrahydro-imidazo [1,5-a] pyridin-3 (2H) -one in 150 ml Dissolved ethanol and mixed with 7 g of sodium hydroxide in 40 ml of water. The mixture is heated to reflux for one hour. The reaction mixture is concentrated the residue was taken up with water and the solution with hydrochloric acid acidified. The precipitated crystals are filtered off and dried.

Yield: 7.3 g = 97% of theory Fp.:207°C (decomposition)

g) 2- (4-chloro-2-fluoro-5-hydroxy-phenyl) -5,6,7,8-tetrahydro-imidazo [1,5 - a] pyridin-3 (2H) -one

7.3 g of 2- (4-chloro-2-fluoro-5-hydroxy-phenyl) -5,6,7,8-tetrahydro-imidazo [1,5-a] pyridine-3 (2H) -one-1-carboxylic acid are in a 100 ml round bottom flask immersed in an oil bath preheated to 220 ° C and until complete Decarboxylation heated. The product is recrystallized from methanol.

Yield: 5.7 g = 87% of theory Mp. 10:9:00 C

The following compounds according to the invention were also analogous to the examples above of general formula I:

The following examples explain the possible uses of the invention Links:  

Example A

In the greenhouse, the compounds according to the invention listed in the table were sprayed at a rate of 3 kg of active ingredient / ha, emulsified in 500 liters of water / ha, onto test plant species of the genera Matricaria and Viola using the aor and post-emergence method. The treatment result was rated three weeks after the treatment, which means
0 = no effect
4 = destruction of the test plants

With the compounds of the invention Examples 4, 10, 12, 14 to 19 and 21 to 27 became one in this test Destruction of the test plants (= 4) both in the pre-emergence and in the Post-emergence reached in the test plant species.

Example B

The plant species listed were in the greenhouse after emergence with the listed compounds at a rate of 0.3 kg of active ingredient / ha treated. For this purpose the compounds were used as an emulsion Sprayed 500 liters of water / ha evenly over the plants. Showed here three weeks after the treatment, the compounds according to the invention are high Selectivity with excellent weed action. The means of comparison did not show this selectivity.

Mean in the table below
0 = no effect
4 = destruction of the test plants

BR = Brassica ssp. SO = Solanum spp. HE = Helianthus annuus AB = Abutilon hybridum MA = Matricaria chamomilla VI = Viola tricolor CH = Chrysanthemum segetum IP = Ipomoea purpurea ZE = Zea mays TR = Triticum aestivum HO = Hordeum vulgare OR = Oryza sativa  

Means of comparison

Oxadiazon = 5-tert-butyl-3- (2,4-dichloro-5-isopropoxyphenyl) -1,3,4-oxadiazol-2 (3-H) -one

Example C

In the greenhouse, the compounds listed in the table with the applied application rates also mentioned. For this purpose, the active ingredients placed in vessels with 1500 ml of water. As test plant species were Echinochloa crus-galli, Fimbristylis miliacea, Paspalum distichum and Cyperus difformis used in the 2- to 5-leaf stage.

In the following table mean:

0 = no damage 1 = slight damage 2 = moderate damage 3 = severe damage 4 = totally destroyed EC = Echinochloa crus-galli FI = Fimbristylis miliacea PA = Paspalum distichum CY = Cyperus difformis  

As the table shows, the compounds according to the invention are very effective against important rice weeds.

Claims (5)

1. Imidazopyridinone derivatives of the general formula I in which X is a hydrogen or a halogen atom, Y is a hydrogen or a halogen atom,
however, at least X or Y is a halogen atom, zein is hydrogen or a halogen atom, a trihalomethyl group or one of the groups -O-R₂, -S-R₂ or -N (R₂) ₂, R₁ is a hydrogen atom, a hydroxycarbonyl or a C₁- C₄-alkoxycarbonyl radical and R₂ is a hydrogen atom, a C₁-C₁₄-alkyl, C₃-C₈-cycloalkyl, C₂-C₈-alkenyl or C₂-C₈-alkynyl radical which is optionally substituted by one or more halogen atoms, a hydroxycarbonyl-C₁-C₈-alkyl - Or C₁-C₄-alkoxycarbonyl-C₁-C₈-alkyl radical, a C₁-C₈-alkoxy-C₁-C₈-alkyl radical, a substituted by a saturated heterocycle C₁-C₄-alkyl radical or an optionally one or more, the same or different by Halogen, C₁-C₄-alkyl, halogen-C₁-C₄-alkyl, nitro or C₁-C₄-alkoxy substituted phenyl or phenyl-C₁-C₄-alkyl radical. 2. Process for the preparation of imidazopridinone derivatives of the general formula I, characterized in that

• A) Compounds of the general formula II in which R₁, X, Y and Z have the meanings given under the general formula I, hydrogenated by reaction with hydrogen, or
• B) esters of the general formula III in which X, Y and Z have the meanings given under the general formula I and R is C₁-C₄-alkyl, saponified to the corresponding acids and, if desired, the acids decarboxylated by heating, or
• C) Compounds of the general formula IV in which R₁, X and Y have the meanings given under the general formula I, with a compound of the general formula VR₂-A (V) in which R₂ has the meanings given under the general formula I but does not represent a hydrogen atom, and A represents fluorine, chlorine, bromine, iodine or a tosyl radical.

3. Herbicidal agents, characterized by a content of at least one A compound according to claim 1. 4. Use of agents according to claim 3 for combating monocotyledons and dicotyledonous weed species in main agricultural crops. 5. A process for the preparation of herbicidal compositions, characterized in that compounds of general formula I according to claim 1 with Carriers and / or auxiliaries mixed.