WO2023040686A1

WO2023040686A1 - Pyridazinone compound, preparation method, herbicide composition and use thereof

Info

Publication number: WO2023040686A1
Application number: PCT/CN2022/116949
Authority: WO
Inventors: 王凤云; 赵文; 徐丹; 白从强; 张璞; 吴耀军; 封莹莹
Original assignee: 江苏中旗科技股份有限公司
Priority date: 2021-09-16
Filing date: 2022-09-05
Publication date: 2023-03-23

Abstract

A pyridazinone compound, a preparation method, a herbicide composition and the use thereof. The present invention specifically relates to a pyridazinone compound represented by general formula I or an agriculturally acceptable salt thereof, a method for preparing the compound of formula I from a compound of formula II, a compound of formula III or a compound of formula IV, and a compound of formula III as raw materials, and the use of the herbicide composition containing the compound of formula I or the agriculturally acceptable salt thereof in controlling weeds. The herbicide has a wide application range, good safety and a high selectivity, and almost never damages normal crops while effectively inhibiting weeds; and the preparation method of the herbicide is easy to operate, low in cost and suitable for large-scale industrial production.

Description

A kind of pyridazinone compound, preparation method, herbicide composition and use

technical field

The invention belongs to the technical field of pesticides, and specifically relates to a pyridazinone compound, a preparation method, a herbicide composition and use.

Background technique

Patents WO2012/136703A1 and WO2017/178582A1 disclose that pyridazinone compounds can effectively control various problematic weeds. However, it has also been found in use that the pyridazinone compounds disclosed in the above-mentioned patents are not good enough in selectivity to crops, and have certain toxic effects on crops in conventional dosages. However, the novel pyridazinone compound herbicides according to the present invention not only exhibit favorable herbicidal performance and improved characteristics, but also have improved selectivity to crops. Most importantly, this new class of pyridazinone compounds can effectively control weeds while reducing the toxicity to normal crops.

Contents of the invention

The technical problem to be solved by the present invention is to provide a pyridazinone compound, a preparation method, a herbicide composition and its use, which can improve the selectivity and safety of normal crops while effectively eliminating weeds.

The technical scheme that the present invention solves the problems of the technologies described above is as follows:

The present invention provides a pyridazinone compound represented by formula I or an agriculturally acceptable salt thereof,

Wherein, R ₁ represents hydrogen, halogen, C ₁ ~C ₆ alkyl, C ₃ ~C ₆ cycloalkyl, C ₂ ~C ₆ alkenyl, C ₂ ~C ₆ alkynyl, C ₁ ~C ₆ haloalkyl, C ₁ ～C ₆ alkoxy, C ₁ ～C ₃ haloalkoxy, C ₁ ～C ₆ alkoxy-C ₁ ～C ₃ alkyl, C ₁ ～C ₆ alkyl-S(O) _p -or C ₁ ~C ₆ haloalkyl-S(O) _p -;

p is 0, 1 or 2;

Ar represents one of the following groups:

R ₂ , R ₃ , and R ₄ independently represent hydrogen, halogen, nitro, cyano, C ₁ ~C ₆ alkyl, C ₃ ~C ₆ cycloalkyl, C ₂ ~C ₆ alkenyl, C ₂ ~ C ₆ alkynyl, C ₁ ~C ₆ haloalkyl, C ₁ ~C ₆ alkoxy, C ₁ ~C ₃ haloalkoxy, C ₁ ~C ₆ alkoxy-C ₁ ~C ₃ alkyl, C ₁ ~C ₆ alkyl-S(O) _p -, C ₁ ~C ₆ haloalkyl-S(O) _p -, or one of the following groups:

p is 0, 1 or 2;

R _a , R _b , R _c , R _d , R _e , and R _f independently represent hydrogen, halogen, C ₁ -C ₆ alkyl, C ₃ -C ₆ cycloalkyl, C ₁ -C ₆ alkoxy Or C ₁ ~C ₆ alkoxy-C ₁ ~C ₃ alkyl;

R _h and R _g independently represent hydrogen, halogen, C ₁ -C ₆ alkyl, C ₃ -C ₆ cycloalkyl or aryl;

The aryl is optionally substituted by one or more of the following groups: halogen, C ₁ -C ₃ alkoxy, C ₁ -C ₃ alkyl, C ₁ -C ₃ haloalkyl;

R _i and R _j independently represent hydrogen, C ₁ -C ₆ alkyl, C ₃ -C ₆ cycloalkyl, benzyl or aryl;

The benzyl or aryl is optionally substituted by one or more of the following groups: halogen, C ₁ -C ₃ alkoxy, C ₁ -C ₃ alkyl, C ₁ -C ₃ haloalkyl.

In some preferred embodiments, R ₁ represents C ₁ -C ₆ alkyl or C ₃ -C ₆ cycloalkyl; specifically, C ₃ -C ₆ cycloalkyl is selected from cyclopropyl, cyclobutyl, cyclo Pentyl or cyclohexyl;

Ar represents one of the following groups:

R ₂ , R ₃ , and R ₄ independently represent hydrogen, halogen, nitro, cyano, C ₁ ~C ₆ alkyl, C ₃ ~C ₆ cycloalkyl, C ₂ ~C ₆ alkenyl, C ₂ ~ C ₆ alkynyl, C ₁ ~C ₆ haloalkyl, C ₁ ~C ₆ alkoxy, C ₁ ~C ₃ haloalkoxy, C ₁ ~C ₆ alkoxy-C ₁ ~C ₃ alkyl or the following groups One of the regiments:

R _a , R _b , R _c , R _d , R _e , and R _f independently represent hydrogen, halogen, C ₁ -C ₆ alkyl or C ₃ -C ₆ cycloalkyl;

In some more preferred embodiments, R ₁ represents C ₁ -C ₄ alkyl or cyclopropyl; specifically, C ₁ -C ₄ alkyl is selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or tert-butyl;

Ar represents one of the following groups:

R ₂ , R ₃ , and R ₄ independently represent hydrogen, fluorine, chlorine, cyano, nitro, C ₁ ~C ₃ alkyl, C ₃ ~C ₆ cycloalkyl, C ₁ ~C ₆ haloalkyl, C ₁ ~ C ₆ alkoxy group or one of the following groups:

R _a , R _b , R _c , R _d , R _e , and R _f independently represent hydrogen, fluorine, and C ₁ -C ₆ alkyl;

R _h and R _g independently represent hydrogen and C ₁ -C ₆ alkyl;

R _i and R _j independently represent hydrogen, methyl, ethyl, benzyl;

The benzyl group is optionally substituted with one or more of the following groups: chloro, fluoro, methyl, ethyl, trifluoromethyl or methoxy.

further,

R _a , R _b , R _c , R _d , R _e , and R _f independently represent hydrogen, fluorine, and C ₁ -C ₄ alkyl;

R _h and R _g each independently represent hydrogen and a C ₁ -C ₄ alkyl group.

In the present invention, compounds of formula I may contain an asymmetric center and may exist as single enantiomers, enantiomeric pairs in any ratio; or more than one asymmetric center, including all possible ratios of asymmetric Enantiomers. Usually one of these enantiomers has enhanced biological activity;

In the present invention, if there are disubstituted or trisubstituted alkenes, the alkenes can exist in the form of E or Z or a mixture of the two in any ratio;

In the present invention, compounds of formula I may be in equilibrium with alternative tautomers. Although compounds of formula I are described in the ketone form, alternative enol forms are also possible, as shown in formula I' below;

All tautomers (single tautomers or mixtures thereof), racemic mixtures and single isomers are included within the scope of the present invention.

Further, the agriculturally acceptable salts may be salts in the following forms: amines (including primary, secondary and tertiary amines, preferably ammonia, dimethylamine and triethylamine), alkali metal and alkaline earth metal bases, transition Metal or quaternary ammonium bases; preferred aluminum salts, calcium salts, cobalt salts, copper salts, iron salts, magnesium salts, potassium salts, sodium salts or zinc salts of compounds of formula I; more preferably copper salts of compounds of formula I, potassium salts or sodium salt.

The present invention also provides a herbicide composition, which is characterized in that it includes the above-mentioned pyridazinone compound or its agriculturally acceptable salt; preferably, it also includes an agriculturally acceptable co-preparation product; more preferably, Also comprising one or more other pesticides, preferably herbicides and/or safeners;

Further, the herbicide composition can be in the form of a concentrate, and these concentrates can be diluted before use, and can also be made into a ready-to-use composition; usually final dilution is performed with water, and liquid fertilizers, micronutrients, biological organisms can also be used , oil or solvent dilution;

Further, the herbicidal composition comprises 0.1% to 99% by weight of the compound of formula I, preferably 0.1% to 95% of the compound of formula I; and 1% to 99.9% by weight of the co-formulation, the The co-preparation product is carrier, solvent, surfactant (SAA) or adjuvant, preferably 0-25% surfactant;

Further, the herbicide composition can be formulated into various dosage forms, including emulsion concentrate (EC), suspension concentrate (SC), suspoemulsion (SE), capsule suspension (CS), water-dispersible granules (WG), emulsifiable granules (EG), water-in-oil emulsion (EO), oil-in-water emulsion (EW), microemulsion (ME), oil dispersion (OD), oil suspension (OF ), oil-soluble liquid (OL), soluble concentrate (SL), ultra-low volume suspension (SU), ultra-low volume liquid (UL), parent drug (TK), dispersible concentrate (DC), Soluble powder (SP), wettable powder (WP), ZC (combination of SC and CS) or soluble granule (SG). In general, the dosage form will depend on the intended use and the physical, chemical and biological properties of the compound of formula I and all other ingredients.

Soluble powder (SP) can be prepared by mixing the compound of formula I with one or more water-soluble inorganic salts (such as sodium bicarbonate, sodium carbonate or magnesium sulfate) or one or more water-soluble organic solids (such as polysaccharides) and optionally One or more wetting agents, one or more dispersing agents, or mixtures of such agents are mixed to improve water dispersibility/water solubility. This mixture is then ground to a fine powder, similar compositions may also be granulated to form water soluble granules (SG).

Wettable powder (WP) can be obtained by formula I compound and one or more solid diluents or carrier, one or more wetting agents and preferably one or more dispersing agents, and optionally one or more Suspending agents are mixed to facilitate dispersion in liquids. This mixture is then ground to a fine powder, similar compositions can also be granulated to form water dispersible granules (WG).

Granules (GR) can be prepared by granulating a compound of formula I in admixture with one or more pulverulent solid diluents or carriers, or by absorbing a compound of formula I (or a solution thereof in a suitable agent) into a porous particulate material (such as pumice, attapulgite clay, fuller's earth, diatomaceous earth (kieselguhr), diatomaceous earth (diatomaceous earths) or corncob meal) or by absorbing the compound of formula I (or its solution in a suitable reagent) into hard The core material (such as sand, silicates, inorganic carbonates, sulfates or phosphates) and dried as required, is formed from pre-formed blank granules. Agents that commonly aid absorption or adsorption include solvents (such as aliphatic and aromatic petroleum solvents, alcohols, ethers, ketones, and esters) and sticking agents (such as polyvinyl acetates, polyvinyl alcohols, dextrins, sugars, and vegetable oils). One or more other additives (such as emulsifying, wetting or dispersing agents) may also be included in these granules.

Dispersible concentrates (DC) can be prepared by dissolving a compound of formula I in water or an organic solvent such as a ketone, alcohol or glycol ether. These solutions may contain surfactants (eg to improve water dilution or to prevent crystallization in spray cans).

Emulsion concentrates (EC) or oil-in-water emulsions (EW) can be obtained by dissolving the compound of formula I in an organic solvent (optionally containing one or more wetting agents, one or more emulsifying agents or mixture). Organic solvents suitable for EC include aromatic hydrocarbons (such as alkylbenzenes or alkylnaphthalenes, such as SOLVESSO100, SOLVESSO150 or SOLVESSO200; SOLVESSO is a registered trademark), ketones (such as cyclohexanone or methylcyclohexanone) and alcohols (such as benzyl alcohol, furfuryl alcohol or butanol) or fatty acid dimethylamide (such as C ₈ ~C ₁₀ fatty acid dimethylamide). EC products can spontaneously emulsify when added to water, producing an emulsion with sufficient stability to allow spray application with appropriate equipment.

Among them, the preparation of oil-in-water emulsion (EW) involves a compound of formula I in liquid state (if it is not liquid at room temperature, it can be melted at a reasonable temperature below 70 ℃) or in solution (dissolving it in a suitable solvent in), the resulting liquid or solution is then emulsified under high shear into water containing one or more SAAs to produce an emulsion. Solvents suitable for EW include vegetable oils, aromatic solvents such as alkylbenzenes or alkylnaphthalenes, and other available organic solvents with low solubility in water.

Microemulsions (MEs) can be prepared by mixing water with a blend of one or more solvents and one or more SAAs, spontaneously resulting in a thermodynamically stable isotropic liquid formulation. The compound of formula I is initially present in the water or solvent/SAA blend. Suitable solvents for ME include those previously described for EC or EW. ME can be an oil-in-water system or a water-in-oil system (which can be determined by conductivity) and is suitable for mixing water-soluble and oil-soluble pesticides in the same formulation. ME is suitable for dilution into water and remains as a microemulsion or forms a conventional oil-in-water emulsion.

Suspension concentrates (SC) may be aqueous or non-aqueous suspensions of finely divided insoluble solid particles of a compound of formula I. SCs are prepared by ball or bead milling a solid compound of formula I in a suitable medium to yield a fine particle suspension of the compound, optionally with the addition of one or more dispersing agents. One or more wetting agents can be included in the composition, and suspending agents can also be included to reduce the rate of settling of the particles. Optionally, the compound of formula I can be dry ground and added to water containing the above reagents to obtain the desired final product.

Aerosol formulations comprise a compound of formula I and a suitable propellant (such as n-butane), and also include dissolving or dispersing the compound of formula I in a suitable medium (such as water or a water-miscible liquid, such as n-butane). Propanol) to obtain compositions that can be used in unpressurized hand spray pumps.

Capsule suspension (CS) is similar to the method for preparing EW formulations, but includes a polymerization stage to obtain an aqueous dispersion of oil droplets, wherein each oil droplet is surrounded by a polymer shell and contains a compound of formula I and optionally a carrier or thinner. The polymer shell can be prepared by interfacial polycondensation or by coacervation procedures. These compositions allow for controlled release of the compound of formula I. The compound of formula I can also be dispensed in a biodegradable polymer matrix to achieve slow and controlled release of the compound.

Soluble concentrates (SL) can be prepared by dissolving the active ingredient in an aqueous liquid optionally with one or more wetting agents and/or one or more buffering agents.

Further, the herbicidal composition may also include one or more additives to improve the biological properties of the composition, the additives include surfactants (SAA) or oil-based spray additives, preferably certain mineral oils or natural The addition of vegetable oils (such as soybean and rapeseed oils), modified vegetable oils (such as methylated rapeseed oil (MRSO)) and other bioenhancing adjuvants (ingredients that can assist or modify the action of the compound of formula I);

In some preferred embodiments, the co-formulations include: wetting agents, dispersants or emulsifiers, preferably cationic, anionic, amphoteric or nonionic SAA;

The cationic type of SAA includes quaternary ammonium compounds (such as cetyltrimethylammonium bromide), imidazoline or amine salts;

The anionic types of SAA include alkali metal salts of fatty acids, salts of aliphatic monoesters of sulfuric acid (such as sodium lauryl sulfate), salts of sulfonated aromatic compounds (such as sodium dodecylbenzenesulfonate, dodecyl Calcium phenylbenzenesulfonate, butylnaphthalenesulfonate and mixtures of sodium di-isopropyl-naphthalenesulfonate and sodium tri-isopropyl-naphthalenesulfonate), ether sulfates, alcohol ether sulfates (such as lauryl alcohol sodium polyether-3-sulfate), ether carboxylates (e.g. sodium laureth-3-carboxylate), phosphate esters (from one or more fatty alcohols) with phosphoric acid (mainly monoesters) or with penta Products of reactions between phosphorus oxides (mainly diesters), for example between lauryl alcohol and tetraphosphoric acid and which may be ethoxylated, also sulfosuccinamates, paraffins or olefin sulfonic acids Salt, taurate, lignosulfonate, and phosphate/sulfate esters of tristyrylphenol;

The amphoteric type of SAA comprises betaine, propionate or glycinate;

The non-ionic type of SAA includes condensation products of alkylene oxides (such as ethylene oxide, propylene oxide, butylene oxide or mixtures thereof) and fatty alcohols (such as oleyl alcohol or cetyl alcohol), derived from long-chain fatty acids or hexitol anhydride partial esters, condensation products of said partial esters with ethylene oxide, block polymers (containing ethylene oxide and propylene oxide), alkanolamides, monoesters (such as fatty acid polyethylene glycol glycol esters), amine oxides (such as lauryl dimethylamine oxide), lecithin, sorbitan and its esters, alkyl polyglycosides or tristyrylphenols;

The suspending agent includes hydrophilic colloids (such as polysaccharides, polyvinylpyrrolidone or sodium carboxymethylcellulose) and swelling clays (such as bentonite or attapulgite).

Further, the harmful biological agent can be other herbicides or plant growth regulators;

In some preferred embodiments, the herbicide composition comprises (A) a compound of formula I and (B) one or more herbicides selected from the group consisting of acetochlor, acifluorfen (trifluorocarboxy Sodium chlorpyrifos), aclofen, alachlor, dichlorpyr, ametrazine, amenzazone, sulfuron-methyl, cypropyrimidic acid, aminopyralidic acid, acetam, saponin, sulphur Grass spirit, atrazine, flubutyramid, fluoxam, fluramid, bensulfuron-methyl (including bensulfuron-methyl), thiazopine, bicyclopyrone, azafen, bismuth Sodium fenpyramid, bromoxynil, butachlor, butafluzone, fluprofen, mefentrazone, mefentrazone-ethyl (including mefentrazone-ethyl), sulfentrachlor acid, chlorimuron-methyl (including chlorimuron-ethyl), chlorotoluron, chlorsulfuron, etesulfuron, indolinones (including indoxafen-methyl), clethodim, clodinafop-propargyl (including Clodinafop-propargyl-propargyl), clomazone, clopyralid, clofenac, cyhalofop-methyl (including cyhalofop-butyl), 2,4-D (including its choline salt and 2-Ethylhexyl ester), triauron, betaine, dicamba (including its aluminum, aminopropyl, di-aminopropylmethyl, choline, tripropionic acid, diglycolamine, dimethylamine, Dimethylamine, Potassium and Sodium Salts), Diclopyr (including Diclopyr-Methyl), Diclosulam, Phylloquityl, Diflufenamide, Difenpyrazone, Metolachlor, Dimethenamid, Diquat Dibromide, Diuron, EPTC, Pentrapyr, Ethametsulfuron, Beetfur, Fenoxaprop-P-P-P-P-P-P-P-ethyl, Fenquitriton, flucarbazone-methyl, florasulam, fluoxaprop-ethyl (including fluoxaprop-butyl-ethyl), flucarbazone (including flucarbazone sodium), fluthiazin Grass amine, flumetriamine, flumesulfuron, fluorometholone, fluroxyfen, propargyl flufenamide, fluridine sulfuron-methyl (including fluridine-sulfuron-methyl sodium), fluroxypyr (including fluroxypyr), furazone, meridoxenic acid (including meridoxen-methyl), fomesafen, foramsulfuron-methyl, glufosinate-ammonium (including its ammonium salt), glyphosate (including its amines, isopropylammonium and potassium salts), haclopyridine (including haclopyridine-methyl), clopyrazosulfuron-methyl (including clopyrazosulfuron-methyl), haloxyfop (including pyroxapyr), hexazinone, imazamox, imazamox, imazamox, imazapyr, imazaquinac, imazethapyr, indazin flufen, iodosulfuron-methyl (including iodine Metsulfuron-methyl sodium salt), iodosulfuron-methyl (including iodosulfuron-methyl sodium), ioxynil, ifencarzone, isoproturon, isoxamid, isoxaflutole, lactofen Grass Spirit, Liguron, MCPA, Homo-2-methyl-4-chloropropionic acid, mefenazamide, mesosulfuron-methyl (including mesosulfuron-methyl), mesotrione, benzotrione , Metazachlor, Xiugulong, Metolachlor, Methoxuron, Metrizone, Metsulfuron, Methazone, Napropamide, Nicosulfuron, Methachlor, Methasulfuron, Propylene Oxadiazone, Oxadiazone, Epoxysulfuron, Oxazicone, Oxyfluorfen, Paraquat Dichloride, Pendimethalin, Penoxsulam, Methochlor, Betainin , picloram, flupimid, pinoxaden, pretilachlor, fluorosulfuron-methyl, amfluralin, promethazin, Toxachlor, propanil, aclofen-methyl, aniline, propasulfuron-methyl, pentoxychlor, procarbocarb, trifluprosulfuron-methyl, metazachlor (including amethyclofen-ethyl), pyrazole sulfonate , pyrazolate, pyrazosulfuron-methyl (including pyrazosulfuron-ethyl), saflufenacil, pyridate, cyclazone, pyrizachlor, roxasulfone, acesulfame, quinclorac, quizalofop (including quizalofop-ethyl), rimsulfuron-methyl, saflufenacil, sethoxydim, sizafen, S-metolachlor, sulcotrione, sulfentrazone , rimsulfuron-methyl (including sulfuron-methyl), sulfuron-methyl, buthiuron-methyl, tefurtrione, tembotrione, pyroxydone, terbuthylazine, dequat, thionsulfuron-methyl, thifensulfuron-methyl, Defenathia, Tobilide, Metramezone, Trimetrione, Flucarbazone, Tricamba, Tribenuron-methyl, Tribenuron-methyl (including Tribenuron-methyl), Trichlorella Ding, trifluxysulfuron-methyl (including trifluxysulfuron-sodium), trifluxalazine, trifluralin, triflumesulfuron-methyl, quinzadone, bifenflurone, cyclopyramidone, benzene Fenflumezone, Triflumetrione, Triflumezin, Flumesulam, Fluoxetine, Fluoxetin, Cycloheptapyrone, Dioxopyritrione, Epyrifenacil, Dimesulfazet, Tetflupyrolimet, Beflubutamid-M, Bixlozone , Rimisoxafen, Tolpyralate, Lancotrione, Cyclopyranil;

In some preferred embodiments, the compounds of formula I can also be used in mixtures with other agrochemicals (such as fungicides, nematicides or insecticides), examples of which are given in "The Pesticide Manual [ Pesticides Handbook], Sixteenth Edition, UK Crop Protection Council, 2012".

The present invention also provides a method for controlling weeds, which is characterized in that it comprises applying the above-mentioned pyridazinone compound or its agriculturally acceptable salt or the above-mentioned herbicide composition to the weeds on or in its area;

Further, the present invention also provides a method for selectively controlling weeds in a place including crop plants and weeds, wherein the method comprises applying a weed control amount of the above-mentioned pyridazinone compound or its agricultural method to the place. acceptable salts or the above herbicidal compositions. "Control" means killing, reducing or retarding growth or preventing or reducing germination. Plants to be controlled are generally unwanted plants (weeds). "Locus" means an area where a plant is growing or will grow. Application to the locus may be pre- and/or post-emergence of the crop plants. Some crop plants are inherently resistant to the herbicidal effect of the compounds of the formula I. Preferred crop plants include corn, wheat, barley and rice. Tolerance can be engineered into crop plants as desired, for example by genetic engineering. Thus, the crop plants can be genetically engineered to be tolerant to 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibitors. Methods for making crop plants tolerant to HPPD inhibitors can be referred to WO0246387. Accordingly, in some more preferred embodiments, the crop plant contains a transgenic polynucleotide comprising a DNA sequence encoding an HPPD inhibitor-resistant HPPD enzyme, the HPPD inhibitor-resistant HPPD enzyme From a bacterium (more specifically, from Pseudomonas fluorescens or Shewanella colwelliana), or from a plant (more specifically, from a monocot or still more specifically For example, from barley, corn, wheat, rice, Brachiaria, Cenchrus, Lolium, Fescue, Setaria, Grychograss, Sorghum, or Avena species). Several HPPD-tolerant soybean transgenic "events" have been published, such as SYHT04R (WO2012/082542), SYHTOH2 (WO2012/082548) and FG72. Accordingly, the herbicidal compounds of the present invention have been widely applied to a variety of crop plants including cereals such as barley and wheat, cotton, rapeseed, sunflower, corn, rice, soybean, sugar beet, sugar cane and turf. Crop plants may also include trees, such as palm trees, coconut trees or other nut trees, vines (such as grapes), shrub fruit trees, fruiting plants or vegetables;

The application rates of the compounds of the formula I can be varied within a relatively wide range and depend on the nature of the soil, the method of application (pre- or post-emergence; seed dressing; application to seed furrows; no-till application, etc.), the crop plant, the weeds, prevailing climatic conditions, other factors governed by the method of application, timing of application, and target crop. The application rate of the compound of formula I in the present invention can be 10-2000g/ha, preferably 25-1000g/ha, more preferably 25-250g/ha;

Generally, the herbicidal composition is applied by spraying, preferably by a sprayer mounted on a tractor over a large area, or other methods such as dusting (for powder), dripping or soaking;

Crop plants also include those that have been made tolerant to other herbicides or classes of herbicides (such as ALS inhibitors, GS inhibitors, EPSPS inhibitors, PPO inhibitors, and ACC enzyme inhibitors) by conventional breeding methods or genetic engineering crop plants. An example of a crop that has been made tolerant to imidazolinones (eg imazamox) by conventional breeding methods is summer rape (canola). Examples of crops that have been genetically engineered to be tolerant to herbicides include glyphosate- or glufosinate-resistant maize varieties, which are commercially available under the trade name;

Crop plants also include crops that have been genetically engineered to be resistant to harmful insects, such as Bt corn (resistant to the European corn borer), Bt cotton (resistant to the boll weevil), and Bt potatoes (resistant to the Colorado beetle). sex). An example of Bt corn is the Bt 176 corn hybrid (Syngenta Seeds). Bt toxins are proteins naturally formed by the soil bacterium Bacillus thuringiensis. For examples of toxins or transgenic plants capable of synthesizing such toxins see EP-A-451878, EP-A-374753, WO93/07278, WO95/34656, WO03/052073 and EP-A-427529. Examples of transgenic plants comprising one or more genes encoding insecticide resistance and expressing one or more toxins are corn, cotton, potato, and plant crops or seed material thereof, all resistant to both herbicides and insect ingestion ( "stacking" transgenic events). For example, seeds can be resistant to glyphosate while possessing the ability to express the insecticidal Cry3 protein. Crop plants also include those obtained by conventional breeding or genetic engineering and containing export traits (eg improved storage stability, higher nutritional value and improved aroma). Herbicidal compositions can be used to control unwanted vegetation (collectively "weeds"). The weeds to be controlled can be either monocotyledonous species such as Bentgrass, Aurantium, Avena, Brachiaria, Brome, Tribulus, Cyperus, Crabgrass, Barnyardgrass , Lolium , Lolium , Yujiuhua , Cystonia , Sagittarius , Sorghum , Setaria , and Sorghum , and also dicotyledonous species such as Abutilon , Amaranthus , Ragweed , Chenopodium genus, Chrysanthemum genus, Liquorgrass genus, Lara genus, Ipomoea genus, Nasturtium genus, Chrysanthemum genus, Sinusia genus, Solanum genus, Chickweed genus, Popona genus, Viola genus and Xanthium genus.

The present invention also provides the use of the above-mentioned pyridazinone compound or its agriculturally acceptable salt or the above-mentioned herbicide composition in controlling weeds.

The present invention also provides a method for preparing the above-mentioned pyridazinone compound or an agriculturally acceptable salt thereof, which is characterized in that it comprises the following steps:

(1) In the presence of an inert organic solvent and a base, add the compound of formula II and formula III to react to generate the compound of formula IV;

Wherein, R ₁ and Ar are as defined in any one of claims 1 to 6; R ₅ represents halogen, -OH, C ₁ to C ₆ alkoxy, aryloxy or N-linked imidazole;

Preferably, in the presence of an inert organic solvent and a base, the compound of formula IIc is added to react with the compound of formula III to generate the compound of formula IV;

Preferably, R and Ar are as defined in any one of claims 1 to 6; LG is a suitable _leaving group;

(2) The compound of formula IV undergoes a rearrangement reaction to generate the compound of formula I.

The present invention also provides the second preparation method of the above-mentioned pyridazinone compounds or their agriculturally acceptable salts, which is characterized in that it comprises the following steps: reacting the compound of formula V and formula III in a reaction medium to generate the compound of formula I;

Wherein, the definitions of _R1 and Ar are as described in any one of claims 1-6; the reaction medium includes a palladium catalyst, a suitable phosphine ligand or a phosphine ligand salt, a suitable base and/or carbon monoxide.

In some preferred embodiments, the pyridazinone compounds described in the present invention are selected from the following Table 1 or Table 2:

Table 1 is selected from the compound of formula I-1

Table 2 is selected from the compound of formula I-2

In the present invention, if there is a conflict between the Chinese name of the compound and the structural formula, the structural formula shall prevail; except for those with obvious mistakes in the structural formula.

The beneficial effect of the present invention is that it provides a pyridazinone compound, a preparation method, a herbicide composition and its use. The herbicide has a wide application range, good safety and high selectivity, and can effectively suppress weeds. At the same time, normal crops are almost not damaged; and the preparation method of the herbicide of the present invention is simple in operation and low in cost, and is suitable for large-scale industrial production.

Detailed ways

The present invention is illustrated below in conjunction with examples, but the present invention is not limited. In the field, simple replacements or improvements made by skilled persons to the present invention all belong to the technical solutions protected by the present invention.

Example 1:

2-(2-(2-Benzo[d][1,3]dioxolan-5-yl)-6-methyl-3-oxo-2,3-dihydropyridazine-4-carbonyl ) Preparation of cyclohexane-1,3-dione (compound 1-1.1).

Step 1. Preparation of ethyl 2-(benzo[d][1,3]dioxolan-5-yl)-6-methyl-3-oxo-2,3-dihydropyridazine-4-carboxylate preparation.

Ethyl-3-methyl-6-oxo-1H-pyridazine-5-carboxylate (5.0g, 27.4mmol) (available from the preparation method of reference CN108884074A) in dichloromethane (200mL) To the solution was added copper(II) acetate monohydrate (12.6 g, 63.1 mmol), molecular sieves, pyridine (4.4 mL, 54.9 mmol) and triethylamine (7.7 mL, 54.9 mmol). To the stirred suspension was added 3,4-(methylenedioxy)phenylboronic acid (6.37 g, 38.4 mmol) (commercially available) portionwise over 5 minutes and the reaction mixture was stirred at room temperature for 16 hours. The reaction mixture was filtered through celite and the residue was washed with additional dichloromethane. The filtrate was washed with 2N aqueous hydrochloric acid (2x200 mL), dried over magnesium sulfate, filtered and concentrated in vacuo. Purification by column chromatography eluting with 20%-100% ethyl acetate in isohexane gave 2-(benzo[d][1,3]dioxolane-5- yl)-6-methyl-3-oxo-2,3-dihydropyridazine-4-carboxylic acid ethyl ester (5.10 g).

¹ H NMR (400MHz, CDCl ₃ ) δ7.66(s, 1H), 7.05–7.00(m, 2H), 6.87(dd, J=8.0, 0.7Hz, 1H), 6.02(s, 2H), 4.41( q,J=7.1Hz,2H),2.42(s,3H),1.39(t,J=7.1Hz,3H).

Step 2. Preparation of 2-(benzo[d][1,3]dioxolan-5-yl)-6-methyl-3-oxo-2,3-dihydropyridazine-4-carboxylic acid.

To 2-(benzo[d][1,3]dioxolan-5-yl)-6-methyl-3-oxo2,3-dihydropyridazine cooled to 0°C (ice bath) - A solution of ethyl 4-carboxylate (11.39 g, 37.7 mmol) in tetrahydrofuran (200 mL) was added a solution of lithium hydroxide monohydrate (2.37 g, 56.5 mmol) in water (100 mL). The reaction mixture was allowed to warm to room temperature and stirred for 30 minutes. The tetrahydrofuran was removed in vacuo, and the aqueous mixture was washed with dichloromethane (3 x 40 mL). The aqueous solution was cooled to 0° C. and stirred while adding concentrated hydrochloric acid solution until pH=1 was reached. A bright yellow solid precipitated during this process. The solid was collected by filtration. The solid was dissolved in dichloromethane and the solution was dried over magnesium sulfate, filtered and concentrated in vacuo to give 2-(benzo[d][1,3]dioxolane-5- yl)-6-methyl-3-oxo-2,3-dihydropyridazine-4-carboxylic acid (9.5 g, 87%).

Step 3. 2-(2-(2-Benzo[d][1,3]dioxolan-5-yl)-6-methyl-3-oxo-2,3-dihydropyridazine-4- Preparation of carbonyl)cyclohexane-1,3-dione (compound 1-1.1).

To 2-(benzo[d][1,3]dioxolan-5-yl)-6-methyl-3-oxo-2,3-dihydropyridazine-4-carboxylic acid (0.94g , 3.44 mmol) in dichloromethane (anhydrous, 13 mL) were added 3 drops of N,N-dimethylformamide (anhydrous), followed by dropwise addition of oxalyl chloride (0.33 mL, 3.79 mmol) . The reaction mixture was stirred at room temperature for 16 hours. Additional N,N-dimethylformamide (1 drop) and oxalyl chloride (0.1 mL) were added and stirring was continued at room temperature for 1 hour. To a cooled (0 °C (ice bath)) solution of cyclohexane-1,3-dione (0.41 g, 3.62 mmol) in dichloromethane (anhydrous, 7.0 mL) was added triethylamine (1.44 mL, 10.3 mmol). The acid chloride solution was then added to the solution of cyclohexane-1,3-dione in triethylamine within 10 minutes and the reaction mixture was stirred at 0° C. for a further 5 minutes. Additional triethylamine (0.48 mL, 3.45 mmol) was added followed by acetone cyanohydrin (as a stock solution in anhydrous dichloromethane) (10 mol%, 0.34 mmol). The reaction flask was transferred to a preheated oil bath and heated with stirring at reflux (40 °C) for 6 hours and then at room temperature for an additional 16 hours. The reaction mixture was concentrated in vacuo to give a black residue. Purification by column chromatography afforded 2-(2-(2-benzo[d][1,3]dioxolan-5-yl)-6-methyl-3-oxo-2 as an orange foam ,3-dihydropyridazine-4-carbonyl)cyclohexane-1,3-dione (400 mg, 30% yield).

¹ H NMR (400MHz, CDCl ₃ ) δ7.09(s, 1H), 7.05–7.00(m, 2H), 6.85(d, J=8.8Hz, 1H), 6.00(s, 2H), 2.73(t, J=6.3Hz, 2H), 2.47(t, J=6.5Hz, 2H), 2.40(s, 3H), 2.05(s, 3H).

Example 2:

2-(2-(2,3-Dihydrobenzo[b][1,4]dioxin-6-yl)-6-methyl-3-oxo-2,3-dihydropyridazine- Preparation of 4-carbonyl)cyclohexane-1,3-dione (compound 1-2.1).

Step 1. 2-(2,3-Dihydrobenzo[b][1,4]dioxin-6-yl)-6-methyl-3-oxo-2,3-dihydropyridazine-4- Preparation of ethyl carboxylate.

To a solution of ethyl-3-methyl-6-oxo-1H-pyridazine-5-carboxylate (5.0 g, 27.4 mmol) in dichloromethane (200 mL) was added copper(II) acetate monohydrate ( 12.6 g, 63.1 mmol), molecular sieves, pyridine (4.4 mL, 54.9 mmol) and triethylamine (7.7 mL, 54.9 mmol). To the stirred suspension was added benzo-1,4-dioxane-6-boronic acid (6.91 g, 38.4 mmol) (commercially available) in portions over 5 minutes and the reaction mixture was stirred at room temperature for 16 hours. The reaction mixture was filtered through celite and the residue was washed with additional dichloromethane. The filtrate was washed with 2N aqueous hydrochloric acid (2 x 200 mL), dried over magnesium sulfate, filtered and concentrated in vacuo. Purification by column chromatography eluting with 20%-100% ethyl acetate in isohexane gave 2-(2,3-dihydrobenzo[b][1,4]di Oxin-6-yl)-6-methyl-3-oxo-2,3-dihydropyridazine-4-carboxylic acid ethyl ester (5.6 g).

Step 2. 2-(2,3-Dihydrobenzo[b][1,4]dioxin-6-yl)-6-methyl-3-oxo-2,3-dihydropyridazine-4- Preparation of Carboxylic Acids.

To 2-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-6-methyl-3-oxo-2 cooled to 0°C (ice bath), To a solution of ethyl 3-dihydropyridazine-4-carboxylate (11.92 g, 37.7 mmol) in tetrahydrofuran (200 mL) was added a solution of lithium hydroxide monohydrate (2.37 g, 56.5 mmol) in water (100 mL) . The reaction mixture was allowed to warm to room temperature and stirred for 30 minutes. The tetrahydrofuran was removed in vacuo, and the aqueous mixture was washed with dichloromethane (3 x 40 mL). The aqueous solution was cooled to 0° C. and stirred while adding concentrated hydrochloric acid solution until pH=1 was reached. A bright yellow solid precipitated during this process. The solid was collected by filtration. The solid was dissolved in dichloromethane and the solution was dried over magnesium sulfate, filtered and concentrated in vacuo to give 2-(2,3-dihydrobenzo[b][1,4]di Oxin-6-yl)-6-methyl-3-oxo-2,3-dihydropyridazine-4-carboxylic acid (86%).

Step 3. 2-(2-(2,3-Dihydrobenzo[b][1,4]dioxin-6-yl)-6-methyl-3-oxo-2,3-dihydropyridazine - Preparation of 4-carbonyl)cyclohexane-1,3-dione (compound 1-2.1).

To 2-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-6-methyl-3-oxo-2,3-dihydropyridazine-4- To a solution of carboxylic acid (0.99 g, 3.44 mmol) in dichloromethane (anhydrous, 13 mL) was added 3 drops of N,N-dimethylformamide (anhydrous), followed by dropwise addition of oxalyl chloride (0.33 mL ,3.79mmol). The reaction mixture was stirred at room temperature for 16 hours. Additional N,N-dimethylformamide (1 drop) and oxalyl chloride (0.1 mL) were added and stirring was continued at room temperature for 1 hour. To a cooled (0 °C (ice bath)) solution of cyclohexane-1,3-dione (0.41 g, 3.62 mmol) in dichloromethane (anhydrous, 7.0 mL) was added triethylamine (1.44 mL ,10.3mmol). The acid chloride solution was then added to the solution of cyclohexane-1,3-dione in triethylamine within 10 minutes and the reaction mixture was stirred at 0° C. for a further 5 minutes. Additional triethylamine (0.48 mL, 3.45 mmol) was added followed by acetone cyanohydrin (as a stock solution in anhydrous dichloromethane) (10 mol%, 0.34 mmol). The reaction flask was transferred to a preheated oil bath and heated with stirring at reflux (40 °C) for 6 hours and then at room temperature for an additional 16 hours. The reaction mixture was concentrated in vacuo to give a black residue. Purification by column chromatography gave 2-(2-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-6-methyl-3-oxo as an orange foam (2,3-dihydropyridazine-4-carbonyl)cyclohexane-1,3-dione (400 mg, 30% yield).

¹ H NMR (400MHz, CDCl ₃ )δ7.32(s,1H),6.98(t,J=1.4Hz,1H),6.95(d,J=1.9Hz,2H),4.28(s,4H),2.55 (d, J = 8.1 Hz, 4H), 2.32 (s, 3H), 1.91 (s, 2H).

Example 3:

2-(2-(2-(2,2-Dimethylbenzo[d][1,3]dioxolan-5-yl)-6-methyl-3-oxo-2,3- Preparation of dihydropyridazine-4-carbonyl)cyclohexane-1,3-dione (compound 1-1.221).

Step 1. Preparation of 2,2-dimethylbenzo[d][1,3]dioxazole.

Catechol (11.00g, 0.1mol) was added to a 250mL four-necked flask, then toluene (100mL) and p-toluenesulfonic acid (0.19g, 1mmol) were added, and a water trap was put on. Reflux and stir in an oil bath at 110°C for 2 hours. Then, 2,2-dimethoxypropane (45.0 g, 0.432 mol) was added dropwise to the reaction liquid, and the reflux stirring was continued until the reaction was completed. GC-MS monitored the reaction end point. After the reaction was completed, the solvent was removed, and the residue was purified by column chromatography (100% petroleum ether) to obtain 2,2-dimethylbenzo[d][1,3]bisoxazole (11.46g, 76.31% yield) .

¹ H NMR (400MHz, CDCl ₃ ) δ6.91–6.85 (m, 4H), 1.72 (s, 6H).

Step 2. Preparation of 5-bromo-2,2-dimethylbenzo[d][1,3]dioxazole.

2,2-Dimethylbenzo[d][1,3]bisoxazole (2.228g, 14.837mmol) was dissolved in methanol (30mL), and N-bromosuccinimide (2.641g, 14.837mmol), the reaction solution was stirred in an oil bath at 40°C, and the reaction end point was monitored by GC-MS. After the reaction was completed, the solvent was directly removed, and the residue was purified by column chromatography (10% ethyl acetate) to obtain 5-bromo-2,2-dimethylbenzo[d][1,3]bisoxazole (3.95g , 70% yield).

¹ H NMR (400MHz, CDCl ₃ ) δ6.88 (dd, J=8.1, 2.0Hz, 1H), 6.86 (d, J=2.0Hz, 1H), 6.59 (d, J=8.1Hz, 1H), 1.66 (s,6H).

Step 3. Preparation of (2,2-dimethylbenzo[d][1,3]dioxolan-5-yl)boronic acid.

5-Bromo-2,2-dimethylbenzo[d][1,3]dioxazole (4.58g, 20mmol) and triisopropyl borate (5.643g, 30mmol) were dissolved in anhydrous THF (20mL ), the air in the bottle was replaced with nitrogen, the reaction solution was cooled to -78°C, and n-butyllithium (9.6mL, 24mmol) was added dropwise. During the dropwise addition, keep the reaction temperature not exceeding -65°C. After the dropwise addition was completed, the mixture was kept stirring for 1 hour, and then the temperature was allowed to rise slowly to room temperature. After the reaction was completed, the reaction solution was quenched with saturated aqueous ammonium chloride solution, and the pH was adjusted to 1 with hydrochloric acid. After stirring for a period of time, the organic phase was separated, and the aqueous phase was extracted with ethyl acetate (20mL*2). The organic phases were combined and washed with anhydrous After drying over sodium sulfate and precipitation, (2,2-dimethylbenzo[d][1,3]dioxolan-5-yl)boronic acid (3.14 g, 80% yield) was obtained.

It was directly used in the next reaction without purification.

Step 4. Preparation of 4-bromo-6-methylpyridazinone.

6-Methylpyridazinone (5.00g, 45mmol) was dissolved in acetic acid (100mL), then potassium acetate (13.24g, 135mmol) was added in batches, and then liquid bromine (14.38g, 90mmol) was slowly added dropwise to it And the reaction solution was stirred in an oil bath at 90°C. After the reaction was completed, the reaction solution was quenched with aqueous sodium thiosulfate solution, then extracted with ethyl acetate (20 mL*2), and the organic phase was washed with saturated sodium bicarbonate, dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The crude material was purified by column chromatography (30% ethyl acetate) to give 4-bromo-6-methylpyridazinone (2.703 g, 31% yield) as a white solid. M.p. (°C): 176-178.

¹ H NMR (400MHz, CDCl ₃ )δ12.36(b,1H),7.61(s,1H),2.36(s,3H).

Step 5. Preparation of 4-bromo-2-(2,2-dimethylbenzo[d][1,3]dioxolan-5-yl)-6-methylpyridazin-3(2H)-one .

To a solution of 4-bromo-6-methylpyridazinone (1.80 g, 9.56 mmol) in dichloromethane (100 mL) was added copper(II) acetate monohydrate (5.72 g, 28.68 mmol), molecular sieves, pyridine (2.26 g, 28.68mmol) and triethylamine (2.90g, 28.68mmol). To the stirred suspension was added portionwise (2,2-dimethylbenzo[d][1,3]dioxolan-5-yl)boronic acid (1.855 g, 9.56 mmol) over 5 minutes and the reaction mixture Stir at room temperature for 16 hours. The reaction mixture was filtered through celite and the residue was washed with additional dichloromethane. The filtrate was washed with 2N aqueous hydrochloric acid (2 x 200 mL), dried over magnesium sulfate, filtered and concentrated in vacuo. Purification by column chromatography eluting with 20%-100% ethyl acetate in petroleum ether afforded 4-bromo-2-(2,2-dimethylbenzo[d][1 ,3] Dioxolan-5-yl)-6-methylpyridazin-3(2H)-one (1.457 g, 45%).

¹ H NMR (400MHz, CDCl ₃ ) δ9.34(s, 1H), 8.19(s, 1H), 6.93(dd, J=8.2, 2.2Hz, 1H), 6.88(d, J=2.1Hz, 1H) ,6.81(d,J=8.2Hz,1H),2.47(s,3H),1.71(s,6H).

Step 6. 2-(2-(2-(2,2-Dimethylbenzo[d][1,3]dioxolan-5-yl)-6-methyl-3-oxo-2,3 - Preparation of dihydropyridazine-4-carbonyl)cyclohexane-1,3-dione (compound I-1.221).

4-Bromo-2-(2,2-dimethylbenzo[d][1,3]dioxolan-5-yl)-6-methylpyridazin-3(2H)-one (1.457 g, 4.32mmol), 1,3-cyclohexanedione (0.532g, 4.75mmol), palladium acetate (0.009698g, 0.0432mmol), Dpephos (0.232g, 0.432mmol) and triethylamine (0.874g, 8.64mmol ) was added to a 100mL autoclave, and acetonitrile (50mL) was added to dissolve it. First replace the air in the kettle with nitrogen, and then replace the nitrogen in the kettle with carbon monoxide. The reaction was stirred at 60°C for 4 hours under 10 bar pressure. After completion of the reaction, cool to room temperature, wash the reaction solution with 1M hydrochloric acid, then dry the organic phase with anhydrous sodium sulfate, and purify with column chromatography (0%～5% methanol) after precipitation to obtain 2-(2-(2- (2,2-Dimethylbenzo[d][1,3]dioxolan-5-yl)-6-methyl-3-oxo-2,3-dihydropyridazine-4-carbonyl ) cyclohexane-1,3-dione (196 mg, 82%).

¹ H NMR (400MHz, CDCl ₃ ) δ7.09(s, 1H), 6.96(dd, J=8.3, 2.2Hz, 1H), 6.92(d, J=2.1Hz, 1H), 6.76(d, J= 8.3Hz, 1H), 2.72(t, J=6.3Hz, 2H), 2.46(t, J=6.3Hz, 2H), 2.40(s, 3H), 1.68(s, 6H).

Example 4:

2-(2-(2-(8-methoxy-2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-6-methyl-3-oxo- Preparation of 2,3-dihydropyridazine-4-carbonyl)cyclohexane-1,3-dione (compound 1-2.4).

Step 1. Preparation of 5-bromo-3-methoxybenzene-1,2-diol.

5-Bromo-2-hydroxy-3-methoxybenzaldehyde (5.00 g, 0.0216 mol) was added to an aqueous solution of sodium hydroxide (0.864 g, 0.0216 mol) (90 mL). The solution was stirred at room temperature, then hydrogen peroxide (13.491 g, 0.119 mol) (diluted with 90 mL of water) was slowly added dropwise, and stirring was continued for several hours after the addition was complete. After the reaction was completed, dilute hydrochloric acid was added to the solution to make the solution acidic, extracted with dichloromethane (20 mL*2), and the combined organic phases were dried over anhydrous sodium sulfate. Beige-yellow 5-bromo-3-methoxybenzene-1,2-diol (3.98 g, 84%) was obtained after precipitation.

¹ H NMR (400MHz, CDCl ₃ ) δ6.77(d, J=2.1Hz, 1H), 6.61(d, J=2.1Hz, 1H), 5.36(d, J=13.9Hz, 2H), 3.86(s ,3H).

Step 2. Preparation of 7-bromo-5-methoxy-2,3-dihydrobenzo[b][1,4]dioxin.

Dissolve 5-bromo-3-methoxybenzene-1,2-diol (1.34g, 6.118mmol) in N,N-dimethylformamide (50mL), add potassium carbonate (1.268g, 9.177mmol) and dibromoethane (1.724 g, 9.177 mmol). The reaction solution was stirred in an oil bath at 80°C, and the reaction was detected by LC-MS. After the reaction is completed, cool to room temperature, pour the reaction solution into ice water, extract with ethyl acetate (20mL*2), combine the organic phase and wash with saturated NaCl aqueous solution, and finally dry the organic phase with anhydrous sodium sulfate, and use Column chromatography (10% EA) gave 7-bromo-5-methoxy-2,3-dihydrobenzo[b][1,4]dioxin (0.77 g, 51%).

Step 3. Preparation of (8-methoxy-2,3-dihydrobenzyl[b][1,4]dioxin-6-yl)boronic acid.

Purified by column chromatography with reference to the method of step 3 in the above-mentioned Example 3 to obtain (8-methoxy-2,3-dihydrobenzyl[b][1,4]dioxin-6-yl)boronic acid ( 1.71 g, 90%).

Step 4. 4-Bromo-2-(8-methoxy-2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-6-methylpyridazine-3(2H) - Preparation of ketones.

Referring to the method of step 5 in Example 3, 4-bromo-2-(8-methoxy-2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-6 -Methylpyridazin-3(2H)-one (0.569 g, 30%).

Step 5. 2-(2-(2-(8-Methoxy-2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-6-methyl-3-oxo - Preparation of 2,3-dihydropyridazine-4-carbonyl)cyclohexane-1,3-dione (compound 1-2.4).

Referring to the method in Example 3, the foamy 2-(2-(2-(8-methoxy-2,3-dihydrobenzo[b][1,4]dioxin-6-yl )-6-methyl-3-oxo-2,3-dihydropyridazine-4-carbonyl)cyclohexane-1,3-dione (63 mg, 10%).

¹ H NMR (400MHz, CDCl ₃ ) δ7.09(s, 1H), 6.77(d, J=2.4Hz, 1H), 6.72(d, J=2.3Hz, 1H), 4.35–4.31(m, 2H) ,4.27(dt,J=6.1,1.8Hz,2H),3.88(s,3H),2.73(t,J=6.3Hz,2H),2.46(t,J=6.5Hz,2H),2.41(s, 3H), 2.05 (q, J=6.4Hz, 2H).

Example 5:

2-(2-(7-Methoxybenzo[d][1,3]dioxolan-5-yl)-6-methyl-3-oxo-2,3-dihydropyridazine-4 Preparation of -carbonyl)cyclohexane-1,3-dione (compound 1-1.4).

Step 1. Preparation of 6-bromo-4-methoxybenzo[d][1,3]dioxin.

Referring to the method of Example 4, replace dibromoethane with diiodomethane in step 2 to obtain 6-bromo-4-methoxybenzene[d][1,3]dioxin (yield 52%).

¹ H NMR (400MHz, CDCl ₃ ) δ6.77(d, J=2.0Hz, 1H), 6.74(d, J=2.0Hz, 1H), 5.90(s, 2H), 3.90(s, 3H).

Step 2. Preparation of (7-methoxybenzo[d][1,3]dioxolan-5-yl)boronic acid.

Refer to the method of step 3 in Example 4 to obtain (7-methoxybenzo[d][1,3]dioxolan-5-yl)boronic acid (yield 97%).

¹ H NMR (400MHz, CDCl ₃ ) δ6.62(d, J=2.0Hz, 1H), 6.58(d, J=2.0Hz, 1H), 5.95(s, 2H), 3.90(s, 3H), 1.61 (s,2H).

Step 3. Preparation of 4-bromo-2-(7-methoxybenzo[d][1,3]dioxolan-5-yl)-6-methylpyridazin-3(2H)-one.

Referring to the method of step 4 in Example 4, 4-bromo-2-(7-methoxybenzene[d][1,3]dioxolan-5-yl)-6-methylpyridazine-3 (2H)-Kone (15% yield).

Step 4. 2-(2-(7-Methoxybenzo[d][1,3]dioxolan-5-yl)-6-methyl-3-oxo-2,3-dihydropyridazine- Preparation of 4-carbonyl)cyclohexane-1,3-dione (compound 1-1.4).

With reference to the method of step 5 of Example 4, 2-(2-(7-methoxybenzene[d][1,3]dioxolan-5-yl)-6-methyl-3-oxo- 2,3-Dihydropyridazine-4-carbonyl)cyclohexane-1,3-dione (30% yield).

¹ H NMR (400MHz, CDCl ₃ )δ6.86(m,1H),6.72(m,2H),6.65(m,2H),5.95(s,3H),3.83(s,3H),3.69(m, 2H), 1.25(m, 1H).

Embodiment 6:

2-(2-(8-Chloro-2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-6-methyl-3-oxo-2,3-di Preparation of hydropyridazine-4-carbonyl)cyclohexane-1,3-dione (compound 1-2.6).

Step 1. Preparation of 5-bromo-3-chloro-2-hydroxybenzaldehyde.

Dissolve 2-chloro-4-bromophenol (10.00g, 0.048mol) in trifluoroacetic acid (150mL), then add hexamethylenetetramine (13.457g, 0.096mol), and stir at room temperature for 20 minutes under nitrogen protection. Then the temperature was raised to 90°C and the oil bath was refluxed, and detected by GC-MS. After the reaction was completed, cool to room temperature, add water (40mL) and sulfuric acid aqueous solution (40mL) to the reaction successively, stir at room temperature for 1 hour, then extract with ethyl acetate (20mL*2), combine the organic phases and wash with saturated brine, and finally wash with Drying over anhydrous sodium sulfate, precipitation and purification by column chromatography gave 5-bromo-3-chloro-2-hydroxybenzaldehyde (7.08g, 62%).

¹ H NMR (400MHz, CDCl ₃ ) δ11.40(s, 1H), 9.85(s, 1H), 7.74(d, J=2.4Hz, 1H), 7.63(d, J=2.4Hz, 1H).

Step 2. Preparation of 5-bromo-3-chlorobenzene-1,2-diol.

Dissolve 5-bromo-3-chloro-2-hydroxybenzaldehyde (3.642g, 0.015mol) in aqueous solution of sodium hydroxide (0.601g, 0.015mol), stir at room temperature, and then add hydrogen peroxide (9.353g, 0.083 mol) of 50mL aqueous solution. Continue to keep stirring at the current temperature after the dropwise addition is completed. After the reaction is complete, dilute hydrochloric acid aqueous solution is added to the reaction solution, the aqueous phase is extracted with dichloromethane, the combined organic phase is washed with aqueous sodium sulfite solution, and finally the organic phase is dried with anhydrous sodium sulfate, and the white solid 5-bromo- 3-Chlorobenzene-1,2-diol (2.466 g, 73%).

Step 3. Preparation of 7-bromo-5-chloro-2,3-dihydrobenzo[b][1,4]dioxane.

Dissolve 5-bromo-3-chlorobenzene-1,2-diol (5.55g, 0.025mol) in N,N-dimethylformamide (100mL), then add potassium carbonate (5.252g, 0.038mol) and dibromoethane (7.139 g, 0.038 mol). The reaction solution was stirred under an oil bath at 80°C. After the reaction was completed, the reaction solution was cooled to room temperature, then poured into ice water, extracted with ethyl acetate (50mL*2), combined the organic phases and dried with anhydrous sodium sulfate, purified by column chromatography (100% petroleum ether ) to give 7-bromo-5-chloro-2,3-dihydrobenzo[b][1,4]dioxane (4.42 g, 70%) as a white solid.

Step 4. Preparation of (8-chloro-2,3-dihydrobenzo[b][1,4]dioxin-6-yl)boronic acid.

Referring to the method of Example 3, a white solid (8-chloro-2,3-dihydrobenzo[b][1,4]dioxin-6-yl)boronic acid (4.57 g, 90%) was obtained.

Step 5. 4-Bromo-2-(8-chloro-2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-6-methylpyridazin-3(2H)-one preparation.

Referring to the method of Example 3, a light yellow powder solid 4-bromo-2-(8-chloro-2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-6-methanol was obtained Pyridazin-3(2H)-one (1.56 g, 31%).

Step 6. 2-(2-(8-Chloro-2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-6-methyl-3-oxo-2,3- Preparation of dihydropyridazine-4-carbonyl)cyclohexane-1,3-dione (compound 1-2.6).

Referring to the method of Example 3, yellow foamy solid 2-(2-(8-chloro-2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-6-methyl -3-oxo-2,3-dihydropyridazine-4-carbonyl)cyclohexane-1,3-dione (0.322 g, 17%).

¹ H NMR (400MHz, CDCl ₃ ) δ7.22 (d, J=2.5Hz, 1H), 7.09–7.06 (m, 2H), 4.39–4.36 (m, 2H), 4.30–4.27 (m, 2H), 2.73(t, J=6.3Hz, 2H), 2.47(t, J=6.5Hz, 2H), 2.40(s, 3H), 2.05(t, J=6.5Hz, 2H).

Embodiment 7:

2-(6-cyclopropyl-2-(2,3-dihydrobenzo[B][1,4]dioxin-6-yl)-3-oxo-2,3-dihydropyridazine - Preparation of 4-carbonyl)cyclohexane-1,3-one (compound I-2.220).

Step 1. Ethyl-6-cyclopropyl-2-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-3-oxo-2,3-di Preparation of hydropyridazine-4-carboxylate.

To ethyl-3-cyclopropyl-6-oxo-1H-pyridazine-5-carboxylate (2.00g, 9.61mmol) (preparation method with reference to document CN 108884074A) in dichloromethane (70mL) stirring To the solution were added molecular sieves (0.88 g), copper(II) acetate monohydrate (4.01 g, 22.1 mmol), triethylamine (2.7 mL, 19.2 mmol) and pyridine (1.6 mL, 19.2 mmol). (2,3-Dihydrobenzo[b][1,4]dioxin-6-yl)boronic acid (2.59 g, 14.4 mmol) (commercially available) was then added in portions over 10 minutes. The reaction mixture was stirred at room temperature for 4 hours with compressed air being bubbled through. After 4 hours, the compressed air was turned off and stirring was continued for another 16 hours. The reaction mixture was filtered through celite and the residue was washed with additional dichloromethane. The filtrate was washed with 2N aqueous hydrochloric acid (2×100 mL) and saturated brine solution (100 mL). The organic layer was dried over magnesium sulfate, filtered and concentrated in vacuo to leave a dark yellow gum. Purification by column chromatography eluting with 0-100% ethyl acetate in isohexane gave ethyl-6-cyclopropyl-2-(2,3-dihydrobenzene as a bright yellow gum And[b][1,4]dioxin-6-yl)-3-oxo-2,3-dihydropyridazine-4-carboxylate (2.46 g, 74%).

Step 2. 6-Cyclopropyl-2-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-3-oxo-2,3-dihydropyridazine-4 - Preparation of carboxylic acids.

Ethyl-6-cyclopropyl-2-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-3-oxo-2,3-dihydropyridine A solution of oxazine-4-carboxylate (2.39 g, 6.97 mmol) in tetrahydrofuran (50 mL) was added water (25 mL) followed by lithium hydroxide (0.45 g, 10.5 mmol). The resulting solution was stirred at room temperature for 90 minutes. The tetrahydrofuran was removed in vacuo and the residual aqueous mixture was diluted with water (25 mL) and washed with ethyl acetate (30 mL). The vigorously stirred aqueous layer was acidified to pH = 1 with concentrated hydrochloric acid solution, during which a yellow precipitate formed. The precipitate was collected by filtration to give 6-cyclopropyl-2-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-3-oxo-2 as a yellow solid , 3-Dihydropyridazine-4-carboxylic acid (1.78 g, 81%).

Step 3. 2-(6-Cyclopropyl-2-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-3-oxo-2,3-dihydropyridine Preparation of oxazin-4-carbonyl)cyclohexane-1,3-one (compound 1-2.220).

6-cyclopropyl-2-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-3-oxo-2,3-dihydropyridazine-4 -Carboxylic acid (1.00 g, 3.16 mmol) was added to anhydrous dichloromethane (20 mL) and to it was added a drop of anhydrous N,N-dimethylformamide. Then oxalyl chloride (0.35 mL, 4.11 mmol) was added dropwise to the mixture and stirred for 1 h. The reaction mixture was concentrated under reduced pressure under nitrogen atmosphere. The crude reaction mass was then dissolved in anhydrous dichloromethane (15 mL), activated molecular sieves were added and the reaction mixture was cooled in an ice-salt bath. Triethylamine (1.23 mL, 9.48 mmol) was then added dropwise to the reaction mixture over 15 minutes. Then 1,3-cyclohexanedione (425 mg, 3.79 mmol) in dichloromethane (10 mL) was added dropwise to the reaction mixture. Stir at room temperature for 1 hour. Triethylamine (1.23 mL, 9.48 mmol) and acetone cyanohydrin (0.22 mL, 2.37 mmol) were then added and the reaction was stirred for 2.5 h. The crude product was diluted with dichloromethane and washed with 1N hydrochloric acid. Purification by column chromatography (0%-5% MeOH) gave the desired product as a solid 2-(6-cyclopropyl-2-(2,3-dihydrobenzo[b][1, 4] Dioxin-6-yl)-3-oxo-2,3-dihydropyridazin-4-carbonyl)cyclohexane-1,3-one (850 mg, 63%).

¹ H NMR (400MHz, CDCl ₃ ) δ7.10(d, J=2.5Hz, 1H), 7.05(dd, J=8.7, 2.5Hz, 1H), 7.00(s, 1H), 6.89(d, J= 8.7Hz, 1H), 4.26(s, 4H), 2.72(t, J=6.3Hz, 2H), 2.46(t, J=6.5Hz, 2H), 2.03(d, J=6.4Hz, 2H), 1.92 (tt, J = 8.3, 5.0 Hz, 1H), 0.98 (dt, J = 8.3, 2.8 Hz, 2H), 0.92 (dt, J = 5.5, 3.0 Hz, 2H).

Embodiment 8:

2-(2-(8-(4,5-dihydroisoxazol-3-yl)-2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-6 - Preparation of methyl-3-oxycarbonyl-2,3-dihydropyridazine-4-carbonyl)cyclohexane-1,3-dione (compound I-2.216).

Step 1. Preparation of 7-bromo-2,3-dihydrobenzo[b][1,4]dioxin-5-carbaldehyde

Dissolve 5-bromo-2,3-dihydroxybenzaldehyde (5.42g, 0.025mol) in N,N-dimethylformamide (100mL), then add potassium carbonate (5.252g, 0.038mol) and dibromo Ethane (7.139 g, 0.038 mol). The reaction solution was stirred under an oil bath at 100°C. After the reaction was completed, the reaction solution was cooled to room temperature, then poured into ice water, extracted with ethyl acetate (50mL*2), combined the organic phases and dried with anhydrous sodium sulfate, purified by column chromatography (100% petroleum ether ) to give 7-bromo-2,3-dihydrobenzo[b][1,4]dioxin-5-carbaldehyde (4.25 g, 70%) as a white solid.

¹ H NMR (400MHz, CDCl ₃ ) δ10.29(s, 1H), 7.49(d, J=2.5Hz, 1H), 7.22(d, J=2.5Hz, 1H), 4.38(ddd, J=4.6, 2.9,0.9Hz,2H),4.33(ddd,J=4.6,2.9,0.9Hz,2H).

Step 2. Preparation of 7-bromo-2,3-dihydrobenzo[b][1,4]dioxin-5-carbaldehyde oxime.

7-Bromo-2,3-dihydrobenzo[b][1,4]dioxin-5-carbaldehyde (2.12g, 8.732mmol) was added into a 250ml one-necked flask, and then dissolved with ethanol (50ml). Further hydroxylamine hydrochloride (0.73 g, 10.478 mmol), pyridine (1.66 g, 20.957 mmol) were added. Stir at room temperature and monitor the reaction by LC-MS. After the reaction was completed, the solvent was precipitated, and the residue was dissolved in dichloromethane, and the solution was washed twice with dilute hydrochloric acid, then twice with saturated brine, and finally the organic phase was dried over anhydrous sodium sulfate. Purification by column chromatography afforded a white solid (1.04 g, 46%).

¹ H NMR (400MHz, CDCl ₃ ) δ8.32(s, 1H), 7.67(d, J=6.5Hz, 1H), 7.41(d, J=2.4Hz, 1H), 7.03(d, J=2.4Hz ,1H),4.32–4.29(m,2H),4.28–4.25(m,2H).

Step 3. Preparation of 7-bromo-N-hydroxy-2,3-dihydrobenzo[b][1,4]dioxin-5-amino acid chloride.

Dissolve 7-bromo-2,3-dihydrobenzo[b][1,4]dioxin-5-carbaldehyde oxime (0.88g, 3.401mmol) in methanol (20ml), then gradually add NCS (0.55 g, 4.081 mmol), the reaction solution was stirred in an oil bath at 40°C, and the end point of the reaction was monitored by TLC or LC-MS. After the reaction was completed, it was directly used in the next reaction without treatment.

Step 4. Preparation of 3-(7-bromo-2,3-dihydrobenzo[b][1,4]dioxin-5-yl)-4,5-dihydroisoxazole.

Dissolve 7-bromo-N-hydroxyl-2,3-dihydrobenzo[b][1,4]dioxin-5-amino acid chloride (3.401mmol) in dichloromethane (50ml), add triethyl The amines adjust the pH of the solution to around 9. Then, ethylene was introduced at 1 MPa, and stirred at room temperature for about 4 hours. After the reaction was completed, the reaction solution was washed with dilute hydrochloric acid, the organic phase was separated and the aqueous phase was extracted with dichloromethane (20 mL*2). The organic phases were combined and dried over anhydrous sodium sulfate. Purify by column chromatography after desolvation.

¹ H NMR (400MHz, CDCl ₃ ) δ7.38(d, J=2.4Hz, 1H), 7.07(d, J=2.3Hz, 1H), 4.44(t, J=10.2Hz, 2H), 4.34–4.26 (m,5H),3.38(t,J=10.2Hz,2H).

Step 5. Preparation of (8-(4,5-dihydroisoxazol-3-yl)-2,3-dihydrobenzo[b][1,4]dioxin-6-yl)boronic acid.

Dissolve 3-(7-bromo-2,3-dihydrobenzo[b][1,4]dioxin-5-yl)-4,5-dihydroisoxazole (3 mmol) in anhydrous THF , then triisopropyl borate (4.5 mmol) was added thereto, and then replaced with nitrogen. The reaction was cooled to -78°C, at which point n-butyllithium (4.5 mmol) was added dropwise. Keep the temperature not exceeding -65°C. After the dropwise addition was complete, the temperature was allowed to rise slowly to room temperature and stirred. After the reaction was completed, the reaction was quenched with saturated ammonium chloride solution, then acidified with dilute hydrochloric acid to pH = 1, stirred at room temperature for a period of time, extracted with ethyl acetate (20mL*2), the combined organic phases were dried with anhydrous sodium sulfate, and removed It was directly used in the next reaction after dissolution.

Step 6. 4-Bromo-2-(8-(4,5-dihydroisoxazol-3-yl)-2,3-dihydrobenzo[b][1,4]dioxin-6-yl) - Preparation of 6-methylpyridazin-3(2H)-one.

To a solution of 4-bromo-6-methylpyridazinone (1.80 g, 9.56 mmol) in dichloromethane (100 mL) was added copper(II) acetate monohydrate (5.72 g, 28.68 mmol), molecular sieves, pyridine (2.26 g, 28.68mmol) and triethylamine (2.90g, 28.68mmol). To the stirred suspension was added portionwise (8-(4,5-dihydroisoxazol-3-yl)-2,3-dihydrobenzo[b][1,4]dioxin- 6-yl)boronic acid (2.38g, 9.56mmol) and the reaction mixture was stirred at room temperature for 16 hours. The reaction mixture was filtered through celite and the residue was washed with additional dichloromethane. The filtrate was washed with 2N aqueous hydrochloric acid (200 mL*2), dried over magnesium sulfate, filtered and concentrated in vacuo. Purification by column chromatography eluting with 20%-100% ethyl acetate in petroleum ether afforded 4-bromo-2-(8-(4,5-dihydroisoxazole-3) as a white solid -yl)-2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-6-methylpyridazin-3(2H)-one (1.687 g, 45%). EI-MS: 393.20 [M+H] ⁺ .

¹ H NMR (400MHz, CDCl ₃ ) δ7.57(s, 1H), 7.46(d, J=2.6Hz, 1H), 7.21(d, J=2.6Hz, 1H), 4.43(t, J=10.2Hz ,2H),4.38–4.34(m,2H),4.33–4.29(m,2H),3.41(t,J＝10.1Hz,2H),2.37(s,3H).

Step 7. 2-(2-(8-(4,5-Dihydroisoxazol-3-yl)-2,3-dihydrobenzo[b][1,4]dioxin-6-yl)- Preparation of 6-methyl-3-oxo-2,3-dihydropyridazine-4-carbonyl)cyclohexane-1,3-dione (compound 1-2.216).

4-bromo-2-(8-(4,5-dihydroisoxazol-3-yl)-2,3-dihydrobenzo[b][1,4]dioxin-6-yl) -6-methylpyridazin-3(2H)-one (1.694g, 4.32mmol), 1,3-cyclohexanedione (0.532g, 4.75mmol), palladium acetate (0.009698g, 0.0432mmol), Dpephos ( 0.232g, 0.432mmol) and triethylamine (0.874g, 8.64mmol) were added to a 100mL autoclave, and acetonitrile (50mL) was added to dissolve it. First replace the air in the kettle with nitrogen, and then replace the nitrogen in the kettle with CO. The reaction was stirred at 60°C for 4 hours under 10 bar pressure. After completion of the reaction, cool to room temperature, wash the reaction solution with 1M hydrochloric acid, then dry the organic phase with anhydrous sodium sulfate, and purify with column chromatography (0%～5% MeOH) after precipitation to obtain 2-(2-(8- (4,5-Dihydroisoxazol-3-yl)-2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-6-methyl-3-oxo- 2,3-Dihydropyridazine-4-carbonyl)cyclohexane-1,3-dione (1.599 g, 82%). EI-MS: 452.43 [M+H] ⁺ .

¹ H NMR (400MHz, CDCl ₃ ) δ7.43(d, J=2.5Hz, 1H), 7.21(d, J=2.6Hz, 1H), 7.08(s, 1H), 4.42(t, J=10.1Hz ,3H),4.36–4.27(m,5H),3.40(t,J=10.1Hz,3H),2.73(s,2H),2.47(d,J=7.7Hz,2H),2.39(s,3H) ,2.06(s,2H).

Preferred example 1 of the herbicidal compound of the present invention in table 3

Preferred example 2 of the herbicidal compound of the present invention

The nuclear magnetic data of above-mentioned preferred compound of table 5

Test example:

biological example

Pre-emergence test test: put 8cm deep field standard soil (loam, pH value 6.7, organic matter content is 1.59%) in the plastic basin pot with diameter 7cm deep 10cm, add water to soak the soil to saturation, and each pot sows a certain amount of Evenly cover one deck soil after seed (for testing monocotyledon, dicotyledon weed seed and main crop seed); Dilute it with 1% Tween-80 static tap water to the required concentration for later use, and carry out soil spray treatment 24 hours after sowing. The spray adopts the 3WP-2000 biometric spray tower produced by the ^Nanjing Agricultural Mechanization Research Institute of the Ministry of Agriculture. The speed is 210mm/s, the walking distance is 1340mm, and the liquid volume is 42mL. After treatment, they were placed in a constant temperature light culture room for cultivation. The temperature in the cultivation room was set at 22°C during the day and 15°C at night or 28°C during the day and 22°C at night; the light cycle was 12:12 (D:L). The test plants were evaluated 30 days after application (100=complete damage to plants, 0=no damage to plants).

Post-emergence test test: put 8cm deep field standard soil (loam, pH value 6.7, organic matter content is 1.59%) in the plastic basin pot with diameter 7cm deep 10cm, add water to soak the soil to saturation, and every pot sows a certain amount of Seeds (for the monocotyledonous, dicotyledonous weed seeds and main crop seeds) are evenly covered with a layer of soil; put into a constant temperature light cultivation room to cultivate until the weeds 2-4 leaf stage. The temperature in the cultivation room was set at 22°C during the day and 15°C at night or 28°C during the day and 22°C at night; the light cycle was 12:12 (D:L). After dissolving the original drug under test with a mixed solvent of acetone-dimethylformamide (1:1), dilute it with 1% Tween-80 standing tap water to the required concentration for later use, and spray the stems and leaves. The spray adopts the 3WP-2000 biometric spray tower produced by the ^Nanjing Agricultural Mechanization Research Institute of the Ministry of Agriculture. The speed is 210mm/s, the walking distance is 1340mm, and the liquid volume is 42mL. The test plants were evaluated 21 days after application (100=complete damage to plants, 0=no damage to plants).

Biological activity evaluation

The activity level criteria for plant damage are as follows:

Level 5: The inhibition rate of fresh weight is 85% and above;

Level 4: Fresh weight inhibition rate is greater than or equal to 60% and less than 85%;

Level 3: The fresh weight inhibition rate is greater than or equal to 40% and less than 60%;

Level 2: Fresh weight inhibition rate is greater than or equal to 20% and less than 40%;

Level 1: Fresh weight inhibition rate is greater than or equal to 5% and less than 20%;

Level 0: Fresh weight inhibition rate is less than 5%;

Table 6 Weed activity test

Note: The compound application dose is 500g/ha.

Table 7 post-emergence test test

The results in Table 7 show that compared with the monomethoxyphenyl compounds specifically mentioned in WO2012/136703A1 and the bismethoxyphenyl compounds mentioned in WO2017/178582, the safety of the compound of this patent on wheat and corn taller, especially corn, and maintained good activity against representative weeds. The structures of the reference compounds (1.5WO2012/136703A1) and (1.3WO2017/178582A1) are as follows:

Table 8 post-emergence test test

The results in Table 8 show that the compound of the present invention has almost no damage to wheat and corn, and still has a good inhibitory effect on representative weeds.

The above is only the preferred embodiment of the present invention, it should be pointed out that for those skilled in the art, without departing from the inventive concept of the present invention, some modifications and improvements can also be made, and these all belong to the present invention. protection scope of the invention.

Claims

A pyridazinone compound represented by formula I or an agriculturally acceptable salt thereof,

Wherein, R 1 represents hydrogen, halogen, C 1 ~C 6 alkyl, C 3 ~C 6 cycloalkyl, C 2 ~C 6 alkenyl, C 2 ~C 6 alkynyl, C 1 ~C 6 haloalkyl, C 1 ～C 6 alkoxy, C 1 ～C 3 haloalkoxy, C 1 ～C 6 alkoxy-C 1 ～C 3 alkyl, C 1 ～C 6 alkyl-S(O) p - or C 1 ~C 6 haloalkyl-S(O) p -;

p is 0, 1 or 2;

Ar represents one of the following groups:

R 2 , R 3 , and R 4 independently represent hydrogen, halogen, nitro, cyano, C 1 ~C 6 alkyl, C 3 ~C 6 cycloalkyl, C 2 ~C 6 alkenyl, C 2 ~ C 6 alkynyl, C 1 ~C 6 haloalkyl, C 1 ~C 6 alkoxy, C 1 ~C 3 haloalkoxy, C 1 ~C 6 alkoxy-C 1 ~C 3 alkyl, C 1 ~C 6 alkyl-S(O) p -, C 1 ~C 6 haloalkyl-S(O) p -, or one of the following groups:

p is 0, 1 or 2;

R a , R b , R c , R d , R e , and R f independently represent hydrogen, halogen, C 1 -C 6 alkyl, C 3 -C 6 cycloalkyl, C 1 -C 6 alkoxy Or C 1 ~C 6 alkoxy-C 1 ~C 3 alkyl;

R h and R g independently represent hydrogen, halogen, C 1 -C 6 alkyl, C 3 -C 6 cycloalkyl or aryl;

The aryl is optionally substituted by one or more of the following groups: halogen, C 1 -C 3 alkoxy, C 1 -C 3 alkyl, C 1 -C 3 haloalkyl;

R i and R j independently represent hydrogen, C 1 -C 6 alkyl, C 3 -C 6 cycloalkyl, benzyl or aryl;

The benzyl or aryl is optionally substituted by one or more of the following groups: halogen, C 1 -C 3 alkoxy, C 1 -C 3 alkyl, C 1 -C 3 haloalkyl.
The pyridazinone compound or its agriculturally acceptable salt according to claim 1, wherein,

R 1 represents C 1 -C 6 alkyl or C 3 -C 6 cycloalkyl;

Ar represents one of the following groups:

R 2 , R 3 , and R 4 independently represent hydrogen, halogen, nitro, cyano, C 1 ~C 6 alkyl, C 3 ~C 6 cycloalkyl, C 2 ~C 6 alkenyl, C 2 ~ C 6 alkynyl, C 1 ~C 6 haloalkyl, C 1 ~C 6 alkoxy, C 1 ~C 3 haloalkoxy, C 1 ~C 6 alkoxy-C 1 ~C 3 alkyl or the following groups One of the regiments:

R a , R b , R c , R d , R e , and R f independently represent hydrogen, halogen, C 1 -C 6 alkyl or C 3 -C 6 cycloalkyl;

R h and R g independently represent hydrogen, halogen, C 1 -C 6 alkyl, C 3 -C 6 cycloalkyl or aryl;

The aryl is optionally substituted by one or more of the following groups: halogen, C 1 -C 3 alkoxy, C 1 -C 3 alkyl, C 1 -C 3 haloalkyl;

R i and R j independently represent hydrogen, C 1 -C 6 alkyl, C 3 -C 6 cycloalkyl, benzyl or aryl;

The benzyl or aryl is optionally substituted by one or more of the following groups: halogen, C 1 -C 3 alkoxy, C 1 -C 3 alkyl, C 1 -C 3 haloalkyl.
The pyridazinone compound or its agriculturally acceptable salt according to claim 2, wherein,

R 1 represents C 1 -C 4 alkyl or cyclopropyl;

Ar represents one of the following groups:

R 2 , R 3 , and R 4 independently represent hydrogen, fluorine, chlorine, cyano, nitro, C 1 ~C 3 alkyl, C 3 ~C 6 cycloalkyl, C 1 ~C 6 haloalkyl, C 1 ~ C 6 alkoxy group or one of the following groups:

R a , R b , R c , R d , R e , and R f independently represent hydrogen, halogen, C 1 -C 6 alkyl or C 3 -C 6 cycloalkyl;

R h and R g independently represent hydrogen, C 1 -C 6 alkyl, C 3 -C 6 cycloalkyl or aryl;

The aryl is optionally substituted by one or more of the following groups: halogen, C 1 -C 3 alkoxy, C 1 -C 3 alkyl, C 1 -C 3 haloalkyl;

R i and R j independently represent hydrogen, methyl, ethyl, benzyl or aryl;

The benzyl or aryl groups are optionally substituted with one or more of the following groups: chloro, fluoro, methyl, ethyl, trifluoromethyl, methoxy.
The pyridazinone compound or its agriculturally acceptable salt according to claim 3, which has the structure shown in formula I-1 or formula I-2:

Wherein, R represents methyl or cyclopropyl;

R 2 , R 3 , and R 4 independently represent hydrogen, fluorine, chlorine, cyano, nitro, C 1 ~C 3 alkyl, C 3 ~C 6 cycloalkyl, C 1 ~C 6 haloalkyl, C 1 ~ C 6 alkoxy group or one of the following groups:

R a , R b , R c , R d , R e , and R f independently represent hydrogen, fluorine, and C 1 -C 6 alkyl;

R h and R g independently represent hydrogen and C 1 -C 6 alkyl;

R i and R j independently represent hydrogen, methyl, ethyl, benzyl;

The benzyl group is optionally substituted with one or more of the following groups: chloro, fluoro, methyl, ethyl, trifluoromethyl or methoxy.
The pyridazinone compound or its agriculturally acceptable salt according to claim 4 is selected from the compounds in Table 1 or Table 2.
The pyridazinone compound or its agriculturally acceptable salt according to any one of claims 1 to 5, characterized in that, the agriculturally acceptable salt can be a salt of the following forms: amines, alkali metals and alkaline earth metal bases, transition metals or quaternary ammonium bases; preferred aluminum salts, calcium salts, cobalt salts, copper salts, iron salts, magnesium salts, potassium salts, sodium salts or zinc salts of compounds of formula I; more preferably formula I Copper, potassium or sodium salts of compounds.
A herbicide composition characterized by comprising the pyridazinone compound or an agriculturally acceptable salt thereof according to any one of claims 1-6.
A herbicide composition characterized by comprising the pyridazinone compound or its agriculturally acceptable salt according to any one of claims 1 to 6, and an agriculturally acceptable co-preparation product.
A herbicide composition, characterized in that it comprises the pyridazinone compound or its agriculturally acceptable salt according to any one of claims 1 to 6, an agriculturally acceptable co-preparation and one or more other pesticides.
A herbicide composition, characterized in that it comprises the pyridazinone compound or its agriculturally acceptable salt according to any one of claims 1 to 6, an agriculturally acceptable co-formulation and a herbicide.
A herbicide composition characterized by comprising the pyridazinone compound or its agriculturally acceptable salt according to any one of claims 1-6, an agriculturally acceptable co-preparation and a safener.
A method for controlling weeds, characterized in that, comprising the weed control amount of the pyridazinone compound or its agriculturally acceptable salt according to any one of claims 1 to 6 or the compound described in claim 7 The herbicidal composition is applied to the weed or the area in which it is located.
A method for preparing the pyridazinone compound or its agriculturally acceptable salt according to any one of claims 1 to 6, characterized in that it comprises the following steps:

(1) In the presence of an inert organic solvent and a base, add the compound of formula II and formula III to react to generate the compound of formula IV;

Wherein, R 1 and Ar are as defined in any one of claims 1 to 6; R 5 represents halogen, -OH, C 1 to C 6 alkoxy, aryloxy or N-linked imidazole;

Preferably, in the presence of an inert organic solvent and a base, the compound of formula IIc is added to react with the compound of formula III to generate the compound of formula IV;

Preferably, R and Ar are as defined in any one of claims 1 to 6; LG is a suitable leaving group;

(2) The compound of formula IV undergoes a rearrangement reaction to generate the compound of formula I.
A method for preparing the pyridazinone compound or its agriculturally acceptable salt according to any one of claims 1 to 6, characterized in that it comprises the following steps: reacting the compound of formula V and formula III in the reaction medium Generate a compound of formula I; wherein, R and Ar are as defined in any one of claims 1 to 6; the reaction medium includes a palladium catalyst, a suitable phosphine ligand or a phosphine ligand salt, a suitable base and/or or carbon monoxide.
Use of the pyridazinone compound or its agriculturally acceptable salt according to any one of claims 1 to 6 or the herbicide composition of claim 7 in controlling weeds.