Pyrazole carboxamide derivative as well as preparation method and application thereof

Abstract

The invention provides pyrazole carboxamide derivatives as well as a preparation method and application thereof, and relates to pyrazole carboxamide compounds which have a chemical structural general formula as shown in 7: # imgabs0 #, in which R1 is selected from 2-fluorine, 3-chlorine and 2, 4-dichloro; r < 2 > is selected from a group consisting of 3-pyridylmethylene, 2-benzothiazolyl, 2-furyl, 2-thienyl, N, N-cyclopentyl and cyclopropyl; x is selected from O and S; y is selected from C and N; the invention discloses a structural general formula and a synthesis method of the compound, application of the compound as a herbicide, application of the compound in preventing and controlling agricultural, forestry and horticultural weeds in combination with agriculturally acceptable auxiliaries or synergists and commercial herbicides, and a preparation method of the compound.

Description

Technical Field

[0001] The technical scheme of the present invention relates to pyrazolecarboxamide compounds, in particular to pyrazolecarboxamide derivatives. Background Art

[0002] Weeds seriously threaten agricultural production, and crop yield losses due to weed damage reach 9.7% each year. At present, herbicides are still the main means of weed control in agricultural production, playing an important role in national food security (Plant Protection, 2023, 49, 295-302.). However, the discovery of new herbicide mechanisms in the past 40 years has been slow, limiting the development and commercialization of new target herbicides. Due to the long-term excessive abuse of commercial herbicides, the resistance of existing herbicides has worsened, creating a vicious cycle (J. Agric. Food Chem. 2020, 6, 5059-5067.). Therefore, only by researching and developing herbicides with novel structures and mechanisms of action can the problem of weed resistance be effectively alleviated.

[0003] Transketolase (TKL) is an important enzyme in plant carbon metabolism and Calvin cycle. It limits the photosynthetic rate of plants to the greatest extent. Changes in TKL activity significantly affect plant growth rate, changes in phenylalanine and aromatic amino acid metabolites. TKL has been confirmed to be a new potential target for herbicides (Toxins 2018, 10, 41.). Once TKL activity is inhibited, the Calvin cycle, starch and sucrose synthesis, shikimate pathway and phenylpropanoid metabolism that depend on TKL substrates and products will be inhibited, leading to the death of weeds.

[0004] In recent years, our research group has discovered high herbicidal activity lead compounds targeting TKL, such as pyrazolamine compound 4u, naphthylimide-aroyl compound 4w, 1,2,4-triazole compounds 5av and 5aw (J. Agric. Food Chem. 2022, 70, 12819-12829.), which have a new herbicide target TKL. 2 Under the condition of 100 mg / L, these compounds have an inhibition rate of about 90% on weeds such as crabgrass and Amaranthus retroflexus. Therefore, further optimization of the structure of these lead compounds has the potential to develop highly effective herbicide candidate compounds. Pyrazole derivatives have shown good biological activities in anti-tumor, antibacterial, antimalarial, insecticidal, and weed control (Eur. J. Med. Chem. 2010, 45, 2650-2655.). For example, Jin et al. reported that pyrazole compounds have good inhibitory effects on rape roots and barnyard grass roots at a concentration of 100 mg / L. Tan et al. reported that pyrazole carboxamide semicarbazide compounds have good herbicidal activity and selectivity against dicotyledonous weeds such as velvetleaf, Amaranthus retroflexus, and Amaranthus concavus.

[0005] The present invention takes pyrazole heterocycle and amide bond as the core skeleton, optimizes the structure of 1,2,4-triazole lead compound 5aw, designs and synthesizes a series of pyrazole carboxamide compounds 7a-7v, and characterizes the structures of the target compounds. Through systematic herbicidal activity screening, it is expected to provide more efficient candidate compounds for the creation of new herbicides. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a method for synthesizing a new type of pyrazole carboxamide derivatives and a method for determining the biological activity of the derivatives in regulating agricultural, horticultural and forestry weeds, and to provide applications of the compounds in the agricultural, horticultural and forestry fields.

[0007] The technical solution adopted by the present invention to solve the technical problem is: the chemical structure of the pyrazole carboxamide compound having herbicidal activity in the agricultural field, the horticultural field, and the forestry field is shown in Formula 7:

[0008]

[0009] Among them, R 1 Selected from: 2-fluoro, 3-chloro, 2,4-dichloro; R 2 is selected from: 3-pyridylmethylene, 2-benzothiazolyl, 2-furyl, 2-thienyl, N,N-cyclopentyl, cyclopropyl; X is selected from: O, S; Y is selected from: C, N;

[0010] The synthesis method of the pyrazole carboxamide derivative 7 of the present invention is characterized in that the reaction equation is as follows:

[0011]

[0012] Among them, R 1 Selected from: 2-fluoro, 3-chloro, 2,4-dichloro; R 2 is selected from: 3-pyridylmethylene, 2-benzothiazolyl, 2-furyl, 2-thienyl, N,N-cyclopentyl, cyclopropyl; X is selected from: O, S; Y is selected from: C, N;

[0013] The specific method for the synthesis of the pyrazole carboxamide derivative 7 of the present invention and the determination of the biological activity is divided into the following steps:

[0014] A. Preparation method of compound 3:

[0015] In a 100 mL single-necked flask, a certain volume of anhydrous ethanol was added. Under an ice bath, the cut 32 mmol Na block was added to the anhydrous ethanol several times, and the mixture was stirred continuously. After the Na block was completely dissolved, 16 mmol of a heterocyclic ketone compound was added, wherein the heterocyclic ketone was selected from 2-acetylthiophene and 2-acetylfuran. The mixture was stirred continuously for 30 minutes under an ice bath, and then 32 mmol of diethyl oxalate was added dropwise. The mixture was reacted overnight at room temperature. After the reaction was completed, the solvent was removed by rotary evaporation under reduced pressure. 50 mL of ethyl acetate was added to the reaction bottle to dissolve the mixture, and the pH was adjusted to 1 with 10% dilute hydrochloric acid, and the pH was adjusted to 7 with a saturated sodium bicarbonate solution. The organic phase was washed with saturated saline, and the layers were separated by extraction. The organic layer solution was dried with anhydrous sodium sulfate, filtered under reduced pressure, and the solvent was removed by rotary evaporation. The mixture was recrystallized with anhydrous ethanol to obtain α,γ-diketone ester 3 with a yield of 95%. The amount of compound 3 prepared and the volume of the reaction container were enlarged or reduced in a corresponding proportion.

[0016] B. Preparation method of compound 4:

[0017] In a dry 100 mL flask, 1.0 mmol of α,γ-diketone ester 3 containing a furan ring or a thiophene ring and 1.0 mmol of a hydrazine compound are added in sequence, wherein the hydrazine compound is selected from: 2-fluorophenylhydrazine, 2,4-dichlorophenylhydrazine, 3-chloro-2-hydrazinepyridine, then, an appropriate volume of anhydrous ethanol solvent is added, the temperature is slowly raised to reflux, and the reaction process is monitored by TLC. After the reaction is completed, the solvent is removed by rotary evaporation under reduced pressure, ethyl acetate is added to dissolve the remaining solid, saturated brine is used for shaking washing, extraction, the organic layer is dried with anhydrous sodium sulfate, filtered under reduced pressure, and the solvent is removed by rotary evaporation. The crude product is purified by column chromatography to obtain a pyrazole carboxylic acid ester compound 4, the eluent is petroleum ether: ethyl acetate 4:1-3:1, and the yield is 84-92%; the amount of compound 4 prepared and the volume of the reaction container are enlarged or reduced in corresponding proportions;

[0018] C. Preparation method of compound 5:

[0019] In a single-necked flask, 1 mmol of ester compound 4 was dissolved in a certain volume of tetrahydrofuran, 2 mmol of 2 mol / L NaOH solution was slowly added dropwise under an ice bath, and the temperature was raised to 50° C. The reaction process was monitored by TLC. After the reaction was completed, the temperature was cooled to room temperature, 10% HCl solution was used to adjust pH=2, and ethyl acetate (50 mL*3) was used for extraction. The upper layer solutions were combined, dried over anhydrous sodium sulfate, filtered under reduced pressure, and the solvent was removed by vacuum rotary evaporation without further purification to obtain pyrazole carboxylic acid compound 5 with a yield of 90-98%. The amount of compound 5 prepared and the volume of the reaction container were enlarged or reduced in a corresponding proportion;

[0020] D. Preparation method of compound 7:

[0021] In a 100 mL single-necked flask, 1 mmol of pyrazole acid derivative 5, 20 mL of dry dichloromethane, and 1 mmol of an amino compound are added in sequence, wherein the amino compound is selected from: 2-aminobenzothiazole, 3-aminomethylpyridine, 2-aminothiophene, 2-aminofuran, piperidine, and cyclopropylamine. Under magnetic stirring, 1 mmol of dicyclohexylcarbodiimide (DCC) and 0.5 mmol of 1-hydroxybenzotriazole (HOBT) are added. The reaction process is monitored by TLC. After the reaction is completed, the mixture is filtered under reduced pressure, washed with saturated brine, extracted and layered, and the organic layer solution is dried with anhydrous sodium sulfate, filtered under reduced pressure, and the solvent is removed by rotary evaporation. The crude product is purified by column chromatography to obtain the target compound 7. The eluent is petroleum ether:ethyl acetate=1:1, and the yield is 80-87%. The amount of compound 7 prepared and the volume of the reaction container are increased or decreased in corresponding proportions.

[0022] E. Determination of the herbicidal activity of the pyrazole carboxamide derivative 7 of the present invention:

[0023] The herbicidal activity of the pyrazole carboxamide derivative 7 of the present invention is tested by the small cup method and the stem and leaf spray method, and the specific steps are as follows: 20 mg of the sample is dissolved in 1 ml of N,N-dimethylformamide to prepare a 20 g / L mother solution, and then the mother solution is diluted to 100 mg / L of the agent using an aqueous solution containing 0.1% Tween 80 emulsifier. Small cup method: 10 weed seeds with uniform germination are selected with tweezers and evenly distributed on a filter paper in a 50 ml small beaker. Each treatment is repeated 3 times, and 1 ml of the reagent solution is sucked with a pipette and slowly dripped onto the filter paper. All treatments are placed in an artificial climate chamber for moisturizing culture, with a temperature of 25±0.5°C, a humidity of 60±5%, a light intensity, and a light cycle of 16:8 for day and night. After 7 days, the root length and stem length of the weeds are measured, and the root inhibition rate and stem inhibition rate of the compound on the weeds are calculated. Stem and leaf spray method: The concentration used is 150 grams of effective content / hectare. In the stem and leaf treatment method, when dicotyledonous weeds grow to the two-leaf stage and monocotyledonous weeds grow to the 3-5-leaf stage, use a walking spray tower to evenly spray the test agent on the weed leaves, and use a solution without adding reagents as a blank control. Each treatment is repeated 3 times, and the treated weeds are cultured in an artificial climate room. After 14 days, the degree of inhibition of the sample on weed growth is investigated by visual inspection. The test plants are species of most typical weeds that actually occur in the fields in my country's agricultural production. Their names are as follows: Digitaria sanguinalis L., Amaranthus retroflexus L.

[0024]

[0025] The beneficial effects of the present invention are: the pyrazolecarboxamide derivative 7 is derivatized and synthesized, and the herbicidal activity of the pyrazolecarboxamide derivative 7 is screened. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 . The herbicidal activity of the pyrazole carboxamide derivative 7 of the present invention against crabgrass (cup method: inhibition rate of 100 μg / ml / %);

[0027] Figure 2 . The herbicidal activity of the pyrazolecarboxamide derivative 7 of the present invention against Amaranthus retroflexus (cup method: inhibition rate / %) at 100 μg / ml.

[0028] The present invention further illustrates the synthesis, biological activity and application of pyrazole carboxamide derivative 7 through specific preparation and biological activity determination examples. The examples are only used to specifically illustrate the present invention but not to limit the present invention. In particular, the biological activity is only an example but not to limit the present invention. The specific implementation method is as follows:

[0029] Example 1: Preparation of Compound 3:

[0030] In a 100 mL single-necked flask, a certain volume of anhydrous ethanol was added. Under an ice bath, the cut 32 mmol Na block was added to the anhydrous ethanol several times, and the mixture was stirred continuously. After the Na block was completely dissolved, 16 mmol of a heterocyclic ketone compound was added, wherein the heterocyclic ketone was selected from: 2-acetylthiophene and 2-acetylfuran. The mixture was stirred continuously for 30 minutes under an ice bath. Then, 32 mmol of diethyl oxalate was added dropwise. The mixture was reacted overnight at room temperature. After the reaction was completed, the solvent was removed by rotary evaporation under reduced pressure. 50 mL of ethyl acetate was added to the reaction bottle to dissolve the mixture. The mixture was adjusted to pH=1 with 10% dilute hydrochloric acid and adjusted to pH=7 with saturated sodium bicarbonate solution. The organic phase was washed with saturated saline solution, and the layers were separated by extraction. The organic layer solution was dried with anhydrous sodium sulfate, filtered under reduced pressure, and the solvent was removed by rotary evaporation. The mixture was recrystallized with anhydrous ethanol to obtain α,γ-diketone ester 3 with a yield of 95%. When X=O, the NMR data were as follows: 1 HNMR (CD3Cl, 400MHz) δ7.67-7.66 (m, 1H, furan-H), 7.33 (d, J = 4.0 Hz, 1H, furan-H), 6.92 (s, 1H, C = CH-H), 6.61-6.60 (m, 1H, furan-H), 4.37 (q, J = 8.0 Hz, 2H, CH2-H), 1.38 (t, J = 8.0 Hz, 3H, CH3-H). The amount of compound 3 prepared and the volume of the reaction container are enlarged or reduced in the corresponding proportion; Example 2: Preparation method of compound 4:

[0031] In a dry 100 mL flask, 1.0 mmol of α,γ-diketoester 3 containing a furan ring or a thiophene ring and 1.0 mmol of a hydrazine compound are added in sequence, wherein the hydrazine compound is selected from: 2-fluorophenylhydrazine, 2,4-dichlorophenylhydrazine, and 3-chloro-2-hydrazinepyridine. Then, an appropriate volume of anhydrous ethanol solvent is added, the temperature is slowly raised to reflux, and the reaction process is monitored by TLC. After the reaction is completed, the solvent is removed by rotary evaporation under reduced pressure, ethyl acetate is added to dissolve the remaining solid, saturated brine is used for shaking washing, extraction, and the organic layer is dried with anhydrous sodium sulfate, filtered under reduced pressure, and the solvent is removed by rotary evaporation. The crude product is purified by column chromatography to obtain a pyrazole carboxylic acid ester compound 4, and the eluent is petroleum ether: ethyl acetate 4:1-3:1, with a yield of 84-92%. When X=O, Y=C, R 1 =2-Fluorine, the NMR data are as follows: 1 HNMR (DMSO-d6, 400MHz) δ7.70-7.66 (m, 2H, furan-H, 1H, Ph-H), 7.50 (t, J = 8.0 Hz, 1H, Ph-H), 7.43 (t, J = 8.0 Hz, 1H, Ph-H), 7.23 (s, 1H, Pyrazol-H), 6.52-6.51 (m, 1H, furan-H), 6.24 (d, J = 4.0 Hz, 1H, Ph-H), 4.32 (q, J = 4.0 Hz, 2H, CH2-H), 1.30 (t, J = 8.0 Hz, 3H, CH3-H). The amount of compound 4 prepared and the volume of the reaction vessel were enlarged or reduced in the corresponding proportion;

[0032] Example 3: Preparation of Compound 5:

[0033] In a single-necked flask, 1 mmol of ester compound 4 was dissolved in a certain volume of tetrahydrofuran, and 2 mmol of 2 mol / L NaOH solution was slowly added dropwise under an ice bath, and the temperature was heated to 50°C. The reaction process was monitored by TLC. After the reaction was completed, the temperature was cooled to room temperature, and pH was adjusted to 2 using 10% HCl solution. Ethyl acetate (50 mL*3) was used for extraction, and the upper layer solutions were combined, dried over anhydrous sodium sulfate, filtered under reduced pressure, and the solvent was removed by vacuum rotary evaporation without further purification to obtain pyrazole carboxylic acid compound 5 with a yield of 90-98%. When X=O, Y=C, R 1 =2-Fluorine, the NMR data are as follows: 1H NMR (400MHz,CDCl3)δ7.59-7.54(m,2H,furan-H,Ph-H),7.43(d,J=1.6Hz,1H,furan-H),7.34(t,J=7.7Hz,1H,Ph-H),7.31–7.29(m,2H,Ph-H,pyrazol-H),6.37(dd,J=3.5,1.8Hz,1H,Ph-H),5.99(d,J=3.5Hz,1H,furan-H). The amount of compound 5 prepared and the volume of the reaction vessel were enlarged or reduced in the corresponding proportion;

[0034] Example 4: Preparation of Compound 7:

[0035] In a 100 mL single-necked flask, 1 mmol of pyrazole acid derivative 5, 20 mL of dry dichloromethane, and 1 mmol of an amino compound are added in sequence, wherein the amino compound is selected from: 2-aminobenzothiazole, 3-aminomethylpyridine, 2-aminothiophene, 2-aminofuran, piperidine, and cyclopropylamine. Under magnetic stirring, 1 mmol of dicyclohexylcarbodiimide (DCC) and 0.5 mmol of 1-hydroxybenzotriazole (HOBT) are added. The reaction process is monitored by TLC. After the reaction is completed, the mixture is filtered under reduced pressure, washed with saturated brine, extracted and layered, and the organic layer solution is dried with anhydrous sodium sulfate, filtered under reduced pressure, and the solvent is removed by rotary evaporation. The crude product is purified by column chromatography to obtain the target compound 7. The eluent is petroleum ether:ethyl acetate = 1:1. The yield is 80-87%. When X = O, Y = C, R 1 =2-fluoro, R 2 = cyclopropyl, the NMR data are as follows: 1 H NMR (400MHz,CDCl3)δ7.55-7.46(m,2H,furan-H,Ph-H),7.37-7.24(m,4H,Ph-H,furan-H),7.20(s,1H,pyrazol-H),6.97(s,1H,NH-H),6.33–6.32(m,1H,furan-H,),5.95(d,J=3.1Hz,1H,Ph-H),2.90-2.88(m,1H,cyclopropane-H),0.83(q,J=6.3Hz,2H,cyclopropane-H),0.65-0.63(m,2H,cyclopropane-H). The amount of compound 7 prepared and the volume of the reaction vessel were enlarged or reduced in the corresponding proportion. The physicochemical parameters and structural parameters of compound 7 are shown in Table 1;

[0036] Example 5: Results of determination of herbicidal activity of pyrazolecarboxamide derivative 7 of the present invention:

[0037] The common weeds tested in the present invention are as follows: Digitaria sanguinalis L. (Ds) and Amaranthus retroflexus L. (Ar). These weeds are very representative and can represent most of the weeds occurring in the field during agricultural production. The herbicidal activity test adopts the small cup method and the stem and leaf treatment method.

[0038] The results of the small cup method are as follows Figure 1 As shown, at 100 μg / ml, most of the pyrazole carboxamide derivatives 7 synthesized by the present invention showed good herbicidal activity against crabgrass and Amaranthus retroflexus. Except for compounds 7a and 7b (root inhibition rates were 57.4% and 55.5%, respectively), most of the compounds showed good herbicidal activity against Ds, with root and stem inhibition rates both above 60%. Among them, the herbicidal inhibition activity of compounds 7h, 7n, 7p, 7r, 7u and 7v against Ds all reached more than 80%, which was significantly better than the herbicidal inhibition activity of the positive control nicosulfuron (Ns) against Ds (root and stem inhibition rates were 79.5% and 78.4%). The herbicidal effect of the compounds on Ar is shown in FIG. Figure 2 As shown, except for compound 71 (root inhibition 59.3%), the root and stem inhibition of the remaining compounds on Ar were all above 60%, showing good herbicidal effects. Among them, compounds 7h, 7i, 7n, 7o, 7p, 7r, 7t, 7u and 7v had root inhibition of Ar greater than 80.8% and stem inhibition greater than 79.1%, and their herbicidal effects on Ar were better than the positive control nicosulfuron (root and stem inhibition rates of 80.3% and 78.4%). More importantly, among all the compounds, compound 7r showed the highest inhibition on both Ds and Ar, with an inhibition rate of about 95%.

[0039] Most of the pyrazolecarboxamide derivatives of the present invention have good herbicidal effect at an effective content of 150 g / hectare by stem and leaf spraying.

[0040] As shown in Table 2, compound 7g has a good herbicidal effect on Ar, with an inhibition rate of 70-89%. Compounds 7h, 7i, 7n, 7o, 7p and 7t have an inhibition rate of 70-89% on Ds and Ar, showing a good herbicidal effect, which is comparable to the positive control nicosulfuron. Compound 7u has an inhibition rate of more than 90% on Ds and an inhibition rate of 70-89% on Ar. Compound 7v has an inhibition rate of more than 90% on Ar and an inhibition rate of 70-89% on Ds. In addition, compound 7r has the best herbicidal effect on Ds and Ar (inhibition rate exceeds 90%), which is consistent with the test results of the small cup method. It can be seen that compound 7r is a promising herbicide lead compound targeting transketolase, and further optimization of its structure is expected to discover highly efficient herbicide candidate compounds.

[0041] Example 6: Use of the pyrazolecarboxamide derivative 7 of the present invention in combination with an agriculturally acceptable adjuvant and any one or more of the following commercial herbicides in the preparation of a compound herbicide:

[0042] The commercial herbicide is selected from nicosulfuron, bensulfuron-methyl, monosulfuron, sulfamethoxam, penoxsulam, alachlor, acetochlor, butachlor, isopropyl metolachlor, fluramide, mesotrione, mesotrione, benzachlor, pendimethalin, atrazine, promethazine, cyanazine, ametryn, metribuzin, nitroprop-butyl, oxyfluorfen, trifluorfen, lactofen, ethoxyfluorfen Ether, pyraclostrobin, isopropylpyraclostrobin, imazapic acid, imazapic acid, imazaquin acid, methoxyfenpyrazone, methyl imazapic acid, pyraclostrobin, pyraclostrobin, bispyribac-butyl, pyrimidine oxadiazine, cyclamate, betaine, betaine, avena cinerea, diamine, barnyardgrass, chlorfenapyr, chlorfenapyr, fluazifop-butyl, fluazifop-butyl, oxazolidinone, quizalofop-butyl, thiazolinone , fluroxypyr, fluthiopyr, fluazifop-butyl, thiamethoxam, dimethoate, paraquat, glyphosate, sedge barnyardgrass, flufenac, fluazifop-butyl, fluthiophene-butyl, flumethoate-butyl, pyrazoline, pyraclostrobin, pyraclostrobin, chlorpyrifos, isoxathiapiprolin, isoxathiapiprolin, bromoxynil, etc.; the total mass percentage of the pyrazolecarboxamide derivative 7 of the present invention in the obtained compound herbicide is 1%-90%, and the ratio of the pyrazolecarboxamide derivative 7 of the present invention to the commercial herbicide is 1%:99% to 99%:1% by mass; the dosage form suitable for the compound herbicide is selected from any one of the following dosage forms: wettable powder, microcapsule suspension, dispersible liquid preparation, dispersible solid preparation, seed treatment emulsion, water emulsion, large granule, microemulsion, oil suspension, water-soluble Granules, soluble concentrates, water-dispersible granules, poisonous valleys, aerosols, slow-release blocks, capsule granules, dry seed powders, emulsifiable concentrates, electrostatic sprays, water-in-oil emulsions, oil-in-water emulsions, smoke cans, fine granules, smoke candles, smoke tubes, smoke sticks, seed treatment suspensions, smoke tablets, smoke pills, gasifiers, drifting powders, ointments, hot mists, solid / liquid mixed preparations, liquid / liquid mixed preparations, cold mists, solid / solid mixed preparations, lacquers, seed treatment liquids, microgranules, oil-dispersible powders, concentrated glues, pouring agents, smears, suspension emulsions, film-forming oils, soluble powders, water-soluble powders for seed treatment, ultra-low volume suspensions, tracking powders, ultra-low volume liquids, steam release agents, and water-dispersible powders for wet seed dressing; the plants suitable for the compound herbicide are selected from rice millet, wheat, barley, oats, corn, sorghum, sweet potato, potato, cassava, soybean, snow pea, broad bean, pea, mung bean, adzuki bean, cotton, sericulture, peanut, rape, sesame, sunflower, beet, sugar cane, coffee, cocoa, ginseng, fritillaria, rubber, coconut, oil palm, sisal, tobacco, tomato, pepper, radish, cucumber, cabbage, celery, mustard tuber, beet, rape, onion, garlic, watermelon, melon, cantaloupe, papaya, apple, citrus, peach, tea, wild vegetables, bamboo shoots, hops, pepper, banana, papaya, orchid, bonsai; the compound herbicide is suitable for controlling weeds selected from: grass weeds: crabgrass, foxtail grass, goosegrass, barnyard grass, kiwi fruit, tiger tail grass, wild oats, teff, golden foxtail grass, long-awned stick grass, and black foxtail grass;Broadleaf weeds: Amaranthus retroflexus, Purslane, Chenopodium album, Artemisia selengensis, Amaranthus chinensis, Xanthium sibiricum, Ambrosia ragweed, Amaranthus, Abutilon, Kochia scoparia, Solanum nigrum, Eryngium spp., Chickweed, Elsholtzia ciliata, Echinops sylvestris, Rumex sylvestris, Cupressus chinensis, Bindweed, Cuscuta chinensis, etc.; Cyperus weeds: Cyperus rotundus, Cyperus heterosexualus, Cyperus watergrass, Salsola salsa, Onion cypress, etc.;

[0043] Table 1 Chemical structure and physicochemical parameters of pyrazole carboxamide derivative 7 of the present invention

[0044]

[0045]

[0046]

[0047] Table 2 Herbicidal activity of pyrazolecarboxamide derivative 7 of the present invention by foliar spraying (inhibition rate / % at 150 g effective content / hectare)

[0048]

[0049] Rating scale for percentage inhibition compared with blank control: ++++≥90%; +++70–89%; ++50–69%; +30–49%; –<30%.

Claims

1. A pyrazole carboxamide derivative, characterized in that It has a general chemical structure as shown in Formula 7: Among them, R 1 Selected from: 2-fluoro, 3-chloro, 2,4-dichloro; R 2 is selected from: 3-pyridylmethylene, 2-benzothiazolyl, 2-furyl, 2-thienyl, N,N-cyclopentyl, cyclopropyl; X is selected from: O, S; Y is selected from: C, N.

2. The method for synthesizing the pyrazolecarboxamide derivative 7 according to claim 1, characterized in that: The reaction equation is as follows: Among them, R 1 Selected from: 2-fluoro, 3-chloro, 2,4-dichloro; R 2 is selected from: 3-pyridylmethylene, 2-benzothiazolyl, 2-furyl, 2-thienyl, N,N-cyclopentyl, cyclopropyl; X is selected from: O, S; Y is selected from: C, N; The synthesis of the pyrazole carboxamide derivatives of the present invention is divided into the following steps: A. Preparation method of compound 3: In a 100 mL single-necked flask, a certain volume of anhydrous ethanol was added. Under an ice bath, the cut 32 mmol Na block was added to the anhydrous ethanol several times, and the mixture was stirred continuously. After the Na block was completely dissolved, 16 mmol of a heterocyclic ketone compound was added, wherein the heterocyclic ketone was selected from 2-acetylthiophene and 2-acetylfuran. The mixture was stirred continuously for 30 minutes under an ice bath, and then 32 mmol of diethyl oxalate was added dropwise. The mixture was reacted overnight at room temperature. After the reaction was completed, the solvent was removed by rotary evaporation under reduced pressure. 50 mL of ethyl acetate was added to the reaction bottle to dissolve the mixture, and the pH was adjusted to 1 with 10% dilute hydrochloric acid, and the pH was adjusted to 7 with a saturated sodium bicarbonate solution. The organic phase was washed with saturated saline, and the layers were separated by extraction. The organic layer solution was dried with anhydrous sodium sulfate, filtered under reduced pressure, and the solvent was removed by rotary evaporation. The mixture was recrystallized with anhydrous ethanol to obtain α,γ-diketone ester 3 with a yield of 95%. The amount of compound 3 prepared and the volume of the reaction container were enlarged or reduced in a corresponding proportion. B. Preparation method of compound 4: In a dry 100 mL flask, 1.0 mmol of α,γ-diketone ester 3 containing a furan ring or a thiophene ring and 1.0 mmol of a hydrazine compound are added in sequence, wherein the hydrazine compound is selected from: 2-fluorophenylhydrazine, 2,4-dichlorophenylhydrazine, 3-chloro-2-hydrazinepyridine, then, an appropriate volume of anhydrous ethanol solvent is added, the temperature is slowly raised to reflux, and the reaction process is monitored by TLC. After the reaction is completed, the solvent is removed by rotary evaporation under reduced pressure, ethyl acetate is added to dissolve the remaining solid, saturated brine is used for shaking washing, extraction, the organic layer is dried with anhydrous sodium sulfate, filtered under reduced pressure, and the solvent is removed by rotary evaporation. The crude product is purified by column chromatography to obtain a pyrazole carboxylic acid ester compound 4, the eluent is petroleum ether: ethyl acetate 4:1-3:1, and the yield is 84-92%; the amount of compound 4 prepared and the volume of the reaction container are enlarged or reduced in corresponding proportions; C. Preparation method of compound 5: In a single-necked flask, 1 mmol of ester compound 4 was dissolved in a certain volume of tetrahydrofuran, 2 mmol of 2 mol / L NaOH solution was slowly added dropwise under an ice bath, and the temperature was raised to 50° C. The reaction process was monitored by TLC. After the reaction was completed, the temperature was cooled to room temperature, 10% HCl solution was used to adjust pH=2, and ethyl acetate (50 mL*3) was used for extraction. The upper layer solutions were combined, dried over anhydrous sodium sulfate, filtered under reduced pressure, and the solvent was removed by vacuum rotary evaporation without further purification to obtain pyrazole carboxylic acid compound 5 with a yield of 90-98%. The amount of compound 5 prepared and the volume of the reaction container were enlarged or reduced in a corresponding proportion; D. Preparation method of compound 7: In a 100 mL single-necked flask, 1 mmol of pyrazole acid derivative 5, 20 mL of dry dichloromethane, and 1 mmol of an amino compound are added in sequence, wherein the amino compound is selected from: 2-aminobenzothiazole, 3-aminomethylpyridine, 2-aminothiophene, 2-aminofuran, piperidine, and cyclopropylamine. Under magnetic stirring, 1 mmol of dicyclohexylcarbodiimide (DCC) and 0.5 mmol of 1-hydroxybenzotriazole (HOBT) are added. The reaction process is monitored by TLC. After the reaction is completed, the mixture is filtered under reduced pressure, washed with saturated brine, extracted and layered, and the organic layer solution is dried with anhydrous sodium sulfate, filtered under reduced pressure, and the solvent is removed by rotary evaporation. The crude product is purified by column chromatography to obtain the target compound 7. The eluent is petroleum ether:ethyl acetate=1:1, and the yield is 80-87%. The amount of compound 7 prepared and the volume of the reaction container are increased or decreased in corresponding proportions.

3. Use of the pyrazolecarboxamide derivative 7 according to claim 1 and an agriculturally acceptable adjuvant in the preparation of a herbicide.

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