2-arylpyridine compounds and their use in weed control

Abstract

This invention relates to the field of chemical pesticide technology, and in particular to a 2-arylpyridine compound and its application in weed control. The 2-arylpyridine compound is compound 1, compound 2, or compound 3. Compounds 1, 2, and 3 can act as non-selective protoporphyrinogen oxidase (PPO) inhibitors, exhibiting excellent herbicidal activity against common annual weeds such as crabgrass, purslane, and cocklebur in non-cultivated land. Particularly noteworthy is that these compounds can achieve broad-spectrum and long-lasting control effects on complex weed communities in non-cultivated land at relatively low application rates, thus possessing promising agricultural application prospects and development value.

Description

Technical Field

[0001] This invention relates to the field of chemical pesticide technology, and in particular to a 2-arylpyridine compound and its application in weed control. Background Technology

[0002] Non-arable land typically refers to areas such as field ridges, ditches, roadsides, woodlands, and industrial and mining sites. In the agricultural ecosystem, these areas serve as both buffer zones and important breeding grounds and sources of weed seed. Weeds in these habitats are diverse and have complex community structures, usually consisting of a mixture of grasses (such as barnyard grass, crabgrass, and goosegrass) and broadleaf weeds (such as purslane, amaranth, and cocklebur). They are characterized by long emergence periods, large populations, and strong regeneration capabilities. If control measures are inadequate, weeds on non-arable land not only affect environmental sanitation and landscape but also continuously supply seed sources to neighboring farmland, exacerbating weed infestations and further increasing the use of chemical herbicides. Therefore, strengthening the control and management of weeds on non-arable land is crucial for reducing the initial weed population in farmland, delaying the development of herbicide resistance, and reducing overall pesticide input.

[0003] Protoporphyrinogen oxidase (PPO) inhibitors are a class of herbicides with a well-defined mechanism of action. They inhibit PPO enzyme activity in plants, interfering with the biosynthesis of chlorophyll and heme, leading to rapid oxidative damage to cell membranes and causing weeds to wither and die within a short period. These herbicides are highly effective, low in toxicity, act rapidly, and are unlikely to induce cross-resistance, making them a current research hotspot in herbicide development. Several benzoxazine PPO inhibitors, such as propyzamide and trifluralin, have been commercialized and are widely used in weed control in crop fields and non-cultivated land.

[0004] However, existing PPO inhibitors still have certain shortcomings in practical applications on non-cultivated land. In terms of duration of action, while varieties such as propyzamide have good rapid-acting properties, their effective period is typically only a few weeks to two months, making it difficult to achieve long-term control of weed communities in non-cultivated land. This often requires secondary applications, increasing labor costs and pesticide input. In terms of herbicide spectrum, these agents are generally more effective against broadleaf weeds than against grassy weeds, but their effectiveness against dominant grassy weeds such as crabgrass and goosegrass in non-cultivated land is relatively weak, failing to meet the needs for full-spectrum control of complex weed communities. These shortcomings, to some extent, restrict the further promotion of PPO inhibitors in long-lasting, broad-spectrum weed control management in non-cultivated land.

[0005] Based on the above situation, developing a novel PPO inhibitor herbicide that combines broad-spectrum, high-efficiency, and long-lasting effects, enabling comprehensive and sustained control of grass and broadleaf weed communities in non-cultivated land at low doses, is a pressing need in this field. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a 2-arylpyridine compound and its application in weed control, thereby resolving the issues of poor residual efficacy of existing herbicides against weeds in non-cultivated land and unsatisfactory efficacy against gramineous weeds.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] This invention provides a 2-arylpyridine compound, wherein the 2-arylpyridine compound is compound 1, compound 2, or compound 3, and has the following structural formula:

[0009] .

[0010] The present invention also provides the application of the 2-arylpyridine compounds described in the above technical solution in weed control.

[0011] Preferably, the grass includes broadleaf weeds and / or grasses.

[0012] Preferably, the broadleaf weeds include fleshy broadleaf weeds and / or erect broadleaf weeds.

[0013] Preferably, the fleshy broadleaf weed includes purslane.

[0014] Preferably, the erect broadleaf weeds include cocklebur.

[0015] Preferably, the grassy weeds include crabgrass.

[0016] Preferably, the amount of the 2-arylpyridine compound used is 90~240 g / ha.

[0017] Preferably, the amount of the 2-arylpyridine compound used is 120~150 g / ha.

[0018] The present invention also provides a herbicide comprising the 2-arylpyridine compound described in the above technical solution and a carrier acceptable in the field of pesticides.

[0019] The beneficial effects of this invention are:

[0020] Compounds 1, 2, and 3 act as non-selective protoporphyrinogen oxidase (PPO) inhibitors, exhibiting excellent herbicidal activity against common annual weeds such as crabgrass, purslane, and cocklebur in non-cultivated land. Particularly noteworthy is that these compounds achieve broad-spectrum and long-lasting control of complex weed communities in non-cultivated land at relatively low application rates, thus demonstrating promising agricultural application prospects and development value. Detailed Implementation

[0021] This invention provides a 2-arylpyridine compound, wherein the 2-arylpyridine compound is compound 1, compound 2, or compound 3, and has the following structural formula:

[0022] .

[0023] This invention also provides the application of the 2-arylpyridine compounds described in the above-mentioned technical solutions in weed control. In this invention, the weeds preferably include broadleaf weeds and / or grass weeds. In this invention, the broadleaf weeds preferably include fleshy broadleaf weeds and / or erect broadleaf weeds. In this invention, the fleshy broadleaf weeds preferably include purslane. In this invention, the erect broadleaf weeds preferably include cocklebur. In this invention, the grass weeds preferably include crabgrass. In this invention, the amount of the 2-arylpyridine compound used is preferably 90-240 g / ha. In this invention, the amount of the 2-arylpyridine compound used is preferably 120-150 g / ha.

[0024] The present invention also provides a herbicide comprising the 2-arylpyridine compound described in the above technical solution and a carrier acceptable in the field of pesticides.

[0025] To further illustrate the present invention, the following detailed description is provided in conjunction with embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0026] Example 1

[0027] Test reagents:

[0028] 10% Compound 1 EC (10 g of Compound 1 technical grade, 10 g of cyclohexanone, 3 g of calcium dodecylbenzenesulfonate, 5 g of agricultural emulsion No. 600, xylene to 100 g, the same below), 10% Compound 2 EC, 10% Compound 3 EC (all of the above are compounds of the present invention, and the synthesis method is referred to CN 117088866B and CN 117800945B); the control agent is: 50% propyzamide WP (commercially available).

[0029] Test subjects:

[0030] The experimental crops were non-arable land, and the target weeds were annual weeds, mainly including crabgrass (Digitaria sanguinalis (L.) Scop.), purslane (Portulaca oleracea L.), and cocklebur (Xanthium strumarium L.).

[0031] Experimental Design:

[0032] The experiment consisted of 14 treatments (each agent had four active ingredient dosage gradients of 90, 120, 150, and 240 g / ha; the positive control agent was administered at a dose of 150 g / ha according to the recommended dosage; and a blank control (CK) was also included). Each treatment was replicated four times in a randomized block design with a plot area of ​​20 m². 2 .

[0033] Table 1 Treatment of test reagents

[0034]

[0035] Solution:

[0036] The experiment consisted of 14 treatments, each replicated 4 times, for a total of 56 plots, each plot being 20 m². 2 (5 m long × 4 m wide), with randomized blocks between cells.

[0037] Application method:

[0038] During the vigorous growth period of weeds, foliar spraying was carried out using a backpack electric sprayer with a water volume of 450 L / ha, and the treatment was carried out once.

[0039] Survey and Calculation Methods

[0040] Fourteen days after application, the number of weeds in each plot was investigated, and the control efficacy per plant was calculated. Twenty-eight days after application, the number of weeds in each plot was investigated, and the fresh weight of the above-ground portion of the weeds was weighed to calculate the control efficacy per plant and the control efficacy per fresh weight. The experimental data were statistically analyzed using DPS software, and the significance of differences was tested using Duncan's new multiple range test (P<0.05).

[0041] Application method:

[0042] The pesticide was applied by foliar spraying using a backpack electric sprayer (fan-shaped nozzle, maximum working pressure of 0.45 MPa) manufactured by Shixia Holdings Co., Ltd., with a water consumption of 450 L / ha, and the pesticide was applied once.

[0043] Survey Methodology:

[0044] The experiment was conducted in accordance with the "Guidelines for Field Efficacy Testing of Pesticides" and the requirements of the test agreement signed with the client.

[0045] Weed control efficacy survey: Two surveys were conducted. Fourteen days after application, four points were randomly selected from each plot, each 0.25 m². 2 The number of weeds was investigated, and the control efficacy per plant was calculated. 28 days after application, four points were randomly selected from each plot, each 0.25 m². 2 Remove all weeds, classify them by fresh weight, and calculate the control efficacy per plant and the control efficacy per fresh weight.

[0046] Calculation method:

[0047] The experiment was conducted according to the requirements of the "Guidelines for Field Efficacy Trials of Pesticides". DPS software was used for statistical analysis of the data, and Duncan's multiple range test was applied to determine the significance of differences (P<0.05). The formulas for calculating the control efficacy per plant and the control efficacy per fresh weight are as follows:

[0048] Table 2 Calculation Formula

[0049]

[0050] Table 3. Plant control efficacy (%) of compounds 1, 2 and 3 against weeds in non-cultivated land — 14 days after application

[0051]

[0052] Note: Different lowercase letters in the same column indicate significant differences between different treatments (P<0.05).

[0053] Field efficacy trials 14 days after application showed that the total herbicide efficacy of the three compounds at a high dose of 240 g / ha was excellent and there was no significant difference between them, but all were significantly better than their respective treatment effects at a low dose of 90 g / ha. Among them, 10% compound 1 EC showed the most outstanding broad-spectrum efficacy at high doses (240 g / ha), achieving the highest total herbicide efficacy (93.49%). It not only demonstrated excellent control of the difficult-to-control grassy weed, barnyardgrass (92.04%), but also achieved thorough or highly effective control of broadleaf weeds, purslane (94.29%) and cocklebur (100.00%), significantly outperforming other compounds in the same series and the control agent. At the same dose, while 10% compounds 2 EC and 3 EC showed good control of purslane, compound 3's control efficacy against cocklebur (68.75%–93.75%) and compounds 2 and 3's control efficacy against barnyardgrass (both below 90%) were insufficient, significantly lower than compound 1. Furthermore, the total herbicide efficacy of the control agent 50% propyzamide WP (150 g / ha) showed no significant difference compared to the treatments of the three compounds at a moderate dose of 150 g / ha.

[0054] Table 4. Plant control efficacy (%) of compounds 1, 2 and 3 against weeds in non-cultivated land — 28 days after application

[0055]

[0056] Note: Different lowercase letters in the same column indicate significant differences between different treatments (P<0.05).

[0057] Field trials 28 days after application showed that 10% compound 1 EC maintained its highest total weed control efficacy (91.17%) at a high dose of 240 g / ha, with both plant control and fresh weight control significantly superior to the control herbicide 50% propyzamide WP, demonstrating good sustained efficacy stability. At a medium dose of 150 g / ha, the compound still achieved a total weed control efficacy of 86.67%, significantly higher than the control herbicide, reflecting high dose utilization. Regarding different weed species, 10% compound 1 EC showed excellent and consistent control effects against the grass weed *Digitaria sanguinalis* and broadleaf weeds *Portulaca oleracea* and *Xanthium sibiricum*. Specifically, against the more difficult-to-control *Digitaria sanguinalis*, the control efficacy at 240 g / ha reached 88.89%, significantly superior to other compounds in the same series and the control herbicide.

[0058] Compounds 2 and 3 in the same series showed certain shortcomings in weed control during the later stages of application. Compound 2 maintained a high efficacy against cocklebur (97.73%), while compound 3, at a low dose of 150 g / ha, showed reduced efficacy against barnyardgrass and cocklebur to 77.51% and 90.91%, respectively, both significantly lower than the control agent. At a low dose of 90 g / ha, the total weed control efficacy of compounds 2 and 3 was only 70.67% and 68.67%, respectively, which are at a low level. These results indicate that the 10% compound 1 EC of this invention is significantly superior to existing agents and its homologues in terms of broad spectrum, efficacy level, and persistence.

[0059] Table 5. Fresh weight control efficacy (%) of compounds 1, 2 and 3 against weeds in non-cultivated land — 28 days after application

[0060]

[0061] Note: Different lowercase letters in the same column indicate significant differences between different treatments (P<0.05).

[0062] The results of the fresh weight efficacy test 28 days after application showed that the 10% compound 1 EC of this invention exhibited outstanding weed control advantages. At a high dose of 240 g / ha, the compound achieved a fresh weight control efficacy of 94.75% against total weeds; at a medium dose of 150 g / ha, its fresh weight control efficacy was 91.67%, significantly higher than the control agent 50% propyzamide WP (87.93%). The 10% compound 1 EC showed particularly outstanding efficacy against the grass weed *Digitaria sanguinalis*, reaching 93.02% at the high dose and 89.88% at the medium dose, both significantly better than compounds in the same series and the control agent, thus compensating to some extent for the weakness of existing PPO inhibitors against grass weeds. Simultaneously, the compound also showed excellent late-stage weed control ability against broadleaf weeds *Portulaca oleracea* and *Xanthium sibiricum*, with fresh weight control efficiencies of 99.14% and 99.26%, respectively, at high doses.

[0063] Compounds 2 and 3 of the same series showed total herbicide fresh weight control efficacy of 89.76% and 89.41% at a high dose of 240 g / ha, respectively. However, at a low dose of 90 g / ha, both efficacy decreased to around 75% (75.86% and 75.12%, respectively), showing a significant difference compared to compound 1. In summary, the 10% compound 1 EC of this invention can achieve long-lasting control of various gramineous and broadleaf weeds in non-cultivated land at relatively low application rates. Its comprehensive herbicidal performance is superior to existing herbicides and their congeners, demonstrating promising application prospects.

[0064] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A 2-arylpyridine compound, characterized in that, The 2-arylpyridine compound is compound 1, compound 2, or compound 3, with the following structural formula: 。 2. The use of the 2-arylpyridine compound of claim 1 in weed control.

3. The application according to claim 2, characterized in that, The grasses include broadleaf weeds and / or grasses.

4. The application according to claim 3, characterized in that, The broadleaf weeds include fleshy broadleaf weeds and / or erect broadleaf weeds.

5. The application according to claim 4, characterized in that, The fleshy broadleaf weeds include purslane.

6. The application according to claim 4, characterized in that, The upright broadleaf weeds include cocklebur.

7. The application according to claim 3, characterized in that, The grassy weeds mentioned include crabgrass.

8. The application according to claim 3, characterized in that, The amount of the 2-arylpyridine compound used is 90~240 g / ha.

9. The application according to claim 3 or 8, characterized in that, The amount of the 2-arylpyridine compound used is 120~150 g / ha.

10. A herbicide, characterized in that, This includes the 2-arylpyridine compounds of claim 1 and carriers acceptable in the pesticide field.

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