Pyridine oxazole sulfosulfone compound as well as preparation method and application thereof

Abstract

The invention discloses a pyridine oxazole sulfosulfone compound as well as a preparation method and application thereof. The structural general formula of the compound is # imgabs0 #, wherein RX is any one or more of-H,-CH3,-OCH3,-NO2,-Br,-Cl,-F,-CN and the like. The pyridinoxazole sulfosulfone compound provided by the invention has excellent herbicidal activity, especially has a remarkable effect on preventing and treating annual and perennial weeds of gramineae, the plant control effect on total grass at least reaches 98.4% and the fresh weight control effect at least reaches 94.1% after the pyridinoxazole sulfosulfone compound is applied for 7 days, and meanwhile, the pyridinoxazole sulfosulfone compound has a good effect on preventing and removing barnyard grass of cyhalofop-butyl and quinclorac, and has a good application prospect. And the composition has little residue to later crops and is also safe to non-target bees. The compound is small in dosage, low in cost and short in residual period, the potential threat of pesticides to the environment is relieved, the synthesis method is simple and economical, the compound can serve as a lead compound, and a new reference is provided for developing novel efficient and low-toxicity herbicides.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis and pesticides, and specifically relates to a pyridine oxazole sulfone compound and a preparation method and application thereof. Background Art

[0002] Herbicides are agents that can kill weeds completely or selectively. The application of chemical herbicides has always been the most direct and effective means of controlling weeds in farmland. However, the irrational application of herbicides can cause environmental pollution, weed resistance, and harm to non-weed organisms, which is not conducive to farmland weed control to ensure food safety and quality. The dosage and cost of chemical herbicides in the existing technology are high, and the cost of prevention and control is relatively high. The development of new target herbicides not only reduces the cost of use, but also may solve the problem of weed resistance and achieve efficient and green production in farmland. Summary of the invention

[0003] One of the purposes of the present invention is to provide a pyridine oxazole sulfone compound with excellent control effect, small herbicide dosage, low cost and simple synthesis process.

[0004] The second object of the present invention is to provide a method for preparing the pyridine oxazole sulfone compound.

[0005] The third object of the present invention is to provide the application of the pyridine oxazole sulfone compound.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a pyridine oxazole sulfone compound, the general structural formula of which is shown in Formula I:

[0008]

[0009] Among them, RX is -H, -CH 3 、-OCH 3 、-NO 2 , -Br, -Cl, -F, -CN, etc., any one or more.

[0010] Preferably, the structural formula of the pyridine oxazole sulfone compound is any one of Formulas II to XII:

[0011]

[0012]

[0013]

[0014]

[0015] The present invention also provides a method for preparing the pyridine oxazole sulfone compound, comprising the following steps:

[0016] S1. Compound 1 is dissolved in a solvent, compound X and an acid binding agent are added, the reaction is heated and stirred, and then extracted, washed, dried, filtered, and rotary evaporated to obtain compound 2;

[0017] S2. Compound 2 is dissolved in an organic solvent, a catalyst is added and heated, and then a hydrogen peroxide solution is added dropwise. After the addition, the temperature is continued to rise until the preset conditions are reached, and the precipitated solid is cooled, filtered, washed with water, and dried to obtain the pyridine oxazole sulfone compound;

[0018] Its synthetic route is as follows:

[0019]

[0020] Furthermore, in step S1, the molar ratio of the compound 1 to the acid binding agent is 1:(1-3); and the solvent is at least one of N,N-dimethylformamide, dimethyl sulfoxide, acetonitrile, acetone, tetrahydrofuran and chloroform.

[0021] The general structural formula of the compound X is:

[0022]

[0023] Among them, RX is -H, -CH 3 、-OCH 3 、-NO 2 , -Br, -Cl, -F, -CN, etc.; the molar ratio of compound X to compound 1 is 1:1.

[0024] Specifically, the acid binding agent is at least one of potassium carbonate, sodium carbonate, potassium bicarbonate, sodium bicarbonate and triethylamine; the reaction conditions of the heating and stirring reaction are: stirring rate of 500-600rpm; heating temperature of 50-60°C, reaction time of 4-8h, and the reaction process is monitored by thin layer chromatography.

[0025] Specifically, after the heating and stirring reaction is completed, dichloromethane is used for extraction, and then brine is used for washing several times, and finally, it is dried with magnesium sulfate, filtered, and the solvent is selectively evaporated to obtain compound 2.

[0026] Furthermore, step S2 is specifically as follows: dissolving compound 2 in DMF, adding sodium tungstate as a catalyst, heating to 45-45°C, then dripping 30% hydrogen peroxide solution at a preset speed, and finally heating to 60-65°C, using thin layer chromatography to monitor the reaction until the raw material point disappears, cooling to room temperature, and then pouring into ice water to precipitate solids, filtering, washing with deionized water several times, and drying to obtain the pyridine oxazole sulfone compound.

[0027] Specifically, the usage amount of the sodium tungstate is 10% to 20% of compound 1; the usage amount of the 30% hydrogen peroxide solution is 10 to 20 times of compound 1.

[0028] The present invention also provides an application of the pyridine oxazole sulfone compound as a herbicidal active substance in inhibiting farmland weeds.

[0029] Furthermore, the farmland weeds include annual weeds and perennial weeds.

[0030] Beneficial effects of the present invention:

[0031] The pyridine oxazolidinone sulfone compound provided by the invention has excellent herbicidal activity, especially has a remarkable effect on preventing and controlling annual and perennial weeds of the Gramineae family, and the plant control effect of the total weeds reaches at least 98.4% 7 days after the application, and the fresh weight control effect reaches at least 94.1%. At the same time, it has a good control effect on barnyard grass resistant to cyhalofop-butyl and quinclorac, and has little residue on later crops and is safe for non-target bees. The compound has a small dosage, low cost, short residual period, reduces the potential threat of pesticides to the environment, and the synthesis method is simple and economical, and can be used as a lead compound to provide a new reference for the development of a new type of herbicide with high efficiency and low toxicity. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is the general structural formula of the pyridine oxazole sulfone compound disclosed in the present invention. DETAILED DESCRIPTION

[0033] The following embodiments of the present invention are described in further detail in conjunction with specific examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0034] Example 1

[0035] This example prepares a pyridine oxazole sulfone compound: 2-(2-methoxypyridin-4-yl)-5-((3-methylbenzyl)sulfone)-1,3,4-oxadiazole (wherein R x 3-CH 3 ), the specific steps are as follows:

[0036] 0.627g (3mmol) of compound 1 was dissolved in 20mL of tetrahydrofuran, 0.555g of compound A (3mmol) was added, and then 0.336g of sodium bicarbonate (4mmol) as an acid binding agent was added, and the mixture was heated to 50°C and stirred for 8h. The reaction progress was monitored by thin layer chromatography. After the reaction was completed, dichloromethane (2*50mL) was added, and the mixture was washed three times with brine, dried over anhydrous magnesium sulfate, filtered, and the solvent was rotary evaporated and dried. Compound 2 was dissolved in DMF (5mL), and catalyst sodium tungstate (0.3mmol, 88mg) was added. The mixture was heated to 45°C, and 30% hydrogen peroxide (5mL) solution was slowly added dropwise. After the addition, the mixture was heated to 65°C. The mixture was monitored by TLC until the raw material point disappeared. The mixture was cooled to room temperature and poured into ice water. Solid precipitated, filtered, washed with water, and dried. The solid weighed 0.801g. The yield was calculated to be 77.3%. The synthetic route is as follows:

[0037]

[0038] The target compound of this example was characterized by nuclear magnetic resonance and high-resolution mass spectrometry, and the results are as follows:

[0039] White solid, 1 H NMR (400 MHz, CDCl 3 , δppm): δ8.30(d,J=3.6Hz,1H,Py-H),7.43(d,J=3.6Hz,1H,Py-H),7.216-7.259(m,4H,Ar-H),7.11(d,H,J=4.4Hz,Py-H),4.50(s,2H,CH 2 ),3.98(s,3H,OCH 3 ),2.43(s,3H,Ar-CH 3 ). 13 C NMR (100 MHz, CDCl 3 )δ165.41,164.83,164.03,148.25,138.65,135.17,133.11,129.85,129.03,128.77,126.21,113.25,107.99,83.88,36.84,21.34.HRMS(ESI)C 16 H 16 N 3 O 4 S[M+H]+:calcd.346.0957,found 346.0958.

[0040] Example 2

[0041] This example prepares a pyridine oxazole sulfone compound: 2-(2-methoxypyridin-4-yl)-5-((2,4-dimethylbenzyl)sulfone)-1,3,4-oxadiazole (wherein R x 2,4-CH 3 ), the specific steps are as follows:

[0042] 0.627g (3mmol) of compound 1 was dissolved in 20mL of dimethyl sulfoxide, 0.594g of compound B (3mmol) was added, and then 0.5g of potassium bicarbonate (5mmol) as an acid binding agent was added, and the mixture was heated to 55°C and stirred for 6h. The reaction progress was monitored by thin layer chromatography. After the reaction was completed, dichloromethane (2*50mL) was added, and the mixture was washed three times with brine, dried over anhydrous magnesium sulfate, filtered, and the solvent was rotary evaporated and dried. Compound 3 was dissolved in DMF (5mL), and catalyst sodium tungstate (0.3mmol, 88mg) was added. The mixture was heated to 45°C, and 30% hydrogen peroxide (5mL) solution was slowly added dropwise. After the addition, the mixture was heated to 65°C. TLC was monitored until the raw material point disappeared, and the mixture was cooled to room temperature and poured into ice water. Solid precipitated, filtered, washed with water, and dried. The solid weighed 0.811g. The yield was calculated to be 75.3%. The synthetic route is as follows:

[0043]

[0044] The target compound of this example was characterized by nuclear magnetic resonance and high-resolution mass spectrometry, and the results are as follows:

[0045] White solid, 1 H NMR (400 MHz, DMSO-d 6 )δ8.40(d,J=4.4Hz,1H,Py-H),7.50(d,J=5.2Hz,1H,Py-H),7.29(d,J=8.9H z,2H,Ar-H),7.04(s,1H,Ar-H),6.96(d,J=7.7Hz,1H,Py-H),4.60(s,2H,CH 2 ),3.94-3.92(m,3H,OCH 3 ),2.37(s,3H,CH 3 ),2.24(s,3H,CH 3 ). 13 C NMR (100 MHz, DMSO-d 6 )δ165.07,164.72,164.05,149.15,138.11,137.17,133.37,131.68,130.96,130.58,127.16,113.84,107.70,84.20,21.08,19.15.HRMS(ESI)C17 H 18 N 3 O 4 S[M+H] + :calcd.360.1180,found 360.1151.

[0046] Example 3

[0047] This example prepares a pyridine oxazole sulfone compound: 2-(2-methoxypyridin-4-yl)-5-((2-chlorobenzyl)sulfone)-1,3,4-oxadiazole (wherein R x For 2-Cl), the specific steps are as follows:

[0048] 0.627g (3mmol) of compound 1 was dissolved in 20mL of dimethyl sulfoxide, 0.616g of compound C (3mmol) was added, and then 0.606g of triethylamine (6mmol) as an acid binding agent was added, and the mixture was heated to 55°C and stirred for 5h. The reaction progress was monitored by thin layer chromatography. After the reaction was completed, dichloromethane (2*50mL) was added, and the mixture was washed three times with brine, dried over anhydrous magnesium sulfate, filtered, and the solvent was rotary evaporated and dried. Compound 4 was dissolved in DMF (5mL), and catalyst sodium tungstate (0.3mmol, 88mg) was added. The mixture was heated to 45°C, and 30% hydrogen peroxide (5mL) solution was slowly added dropwise. After the addition, the mixture was heated to 65°C. The mixture was monitored by TLC until the raw material point disappeared. The mixture was cooled to room temperature and poured into ice water. Solid precipitated, filtered, washed with water, and dried. The solid weighed 0.890g. The yield was calculated to be 81.1%. The synthetic route is as follows:

[0049]

[0050] The target compound of this example was characterized by nuclear magnetic resonance and high-resolution mass spectrometry, and the results are as follows:

[0051] Light yellow solid, δ8.30 (d, J = 2.8 Hz 1H Py-H), 7.63 (d, JJ = 6.4 Hz, 1H, Ar-H), 7.40-7.43 (m, 2H, Py-H), 7.24 (m, 3H, Ar-H), 4.64 (s, 2H, CH 2 ),3.98(s,3H,OCH 3 ). 13 C NMR (151 MHz, CDCl 3 )δ165.31,164.82,164.20,148.27,134.41,133.47,133.04,131.57,129.85,129.78,127.15,113.22,107.98,83.88,34.60.HRMS(ESI)C15 H 13 C1N 3 O 4 S[M+H] + :calcd.366.8411,found 366.8412

[0052] Example 4

[0053] This example prepares a pyridine oxazole sulfone compound: 2-(2-methoxypyridin-4-yl)-5-((3,4-dichlorobenzyl)sulfone)-1,3,4-oxadiazole (wherein R x 3,4-Cl), the specific steps are as follows:

[0054] 0.627g (3mmol) of compound 1 was dissolved in 20mL of N,N-dimethylformamide, 0.702g of compound D (3mmol) was added, and then 0.424g of sodium carbonate (4mmol) as an acid binding agent was added, and the mixture was heated to 55°C and stirred for 7h. The reaction progress was monitored by thin layer chromatography. After the reaction was completed, dichloromethane (2*50mL) was added, and the mixture was washed three times with brine, dried over anhydrous magnesium sulfate, filtered, and the solvent was rotary evaporated and dried. Compound 5 was dissolved in DMF (5mL), and catalyst sodium tungstate (0.3mmol, 88mg) was added. The mixture was heated to 45°C, and 30% hydrogen peroxide (5mL) solution was slowly added dropwise. After the addition, the mixture was heated to 65°C. The raw material point disappeared after TLC monitoring. The mixture was cooled to room temperature and poured into ice water. Solid precipitated, filtered, washed with water, and dried. The solid weighed 0.953g. The yield was calculated to be 79.3%. The synthetic route is as follows:

[0055]

[0056] The target compound of this example was characterized by nuclear magnetic resonance and high-resolution mass spectrometry, and the results are as follows:

[0057] White solid, 1 H NMR (400 MHz, CDCl 3 , δppm): δ8.31(d,J=5.3Hz,1H,Py-H),7.58(s,1H,Py-H),7.43-7.40(m,2H,Ar-H),7.33(d,J=8.3Hz,1H,Ar-H),7.26(s,1H,Py-H),4.47(s,2H,CH 2 ),3.98(s,3H,OCH 3 ). 13 C NMR (100 MHz, CDCl 3, δppm): δ164.85,164.63,164.35,148.33,135.84,132.93,132.49,131.07,130.76,128.57,113.22,108.05,83.92,35.41.HRMS(ESI)C 15 H 12 Cl 2 N 3 O 4 S[M+H] + :calcd.401.0123,found 401.0122.

[0058] Example 5

[0059] This example prepares a pyridine oxazole sulfone compound: 2-(2-methoxypyridin-4-yl)-5-((3-methoxy-4-fluorobenzyl)sulfone)-1,3,4-oxadiazole (wherein R x 3-OCH 3 -4-F), the specific steps are as follows:

[0060] 0.627g (3mmol) of compound 1 was dissolved in 20mL of acetone, 0.657g of compound E (3mmol) was added, and then 0.816g of potassium carbonate (3mmol) as an acid binding agent was added, and the mixture was heated to 60°C and stirred for 4h. The reaction progress was monitored by thin layer chromatography. After the reaction was completed, dichloromethane (2*50mL) was added, and the mixture was washed three times with brine, dried over anhydrous magnesium sulfate, filtered, and the solvent was rotary evaporated and dried. Compound 6 was dissolved in DMF (5mL), and catalyst sodium tungstate (0.3mmol, 88mg) was added. The mixture was heated to 45°C, and 30% hydrogen peroxide (5mL) solution was slowly added dropwise. After the addition, the mixture was heated to 65°C. TLC was monitored until the raw material point disappeared, and the mixture was cooled to room temperature and poured into ice water. Solid precipitated, filtered, washed with water, and dried. The solid weighed 0.861g. The yield was calculated to be 75.7%. The synthetic route is:

[0061]

[0062] The target compound of this example was characterized by nuclear magnetic resonance and high-resolution mass spectrometry, and the results are as follows:

[0063] White solid, 1 H NMR (400 MHz, CDCl 3, δppm): δ8.31(d,J=5.3Hz,1H,Py-H),7.58(s,1H,Py-H),7.43-7.40(m,2H,Ar-H),7.33(d,J=8.3Hz,1H,Ar-H),7.26(s,1H,Py-H),4.47(s,2H,CH 2 ),4.06(s,3H,OCH 3 ),3.98(s,3H,OCH 3 ). 13 CNMR (100MHz, CDCl 3 , δppm): δ164.85,164.63,164.35,148.33,135.84,132.93,132.49,131.07,130.76,128.57,113.22,108.05,84.36,53.92,35.41.HRMS(ESI)C 16 H 15 FN 3 O 5 S[M+H] + :calcd.380.0723,found 380.0722.

[0064] Example 6

[0065] This example prepares a pyridine oxazole sulfone compound: 2-(2-methoxypyridin-4-yl)-5-((2-fluorobenzyl)sulfone)-1,3,4-oxadiazole (wherein R x 2-F), the specific steps are as follows:

[0066] 0.627g (3mmol) of compound 1 was dissolved in 20mL of chloroform, 0.567g of compound F (3mmol) was added, and then 0.909g of triethylamine (9mmol) as an acid binding agent was added, and the mixture was heated to 50°C and stirred for 8h. The reaction progress was monitored by thin layer chromatography. After the reaction was completed, dichloromethane (2*50mL) was added, and the mixture was washed three times with brine, dried over anhydrous magnesium sulfate, filtered, and the solvent was rotary evaporated and dried. Compound 7 was dissolved in DMF (5mL), and catalyst sodium tungstate (0.3mmol, 88mg) was added. The mixture was heated to 45°C, and 30% hydrogen peroxide (5mL) solution was slowly added dropwise. After the addition, the mixture was heated to 65°C. TLC was monitored until the raw material point disappeared, and the mixture was cooled to room temperature and poured into ice water. Solid precipitated, filtered, washed with water, and dried. The solid weighed 0.820g. The yield was calculated to be 78.3%. The synthetic route is as follows:

[0067]

[0068] The target compound of this example was characterized by nuclear magnetic resonance and high-resolution mass spectrometry, and the results are as follows:

[0069] White solid, 1 H NMR (400 MHz, CDCl 3 , δppm): δ8.30(d,J=5.2Hz,1H,Py-H),7.55(t,J=7.7Hz,1H,Py-H),7.43(d,J=5.1Hz,1H ,Py-H),7.28(d,J=17.0Hz,2H,Ar-H),7.10(t,J=18.4,8.4Hz,2H,Ar-H),4.56(s,2H,CH 2 ),3.98(s,3H,OCH 3 ). 13 C NMR (100 MHz, CDCl 3 ,δppm): 13 C NMR(151MHz,Chloroform-d)δ165.15,164.85,164.23,148.27,133.05,131.46,13 0.29,124.39,122.89,115.77,115.63,113.24,108.01,83.90,30.13.HRMS(ESI)C 15 H 13 FN 3 O 4 S[M+H] + :calcd.350.3808,found 350.3806.

[0070] Example 7

[0071] This example prepares a pyridine oxazole sulfone compound: 2-(2-methoxypyridin-4-yl)-5-((3,5-difluorobenzyl)sulfone)-1,3,4-oxadiazole (wherein R x 3,5-F), the specific steps are as follows:

[0072] 0.627g (3mmol) of compound 1 was dissolved in 20mL of dimethyl sulfoxide, 0.621g of compound G (3mmol) was added, and then 0.8g of potassium bicarbonate (8mmol) as an acid binding agent was added, heated to 60°C, stirred for reaction for 5h, and the reaction progress was monitored by thin layer chromatography. After the reaction was completed, dichloromethane (2*50mL) was added, washed three times with brine, dried over anhydrous magnesium sulfate, filtered, the solvent was rotary evaporated, and dried. Compound 8 was dissolved in DMF (5mL), catalyst sodium tungstate (0.3mmol, 88mg) was added, the temperature was raised to 45°C, 30% hydrogen peroxide (5mL) solution was slowly added dropwise, and the temperature was raised to 65°C after addition. TLC was monitored until the raw material point disappeared, cooled to room temperature, poured into ice water, solid precipitated, filtered, washed with water, and dried, weighing 0.882g, and the yield was calculated to be 80.1%. Its synthetic route is:

[0073]

[0074] The target compound of this example was characterized by melting point nuclear magnetic resonance and high resolution mass spectrometry, and the results are as follows:

[0075] White solid, 1 H NMR (400 MHz, CDCl 3 ,δppm):8.30(d,J=5.6Hz,1H,Py-H),7.54(s,1H,Ar-H),7.43(s,1H,Ar-H),7.26(s,1H,Ar-H),6.85(d,J=8.3Hz,2H,Py-H),4.52(s,2H,CH 2 ),3.98(s,3H,OCH 3 ). 13 C NMR (100 MHz, CDCl 3 , δppm): δ164.97,164.85,164.30,162.11,160.26,148.30,132.98,132.37,118.99,113.21,111.68,108.02,104.08,83.90,29.56.HRMS(ESI)C 15 H 12 F 2 N 3 O 4 S[M+H] + :calcd.368.0613,found 368.0612

[0076] Example 8

[0077] This example prepares a pyridine oxazole sulfone compound: 2-(2-methoxypyridin-4-yl)-5-((2-chloro-5-bromobenzyl)sulfone)-1,3,4-oxadiazole (wherein R x The specific steps are as follows:

[0078] 0.627g (3mmol) of compound 1 was dissolved in 20mL of chloroform, 0.852g of compound H (3mmol) was added, and then 0.69g of potassium carbonate (5mmol) as an acid binding agent was added, and the mixture was heated to 60°C and stirred for 4h. The reaction progress was monitored by thin layer chromatography. After the reaction was completed, dichloromethane (2*50mL) was added, and the mixture was washed three times with brine, dried over anhydrous magnesium sulfate, filtered, and the solvent was rotary evaporated and dried. Compound 9 was dissolved in DMF (5mL), and catalyst sodium tungstate (0.3mmol, 88mg) was added. The mixture was heated to 45°C, and 30% hydrogen peroxide (5mL) solution was slowly added dropwise. After the addition, the mixture was heated to 65°C. TLC was monitored until the raw material point disappeared, and the mixture was cooled to room temperature and poured into ice water. Solid precipitated, filtered, washed with water, and dried. The solid weighed 1.08g. The yield was calculated to be 81.0%. The synthetic route is as follows:

[0079]

[0080] The target compound of this example was characterized by nuclear magnetic resonance and high-resolution mass spectrometry, and the results are as follows:

[0081] White solid, 1 H NMR (400 MHz, CDCl 3 , δppm): δ8.31(d,J=5.4Hz,1H,Py-H),7.58(d,J=2.0Hz,1H,Py-H),7.54(d,J=8.2Hz,1H,Ar-H) ,7.41-7.42(m,1H,Ar-H),7.36-7.37(m,1H,Ar-H),7.26(d,J=4.2Hz,1H,Py-H),4.58(s,2H,CH 2 ),3.98(s,3H,OCH 3 ). 13 C NMR (100 MHz, CDCl 3 )δ165.02,164.84,164.34,148.31,135.28,132.96,132.68,132.46,130.37,122.72,113.20,108.02,83.91,33.99.HRMS(ESI)C 15 H 12 BrClN 3 O 4S[M+H] + :calcd.443.7817,found443.7817.

[0082] Example 9

[0083] This example prepares a pyridine oxazole sulfone compound: 2-(2-methoxypyridin-4-yl)-5-((2-cyano-4-chlorobenzyl)sulfone)-1,3,4-oxadiazole (wherein R x The specific steps are as follows:

[0084] 0.627g (3mmol) of compound 1 was dissolved in 20mL of N,N-dimethylformamide, 0.692g of compound I (3mmol) was added, and then 0.90g of potassium bicarbonate (9mmol) as an acid binding agent was added, heated to 50°C, stirred for reaction for 8h, and the reaction progress was monitored by thin layer chromatography. After the reaction was completed, dichloromethane (2*50mL) was added, washed three times with brine, and then dried over anhydrous magnesium sulfate, filtered, the solvent was rotary evaporated, and dried. Compound 10 was dissolved in DMF (5mL), and catalyst sodium tungstate (0.3mmol, 88mg) was added, the temperature was raised to 45°C, and 30% hydrogen peroxide (5mL) solution was slowly added dropwise. After the addition, the temperature was raised to 65°C, and TLC was monitored until the raw material point disappeared. The mixture was cooled to room temperature and poured into ice water. Solid precipitated, filtered, washed with water, and dried. The weight was 0.941g. The yield was calculated to be 80.4%. The synthetic route is:

[0085]

[0086] The target compound of this example was characterized by nuclear magnetic resonance and high-resolution mass spectrometry, and the results are as follows:

[0087] White solid, 1 H NMR (400 MHz, CDCl 3 , δppm): δ8.30(d,J=5.2Hz,1H,Py-H),7.61(d,J=8.3Hz,1H,Py-H),7.42(d,J =4.2Hz,2H,Ar-H),7.25(s,1H,Ar-H),7.20-7.22(m,1H,Py-H),4.59(s,2H,CH 2 ),3.98(s,3H,OCH 3 ). 13 C NMR (100 MHz, CDCl 3)δ165.03,164.83,164.32,148.30,135.09,135.00,132.95,132.40,132 .17,129.68,127.43,116.90,113.20,108.00,83.90,33.92.HRMS(ESI)C 16 H 12 C1N 4 O 4 S[M+H] + :calcd.391.8026,found 390.8025.

[0088] Example 10

[0089] This example prepares a pyridine oxazole sulfone compound: 2-(2-methoxypyridin-4-yl)-5-((3-nitro-4-bromobenzyl)sulfone)-1,3,4-oxadiazole (wherein R x 3-NO 2 -4-Br), the specific steps are as follows:

[0090] 0.627g (3mmol) of compound 1 was dissolved in 20mL of chloroform, 0.885g of compound J (3mmol) was added, and then 0.954g of sodium carbonate (9mmol) as an acid binding agent was added, and the mixture was heated to 60°C and stirred for 5h. The reaction progress was monitored by thin layer chromatography. After the reaction was completed, dichloromethane (2*50mL) was added, and the mixture was washed three times with brine, dried over anhydrous magnesium sulfate, filtered, and the solvent was rotary evaporated and dried. Compound 11 was dissolved in DMF (5mL), and catalyst sodium tungstate (0.3mmol, 88mg) was added. The mixture was heated to 45°C, and 30% hydrogen peroxide (5mL) solution was slowly added dropwise. After the addition, the mixture was heated to 65°C. TLC was monitored until the raw material point disappeared, and the mixture was cooled to room temperature and poured into ice water. Solid precipitated, filtered, washed with water, and dried. The solid weighed 1.13g. The yield was calculated to be 82.7%. The synthetic route is as follows:

[0091]

[0092] The target compound of this example was characterized by nuclear magnetic resonance and high-resolution mass spectrometry, and the results are as follows:

[0093] White solid, 1 H NMR (400 MHz, CDCl 3, δppm): δ8.37(s,1H,Ar-H),8.31(d,J=4.4Hz1H,Ar-H),8.17(d,J=5.6Hz,1H,Py-H),7.87(d ,J=5.2Hz,1H,Ar-H),7.43(d,J=3.6Hz,1H,Py-H),7.26(d,J=4.4Hz,1H,Py-H),4.61(s,2H,CH 2 ),3.99(s,3H,OCH 3 ). 13 C NMR (100 MHz, CDCl 3 )δ164.84,164.45,164.40,148.46,148.34,137.89,135.35,132.85,129.80,124.07,123.22,113.20,108.05,83.93,35.61.HRMS(ESI)C 15 H 12 Bn 4 O 4 S[M+H] + :calcd.456.2653,found456.2655

[0094] Embodiment 11

[0095] This example prepares a pyridine oxazole sulfone compound: 2-(2-methoxypyridin-4-yl)-5-(benzylsulfone)-1,3,4-oxadiazole (wherein R x The specific steps are as follows:

[0096] 0.627g (3mmol) of compound 1 was dissolved in 20mL of dimethyl sulfoxide, 0.513g of compound K (3mmol) was added, and then 0.900g of potassium bicarbonate (9mmol) as an acid binding agent was added, heated to 60°C, stirred for reaction for 4h, and the reaction progress was monitored by thin layer chromatography. After the reaction was completed, dichloromethane (2*50mL) was added, washed three times with brine, and then dried over anhydrous magnesium sulfate, filtered, and the solvent was dried by rotary evaporation. Compound 12 was dissolved in DMF (5mL), and catalyst sodium tungstate (0.3mmol, 88mg) was added, the temperature was raised to 45°C, and 30% hydrogen peroxide (5mL) solution was slowly added dropwise. After the addition, the temperature was raised to 65°C, and TLC was monitored until the raw material point disappeared. The mixture was cooled to room temperature and poured into ice water. Solid precipitated, filtered, washed with water, and dried. The weight was 0.761g, and the yield was calculated to be 76.6%. The synthetic route is:

[0097]

[0098] The target compound of this example was characterized by nuclear magnetic resonance and high-resolution mass spectrometry, and the results are as follows:

[0099] Orange solid, 1 H NMR (400 MHz, CDCl 3 ,δppm): δ8.30(d,J=3.6Hz,1H,Py-H),7.46(d,2H,J=5.2Hz,Ar-H),7.43(d,1H ,J=3.2Hz,Py-H),7.302-7.354(m,3H,Ar-H),7.26(s,H,Py-H),4.53(s,2H,CH 2 ),3.98(s,3H,OCH 3 ). 13 C NMR (100 MHz, CDCl 3 )δ165.31,164.82,164.07,148.26,135.34,133.08,129.18,128.87,128.24,113.24,107.99,83.89,36.82.HRMS(ESI)C 15 H 14 N 3 O 4 S[M+H] + :calcd.332.0802,found 332.0802

[0100] Example 12 Indoor bioassay

[0101] The pyridine oxazole sulfone compounds prepared in Examples 1 to 11 were subjected to indoor toxicity determination tests using the stem and leaf spray method (NY / T 1155.4-2006).

[0102] Test agents: (a) Example 1; (b) Example 2; (c) Example 3; (d) Example 4; (e) Example 5; (f) Example 6; (g) Example 7; (h) Example 8; (i) Example 9; (j) Example 10; (k) Example 11; (l) pure water control.

[0103] Test materials: Echinochloa crusgalli, Amaranthus retroflexus

[0104] After soaking and germination, seeds of barnyard grass and Amaranthus retroflexus were sown in a soil-filled area with a cross-sectional area of ​​0.25m. 220 seeds were sown in plastic pots, and the plants were cultured in the greenhouse until the 2-leaf stage before treatment. The liquid was sprayed with a handheld compression sprayer (3NY-1.2) according to the designed dosage concentration gradient (15g / ha, 30g / ha, 45g / ha, 60g / ha, 75g / ha, 90g / ha). The spray volume was 50mL per treatment, and the soil was kept moist after the treatment. Each treatment was repeated 4 times. The fresh weight of the aboveground part of each treatment was weighed 20 days after the treatment, and the fresh weight control effect (%) of each treatment was calculated according to the following formula:

[0105] E=100×(CT) / C

[0106] Where, E is the fresh weight of the protective effect; C is the fresh weight of the aboveground part of the control; T is the fresh weight of the aboveground part of the treatment.

[0107] The test results are shown in Tables 1 to 2.

[0108] Table 1 Results of indoor toxicity test of pyridine oxazole sulfone compounds against barnyard grass

[0109]

[0110]

[0111] Table 2 Results of indoor toxicity test of pyridine oxazole sulfone compounds against Amaranthus retroflexus

[0112]

[0113] From Tables 1 and 2, it can be seen that the EC values ​​of the pyridine oxazole sulfone compounds obtained in Examples 1 to 11 are 90 The values ​​were all lower than 90 g / ha and lower than 6 g / mu, indicating that the pyridine oxazole sulfone compounds obtained in Examples 1 to 11 had good herbicidal activity against the monocotyledonous weeds barnyard grass and the dicotyledonous weed Amaranthus retroflexus.

[0114] Example 13 Honey bee safety test

[0115] The crop safety test was conducted on the pyridine oxazole sulfone compounds prepared in Examples 1 to 11 using the stem and leaf spray method.

[0116] Test agents: (a) Example 1; (b) Example 2; (c) Example 3; (d) Example 4; (e) Example 5; (f) Example 6; (g) Example 7; (h) Example 8; (i) Example 9; (j) Example 10; (k) Example 11; (l) sugar water control.

[0117] Test material: Italian honey bees.

[0118] Healthy Italian honey bees with uniform weight are usually selected from honey bees. Test substances: Reagents a~l original drugs are prepared into 40000ppm mother solution using acetone, and then diluted with 50% sucrose solution to six concentrations of 50, 100, 200, 400, 800, and 1600ppm. The reaction of the honey bees after ingestion is detected by feeding sugar solutions containing different concentrations of the test substances. Honey bees are usually placed in a feeding cage with 20 honey bees, and the technology is repeated three times. The drug-containing sugar solution is provided as the only food. The experiment is repeated three times for each concentration, and the number of deaths after a period of time (72 hours) is observed. Temperature, humidity and light should be kept stable (such as 25℃±2℃, relative humidity 50%-70%). Avoid interference with bees from other environmental stresses or pollution sources. The experimental results are analyzed using Probit to calculate the dose that can kill half of the bees. The results show that Examples 2, 4, 6, 8, and 10 have LD for Chinese honey bees. 50 The concentration of the median lethal dose (i.e., the dose that can kill half of the bees) is greater than 800 ppm, and the rest are greater than 200 ppm (greater than 200 ppm is low toxicity to bees). The test compounds are all low toxic to non-target bees.

[0119] Example 14 Field Test

[0120] The pyridine oxadiazole sulfone compounds prepared in Examples 1, 3, 5, 7, and 11 were applied to control annual and perennial weeds in corn fields: Examples 1, 3, 5, 7, and 11 were diluted with water and sprayed at 75 g / ha, and the total weed control efficacy was 93.23%, 94.12%, 95.18%, and 97.01% 7 days after the application, and the fresh weight control efficacy was 95.17%, 96.45%, 96.27%, and 97.55%. It can be seen that the pyridine oxadiazole sulfone compounds provided by the present invention have obvious control effects on annual and perennial weeds in corn fields, and the weed control spectrum is further broadened. It not only has the potential to be developed into a herbicide, but also has the advantages of low cost and environmental protection.

[0121] The above embodiments are only used to illustrate the present invention, but not to limit the present invention. Although the present invention is described in detail with reference to the embodiments, it should be understood by those skilled in the art that various combinations, modifications or equivalent replacements of the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention, and should be included in the scope of the claims of the present invention.

Claims

1. A pyridine oxazole sulfone compound, characterized in that: Its general structural formula is shown in Formula I: Wherein, RX is any one or more of -H, -CH3, -OCH3, -NO2, -Br, -Cl, -F, -CN, etc.

2. The pyridine oxazole sulfone compound according to claim 1, characterized in that: The structural formula of the pyridine oxazole sulfone compound is any one of Formulas II to XII:

3. A method for preparing a pyridine oxazole sulfone compound according to any one of claims 1 or 2, characterized in that: The following steps are involved: S1. Compound 1 is dissolved in a solvent, compound X and an acid binding agent are added, the reaction is heated and stirred, and then extracted, washed, dried, filtered, and rotary evaporated to obtain compound 2; S2. Compound 2 is dissolved in an organic solvent, a catalyst is added and heated, and then a hydrogen peroxide solution is added dropwise. After the addition, the temperature is continued to rise until the preset conditions are reached, and the precipitated solid is cooled, filtered, washed with water, and dried to obtain the pyridine oxazole sulfone compound; Its synthetic route is as follows:

4. The preparation method according to claim 3, characterized in that: In step S1, the general structural formula of the compound X is: Wherein, RX is any one or more of -H, -CH3, -OCH3, -NO2, -Br, -Cl, -F, -CN, etc.; the molar ratio of compound X to compound 1 is 1:

1.

5. The preparation method according to claim 3, characterized in that: In step S1, the molar ratio of the compound 1 to the acid binding agent is 1:(1-3); the solvent is at least one of N,N-dimethylformamide, dimethyl sulfoxide, acetonitrile, acetone, tetrahydrofuran and chloroform; and the acid binding agent is at least one of potassium carbonate, sodium carbonate, potassium bicarbonate, sodium bicarbonate and triethylamine.

6. The preparation method according to claim 3, characterized in that: The reaction conditions of the heating and stirring reaction are: a stirring rate of 500-600 rpm; a heating temperature of 50-60° C., a reaction time of 4-8 h, and the reaction process is monitored by thin layer chromatography.

7. The preparation method according to claim 5, characterized in that: After the heating and stirring reaction is completed, dichloromethane is used for extraction, and then brine is used for washing several times. Finally, it is dried with magnesium sulfate, filtered, and the solvent is selectively evaporated to obtain compound 2.

8. The preparation method according to claim 3, characterized in that: Step S2 is specifically as follows: dissolving compound 2 in DMF, adding sodium tungstate as a catalyst, heating to 45-45°C, then dripping 30% hydrogen peroxide solution at a preset speed, finally heating to 60-65°C, monitoring the reaction using thin layer chromatography until the raw material point disappears, cooling to room temperature, then pouring into ice water to precipitate solids, filtering, washing with deionized water several times, and drying to obtain the pyridine oxazole sulfone compound; The usage amount of the sodium tungstate is 10% to 20% of compound 1; the usage amount of the 30% hydrogen peroxide solution is 10 to 20 times of compound 1.

9. Use of the pyridine oxadiazole sulfone compound as claimed in any one of claims 1 or 2 or the pyridine oxadiazole sulfone compound prepared by the preparation method as claimed in any one of claims 3 to 8 as a herbicidal active substance in inhibiting weeds in farmland.

10. The use according to claim 9, characterized in that: The farmland weeds include annual weeds and perennial weeds.

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