Cotton defoliant containing thidiazuron derivative containing fluorine and application thereof

Abstract

The application provides a cotton defoliant containing a fluorine-containing thidiazuron derivative, and belongs to the technical field of plant growth regulators. The structural formula of the fluorine-containing thidiazuron derivative is as follows: wherein R is a benzene ring containing 0-5 fluorine atoms at any position. The defoliant can effectively reduce the use temperature of the defoliant, eliminate the phenomenon of withering but not falling after the defoliant is applied, and ensure the yield and quality of cotton.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of plant growth regulators, in particular to a cotton defoliant containing a fluorine-containing thiabendazole derivative and application thereof. BACKGROUND

[0002] Cotton is one of the most important economic crops in China. In recent years, with the change of labor structure and the increase of labor cost in major cotton-producing areas, mechanical cotton picking has been rapidly promoted. Chemical defoliation is the key to mechanical harvesting of cotton, and poor defoliation effect and high impurity rate will affect the quality of mechanical cotton.

[0003] Thiabendazole is a new type of high-efficiency plant growth regulator with strong cell division activity, which can promote photosynthesis, improve fruit quality and increase fruit storage resistance. When used as a defoliant in cotton planting, it can promote the separation of leaf stalks and stems to form natural leaf fall, which is beneficial to mechanical cotton picking and helps to improve cotton grade. However, when using thiabendazole, there is no obvious defoliation effect when the daily minimum temperature is lower than 12℃, which makes the use of thiabendazole too late. If a product that can defoliate at low temperature is found, the application time of defoliant can be postponed, and more cotton bolls can be picked, increasing cotton yield and quality.

[0004] The purpose of the present application is to design and synthesize new fluorine-containing thiabendazole derivatives, study their properties, and develop new cotton defoliants to increase cotton yield and quality. SUMMARY

[0005] The present application provides a cotton defoliant containing a fluorine-containing thiabendazole derivative and its application, which solves the problem of temperature sensitivity of existing cotton defoliants containing thiabendazole and no obvious defoliation effect when the daily minimum temperature is lower than 12℃.

[0006] To solve the above technical problems, the technical scheme of the present application is as follows:

[0007] A cotton defoliant containing a fluorine-containing thiabendazole derivative, the structure of the fluorine-containing thiabendazole derivative is as follows:

[0008]

[0009] Wherein, R is a benzene ring containing 0-5 fluorine atoms at any position.

[0010] Further comprising abscisic acid, the mass ratio of abscisic acid to fluorine-containing thiabendazole derivative is 1:

[0011] (1-30).

[0012] Wherein, the mass ratio of abscisic acid to fluorine-containing thiabendazole derivative is 1: (1-20).

[0013] The mass ratio of the abscisic acid to the fluorine-containing thidiazuron derivative is 1:(1-10).

[0014] The desiccation agent is in the form of wettable powder, dispersible suspension, solution, or microemulsion.

[0015] The cotton desiccation agent is used in cotton desiccation.

[0016] The synthetic route of the fluorine-containing thidiazuron derivative is shown as follows:

[0017]

[0018] The preparation method of the fluorine-containing thidiazuron derivative comprises the following steps:

[0019] In step one, 5-amino-1,2,3-thiadiazole is used as a raw material to react with di-tert-butyl dicarbonate to obtain an amino-protected intermediate.

[0020] In step two, the reaction intermediate obtained in step one is fluorinated by using a fluorination reagent to obtain a 4-fluorinated intermediate.

[0021] In step three, the amino protection is removed to obtain 5-amino-4-fluoro-1,2,3-thiadiazole.

[0022] In step four, 5-amino-4-fluoro-1,2,3-thiadiazole is reacted with different fluorinated phenyl isocyanates to obtain different fluorine-containing thidiazuron derivatives through filtration.

[0023] In step one, the molar ratio of 5-amino-1,2,3-thiadiazole to di-tert-butyl dicarbonate is 1:1-1.5.

[0024] In step two, the fluorination reagent includes Selectfluor, Accufluor, NFSI, and AgF2 reagent, and the molar ratio of the amino-protected intermediate to the fluorination reagent is 1:1.5-3.

[0025] In step two, the solvent used is tetrahydrofuran, acetonitrile, DMF, acetone, or dichloromethane.

[0026] In step two, the reaction temperature is 25-80°C, and the reaction time is 2-8 h.

[0027] In step three, the reagent used for removing the amino protection includes trimethylchlorosilane, hydrochloric acid, sulfuric acid, nitric acid, hydrobromic acid, and trifluoroacetic acid.

[0028] In step four, the different fluorinated phenyl isocyanate includes phenyl isocyanate, 2-fluorophenyl isocyanate, 3-fluorophenyl isocyanate, 4-fluorophenyl isocyanate, 2,3-difluorophenyl isocyanate, 2,4-difluorophenyl isocyanate, 3,4-difluorophenyl isocyanate, 2,5-difluorophenyl isocyanate, 2,6-difluorophenyl isocyanate, 2,3,4-trifluorophenyl isocyanate, 2,3,5-trifluorophenyl isocyanate, and 3,4,5-trifluorophenyl isocyanate.

[0029] In step four, the molar ratio of 5-amino-4-fluoro-1,2,3-thiadiazole to different fluorinated phenyl isocyanate isocyanate is 1:1.01-1.2.

[0030] In step four, the reaction solvent is dichloromethane, tetrahydrofuran, acetonitrile or DMF.

[0031] In step four, the reaction temperature is 25-50°C, and the reaction time is 1-24h.

[0032] Compared with the prior art, the present application has the following beneficial technical effects:

[0033] 1. The defoliant of the present application can effectively reduce the use temperature of the defoliant, eliminate the phenomenon of withering but not falling after the defoliant is applied, and ensure the yield and quality of cotton.

[0034] 2. The defoliant composition of the present application is reasonable, shows a certain synergistic defoliation effect, effectively reduces the defoliant application temperature, and is beneficial to improving the quality of machine-picked cotton. Meanwhile, the defoliant does not contain herbicide and ethephon components, and reduces soil environmental pollution and residues caused by chemical defoliation. DETAILED DESCRIPTION

[0035] The following examples are provided to better understand the present application and are not limited to the best mode contemplated, do not constitute limitations on the scope of the present application, and any product identical or similar to the present application obtained under the inspiration of the present application or by combining the present application with other prior art features falls within the protection scope of the present application.

[0036] Example 1

[0037] The present embodiment provides a preparation method of a fluorine-containing thidiazuron derivative, which comprises the following steps:

[0038] Step one: synthesis of 1-(4-fluoro-1,2,3-thiadiazol-5-yl)-3-phenylurea (R=H)

[0039] Take 5-amino-1,2,3-thiadiazole 15 g (150 mmol) into a 250 ml round bottom flask, add dichloromethane 150 ml, di-tert-butyl dicarbonate 42.5 ml (180 mmol), triethylamine 42.5 ml (300 mmol), 4-dimethylaminopyridine 1.8 g (15 mmol). The reaction mixture was stirred at 30 °C for 2 h, then concentrated, the residue was purified by silica gel chromatography to obtain N-(thiadiazol-5-yl)carbamic acid tert-butyl ester 18.5 g (92 mmol) as a white solid, yield 62%. 1 H NMR (DMSO, 400 MHz) δ: 11.73 (s, 1H), 8.42 (s, 1H), 1.50 (s, 9H). 13 C NMR δ: 153.71, 153.19, 133.96, 82.33, 27.72.

[0040] Step two: synthesis of N-(4-fluoro-thiadiazol-5-yl)carbamic acid tert-butyl ester

[0041] Take N-(thiadiazol-5-yl)carbamic acid tert-butyl ester 10 g (50 mmol), add anhydrous acetonitrile 100 ml, fluorinating agent Selectfluor 35 g (100 mmol), replace with nitrogen 3 times, heat to 60 °C for 4 h, after the reaction is completed, the reaction solution is concentrated, dissolved in ethyl acetate 150 ml, extracted with water 150 ml, the aqueous phase is extracted with 150 ml of ethyl acetate twice, the organic phase is combined and dried with anhydrous sodium sulfate. Filter and evaporate the organic phase, purify by silica gel chromatography to obtain N-(4-fluoro-thiadiazol-5-yl)carbamic acid tert-butyl ester 3.5 g (16 mmol) as a white solid, yield 31.8%. 1 H NMR (DMSO, 400 MHz) δ: 11.73 (s, 1H), 8.42 (s, 1H), 1.50 (s, 9H). 13 C NMR δ: 158.65, 156.17, 151.99, 132.62, 132.41, 84.55, 27.99.

[0042] Step three: synthesis of 4-fluoro-1,2,3-thiadiazole

[0043] Take N-(4-fluoro-thiadiazol-5-yl)carbamic acid tert-butyl ester 3 g (13.7 mmol), add trifluoroethanol 30 ml, trimethylsilyl chloride 2 ml (15.7 mmol), stir at 25 °C for 1 h, monitor the reaction by TLC until the raw material disappears, evaporate the solvent, purify by silica gel chromatography to obtain 4-fluoro-1,2,3-thiadiazole 1.4 g (11.76 mmol), yield 85.9%. 1 H NMR (DMSO, 400 MHz) δ: 7.16 (s, 2H).13 C NMR δ: 156.73, 154.33, 146.45, 146.21.

[0044] Step four: Synthesis of 1-(4-fluoro-1,2,3-thiadiazol-5-yl)-3-phenylurea

[0045] Weigh 4-fluoro-1,2,3-thiadiazole 2 g (16.8 mmol), dissolved in THF 20 ml, sealed by nitrogen replacement. Weigh phenyl isocyanate 2.1 g (17.65 mmol), diluted with THF 20 ml, slowly added into the reaction bottle with a syringe, replaced with nitrogen for 3 times, stirred at 25℃ for 1 h, filtered the precipitated solid, washed with THF and dried to obtain 1-(4-fluoro-1,2,3-thiadiazol-5-yl)-3-phenylurea 2 g (8.4 mmol), yield 50%. 1 H NMR (DMSO, 400 MHz) δ: 10.82 (s, 1H), 9.18 (s, 1H), 7.49 (d, 2H), 7.35 (d, 2H), 7.08 (t, 1H), 13 C NMR δ: 158.57, 156.12, 151.47, 146.45, 146.21.

[0046] The results of different reaction conditions in step one are shown in Table 1.

[0047] Table 1 Different reaction conditions and reaction results in step one

[0048] Reaction condition 1 Reaction condition 2 Reaction condition 3 Reaction condition 4 Reaction condition 5 5-amino-1,2,3-thiadiazole amount (mmol) 150 150 150 150 150 di-tert-butyl dicarbonate amount (mmol) 180 150 225 195 165 dichloromethane amount (ml) 150 150 150 150 150 triethylamine amount (mmol) 300 300 300 300 300 4-dimethylaminopyridine amount 15 15 15 15 15 temperature (°C) 30 30 30 30 30 time (h) 2 2 2 2 2 yield (%) 62 58 66 63 60

[0049] The results of different reaction conditions in step two are shown in Table 2.

[0050] Table 2 Different reaction conditions and reaction results in step two

[0051]

[0052] The results of different reaction conditions in step three are shown in Table 3.

[0053] Table 3 Different reaction conditions and reaction results in step three

[0054]

[0055]

[0056] The results of different reaction conditions in step four are shown in Table 4.

[0057] Table 4 Different reaction conditions and reaction results in step four

[0058]

[0059] Examples 2-11 were prepared essentially as in Example 1, except as noted in Table 5 below.

[0060] Table 5. Different reaction conditions and reaction results of Examples 2-11

[0061]

[0062]

[0063] Example 12

[0064] The present example provides a cotton defoliant containing a fluorine-containing thidiazuron derivative, which is a defoliant (A) in the form of a wettable powder. The defoliant is prepared by thoroughly mixing a fluorine-containing thidiazuron derivative, abscisic acid, and an adjuvant, and then crushing the mixture with an air flow crusher to obtain a defoliant in the form of a wettable powder with different active ingredient contents. The abscisic acid technical material is commercially available and has a purity of 95%. The fluorine-containing thidiazuron derivative is self-made (Example 1) and has a purity of 99.0%. In the present example, the adjuvant is selected from sodium dodecyl sulfonate, sodium lignosulfonate, and kaolin. It should be noted that the percentages in the formulation recipe of the present example are all mass percentages.

[0065] Defoliant A-1: The mass fraction of the fluorine-containing thidiazuron derivative is 5%, the mass fraction of abscisic acid is 5%, the mass fraction of sodium dodecyl sulfonate is 10%, the mass fraction of sodium lignosulfonate is 10%, and the rest is kaolin.

[0066] Defoliant A-2: The mass fraction of the fluorine-containing thidiazuron derivative is 10%, the mass fraction of abscisic acid is 2%, the mass fraction of sodium dodecyl sulfonate is 10%, the mass fraction of sodium lignosulfonate is 10%, and the rest is kaolin.

[0067] Defoliant A-3: The mass fraction of the fluorine-containing thidiazuron derivative is 15%, the mass fraction of abscisic acid is 0.5%, the mass fraction of sodium dodecyl sulfonate is 10%, the mass fraction of sodium lignosulfonate is 10%, and the rest is kaolin.

[0068] Example 13

[0069] The present example provides a cotton defoliant containing a fluorine-containing thidiazuron derivative, which is a defoliant (B) in the form of an aqueous solution. The defoliant is prepared by thoroughly mixing a fluorine-containing thidiazuron derivative, abscisic acid, and lauryl alcohol polyoxyethylene ether, and then obtaining a defoliant in the form of an aqueous solution. The abscisic acid technical material is commercially available and has a purity of 95%. The fluorine-containing thidiazuron derivative is self-made and has a purity of 99.1% (Example 2). The lauryl alcohol polyoxyethylene ether is commercially available and has a purity of 99%. The percentages in the formulation recipe of the present example are all mass percentages.

[0070] Defoliating agent B-1 : the mass fraction of fluorine-containing tribenornate derivative is 2%, the mass fraction of abscisic acid is 2%, and the rest is lauryl alcohol polyoxyethylene ether.

[0071] Defoliating agent B-2: the mass fraction of fluorine-containing tribenornate derivative is 2%, the mass fraction of abscisic acid is 0.5%, and the rest is lauryl alcohol polyoxyethylene ether.

[0072] Defoliating agent B-3: the mass fraction of fluorine-containing tribenornate derivative is 4%, the mass fraction of abscisic acid is 0.2%, and the rest is lauryl alcohol polyoxyethylene ether.

[0073] Example 14

[0074] The present embodiment provides a cotton defoliating agent containing fluorine-containing tribenornate derivative, which is a defoliating agent (C) in the form of water suspension agent. The preparation method is to mix fluorine-containing tribenornate derivative, abscisic acid and adjuvant, grind after crushing by air flow crusher, then mix with xanthan gum, shear, and obtain the defoliating agent in the form of water suspension agent. The abscisic acid technical is purchased from the market, and the purity is 95%. The fluorine-containing tribenornate derivative is self-made, and the purity is 99.1% (Example 3). The adjuvant is selected from lauryl alcohol, sodium lignosulfonate, ethylene glycol, kaolin, organic silicon defoaming agent and kaolin. The percentages of the formulation in the present embodiment are all mass percentages.

[0075] Defoliating agent C-1 : the mass fraction of fluorine-containing tribenornate derivative is 1%, the mass fraction of abscisic acid is 1%, the mass fraction of lauryl alcohol is 5%, the mass fraction of sodium lignosulfonate is 5%, the mass fraction of ethylene glycol is 6%, the mass fraction of kaolin is 0.5%, the mass fraction of organic silicon defoaming agent is 0.5%, the mass fraction of xanthan gum is 0.2%, and the rest is kaolin.

[0076] Defoliating agent C-2: the mass fraction of fluorine-containing tribenornate derivative is 2%, the mass fraction of abscisic acid is 0.5%, the mass fraction of lauryl alcohol is 2%, the mass fraction of sodium lignosulfonate is 8%, the mass fraction of ethylene glycol is 5%, the mass fraction of kaolin is 0.5%, the mass fraction of organic silicon defoaming agent is 0.5%, the mass fraction of xanthan gum is 1%, and the rest is kaolin.

[0077] Defoliating agent C-3: the mass fraction of fluorine-containing tribenornate derivative is 5%, the mass fraction of abscisic acid is 1%, the mass fraction of lauryl alcohol is 10%, the mass fraction of sodium lignosulfonate is 2%, the mass fraction of ethylene glycol is 4%, the mass fraction of kaolin is 0.6%, the mass fraction of organic silicon defoaming agent is 0.6%, the mass fraction of xanthan gum is 1%, and the rest is kaolin.

[0078] Example 14

[0079] The first batch of defoliation test was carried out in Henan modern agricultural development base in 2024, the local temperature was about 20 DEG C, 11 plots were randomly divided, each plot was 3 meters long, 2 meters wide, and water control, thidiazuron 20 g / mu, defoliant A-1, defoliant A-2, defoliant A-3, defoliant B-1, defoliant B-2, defoliant B-3, defoliant C-1, defoliant C-2, defoliant C-3 were set up.The defoliant dosage was calculated according to thidiazuron derivative 20 g / mu.

[0080] Table 6 defoliation test results of thidiazuron derivative and abscisic acid as cotton defoliant

[0081]

[0082] The second batch of defoliation test was carried out in Henan modern agricultural development base in 2024, the local temperature was about 10 DEG C, 13 plots were randomly divided, each plot was 3 meters long, 2 meters wide, and water control, thidiazuron 20 g / mu, thidiazuron derivative 20 g / mu, abscisic acid 2 g / mu (calculated according to abscisic acid), defoliant A-1, defoliant A-2, defoliant A-3, defoliant B-1, defoliant B-2, defoliant B-3, defoliant C-1, defoliant C-2, defoliant C-3 were set up.The defoliant dosage was calculated according to thidiazuron derivative 20 g / mu.

[0083] Table 7 defoliation test results of thidiazuron derivative and abscisic acid as cotton defoliant

[0084]

[0085]

[0086] Wherein, the thidiazuron derivative and abscisic acid used in the thidiazuron derivative group and the abscisic acid group are the same as in A-1.

[0087] The above data show that the prepared defoliant has better defoliation effect than thidiazuron, and can be used for defoliation before cotton harvesting, and still has good defoliation effect when the temperature is low.

[0088] In summary, the application provides thidiazuron derivative and abscisic acid as cotton defoliant, which has good defoliation effect.The defoliant provided by the application does not contain herbicide and ethephon component, is more safe and environmentally friendly, and has better defoliation effect than thidiazuron.In addition, the defoliant can overcome the influence of low temperature environment on the defoliation effect, delay the use time of the defoliant, make the cotton boll more, and improve the cotton yield.

[0089] The present application is described above in connection with the embodiments, but the present application is not limited to the above-described embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present application.

Claims

1. A cotton defoliant containing a fluoxetine derivative, characterized in that... The structural formula of the fluoro-thidiazuron derivative is as follows: wherein R is a benzene ring containing 0-5 fluorine atoms at any position.

2. The cotton defoliant containing the fluoro-thidiazuron derivative according to claim 1, characterized by: The application further comprises abscisic acid, and the mass ratio of the abscisic acid to the fluoro-thidiazuron derivative is 1:(1-30).

3. The cotton defoliant containing the fluoro-thidiazuron derivative according to claim 2, characterized by: The mass ratio of the abscisic acid to the fluoro-thidiazuron derivative is 1:(1-20).

4. The cotton defoliant containing the thidiazuron derivative according to claim 2, characterized by: The mass ratio of the abscisic acid to the fluoro-thidiazuron derivative is 1:(1-10).

5. The cotton defoliant containing the thidiazuron derivative according to claim 1, characterized by: The dosage form of the defoliant is selected from one of wettable powder, dispersible suspension, solution, and microemulsion.

6. The use of the defoliant of any one of claims 1-5 in cotton defoliation.

Images