CN115197103B - Azo compound or azoxygen compound, salt applicable to agriculture and forestry, their composition, preparation and application thereof - Google Patents

Abstract

The invention discloses an azo compound or an azoxygen compound, salts applicable to agriculture and forestry, a composition of the azo compound or the azoxygen compound, and preparation and application of the azoxygen compound or the azoxygen compound, wherein the general formula of the azoxygen compound is shown as a formula (1), and the general formula of the azoxygen compound is shown as a formula (2):

Description

Azo compounds or azoxy compounds, their salts suitable for use in agriculture and forestry, their compositions, and their preparation and use

Technical Field

The present invention relates to an azo compound or an azoxy compound, its salt suitable for agriculture and forestry, their composition, and their preparation and use.

Background Art

Pine wilt disease, also known as pine wilt disease and pine wilt disease, is a worldwide plant quarantine disease and one of the four major global forest diseases. The disease is caused by pine wilt nematodes, which are highly pathogenic and have a long incubation period. Pine trees can die after 40 days of infection and the entire pine forest can be destroyed in 3-5 years. It is called the "cancer" of pine trees.

Agricultural nematode diseases are plant diseases caused by the invasion and parasitism of crop parasitic nematodes. The normal growth and development of the affected plants may be affected by the invading nematodes absorbing nutrients in the body. The secretions of the nematodes during metabolism can also stimulate the cells and tissues of the host plants, causing plant deformities. The more serious agricultural nematode diseases in China include root knot nematode diseases of various crops such as peanuts, soybean cyst nematode diseases, wheat grain nematode diseases, sweet potato stem nematode diseases, rice stem tip nematode diseases, millet nematode diseases, and citrus semi-piercing nematode diseases. Nematode damage in the production process of crops has seriously affected the yield and quality.

Plant diseases refer to the phenomenon that plants undergo a series of morphological, physiological and biochemical pathological changes under the influence of biological or non-biological factors, which hinder the normal growth and development process and thus affect human economic benefits. Plants suffer physiological dysfunction and tissue structure damage under the influence of pathogens or unsuitable environmental conditions. Plant diseases are antagonistic symbiosis between host plants and pathogens. Their occurrence and spread are the result of the interaction between host plants and pathogens. The large-scale occurrence of diseases of crops and trees often causes serious losses to the national economy and people's lives.

Summary of the invention

The first object of the present invention is an azo compound or an oxidized azo compound, wherein the general formula of the azo compound is as shown in formula (1), and the general formula of the oxidized azo compound is as shown in formula (2):

X and Y are each O, S or NR ³ ;

^R1 is H, _C1 - _C6 alkyl, C2- _C6 alkenyl, C2- _C6 alkynyl, _C3 - _C6 cycloalkyl, _C1 - _C4 alkoxy, _C1 - _C4 alkylamino, _C2 - _C8 dialkylamino, _C3 - _C6 cycloalkylamino, _C2 - _C6 alkoxycarbonyl or _C2 - _C6 alkylcarbonyl; or the above _C2 - _C6 alkoxycarbonyl or _{C2 - C6} alkylcarbonyl is arbitrarily substituted with the following groups: halogen, G, CN, _NO2 , hydroxyl, C1- _C4 alkoxy, _C1 - _C4 haloalkoxy, _C1 - _C4 alkylthio, _C1 - _C4 alkylsulfinyl, _C1 - _C4 alkylsulfonyl, _{C2 -C6 alkoxycarbonyl} , _{C2 - C6} alkylcarbonyl, _C3 -C ₆ trialkylsilyl, or phenyl, phenoxy or a 5- or 6-membered heteroaromatic ring, each ring of the above aromatic ring or heteroaromatic ring is optionally substituted with 1-3 of the following groups: C ₁ -C ₄ alkyl, C ₂ -C ₄ alkenyl, C ₂ -C ₄ alkynyl, C ₃ -C ₆ cycloalkyl, C ₁ -C ₄ haloalkyl, C ₂ -C ₄ haloalkenyl, C ₂ -C ₄ haloalkynyl; C _{3 -C 6} halocycloalkyl; halogen, CN, NO ₂ , C ₁ -C ₄ alkoxy, C ₁ -C ₄ haloalkoxy, C 1 -C 4 alkylthio, C ₁ -C ₄ alkylsulfinyl, C ₁ -C ₄ alkylsulfonyl, C ₁ -C ₄ alkylamino, C _{2 -C 8} dialkylamino, C ₃ -C ₆ cycloalkylamino, C ₃ -C ₆ (alkyl)cycloalkylamino, C ₂ -C _{C 2} -C ₆ alkylcarbonyl, C 2 -C 6 alkoxycarbonyl, C ₂ -C ₆ alkylaminocarbonyl, C ₃ -C ₈ dialkylaminocarbonyl or C ₃ -C ₆ trialkylsilyl, C _{1 -C 4 alkoxy, C 1 -C 4} alkylamino, _{C 2} -C ₈ dialkylamino, C ₃ -C ₆ cycloalkylamino, C ₂ -C ₆ alkoxycarbonyl or C ₂ -C ₆ alkylcarbonyl;

Alternatively, when Y is N, ^R1 and Y together form a ring containing 2-6 carbon atoms or a ring containing 2-6 carbon atoms of nitrogen, sulfur or oxygen atoms, wherein the ring is optionally substituted with 1-4 groups selected from _C1 - _C2 alkyl, halogen, CN, _NO2 and _C1 - _C2 alkoxy;

^R3 is H, _C1 - _C6 alkyl, _C2 - _C6 alkenyl, _C2 - _C6 alkynyl or _C3 - _C6 cycloalkyl, the above groups are arbitrarily substituted with one or more of the following groups: halogen, CN, _NO2 , hydroxyl, _C1 - _C4 alkoxy, _C1 -C4 alkylthio, _C1 - _C4 alkylsulfinyl, _C1 - _C4 alkylsulfonyl, C2- _C4 alkoxycarbonyl, _C1 - _C4 alkylamino, _{C2 -C8 dialkylamino} and C3 _{- C6} cycloalkylamino; or, ^R3 is _C2 - _C6 alkylcarbonyl, _{C2 -C6 alkoxycarbonyl} , _C2 - _C6 alkylaminocarbonyl, _C3 - _C8 dialkylaminocarbonyl; or, ^R3 and ^R1 have the same group;

G is a 5- or 6-membered non-aromatic carbocyclic or heterocyclic ring, said G including 1 or 2 ring members selected from C(=O), SO or S(O) ₂ , said G being substituted with 1 to 4 substituents selected from C ₁ -C ₂ alkyl, halogen, CN, NO ₂ and C ₁ -C ₂ alkoxy;

L is the following group which is unsubstituted or substituted by one or more substituents C: C ₁ -C ₆ alkyl, C ₂ -C ₆ alkenyl, C ₂ -C ₆ alkynyl, C ₃ -C ₆ cycloalkyl, C ₁ -C ₄ alkoxy, C ₁ -C ₄ alkylamino, C ₂ -C ₈ dialkylamino, C ₃ -C ₆ cycloalkylamino, C ₂ -C ₆ alkoxycarbonyl or C ₂ -C ₆ alkylcarbonyl; the substituent C is: halogen, G, CN, NO ₂ , hydroxyl, C ₁ -C ₄ alkoxy, C 1 -C 4 haloalkoxy, _{C 1} -C ₄ alkylthio, C ₁ -C ₄ alkylsulfinyl, C _{1 -C 4} alkylsulfonyl, C ₂ -C ₆ alkoxycarbonyl, C ₂ -C ₆ alkylcarbonyl; or L is the following group which is unsubstituted or substituted by one or more substituents D: C ₃ -C 4 The substituent D is: C ₁ -C ₄ alkyl, C ₂ -C 4 alkenyl, C 2 -C 4 alkynyl, C _{3 -C 6 cycloalkyl} , C ₁ -C ₄ haloalkyl, C ₂ -C ₄ haloalkenyl, C ₂ -C ₄ haloalkynyl, C ₃ -C ₆ halocycloalkyl, halogen, CN, NO ₂ , C ₁ -C ₄ alkoxy, C ₁ -C ₄ haloalkoxy, _{C 1 -C 4 alkylthio, C 1 -C 4 alkylsulfinyl, C 1 -C 4 alkylsulfonyl, C 1 -C 4 alkylamino , C 2 -C 8 dialkylamino , C 3 -C 6 cycloalkylamino} , C ₃ -C ₆ (alkyl ₎ cycloalkylamino, C ₂ -C ₄ alkylcarbonyl, C ₂ -C ₆ alkoxycarbonyl, C _C2 - _C6 alkylaminocarbonyl, C3 _{-C8 dialkylaminocarbonyl ,} C3-C6 trialkylsilyl, _C1 - _C4 alkoxy, _C1 - _C4 alkylamino, _C2 - _C8 dialkylamino, _C3 - _C6 cycloalkylamino, _{C2 -C6 alkoxycarbonyl} or _C2 - _C6 alkylcarbonyl;

Alternatively, L and N=N of the azo or azoxy group together form a ring containing 2-6 carbon atoms and nitrogen, sulfur or oxygen atoms, said ring being optionally substituted with 1-4 groups selected from _C1 - _C2 alkyl, halogen, CN, _NO2 and _C1 - _C2 alkoxy.

Further, L is preferably phenyl or substituted phenyl containing one or more substituents E, wherein the substituents E are: C ₁ -C ₆ alkyl, C ₂ -C ₆ alkenyl, C ₃ -C ₆ alkynyl, C ₃ -C ₆ cycloalkyl, C ₁ -C ₆ haloalkyl, C ₂ -C ₆ haloalkenyl, C ₂ -C ₆ haloalkynyl, C ₃ -C ₆ halocycloalkyl, halogen, CN, NO ₂ , hydroxyl, C ₁ -C ₄ alkoxy, C 1 -C 4 haloalkoxy, C ₁ -C ₄ alkylthio, C ₁ -C ₄ alkylsulfinyl, C ₁ -C ₄ alkylsulfonyl _{, C 1 -C 4 haloalkylthio, C 1 -C 4 haloalkylsulfinyl, C 1 -C 4 haloalkylsulfonyl, C 1 -C 4 alkylamino , C 2 -C 8 dialkylamino , C 3 -C} or the following groups which are unsubstituted or substituted by one or more substituents F: phenyl, benzyl or phenoxy, wherein the substituent F is: C ₁ -C ₄ alkyl, C _{2 -C 4 alkenyl, C 2 -C 4} alkynyl, C ₃ -C ₆ cycloalkyl, C ₁ -C ₄ haloalkyl, C _{2 -C 4} haloalkenyl, C ₂ -C ₄ haloalkynyl, C ₃ -C ₆ halocycloalkyl, halogen, CN, NO ₂ , C ₁ -C ₄ alkoxy, C 1 -C ₄ haloalkoxy _{, C 1 -C 4 alkylthio, C 1 -C 4 alkylsulfinyl, C 1 -C 4 alkylsulfonyl, C 1 -C 4 alkylamino , C 2 -C 8 dialkylamino , C 3} -C ₆ cycloalkylamino, _{C 3} -C ₆ (alkyl)cycloalkylamino, _{C C 2} -C ₄ alkylcarbonyl, C ₂ -C ₆ alkoxycarbonyl, C ₂ -C ₆ alkylaminocarbonyl, C ₃ -C ₈ dialkylaminocarbonyl or C ₃ -C ₆ trialkylsilyl.

The second object of the present invention is to provide a method for preparing an azo compound as shown in formula (1) or an oxidized azo compound as shown in formula (2), the chemical formula of the method is as follows:

The method comprises the following steps:

a. dissolving the compound represented by formula (3) in an organic solvent A at room temperature, adding an oxidizing agent A, and reacting to obtain the azo compound represented by formula (1);

b. Dissolve the azo compound represented by formula (1) in organic solvent B, slowly dropwise add a dichloromethane solution of oxidant B, and heat the reaction at 40-50°C (preferably 40°C) for 1-5h (preferably 2h) to obtain the oxidized azo compound represented by formula (2).

Furthermore, the organic solvent A or organic solvent B is independently selected from dichloromethane, chloroform, carbon tetrachloride, acetonitrile, tetrahydrofuran, 1,4-dioxane, N,N-dimethylbenzamide, toluene, xylene, cyclohexane, n-hexane or ethyl acetate, preferably dichloromethane.

Further, the oxidant A or oxidant B is independently 2-iodobenzoic acid, meta-chloroperbenzoic acid, Dess-Martin periodinane, chromic anhydride, sodium hypochlorite, iodobenzodiacetic acid, hydrogen peroxide, sodium peroxide, manganese dioxide, nitric acid, sulfuric acid, potassium permanganate or potassium dichromate. Preferably, oxidant A is iodobenzodiacetic acid; preferably, oxidant B is meta-chloroperbenzoic acid.

Furthermore, the molar ratio of the oxidant A to the compound represented by formula (3) is 1:1 to 1.5.

The molar ratio of the oxidant B to the azo compound represented by formula (1) is 1:1 to 1.5.

Furthermore, the reactions in step a and step b are monitored by TLC until the reaction is completed.

Furthermore, in the step a, after the reaction is completed, the obtained reaction solution A is post-treated to obtain the azo compound represented by formula (1), and the method for post-treating the reaction solution A is as follows: after the reaction is completed, the reaction solution A is extracted with dichloromethane, washed with saturated sodium carbonate, water, and saturated sodium chloride in sequence, dried, desolventized under reduced pressure, and subjected to column chromatography to obtain the azo compound represented by formula (1).

Furthermore, in the step b, after the reaction is completed, the obtained reaction solution B is post-treated to obtain the azoxy compound shown in formula (2), and the method for post-treating the reaction solution B is as follows: after the reaction is completed, the reaction solution B is extracted with dichloromethane, washed with saturated sodium sulfite and saturated sodium chloride in sequence, dried and desolventized, and subjected to column chromatography to obtain the azoxy compound shown in formula (2).

Further, the azo compound or azoxy compound is a cis-trans isomer, an optical isomer, a diastereoisomer, a racemate or a mixture thereof in any ratio. The azo or azoxy compound of the present invention may exist in one or more stereoisomers. Various stereoisomers include enantiomers, diastereomers, atropisomers and geometric isomers. When a stereoisomer is more abundant relative to other isomers or when separated from other isomers, this stereoisomer can show higher activity and/or present beneficial effects. In addition, skilled technicians also know why to separate, enrich, and/or selectively prepare the stereoisomers. Therefore, the compounds of the present invention can exist in a mixture of stereoisomers, a single stereoisomer, or in an optically active form.

The present invention also provides a salt of an azo compound or an azoxy compound, wherein the salt is a salt suitable for use in agriculture, including a salt added with an inorganic or organic acid, wherein the acid is hydrobromic acid, hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, acetic acid, butyric acid, fumaric acid, lactic acid, maleic acid, malonic acid, oxalic acid, propionic acid, salicylic acid, tartaric acid, 4-toluenesulfonic acid or valeric acid.

The present invention also provides a composition for preventing and controlling agricultural and forestry plant diseases, which contains an azo compound or an azoxy compound and at least one other component selected from a surfactant, a solid diluent and a liquid diluent.

The present invention also provides an application of an azo compound or an oxyazozyme compound, its agroforestry-applicable salt, and a composition thereof in preventing and controlling agroforestry plant diseases.

Further, the application includes preventing and controlling nematode diseases or agricultural nematode diseases, especially pine wood nematode disease, southern root knot nematode disease, pecan dry rot and rice sheath blight.

The beneficial effects of the present invention are:

The present invention provides an azo compound or an azo oxide compound, a salt thereof suitable for use in agriculture and forestry, a composition thereof, and preparation and application thereof. The azo or azo oxide compound, a salt thereof suitable for use in agriculture and forestry, and a composition thereof have excellent effects in preventing and controlling pine wood nematode disease, agricultural nematode disease, and agricultural and forestry plant diseases, and the preparation method of the azo or azo oxide compound of the present invention is simple and easy to operate.

DETAILED DESCRIPTION

In order to make the technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

Example 1

Step 1: Dissolve reactant 4 in acetonitrile, add pyridine (2 eq) dropwise to the above solution, cool to 0°C, slowly add reactant 5 (1.1 eq) dropwise, stir for 15 min and transfer to room temperature, monitor by TLC after 2 h until the reaction is complete. After the reaction is complete, extract with dichloromethane, wash with water, wash with saturated sodium chloride, dry with anhydrous sodium sulfate, desolventize under reduced pressure, and column chromatography to obtain compound 3-1.

The structures of raw material compounds 4 and 5 were changed, and the method of step 1 was used to continue synthesizing compounds 3-2 to 3-14.

Step 2: Under room temperature, compound 3-1 was dissolved in dichloromethane, iodophenyl diacetic acid (1 eq) was added under stirring, and the reaction was continued for 15 min, and monitored by TLC. After the reaction was completed, it was extracted with dichloromethane, washed with saturated sodium carbonate, washed with water, washed with saturated sodium chloride, dried with anhydrous sodium sulfate, desolvated under reduced pressure, and column chromatography was performed to obtain compound 1-1.

Compounds 3-2 to 3-14 were reacted using the method of step 2 to obtain 1-2 to 1-14. The ¹ H NMR data of compounds 1-1 to 1-14 are shown in Table 1:

Table 1 ¹ H NMR data of compounds 1-1 to 1-14

Example 2

Step 1: Dissolve reactant 4 in acetonitrile, add pyridine (2 eq) dropwise to the above solution, cool to 0°C, slowly add reactant 6 (1.1 eq) dropwise, stir for 15 min and transfer to room temperature, monitor by TLC after 2 h until the reaction is complete. After the reaction is complete, extract with dichloromethane, wash with water, wash with saturated sodium chloride, dry with anhydrous sodium sulfate, desolventize under reduced pressure, and column chromatography to obtain compound 3-15.

The structures of raw material compounds 4 and 6 were changed, and the method of step 1 was used to continue synthesizing compounds 3-16 to 3-20.

Step 2: Under room temperature, compound 3-15 was dissolved in dichloromethane, iodophenyl diacetic acid (1 eq) was added under stirring, and the reaction was continued for 15 min, and monitored by TLC. After the reaction was completed, it was extracted with dichloromethane, washed with saturated sodium carbonate, washed with water, washed with saturated sodium chloride, dried with anhydrous sodium sulfate, desolvated under reduced pressure, and column chromatography was performed to obtain compound 1-15.

Compounds 3-16 to 3-20 were reacted using the method of step 2 to obtain 1-16 to 1-20. The ¹ H NMR of compounds 1-15 to 1-20 is shown in Table 2:

Table 2 ¹ H NMR data of compounds 1-15 to 1-20

Example 3

Step 1 and step 2 are the same as in Example 1.

Step 3: Dissolve compound 1-1 in dichloromethane at room temperature, slowly dropwise add m-CPBA (1.35 eq) in dichloromethane under stirring, heat at 40°C for 2 h, and monitor by TLC. After the reaction, extract with dichloromethane, wash with saturated sodium sulfite, wash with saturated sodium chloride, dry with anhydrous sodium sulfate, desolventize under reduced pressure, and perform column chromatography to obtain compound 2-1.

Compounds 1-2 to 1-14 were reacted using the method of step 3 to obtain compounds 2-2 to 2-14. The structures, ¹ H NMR data and ¹³ C NMR data of compounds 2-1 to 2-14 are shown in Table 3:

Table 3 ¹ H NMR data and ¹³ C NMR data of compounds 2-1 to 2-14

Example 4

Step 1 and step 2 are the same as in Example 1.

Step 3: Dissolve compound 1-15 in dichloromethane at room temperature, slowly add m-CPBA (1.35eq) in dichloromethane under stirring, heat at 40°C for 2h, and monitor by TLC. After the reaction, extract with dichloromethane, wash with saturated sodium sulfite, wash with saturated sodium chloride, dry with anhydrous sodium sulfate, desolventize under reduced pressure, and perform column chromatography to obtain compound 2-15.

Compounds 1-15 to 1-20 are reacted using the method of step 3 to obtain compounds 2-15 to 2-20. The structures, ¹ H NMR data and ¹³ C NMR data of compounds 2-15 to 2-20 are shown in Table 4:

Table 4 ¹ H NMR data and ¹³ C NMR data of compounds 2-15 to 2-20

Example 5

Step 1, step 2 and step 3 are the same as in Example 3.

Step 4: Dissolve compound 9 (1.2 eq) and sodium iodide (1.2 eq) in DMF at room temperature and stir for 30 min. Add compound 2-1 (1.0 eq), heat under reflux at 100°C, react overnight, and monitor by TLC. After the reaction, extract with dichloromethane, wash with saturated sodium chloride, dry with anhydrous sodium sulfate, desolventize under reduced pressure, and perform column chromatography to obtain compound 2-21.

When compound 9 is p-methylaniline, compound 2-22 is obtained. The ¹ H NMR data and ¹³ C NMR data of compound 2-22 are shown in Table 5:

Table 5 ¹ H NMR data and ¹³ C NMR data of compound 2-22

Example 6

Step 1 and step 2 are the same as in Example 1.

Step 3: Dissolve compound 9 (1.2 eq) and sodium iodide (1.2 eq) in DMF at room temperature and stir for 30 min. Add compound 1-1 (1.0 eq), heat under reflux at 100°C, react overnight, and monitor by TLC. After the reaction, extract with dichloromethane, wash with saturated sodium chloride, dry with anhydrous sodium sulfate, desolventize under reduced pressure, and perform column chromatography to obtain compound 1-21.

Example 7

Step 1, step 2 and step 3 are the same as in Example 6.

Step 4: Dissolve compound 1-21 in dichloromethane at room temperature, slowly add m-CPBA (1.35 eq) in dichloromethane under stirring, heat at 40°C for 2 h, and monitor by TLC. After the reaction, extract with dichloromethane, wash with saturated sodium sulfite, wash with saturated sodium chloride, dry with anhydrous sodium sulfate, desolventize under reduced pressure, and perform column chromatography to obtain compound 2-21.

According to the preparation methods of Examples 1 to 7 and the common knowledge in the art, some other azo compounds or azoxy azo compound derivatives that can be prepared using different raw materials are listed in Table 6.

Table 6 List of azo compounds or azoxy compounds that can be prepared by the present invention

Example 8

The biological activity test of the azo or azoxy compounds provided by the present invention was carried out to verify the activity against pine wood nematodes, southern root-knot nematodes, pecan dry rot and rice sheath blight:

The 1-1 to 1-14 azo and 2-1 to 2-14 azoxy compounds provided by the present invention are dissolved in dimethyl sulfoxide and a 0.1% Tween-80 aqueous solution, mixed to form a uniform solution, and diluted with water to any desired concentration when used. The test method is as follows:

Pine wood nematode (Bursaphelenchus xylophilus): In a 24-well plate, add 450 μL of sample diluent and 50 μL of nematode suspension to prepare a mixed solution with a final concentration of 50 μg·mL ^-1 , and place in a 25°C incubator for incubation. After 24 h, 48 h, and 72 h, observe the poisoning and death of the nematodes, and calculate the mortality rate and the corrected mortality rate. If the control mortality rate is less than 5%, no correction is required; if the control mortality rate is between 5% and 20%, correction is performed according to formula (2).

Southern root-knot nematode (Meloidogyne incongnita): In a 96-well plate, add 50 μL of sample diluent and 50 μL of nematode suspension to prepare a mixed solution with a final concentration of 40 μg·mL ^-1 . Culture in a 25°C incubator. Observe the nematode poisoning and death after 24 h, 48 h, and 72 h, and calculate the mortality rate and corrected mortality rate.

Pecan dry rot: Add the toxic medium with a final sample concentration of 50 μg mL ^-1 to a 7 cm diameter culture dish, let it stand, inoculate the pecan dry rot pathogen cake (Botryosphaeria dothidea), and culture it in a 25°C incubator. When the blank control mycelium grows to 80% of the culture dish, calculate the diameter of the pecan dry rot mycelium cake of each treatment, and calculate the mycelium inhibition rate according to formula (3).

Rice sheath blight: Add a toxic medium with a final sample concentration of 50 μg mL ^-1 to a 7 cm diameter culture dish, let it stand, inoculate with a rice sheath blight pathogen cake (Thanatephorus cucumeris), and culture in a 25°C incubator. When the blank control mycelium grows to 80% of the culture dish, calculate the diameter of the rice sheath blight cake of each treatment, and calculate the mycelium inhibition rate according to formula (3).

The test results of the azo compounds and azoxy compounds in Examples 1-7 are shown in Table 7:

Table 7 Biological activity test results of some target compounds

The corrected mortality (or mycelium inhibition rate) grades in the table are: Grade A is 100%-90%; Grade B is 90%-70%; Grade C is 70%-50%; Grade D is 50%-0%.

The above-mentioned biological activity test was carried out on the basis of the preliminary test. Some compounds with poor activity were excluded through the preliminary test. The test results of the remaining compounds are shown in Table 7. It can be seen from the test results that at a concentration of 50 μg·mL ^-1 , the oxidized azo compounds showed superior nematicidal activity against pine wood nematodes compared to the azo compounds. Except for compound 2-12, the remaining compounds showed a lethality of more than 90%. In the subsequent southern root-knot nematode activity test, only the oxidized azo compounds were tested. At a concentration of 40 μg·mL ^-1 , except for 2-12, the inhibition rate of the tested compounds against southern root-knot nematodes was also greater than 90%. In the fungicidal activity test, 1-1 was used as a control, and some oxidized azo compounds were selected to carry out antibacterial activity tests on pecan dry rot and rice sheath blight. 2-1, 2-6, 2-7, and 2-11 all produced more than 90% antibacterial activity. In addition, the azo compounds 2-8 and 2-9 also showed more than 90% antibacterial activity against pecan dry rot, while the antibacterial effect of the azo compound 1-1 was poor.

Claims (3)

1. Use of an azo compound or an azoxy compound in preventing and controlling pine wood nematodes, southern root-knot nematodes, pecan dry rot and/or rice sheath blight, characterized in that: (A) The structural formula of the compound for controlling only pine wood nematodes is selected from any one of the following: (B) The structural formula of the compound for simultaneously controlling pine wood nematodes and southern root-knot nematodes is selected from any one of the following: (C) The structural formula of the compound for simultaneously controlling pine wood nematodes and hickory dry rot is as follows: (D) The structural formula of the compound for simultaneously controlling pine wood nematodes, southern root-knot nematodes, pecan dry rot and rice sheath blight is selected from any one of the following: 2. The use of an azo compound or an azo oxide compound according to claim 1 in preventing and controlling pine wood nematodes, southern root-knot nematodes, pecan dry rot and/or rice sheath blight, characterized in that the azo compound or the azo oxide compound is a cis-trans isomer, an optical isomer, a diastereomer or a racemate. 3. The use of an azo compound or an azoxy compound according to claim 1 in controlling pine wood nematodes, southern root-knot nematodes, pecan dry rot and/or rice sheath blight, characterized in that the compound is used in combination with at least one other component selected from a surfactant, a solid diluent and a liquid diluent.