CN106699776A - 1,2,4-triazolothiadiazole thioether derivative and preparation method and application thereof - Google Patents

Abstract

The invention discloses a 1,2,4-triazolothiadiazole thioether derivative and a preparation method and application thereof. The 1,2,4-triazolothiadiazole thioether derivative is a 1,2,4-triazol[3,4-b][1,3,4] thiadiazole thioether derivative, and shows better inhibition performance on pythium ultimum (such as tomato damping-off fungi) at the concentration of 100 mug/mL; the inhibition rate is as high as 100 percent. A bactericide prepared from a compound I-1, a compound I-3 and a compound I-4 obtained by the invention has an obvious inhibition effect on preventing and treating the pythium ultimum. The compound belongs to a novel compound with sterilization activity; the foundation is laid for the research and development of novel pesticides.

Description

A kind of 1,2,4-triazolothiadiazole sulfide derivative and its preparation method and application

technical field

The present invention relates to a 1,2,4-triazolothiadiazole sulfide derivative namely 1,2,4-triazolo[3,4-b][1,3,4]thiadiazole sulfide Derivatives and their preparation methods and applications.

Background technique

Today, 1,2,4-triazole, 1,3,4-thiadiazole and pyridine derivatives often exhibit a broad and diverse range of activities. Some reports indicate that fused heterocycle derivatives have the same important applications as monoheterocycles due to their very valuable biological activities. An effective method by introducing 1,3,4-thiadiazole ring into 1,2,4-triazole ring, and has good activities, such as anticancer activity, anti-SIRT1 activity, anti-inflammatory activity and bactericidal activity Wait. Pyridine-conjugated mono-1,2,4-triazoles or 1,3,4-thiadiazoles are often found in the literature, but the biologically active pyridine-conjugated 1,2,4-triazolo[3,4-b] [1,3,4]thiadiazoles are rarely reported.

Contents of the invention

The object of the present invention is to provide a kind of 1,2,4-triazolothiadiazole sulfide derivatives and its preparation method and application, it synthesizes a series of new compounds by relatively simple method under microwave-assisted synthesis, and Some of these compounds have good bactericidal activity, and explore methods and preparation techniques for the synthesis of new pesticides.

The 1,2,4-triazolothiadiazole sulfide derivative is characterized in that the 1,2,4-triazolothiadiazole sulfide derivative is 3-(4-pyridine base)-[1,2,4]-triazolo[3,4-b][1,3,4]thiadiazole-6-sulfide compounds, the structural formula of which is shown in formula (I):

In formula (I): R is C1～C14 alkyl, benzyl, substituted benzyl, thiazole, substituted thiazole, pyridine or substituted pyridine, the substituent of said substituted benzyl is halogen, methyl or nitrile, and substituted pyridine , Substituents of substituted thiazoles are all halogen.

The 1,2,4-triazolothiadiazole sulfide derivative is characterized in that R is selected from undecyl, 2-methylbenzyl, 3,4-dichlorobenzyl, 3 -chlorobenzyl, 4-bromobenzyl, 4-chlorobenzyl, 4-cyanobenzyl, 2-chlorothiazole, 6-chloropyridine, 2-chlorobenzyl.

The preparation method of the 1,2,4-triazolothiadiazole sulfide derivative is characterized in that it comprises the following steps:

1) Mix isonicotinic acid, sulfuric acid and anhydrous methanol, heat and reflux reaction, generate isonicotinic acid methyl ester shown in formula (II), the ratio of the amount of isonicotinic acid, sulfuric acid and anhydrous methanol is: 1:1～2:1～2, preferably 1:1.2:1.2;

2) The isonicotinic acid methyl ester obtained in step 1) is refluxed with hydrazine hydrate with a mass concentration of 80%. After the reaction is completed, the reaction solution is cooled to room temperature, filtered, washed with glacial ethyl acetate, and dried to obtain the formula (Ⅲ ) for isoniazid, the ratio of the amount of isoniazid methyl ester to hydrazine hydrate is 1:2.5 to 4.0, preferably 1:3.5;

3) Isoniazid (10mmol) of formula (Ⅲ), carbon disulfide (12mmol) and potassium hydroxide (12mmol) were mixed and refluxed, and the solvent was spin-dried after the reaction to obtain 4-pyridinedithioacid shown in formula (Ⅳ). Potassium salt of hydrazone;

4) The potassium salt of 4-pyridine dithioacylhydrazone obtained in step 3) was reacted with hydrazine hydrate under reflux for 5 hours, diluted with water after the reaction was completed, acidified with dilute hydrochloric acid, filtered, washed three times with water, and dried to obtain the formula (Ⅴ ) represented by 4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazole-3-mercapto;

5) Dissolve the 4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazole-3-mercapto and carbon disulfide obtained in step 4) in organic solvent A, and then add 2 drops of three Ethylamine, heated to reflux, refluxed and stirred overnight, after the reaction was completed, the mixed solution was poured into crushed ice, acidified with dilute hydrochloric acid to a pH value of 1, precipitated and filtered, and dried to obtain 3-(pyridine -4-yl)-[1,2,4]triazol[3,4-b][1,3,4]thiadiazole-6-mercapto, 2-5 drops of triethylamine added in the present invention;

6) Combine the 3-(pyridin-4-yl)-[1,2,4]triazol[3,4-b][1,3,4]thiadiazole-6-mercapto group obtained in step 5) with RCH ₂ Cl, organic solvent B and inorganic base B are mixed and added into a pressure bottle to assist the reaction with microwaves. After the reaction, the reaction solution is cooled to room temperature, precipitated in an ice bath, filtered, and the filtrate is recrystallized with a recrystallization solvent to obtain the target product such as 3-(4-pyridyl)-[1,2,4]-triazolo[3,4-b][1,3,4]thiadiazole-6-sulfides represented by formula (I) Compound, R in RCH ₂ Cl is a benzene ring or a substituted benzene ring, pyridine or a substituted pyridine, thiazole or a substituted thiazole, and the substituent is a halogen, methyl or nitrile group;

The structural formula of each compound is as follows:

The preparation method of the 1,2,4-triazolothiadiazole sulfide derivative is characterized in that the ratio of the amount of isoniazid, carbon disulfide and inorganic base A in step 3) is 1:1 ~2:1~2, preferably 1:1.2:1.2; the inorganic base A is one or more mixtures of potassium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide or sodium hydride, preferably hydrogen Potassium oxide.

The preparation method of the described 1,2,4-triazolothiadiazole sulfide derivative is characterized in that the potassium salt of 4-pyridine dithioacylhydrazone and the amount of hydrazine hydrate in step 4) The ratio is: 1:1～2, preferably 1:1.5; the amount of water is 1～10ml/mmol, preferably 5ml/mmol, based on the amount of the potassium salt of 4-pyridine dithioacylhydrazone. The amount of the aqueous solution of hydrazine hydrate is calculated by the amount of hydrazine hydrate.

The preparation method of the 1,2,4-triazolothiadiazole sulfide derivative is characterized in that 4-amino-5-(pyridin-4-yl)-4H-1,2 in step 5) , The ratio of the amount of 4-triazole-3-mercapto to carbon disulfide is: 1:1～3, preferably 1:2.4; the organic solvent A is one or more of methanol, ethanol, DMF and pyridine A mixture, preferably pyridine, the amount of organic solvent A is 1 to 10ml based on the amount of 4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazole-3-mercapto /mmol, preferably 4ml/mmol.

The preparation method of the 1,2,4-triazolothiadiazole sulfide derivative is characterized in that the recrystallization solvent in step 6) is one or more of petroleum ether, methanol, n-hexane or ethanol Kind, preferably ethanol; Organic solvent B is one or more mixtures in methanol, ethanol, DMF and pyridine, is preferably DMF, and the volume consumption of organic solvent B is 3-(pyridin-4-yl)-[1, The amount of 2,4]triazol[3,4-b][1,3,4]thiadiazole-6-mercapto is 3-9ml/mmol, preferably 5ml/mmol; the inorganic base B is carbonic acid Potassium, sodium bicarbonate, sodium hydroxide, potassium hydroxide or a mixture of one or more of sodium hydride, preferably sodium hydroxide; 3-(pyridin-4-yl)-[1,2,4]triazole The ratio of [3,4-b][1,3,4]thiadiazole-6-mercapto to RCH ₂ Cl is 1:1-1.5, preferably 1:1.1.

The preparation method of the 1,2,4-triazolothiadiazole sulfide derivative is characterized in that the microwave-assisted conditions in step 6) are: microwave irradiation at 150W, 90°C, and 200psi for 15 minutes.

The application of the 1,2,4-triazolothiadiazole sulfide derivatives in the preparation of fungicides.

In the application, the fungicide is a fungicide for preventing and treating Pythium ultimate, Phytophthora infestans, Corynespora, Botrytis cinerea and Rhizoctonia solani, 1,2,4-triazolothiadiazole sulfide The concentration of the derivative in the fungicide is 100ppm.

Compared with the prior art, the beneficial effects of the present invention are mainly reflected in: the present invention provides a 3-(4-pyridyl)-[1,2,4]-triazolo[3,4-b][ 1,3,4] Thiadiazole-6-sulfide derivatives and their preparation methods and applications in the preparation of fungicides, the compound of the present invention is effective against ultimate Pythium (such as tomato damping-off pathogen) at a concentration of 100 μg/mL Showed better inhibition, the inhibition rate is as high as 100%, and the fungicides obtained as the compound I-1, compound I-3 and compound I-4 obtained by the present invention have obvious inhibitory effect on the prevention and treatment of Pythium ultima. The compound described in the invention is a new compound with bactericidal activity, which provides a basis for the research and development of new pesticides.

Reaction equation of the present invention is as follows:

detailed description

The present invention is further described below in conjunction with specific embodiment, but protection scope of the present invention is not limited thereto:

Example 1

(1) Synthesis of ethyl isonicotinate formula (Ⅱ):

Add isonicotinic acid (0.1mol), sulfuric acid (0.12mol) and anhydrous methanol (0.12mol) into a 150ml single-necked flask, heat to reflux for reaction, extract after the reaction, spin off the solvent, wash and dry to obtain the formula ( Ⅱ) 12.08g of isonicotinic acid methyl ester, the yield is 80%.

(2) Synthesis of isoniazid formula (Ⅲ):

Formula (II) (1.37g, 10mmol) and mass concentration 80% hydrazine hydrate aqueous solution (2mL, 35mmol) were heated to reflux for 6h, cooled to room temperature, filtered, the filter cake was washed with glacial ethyl acetate, and dried to obtain the formula (III) Isoniazid, yield (1.0 g, 73%).

(3) Synthesis of 4-pyridine dithioacylhydrazone potassium salt formula (Ⅳ):

Formula (Ⅲ) isoniazid (10mmol), carbon disulfide (12mmol) and potassium hydroxide (12mmol) mixed reflux reaction, spin dry solvent after reaction and obtain the potassium of 4-pyridine dithioacylhydrazone shown in formula (Ⅳ) Salt.

(4) Synthesis of 4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazole-3-mercapto formula (Ⅴ):

Mix (Ⅳ) (10mmol) and hydrazine hydrate (15mmol) prepared above, heat and reflux for 5h, add 50ml of water to the reaction solution after the reaction, acidify with dilute hydrochloric acid, precipitate, filter, and wash the filter cake with water ( 10ml*3), and dried to obtain a white solid (Ⅴ).

(5) Synthesis of 3-(pyridin-4-yl)-[1,2,4]triazol[3,4-b][1,3,4]thiadiazole-6-mercapto formula (Ⅵ):

Add (Ⅴ) (5 mmol) prepared above, carbon disulfide (12 mmol) and a few drops of triethylamine into 20 ml of pyridine, heat to reflux, and stir overnight. Then the mixture was poured into 100 g of crushed ice, acidified with hydrochloric acid to pH = 1, precipitated, filtered and recrystallized to obtain formula (VI), with a yield of 35%.

(6) synthesis of target compound formula (I):

DMF (5mL), formula (VI) (step (5) method synthesis 0.25g, 1mmol), 2-methyl benzyl chloride (1.1mmol) and NaOH (0.05g, 1.2mmol) were added in the CEM pressure tank, then microwave The synthesizer works under the conditions of (150W, 90°C, 200psi, 15minutes), and the microwave instrument cools it to room temperature through compressed air after completion. The mixture was then poured (40 mL) into crushed ice to form a precipitate which was filtered. The crude product (filtrate) was recrystallized from ethanol to obtain 6-((2-methylbenzyl chloride) mercapto)-3-(pyridin-4-yl)-[1,2 ,4] Triazol[3,4-b][1,3,4]thiadiazole. Yield 57.8%.

(I-1)

6-((2-methylbenzyl chloride)mercapto)-3-(pyridin-4-yl)-[1,2,4]triazol[3,4-b][1,3,4]thiadiazole mp130-133℃, Yield 57.8%, ¹ H NMR (CDCl ₃ , 500MHz), δ: 8.71 (d, J＝6.2Hz, 2H, py-H), 7.99 (d, J＝6.1Hz, 2H, py- H),7.27-7.20(m,2H,Ar-H),7.11-7.01(m,2H,Ar-H),4.19(s,2H,SCH ₂ -),2.43(s,3H,-CH ₃ ) ; ESI-MS: 360[M+H] ⁺ ; Elemental anal. For C ₁₆ H ₁₃ N ₅ S ₂ (%), calculated: C, 56.62; H, 3.86; N, 20.63; found: C, 56.77; H ,3.98; N,20.65.

Example 2

The 2-methylbenzyl chloride in step (6) of Example 1 was replaced by 1.1 mmol of CH ₃ (CH ₂ ) ₁₀ Cl, and other operations were the same as in Example 1 to obtain 3-(pyrazol-4-yl)-6 -(Undecylmercapto)-[1,2,4]triazol[3,4-b][1,3,4]thiadiazole (I-2), the yield is 102.3%.

(Ⅰ-2)

3-(pyrazol-4-yl)-6-(undecylmercapto)-[1,2,4]triazol[3,4-b][1,3,4]thiadiazole Whitesolid,mp120 -122℃, yield 102.3%, ¹ H NMR (CDCl ₃ , 500MHz), δ: 8.74(d, J=6.1Hz, 2H, Py-H), 8.10(d, J=6.1Hz, 2H, py-H ), 4.76(s, 2H, SCH ₂ -), 1.26-1.45(m, 18H, CH ₂ ), 0.89(t, 3H, CH ₃ ); ESI-MS: 390[M+H] ⁺ ; Elemental anal. For C ₁₉ H ₂₇ N ₅ S ₂ (%), calculated: C, 58.58; H, 6.99; N, 17.98; found: C, 58.65; H, 7.12; N, 17.88.

Example 3

The 2-methyl benzyl chloride in step (6) of Example 1 is replaced with 1.1 mmol of 3,4-dichloro benzyl, and other operations are the same as in Example 1 to obtain 6-((3,4-dichloro benzyl )mercapto)-3-(pyridin-4-yl)-[1,2,4]triazol[3,4-b][1,3,4]thiadiazole (Ⅰ-3), yield 61.1% .

(Ⅰ-3)

6-((3,4-dichlorobenzyl)mercapto)-3-(pyridin-4-yl)-[1,2,4]triazol[3,4-b][1,3,4]thiazo Oxadiazole White solid,yield 61.1%, ¹ H NMR(CDCl ₃ ,500MHz),δ:8.76(d,2H,py-H),8.06(d,2H,py-H),7.52(d,1H,Ar -H),7.40(d,1H,Ar-H), 7.29-7.28(m,1H,Ar-H),4.46(s,2H,SCH ₂ -); ESI-MS:326[M+H] ⁺ ; Elemental anal. For C ₁₅ H ₉ Cl ₂ N ₅ S ₂ (%), calculated: C, 45.69; H, 2.30; N, 17.76; found: C, 45.45; H, 2.28; N, 17.65.

Example 4

The 2-methyl benzyl chloride in step (6) of Example 1 is replaced with 1.1 mmol of 3-chloro benzyl chloride, and other operations are the same as in Example 1 to obtain 6-((3-chlorobenzyl) mercapto)-3- (Pyridin-4-yl)-[1,2,4]triazol[3,4-b][1,3,4]thiadiazole (I-4), yield 58.5%.

(Ⅰ-4)

6-((3-chlorobenzyl)mercapto)-3-(pyridin-4-yl)-[1,2,4]triazol[3,4-b][1,3,4]thiadiazole Yellow solid, yield 58.5%, ¹ H NMR (CDCl ₃ , 500MHz), δ: 8.74 (d, J=5.9Hz, 2H, py-H), 8.05 (d, J=6.0Hz, 2H, py-H), 7.35(s,1H,Ar-H),7.32-7.28(m,1H,Ar-H),7.25(d,J=6.3Hz,2H,Ar-H),4.42(s,2H,SCH ₂ -) ; ESI-MS: 326[M+H] ⁺ ; Elemental anal. For C ₁₅ H ₁₀ ClN ₅ S ₂ (%), calculated: C, 50.07; H, 2.80; N, 19.46; found: C, 49.89; H ,2.88; N,19.65.

Example 5

The 2-methylbenzyl chloride in the step (6) of Example 1 is replaced with 1.1 mmol of 4-bromobenzyl chloride, and other operations are the same as in Example 1 to obtain 6-((4-bromobenzyl) mercapto)-3- (Pyridin-4-yl)-[1,2,4]triazol[3,4-b][1,3,4]thiadiazole (I-5), yield 79.4%.

(I-5)

6-((4-bromobenzyl)mercapto)-3-(pyridin-4-yl)-[1,2,4]triazol[3,4-b][1,3,4]thiadiazole Yellow solid, yield 79.4%, ¹ H NMR (CDCl ₃ , 500MHz), δ: 8.75 (d, J=6.2Hz, 2H, py-H), 8.05 (d, J=6.2Hz, 2H, py-H), 7.45(d, J=8.4Hz, 2H, Ar-H), 7.26(d, J=8.4Hz, 2H, Ar-H), 4.42(s, 2H, SCH ₂ -); ESI-MS: 405[M +H] ⁺ ; Elemental anal. For C ₁₅ H ₁₀ BrN ₅ S ₂ (%), calculated: C, 44.56; H, 2.49; N, 17.32; found: C, 44.59; H, 2.23; N, 17.32.

Example 6

The 2-methyl benzyl chloride in step (6) of Example 1 is replaced with 1.1 mmol of 4-benzyl chloride, and other operations are the same as in Example 1 to obtain 6-((4-chlorobenzyl) mercapto)-3- (Pyridin-4-yl)-[1,2,4]triazol[3,4-b][1,3,4]thiadiazole (I-6), 91.9%.

(I-6)

6-((4-chlorobenzyl)mercapto)-3-(pyridin-4-yl)-[1,2,4]triazol[3,4-b][1,3,4]thiadiazole Yellow solid, yield 91.9%, ¹ H NMR (CDCl ₃ , 500MHz), δ: 8.76 (d, 2H, py-H), 8.06 (d, 2H, py-H), 7.34-7.28 (m, 4H, Ar- H), 4.36(s, 2H, SCH ₂ -); ESI-MS: 326[M+H] ⁺ ; Elemental anal. For C ₁₅ H ₁₀ ClN ₅ S ₂ (%), calculated: C, 50.07; H, 2.80 ; N, 19.46; found: C, 49.99; H, 2.68; N, 19.31.

Example 7

The 2-methyl benzyl chloride in the embodiment 1 step (6) is replaced with 1.1mmol of 4-benzonitrile, and other operations are the same as in Example 1 to obtain 4-((3-(pyridin-4-yl)-[ 1,2,4]triazol[3,4-b][1,3,4]thiadiazol-6-mercapto)yl)benzonitrile (I-7), yield 91.9%.

(I-7)

4-((3-(pyridin-4-yl)-[1,2,4]triazol[3,4-b][1,3,4]thiadiazol-6-mercapto)yl)benzonitrile Yellow solid, yield 91.9%, ¹ H NMR (CDCl ₃ , 500MHz), δ:8.76(d,2H,py-H),8.06(d,2H,py-H),7.34-7.28(m,4H,Ar -H), 4.36(s, 2H, SCH ₂ -); ESI-MS: 351[M+H] ⁺ ; Elemental anal. For C ₁₆ H ₁₀ N ₆ S ₂ (%), calculated: C, 54.84; H, 2.88; N, 23.98; found: C, 54.87; H, 2.97; N, 24.11.

Example 8

The 2-methyl benzyl chloride in step (6) of Example 1 is replaced with 1.1 mmol of 2-chlorothiazole, and other operations are the same as in Example 1 to obtain 6-(((2-chlorothiazol-5-yl)methyl )mercapto)-3-(pyridin-4-yl)-[1,2,4]triazol[3,4-b][1,3,4]thiadiazole (I-8), yield 23% .

(I-8)

6-(((2-chlorothiazol-5-yl)methyl)mercapto)-3-(pyridin-4-yl)-[1,2,4]triazol[3,4-b][1,3 ,4] Thiadiazole Yellow solid, mp160-162℃, yield 23.0%, ¹ H NMR (CDCl ₃ , 500MHz), δ: 8.75 (d, J=6.1Hz, 2H, py-H), 8.07(d, J=6.3Hz, 2H, py-H), 7.51(s, 1H, thiazole-H), 4.68(s, 2H, SCH ₂ -); ESI-MS: 368[M+H] ⁺ ; Elemental anal.For C ₁₂ H ₇ ClN ₆ S ₃ (%), calculated: C, 39.29; H, 1.92; N, 22.91; found: C, 39.43; H, 1.88; N, 22.79.

Example 9

The 2-methyl benzyl chloride in step (6) of Example 1 is replaced with 1.1 mmol of 6-chloropyridine, and other operations are the same as in Example 1 to obtain 6-(((6-chloropyridin-3-yl)methyl )mercapto)-3-(pyridin-4-yl)-[1,2,4]triazol[3,4-b][1,3,4]thiadiazole (I-9), yield 74.4% .

(I-9)

6-(((6-chloropyridin-3-yl)methyl)mercapto)-3-(pyridin-4-yl)-[1,2,4]triazol[3,4-b][1,3 ,4] Thiadiazole Yellow solid, mp199-200℃, Yield 74.4%, ¹ H NMR (CDCl ₃ , 500MHz), δ: 8.76(d, J=6.0Hz, 2H, Py-H), 8.48(d, J=2.2Hz,1H,Py-H),8.06(d,J=6.1Hz,2H,Py-H),7.84(dd,J=8.2,2.4Hz,1H,Py-H),7.30(s, 1H, Py-H), 4.52(s, 2H, SCH ₂ -); ESI-MS: 361[M+H] ⁺ ; Elemental anal. For C ₁₄ H ₉ ClN ₆ S ₂ (%), calculated: C, 46.60; H, 2.51; N, 23.29; found: C, 46.75; H, 2.37; N, 23.42.

Example 10

The 2-methyl benzyl chloride in step (6) of Example 1 is replaced with 1.1 mmol of 2-benzyl chloride, and other operations are the same as in Example 1 to obtain 6-((2-chlorobenzyl) mercapto)-3- (Pyridin-4-yl)-[1,2,4]triazol[3,4-b][1,3,4]thiadiazole (I-10), yield 75.2%.

(I-10)

6-((2-Chlorobenzyl)mercapto)-3-(pyridin-4-yl)-[1,2,4]triazol[3,4-b][1,3,4]thiadiazole Yellow solid, yield 75.2%. ¹ H NMR (CDCl ₃ , 500MHz), δ: 8.74 (d, 2H, py-H), 8.01 (d, 2H, py-H), 7.43-7.39 (m, 2H, Ar- H),7.24-7.18(m,2H,Ar-H),4.58(s,2H,SCH ₂ -); ESI-MS:326[M+H] ⁺ ;Elemental anal.For C ₁₅ H ₁₀ ClN ₅ S ₂ (%), calculated: C, 50.07; H, 2.80; N, 19.46; found: C, 50.21; H, 2.88; N, 19.33.

Embodiment 11 bactericidal activity test

Test objects: Pythium ultimum, Phytophthorainfestans, Corynespora cassiicola, Botrytis cinerea and Rhizoctonia solani.

Test method: Pot test method is adopted. Soak cucumber or tomato seeds at 50°C, accelerate germination, and sow them in seedling pots. Seedlings that grow to 2 true leaves are used for testing. The experiment was repeated 4 times. After inoculation with the pathogen, plants were maintained at 18-30°C [average temperature 24°C, relative humidity (RH) above 80%].

Medicament preparation: take each 5 mg of (I-1)-(I-10) compounds prepared in Example 1-10, add 0.5 ml of acetone to dissolve, then add 0.05 ml of 10% soil temperature 80, and finally add 50 ml of water to fully dissolve to obtain 100ppm sample agent. Because 100ppm is 100mg/L so add water=5mg*1000/100mg=50ml, because the final content of organic solvent≤1%, so add the amount of acetone=50ml*1%=0.5ml (dissolving), because the final content of Tween is 0.1 % Therefore, there should be 0.05ml of Tween in 50ml of water, that is, 0.05ml of 10% Tween should be added.

Control agents: zhongshengmycin, dimethomorph, chlorothalonil, fludioxoni and Validamycin.

Inoculation method:

Bacterial suspension spraying method was used to inoculate: after culturing the pathogenic bacteria of the test object, the seed solution was diluted with distilled water to form 3×10 ⁷ cfu/ml bacterial suspension, and sprayed with a watering can to inoculate corresponding plants. After inoculation, culture at 18-30°C with moisture.

Application method: When the seedlings inoculated with the pathogen grow two compound leaves, use a watering can to evenly spray the sample drug and the control drug on the stems and leaves of the test plants, and replace the sample drug with water as a blank control.

After the clean water (blank experiment) was sprayed on the plants and the plants were fully infected, the bactericidal situation was investigated, and the bactericidal index and control effect were calculated.

In the formula (1): EF: relative control effect; CK: terminal average disease index in the control area; PT: terminal average disease index in the treatment area.

Activity test results are shown in Table 1

The bactericidal activity (% control effect) of each compound under table 1 100ppm

Can draw from table 1, compound (I-1) has very good activity to extreme rot mold (Pythium ultimum), and the inhibitory rate reaches 100% under the concentration of 100ppm, and compound (I-3) and (I-4) also They showed good activity, and the inhibition rates reached 55.56% and 66.67%, respectively. None of the other compounds were active against Pythium ultimum. Except for (I-6) which showed weak activity, all other compounds had little activity against Corynespora cassiicola and Botrytis cinerea. All compounds were inactive against Phytophthora infestans and Rhizoctonia solani.

Claims (10)

1. A 1,2,4-triazolothiadiazole sulfide derivative, characterized in that the 1,2,4-triazolothiadiazole sulfide derivative is 3-(4-pyridyl )-[1,2,4]-triazolo[3,4-b][1,3,4]thiadiazole-6-sulfide compounds, the structural formula of which is shown in formula (I): , In formula (I): R is C1~C14 alkyl, benzyl, substituted benzyl, thiazole, substituted thiazole, pyridine or substituted pyridine, the substituent of the substituted benzyl is halogen, methyl or nitrile, and substituted pyridine , Substituents of substituted thiazoles are all halogen. 2. A kind of 1,2,4-triazolothiadiazole sulfide derivative according to claim 1, characterized in that R is selected from undecyl, 2-methylbenzyl, 3,4- Dichlorobenzyl, 3-chlorobenzyl, 4-bromobenzyl, 4-chlorobenzyl, 4-cyanobenzyl, 2-chlorothiazole, 6-chloropyridine, 2-chlorobenzyl. 3. A method for preparing 1,2,4-triazolothiadiazole sulfide derivatives according to claim 1, characterized in that it comprises the steps of: 1) Mix isonicotinic acid, sulfuric acid and anhydrous methanol, heat and reflux to generate isonicotinic acid methyl ester as shown in formula (II), and the ratio of isonicotinic acid, sulfuric acid and anhydrous methanol is: 1:1～2:1～2, preferably 1:1.2:1.2; 2) The methyl isonicotinate obtained in step 1) was refluxed with hydrazine hydrate with a mass concentration of 80%. After the reaction, the reaction solution was cooled to room temperature, filtered, washed with glacial ethyl acetate, and dried to obtain the formula (Ⅲ ) for isoniazid, the ratio of the amount of isoniazid methyl ester to hydrazine hydrate is 1:2.5-4.0, preferably 1:3.5; 3) Mix the isoniazid (10mmol) of formula (Ⅲ), carbon disulfide (12mmol) and potassium hydroxide (12mmol) for reflux reaction, and spin the solvent to obtain 4-pyridyldithioacid represented by formula (Ⅳ) Potassium salt of hydrazone. 4) The potassium salt of 4-pyridine dithioacylhydrazone obtained in step 3) was refluxed with hydrazine hydrate for 5 hours, diluted with water after the reaction, acidified with dilute hydrochloric acid, filtered, washed three times with water, and dried to obtain the formula (Ⅴ ) represented by 4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazole-3-mercapto; 5) Dissolve 4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazole-3-mercapto and carbon disulfide obtained in step 4) in organic solvent A, and then add 2 drops of Tris Ethylamine, heated to reflux, refluxed and stirred overnight, after the reaction was completed, the mixed solution was poured into crushed ice, acidified with dilute hydrochloric acid to a pH value of 1, precipitated and filtered, and dried to obtain 3-(pyridine -4-yl)-[1,2,4]triazol[3,4-b][1,3,4]thiadiazole-6-mercapto; 6) Combine the 3-(pyridin-4-yl)-[1,2,4]triazol[3,4-b][1,3,4]thiadiazole-6-mercapto group obtained in step 5) with RCH ₂ Cl, organic solvent B and inorganic base B are mixed and added into a pressure bottle to assist the reaction with microwaves. After the reaction, the reaction solution is cooled to room temperature, precipitated in an ice bath, filtered, and the filtrate is recrystallized with a recrystallization solvent to obtain the target product such as 3-(4-pyridyl)-[1,2,4]-triazolo[3,4-b][1,3,4]thiadiazole-6-sulfides represented by formula (I) Compound, R in RCH ₂ Cl is a benzene ring or a substituted benzene ring, pyridine or a substituted pyridine, thiazole or a substituted thiazole, and the substituent is a halogen, methyl or nitrile group; The structural formula of each compound is as follows: . 4. The preparation method of 1,2,4-triazolothiadiazole sulfide derivatives according to claim 3, characterized in that the amount of isoniazid, carbon disulfide and inorganic base A in step 3) The ratio is 1:1～2:1～2, preferably 1:1.2:1.2; the inorganic base A is one or more of potassium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide or sodium hydride A mixture, preferably potassium hydroxide. 5. The preparation method of 1,2,4-triazolothiadiazole sulfide derivatives according to claim 3, characterized in that the potassium salt of 4-pyridine dithioacylhydrazone in step 4) and the hydration The ratio of the amount of substance of hydrazine is: 1:1～2, preferably 1:1.5; the consumption of water is 1～10ml/mmol in terms of the amount of substance of the potassium salt of 4-pyridine dithioacylhydrazone, preferably 5ml/mmol. 6. The preparation method of 1,2,4-triazolothiadiazole sulfide derivatives according to claim 3, characterized in that 4-amino-5-(pyridin-4-yl) in step 5) -4H-1,2,4-triazole-3-mercapto and carbon disulfide are in a ratio of 1:1 to 3, preferably 1:2.4; the organic solvent A is methanol, ethanol, DMF and pyridine One or more mixtures, preferably pyridine, the amount of organic solvent A is based on the amount of 4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazole-3-mercapto The amount is 1 to 10 ml/mmol, preferably 4 ml/mmol. 7. The preparation method of 1,2,4-triazolothiadiazole sulfide derivatives according to claim 3, characterized in that the recrystallization solvent in step 6) is petroleum ether, methanol, n-hexane or ethanol One or more in, preferably ethanol; Organic solvent B is one or more mixtures in methanol, ethanol, DMF and pyridine, is preferably DMF, and the volume consumption of organic solvent B is 3-(pyridine-4- base)-[1,2,4]triazol[3,4-b][1,3,4]thiadiazole-6-mercapto is 3-9ml/mmol, preferably 5ml/mmol; ; The inorganic base B is one or more mixtures of potassium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide or sodium hydride, preferably sodium hydroxide; 3-(pyridin-4-yl)-[1, The ratio of 2,4]triazol[3,4-b][1,3,4]thiadiazole-6-mercapto to RCH ₂ Cl is 1:1-1.5, preferably 1:1.1. 8. The preparation method of 1,2,4-triazolothiadiazole sulfide derivatives according to claim 3, characterized in that the microwave auxiliary conditions in step 6) are: 150 W, 90°C, 200 psi Microwave for 15 minutes. 9. A use of the 1,2,4-triazolothiadiazole sulfide derivative according to claim 1 in the preparation of fungicides. 10. application according to claim 9, described fungicide is the fungicide of controlling Pythium ultimate, Phytophthora infestans, Corynesporium, Botrytis Botrytis and Rhizoctonia solani, 1,2,4-triazole The concentration of thiadiazole sulfide derivatives in the fungicide is 100ppm.