A method for synthesizing prothioconazole

Abstract

The application relates to the technical field of organic synthesis, and discloses a synthesis method of propiconazole, which comprises the following steps: taking 2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-1,2,4-triazole-3-thiol as raw material, and reacting under the action of an oxidant and a supported catalyst to obtain propiconazole. Through the technical scheme, the problems of low yield and low purity of propiconazole in the prior art are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic synthesis, in particular, relates to a kind of propiconazole synthesis method. BACKGROUND

[0002] 2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-1,2-dihydro-3H-1,2,4-triazole-3-thione, also known as propiconazole, is a triazole thione fungicide with broad-spectrum fungicidal activity, good control effect and environmental safety, ecological friendly characteristics. It mainly acts on the prevention and control of many diseases of cereal crops such as wheat, barley, rapeseed, peanut, rice and legume crops, and has good control effect on almost all wheat diseases, such as powdery mildew, brown spot, fusarium wilt, leaf spot, rust, sclerotinia, net blotch and cloud spot of wheat and barley, and has broad application prospect in agricultural production.

[0003] Most of the currently reported synthesis processes of propiconazole use excessive ferric chloride or hydrogen peroxide as oxidant to oxidize 2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-1,2,4-triazole-3-thiol to propiconazole. This synthesis method has problems such as large material consumption, large amount of wastewater, large amount of solid waste, low yield and low purity. Therefore, it is of great significance to explore a simple and efficient synthesis method of propiconazole with high yield and high purity. SUMMARY

[0004] The present application provides a synthesis method of propiconazole, which solves the problem of low yield and purity of propiconazole in the related art.

[0005] The technical scheme of the present application is as follows:

[0006] The present application provides a synthesis method of propiconazole, which includes the following steps: taking 2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-1,2,4-triazole-3-thiol as raw material, under the action of oxidant and supported catalyst, propiconazole is obtained by reaction.

[0007] The carrier of the supported catalyst is diatomite, and the active component is sodium tungstate.

[0008] As a further technical scheme, after the reaction, the post-treatment is also included, which is: adding water to the reaction liquid, separating the liquid, extracting the organic phase with dichloromethane, drying, and obtaining propiconazole finished product.

[0009] As a further technical scheme, the oxidant is 30wt% hydrogen peroxide solution.

[0010] As a further technical solution, the molar ratio of the oxidizing agent to 2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-1,2,4-triazole-3-thiol is 1-2:1.

[0011] As a further technical solution, the reaction is carried out in a solvent, and the solvent is toluene.

[0012] As a further technical solution, the temperature of the reaction is 30-50℃, and the time is 4-6h.

[0013] As a further technical solution, the loading of the active component in the supported catalyst is 5wt%.

[0014] As a further technical solution, the mass ratio of the active component of the supported catalyst to 2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-1,2,4-triazole-3-thiol is 1‰-5‰:1.

[0015] As a further technical solution, the supported catalyst is prepared by an impregnation method.

[0016] As a further technical solution, the impregnating solution in the impregnation method is a 5wt% sodium tungstate aqueous solution.

[0017] As a further technical solution, the mass ratio of the impregnating solution to diatomite in the impregnation method is 10:9.5.

[0018] The working principle and beneficial effects of the present application are as follows:

[0019] 1. In the present application, 2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-1,2,4-triazole-3-thiol is used as a raw material, and propiconazole is obtained by reaction under the action of hydrogen peroxide solution and a supported catalyst. The application of the supported catalyst greatly improves the reaction efficiency and shortens the reaction time. The porous structure of diatomite loaded with sodium tungstate improves the oxidation capacity of the hydrogen peroxide solution, thereby improving the reaction yield.

[0020] 2. In the present application, the reaction solution is separated by adding water, and the organic phase is extracted by dichloromethane, and the obtained propiconazole product has high purity.

[0021] 3. In the present application, the reaction temperature is 30-50℃, and at this temperature, the reaction can be stably carried out, thereby reducing the generation of by-products, and thus being beneficial to improve the yield and purity of the product. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work also pertain to the scope of protection of the present application.

[0023] In the following examples, the preparation of the supported catalyst includes the following steps: 9.5 g of diatomaceous earth is immersed in 10 mL of a 5 wt% aqueous sodium tungstate solution, dried, and 10 g of a supported catalyst is obtained.

[0024] Example 1

[0025] (34.63 g, 0.10 mol) of 2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-1,2,4-triazole-3-thiol, 11.33 g of a 30 wt% hydrogen peroxide solution, 0.69 g of a supported catalyst, and 200 mL of toluene are weighed into a 500 mL reaction flask, the reaction temperature is controlled at 30°C, and the reaction is carried out for 6 h. After the reaction is completed, the reaction solution is cooled to room temperature, 200 mL of water is added to the reaction solution, the solution is allowed to stand and separate, the organic phase is extracted with dichloromethane, and dried to obtain 34.32 g of a propiconazole product, with a yield of 98.88% and a purity of 99.19%.

[0026] Example 2

[0027] (34.63 g, 0.10 mol) of 2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-1,2,4-triazole-3-thiol, 17.01 g of a 30 wt% hydrogen peroxide solution, 2.08 g of a supported catalyst, and 200 mL of toluene are weighed into a 500 mL reaction flask, the reaction temperature is controlled at 40°C, and the reaction is carried out for 5 h. After the reaction is completed, the reaction solution is cooled to room temperature, 200 mL of water is added to the reaction solution, the solution is allowed to stand and separate, the organic phase is extracted with dichloromethane, and dried to obtain 34.40 g of a propiconazole product, with a yield of 99.47% and a purity of 99.56%.

[0028] Example 3

[0029] (34.63 g, 0.10 mol) of 2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-1,2,4-triazole-3-thiol, 22.67 g of a 30 wt% hydrogen peroxide solution, 3.46 g of a supported catalyst, and 200 mL of toluene are weighed into a 500 mL reaction flask, the reaction temperature is controlled at 50°C, and the reaction is carried out for 4 h. After the reaction is completed, the reaction solution is cooled to room temperature, 200 mL of water is added to the reaction solution, the solution is allowed to stand and separate, the organic phase is extracted with dichloromethane, and dried to obtain 34.37 g of a propiconazole product, with a yield of 99.15% and a purity of 99.33%.

[0030] Example 4

[0031] Take (34.63 g, 0.10 mol) 2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2- hydroxypropyl]-1,2,4-triazole-3-thiol, 17.01 g 30wt% hydrogen peroxide solution, 2.08 g supported catalyst, 200 mL of toluene in a 500 mL reaction bottle, control the reaction temperature 20℃, reaction 5h. After the reaction is completed, cool to room temperature, add 200 mL water to the reaction solution, stand and separate, extract the organic phase with dichloromethane, dry, get 34.26g of the product of propiconazole, yield 98.52%, purity 99.01%.

[0032] Example 5

[0033] Take (34.63 g, 0.10 mol) 2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2- hydroxypropyl]-1,2,4-triazole-3-thiol, 17.01 g 30wt% hydrogen peroxide solution, 2.08 g supported catalyst, 200 mL of toluene in a 500 mL reaction bottle, control the reaction temperature 60℃, reaction 5h. After the reaction is completed, cool to room temperature, add 200 mL water to the reaction solution, stand and separate, extract the organic phase with dichloromethane, dry, get 34.28g of the product of propiconazole, yield 98.69%, purity 99.13%.

[0034] Comparative Example 1

[0035] Take (34.63 g, 0.10 mol) 2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2- hydroxypropyl]-1,2,4-triazole-3-thiol, 17.01 g 30wt% hydrogen peroxide solution, 200 mL of toluene in a 500 mL reaction bottle, control the reaction temperature 40℃, reaction 5h. After the reaction is completed, cool to room temperature, add 200 mL water to the reaction solution, stand and separate, extract the organic phase with dichloromethane, dry, get 31.72g of the product of propiconazole, yield 60.23%, purity 65.37%.

[0036] Comparative Example 2

[0037] Take (34.63g, 0.10mol) 2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-1,2,4-triazole-3-thiol, 17.01g 30wt% hydrogen peroxide solution, 2.08g 5wt% aqueous sodium tungstate solution, 200mL of toluene in a 500mL reaction flask, control the reaction temperature 40℃, reaction 5h. After the reaction is completed, cool to room temperature, add 200mL water to the reaction solution, stand and separate, extract the organic phase with dichloromethane, dry, get 33.93g of prothioconazole product, yield 90.33%, purity 91.67%.

[0038] Comparative Example 3

[0039] 9.5g zeolite is immersed in 10mL 5wt% aqueous sodium tungstate solution, dried to get 10g of supported catalyst.

[0040] Take (34.63g, 0.10mol) 2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-1,2,4-triazole-3-thiol, 17.01g 30wt% hydrogen peroxide solution, 2.08g 5wt% supported catalyst, 200mL of toluene in a 500mL reaction flask, control the reaction temperature 40℃, reaction 5h. After the reaction is completed, cool to room temperature, add 200mL water to the reaction solution, stand and separate, extract the organic phase with dichloromethane, dry, get 34.09g of prothioconazole product, yield 95.33%, purity 96.27%.

[0041] The above is only the preferred embodiment of the present application, and is not intended to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A process for the synthesis of prothioconazole, characterized in that, The method comprises the following steps: 2-[(2RS)-2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-1,2,4-triazolidine-3-thione is used as raw material, and an oxidant and a supported catalyst are used to react to obtain prothioconazole; The carrier of the supported catalyst is diatomite, and the active component is sodium tungstate; The mass ratio of the active component of the supported catalyst to 2-[(2RS)-2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-1,2,4-triazolidine-3-thione is 1 ‰-5 ‰:1; The oxidant is a 30wt% hydrogen peroxide solution.

2. The process for the synthesis of prothioconazole according to claim 1, characterized in that, After the reaction, post-treatment is further included, which is adding water into the reaction solution, separating the liquid, extracting the organic phase with dichloromethane, drying, and obtaining prothioconazole product.

3. The process for synthesis of prothioconazole as claimed in claim 1 wherein, The molar ratio of the oxidant to 2-[(2RS)-2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-1,2,4-triazolidine-3-thione is 1-2:

1. ​ 4. The process for synthesis of prothioconazole as claimed in claim 1 wherein, The reaction is carried out in a solvent, and the solvent is toluene.

5. The process for synthesis of prothioconazole as claimed in claim 1, wherein, The reaction temperature is 30-50℃, and the reaction time is 4-6h.

6. The process for synthesis of prothioconazole as claimed in claim 1, wherein, The loading amount of the active component in the supported catalyst is 5wt%.

7. The process for synthesis of prothioconazole as claimed in claim 1, wherein, The supported catalyst is prepared by an impregnation method, and the impregnation solution in the impregnation method is a 5wt% sodium tungstate aqueous solution.

8. The process for the synthesis of prothioconazole according to claim 7, characterized by, The mass ratio of the impregnation solution to diatomite in the impregnation method is 10:9.5.