Method for synthesizing pesticide Silthiopham

A technology for the synthesis of silthiocarb and its synthesis method, which is applied in the field of high-efficiency synthesis of the pesticide silthiocarb, can solve the problems of low exchange reaction yields, and achieve the effects of cheap and easy-to-obtain raw materials, simple routes, and high yields

Active Publication Date: 2015-11-25
HANGZHOU NORMAL UNIVERSITY
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] In order to solve the problem of low exchange reaction yield in the current synthesis process of the pesticide silthiocarb, the invention provides a method for synthesizing the pesticide silthiocarb. The raw materials used in the method are cheap and easy to obtain, the route is simple, and the total yield is higher, and avoid the use of tert-butyl nitrous acid ( t -BuONO) and thionyl chloride and other reagents that seriously pollute the environment

Method used

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  • Method for synthesizing pesticide Silthiopham
  • Method for synthesizing pesticide Silthiopham
  • Method for synthesizing pesticide Silthiopham

Examples

Experimental program
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Effect test

Embodiment 1

[0027] (1) Preparation of methyl trimethylsilyl propiolate:

[0028] Under nitrogen protection, trimethylsilylacetylene (5.6 mL, 40.0 mmol) was added to dry THF, cooled to -78 °C, n-butyllithium (27.6 mL, 44.0 mmol) was slowly added to the system, and the Stir at temperature for 30 minutes, then warm to room temperature, and add methyl chloroformate (3.4 mL, 44.0 mmol), then stir the reaction for 2.5 hours. The reaction mixture was poured into ammonium chloride solution to quench the reaction, and ether was added for extraction. The organic phase was washed with water and brine and dried over anhydrous sodium sulfate. The solvent was removed in vacuo, and the obtained crude product was purified by column chromatography (5% EtOAc / PE) to obtain methyl trimethylsilylpropiolate 5.9 g (yield: 95.0%) as a yellow oily product.

[0029] (2) Preparation of methyl 4,5-dimethyl-2-(trimethylsilyl)thiophene-3-carboxylate:

[0030] Under nitrogen protection, methyl trimethylsilylpropiolat...

Embodiment 2

[0036] (1) Preparation of methyl trimethylsilyl propiolate:

[0037] Under nitrogen protection, trimethylsilylacetylene (5.6 mL, 40.0 mmol) was added to dry tetrahydrofuran, cooled to -50°C, and methyl lithium (37.6 mL, 60.0 mmol) was slowly added to the system, and the temperature was kept at this temperature. was stirred for 30 minutes at low temperature, then warmed to room temperature, and methyl chloroformate (4.0 mL, 52.0 mmol) was added, and the reaction was stirred for 2.5 hours. The reaction mixture was poured into ammonium chloride solution to quench the reaction, and ether was added for extraction. The organic phase was washed with water and brine and dried over anhydrous sodium sulfate. The solvent was removed in vacuo, and the obtained crude product was purified by column chromatography (5% EtOAc / PE) to obtain methyl trimethylsilylpropiolate 5.8 g (yield: 93.0%) as a yellow oily product.

[0038] (2) Preparation of methyl 4,5-dimethyl-2-(trimethylsilyl)thiophene-...

Embodiment 3

[0044] (1) Preparation of methyl trimethylsilyl propiolate:

[0045] Under nitrogen protection, trimethylsilylacetylene (5.6 mL, 40.0 mmol) was added to dry THF, cooled to -60°C, phenyllithium (26.7 mL, 40.0 mmol) was slowly added to the system, and the temperature was kept at this temperature. It was stirred for 30 minutes at low temperature, then warmed to room temperature, and methyl chloroformate (4.7 mL, 60.0 mmol) was added, and the reaction was stirred for 2.5 hours. The reaction mixture was poured into ammonium chloride solution to quench the reaction, and ether was added for extraction. The organic phase was washed with water and brine and dried over anhydrous sodium sulfate. The solvent was removed in vacuo, and the obtained crude product was purified by column chromatography (5% EtOAc / PE) to obtain methyl trimethylsilylpropiolate 5.7 g (yield: 92.0%) as a yellow oily product.

[0046] (2) Preparation of methyl 4,5-dimethyl-2-(trimethylsilyl)thiophene-3-carboxylate:...

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Abstract

The invention belongs to the technical field of organic synthesis and provides a method for synthesizing a pesticide Silthiopham. The method is used for solving the problem of the pesticide Silthiopham synthesis process at present that the yield of exchange reaction is low. The method comprises the steps of (1) enabling trimethylsilyl acetylene, which serves as a raw material, to react with methyl chloroformate in the presence of an organic base under the protection of inert gas so as to obtain trimethylsilyl methyl propiolate; (2) enabling trimethylsilyl methyl propiolate to react with 3-mercapto-2-butanone in the presence of a basic catalyst so as to obtain 4,5-dimethyl-2-(trimethylsilyl)thiophen-3-methyl formate; and (3) enabling 4,5-dimethyl-2-(trimethylsilyl)thiophen-3-methyl formate to react with allyl amine in the presence of a catalyst, thereby obtaining the end product pesticide Silthiopham. According to the method, the used raw materials are cheap and readily-available, the route is simple, the overall yield is relatively high, and the consumption of reagents causing serious environmental pollution such as tert-butyl nitrous acid (t-BuONO) and thionyl chloride is avoided.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a high-efficiency synthesis process of the pesticide silthiopyrad. Background technique [0002] Wheat take-all disease (Gaeuummomycesgramini) is one of the serious diseases of wheat. Silthiopham is a seed treatment agent officially launched by Monsanto in 1999, which has special effects on wheat take-all disease caused by wheat take-all fungus. However, the currently known silthiopyrad synthesis methods have the disadvantages of many reaction steps, the use of a variety of highly toxic substances and the use of reagents that cause serious environmental pollution, and the cost is high. Therefore, there is an urgent need to develop a high-efficiency and low-cost method for the synthesis of silthiopyrad. [0003] US Patent No. 5,486,621 reported for the first time the total synthesis of silthiazide N-allyl-4,5-dimethyl-2-(trimethylsilyl)thiophene-3-carboxamid...

Claims

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Application Information

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IPC IPC(8): C07F7/10
Inventor 郑战江王丁徐利文徐征杨科芳
Owner HANGZHOU NORMAL UNIVERSITY
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