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Synthetic technology for 3-phenyl-5-(thiophene-2-yl)-1,2,4-oxadiazole

A synthesis process and oxadiazole technology are applied in the field of pesticide technical preparation, can solve the problems of polluting the environment, do not involve the synthesis of the intermediate 2-thiophenecarbonyl chloride and the intermediate N-hydroxybenzamidine, etc., and improve the total yield. efficiency, avoiding manganese dioxide solids, shortening reaction steps and time

Inactive Publication Date: 2014-08-13
WUHAN INSTITUTE OF TECHNOLOGY
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The existing technology mainly uses pyridine as a solvent to synthesize the target product under the condition of heating and reflux, without involving the synthesis of the intermediate 2-thiophenoyl chloride and the intermediate N-hydroxybenzamidine, and uses pyridine with a strong smell as the solvent. seriously pollute the environment

Method used

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  • Synthetic technology for 3-phenyl-5-(thiophene-2-yl)-1,2,4-oxadiazole
  • Synthetic technology for 3-phenyl-5-(thiophene-2-yl)-1,2,4-oxadiazole
  • Synthetic technology for 3-phenyl-5-(thiophene-2-yl)-1,2,4-oxadiazole

Examples

Experimental program
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Effect test

Embodiment 1

[0023] 1. Synthesis of 12-thiophenecarboxylic acid

[0024]

[0025] Add 16.81g (0.15mol) of 2-thiophenecarbaldehyde, 150ml of methanol, and 3.0g (0.028mol) of sodium chlorate into a 250ml four-necked reaction flask, cool to 10-15°C, and then dropwise add 30wt.% peroxide Hydrogen 6.12g (0.18mol), the dropwise addition temperature does not exceed 20°C, after the dropwise addition is completed, the room is raised to 70°C, and the temperature is continued for 10h; under the condition of 50°C, the methanol is distilled off under reduced pressure to obtain 18.2g of white solid, which is collected The rate is 89%.

[0026] 1.2 Synthesis of 2-thiophenoyl chloride

[0027]

[0028] Dissolve 44.5 g (0.347 mol) of 2-thiophenecarboxylic acid obtained in step 1) in 150 ml of dichloromethane solvent, add 0.5 ml of DMF, and add 120 ml of thionyl chloride (1.6 mol) dropwise under stirring. Complete, heat up and reflux for 12 hours, LC tracking (liquid chromatography) until the reacti...

Embodiment 2

[0036] The synthesis of 2-thiophenecarboxylic acid, the synthesis of 2-thiophenoyl chloride and the synthesis of N-hydroxybenzamidine are the same as in Example 1.

[0037] Synthesis of 3-phenyl-5-(thiophen-2-yl)-1,2,4-oxadiazole

[0038] In a 250ml four-necked reaction flask, add 10.88g (0.08mol) of N-hydroxybenzamidine and 80ml of acetone and stir to dissolve. At room temperature, slowly add 42.4g (0.16mol) of 40% sodium carbonate solution, and then dropwise add 11.72g (0.08mol) 2-thiophenoyl chloride, stirred at room temperature for 2 hours, then raised the temperature and refluxed to continue the reaction for 6 hours. After the reaction was completed, the reactant was poured into 100ml of water for layering, and the water layer was extracted with acetone. The acetone was evaporated under reduced pressure, and cooled to precipitate Solid, 14.7 g of white solid was obtained, the yield was 81.2%, and the melting point was 108-110°C.

Embodiment 3

[0040] The synthesis of 2-thiophenecarboxylic acid, the synthesis of 2-thiophenoyl chloride and the synthesis of N-hydroxybenzamidine are the same as in Example 1.

[0041] Synthesis of 3-phenyl-5-(thiophen-2-yl)-1,2,4-oxadiazole

[0042] Add 10.88g (0.08mol) of N-hydroxybenzamidine and 80ml of tetrahydrofuran into a 250ml four-necked reaction flask and stir to dissolve. At room temperature, slowly add 55.2g (0.16mol) of 40% potassium carbonate solution, and then dropwise add 11.72g (0.08mol) 2-thiophenoyl chloride, stirred at room temperature for 2h, then raised the temperature and refluxed to continue the reaction for 6h, after the reaction was completed, the reactants were poured into 100ml of water for layering, the aqueous layer was extracted with toluene, and tetrahydrofuran and toluene were evaporated under reduced pressure. The solid was precipitated by cooling to obtain 15.3 g of a white solid with a yield of 86.3% and a melting point of 108-110° C. The nuclear magnet...

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Abstract

The invention relates to a synthetic technology for 3-phenyl-5-(thiophene-2-yl)-1,2,4-oxadiazole. The technology includes following steps: 1) filling a reaction container with 2-thiophenecarboxylic acid and a solvent with stirring and dissolving, adding thionyl chloride with a heating reflux process, wherein the mole ratio of the 2-thiophenecarboxylic acid to the thionyl chloride is 1:2-5 and refluxing reaction time is 3-20h, after the reaction being finished, removing the solvent and excess thionyl chloride in a manner of evaporation and carrying out an underpressure distillation process to obtain 2-thiophenecarbonyl chloride; 2) dissolving N-hydroxy-benzamidine in a solvent, adding 2-thiopheneacetyl chloride in a dropwise manner, carrying out a heating reaction after the dropwise addition. After the reaction being finished, pouring the reaction product into water, carrying out a layering process, carrying out an extracting process to a water layer through a solvent and carrying out a concentrating crystallization process to obtain a product. With improvement of the technology, reaction processes are reduced and reaction time is shortened. Yield of the 3-phenyl-5-(thiophene-2-yl)-1,2,4-oxadiazole is increased from 50% to more than 80% and overall yield of the 3-phenyl-5-(thiophene-2-yl)-1,2,4-oxadiazole is increased.

Description

technical field [0001] The invention belongs to the field of pesticide technical preparation, and in particular relates to a synthesis process of a new oxadiazole nematicide 3-phenyl-5-(thiophen-2 base)-1,2,4-oxadiazole. Background technique [0002] Nematicide tioxazafen, chemical name: 3-phenyl-5-(thiophen-2 base)-1,2,4-oxadiazole, is an oxadiazole nematicide reported by Monsanto Company. It is mainly used for soil pest control and nematode treatment. [0003] The existing technology mainly uses pyridine as a solvent to synthesize the target product under the condition of heating and reflux, without involving the synthesis of the intermediate 2-thiophenoyl chloride and the intermediate N-hydroxybenzamidine, and uses pyridine with a strong smell as the solvent. Seriously pollute the environment. Contents of the invention [0004] The technical problem to be solved by the present invention is to propose a synthesis process of 3-phenyl-5-(thiophen-2 base)-1,2,4-oxadiazole...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D413/04
CPCC07D413/04
Inventor 刘安昌邹晓东陈露
Owner WUHAN INSTITUTE OF TECHNOLOGY
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