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Preparation method of 2-chloro -3-trifluoroethoxy pyridine

A technology of pyridine trifluoroethoxypyridine and trifluoroethyl toluenesulfonate, which is applied in the field of preparation of herbicide intermediates, can solve the problems of high cost of trifluxysulfuron-methyl, difficulty in large-scale industrial production, and high price, and achieve Fewer steps, cheap price, and easy-to-obtain raw materials

Active Publication Date: 2011-05-11
江苏省农用激素工程技术研究中心有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the raw material 3-benzyloxypyridine-2-sulfonamide for the preparation of triflupyrsulfuron is difficult to obtain, it generally needs to be prepared by 2,3-difluoropyridine through multi-step reactions, and 2,3-difluoropyridine The price of pyridine is very expensive again, so the cost of preparing trifloxysulfuron-methyl by the above-mentioned method is very high, and it is difficult to industrialized production in large quantities

Method used

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  • Preparation method of 2-chloro -3-trifluoroethoxy pyridine
  • Preparation method of 2-chloro -3-trifluoroethoxy pyridine

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Embodiment 1

[0015] The preparation method steps of the 2-chloro-3-trifluoroethoxypyridine of the present embodiment are as follows:

[0016] ①Put 25.8g of 2-chloro-3-hydroxypyridine (0.2mol), 34.5g of potassium carbonate (0.25mol) and 250ml of dimethylformamide as an organic solvent in a reaction flask, heat up to 70°C, Insulation reaction 5h.

[0017] ② Subsequently, 51 g of trifluoroethyl p-toluenesulfonate (0.2 mol) was added to the system after the reaction in step ①, and the temperature was raised to 85° C., and reacted for 7 hours.

[0018] ③ Distill the system obtained in step ② to recover the organic solvent dimethylformamide, then cool the system to 20°C, add water and stir for 1 hour, filter, wash the filter cake with water, and dry to obtain 33.8g of 2 -Chloro-3-trifluoroethoxypyridine with a purity of 97% and a yield of 80%.

Embodiment 2～ Embodiment 6

[0020] Each embodiment is basically the same as Embodiment 1, and the differences are shown in Table 1.

[0021] Table 1

[0022]

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Abstract

The invention discloses a preparation method of 2-chloro-3-trifluoroethoxy pyridine, comprising the following steps of: (1) adding 2-chloro-3-hydroxy pyridine and alkaline into an organic solvent, stirring and heating to 50 to 100 DEG C, and reacting for 4h to 6h; (2) adding trifluoro-ethyl p-toluenesulfonate in the system obtained in the step (1), and reacting for 4h to 10h under the temperatureof 70 DEG C to 145 DEG C; and (3) carrying out the posttreatment on the system obtained in the step (2) to prepare the 2-chloro-3-trifluoroethoxy pyridine. The invention has less steps, mild reactioncondition and low-price of 2-chloro-3-hydroxy pyridine as raw materials, and is suitable for industrialized production.

Description

technical field [0001] The invention relates to a preparation method of a herbicide intermediate, in particular to a preparation method of 2-chloro-3-trifluoroethoxypyridine. Background technique [0002] 2-Chloro-3-trifluoroethoxypyridine is an important intermediate for the preparation of super-efficient herbicide trifloxysulfuron-methyl newly developed in recent years. [0003] European patent WO9216522 discloses the preparation method of triflupyridine-sulfuron, adding 3-benzyloxypyridine-2-sulfonamide to methanol and adding palladium carbon to catalyze debenzylation to prepare 3-hydroxypyridine-2-sulfonamide Amide; then 3-hydroxypyridine-2-sulfonamide is added to dimethylformamide, then potassium carbonate and trifluoroethyl p-toluenesulfonate are added to react to generate triflupyrsulfuron. Since the raw material 3-benzyloxypyridine-2-sulfonamide for the preparation of triflupyrsulfuron is difficult to obtain, it generally needs to be prepared by 2,3-difluoropyridine...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D213/65
Inventor 周月根孔繁蕾于靓
Owner 江苏省农用激素工程技术研究中心有限公司