A kind of method for preparing 2-chloro-5-substituted pyridine

A technology of chloropyridine and chlorinating agents, which is applied in the preparation of halogenated hydrocarbons, chemical instruments and methods, organic chemistry, etc., can solve the problems of large amount of pollutants, complicated operation, and complicated separation, so as to save equipment investment and simplify The effect of short operating procedures and synthesis steps

Active Publication Date: 2022-08-02
上海垚翀化工科技有限公司
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  • Application Information

AI Technical Summary

Problems solved by technology

[0012] The purpose of the present invention is to provide a method for preparing 5-substituted 2-chloropyridines, so as to overcome the problems of complex separation, low yield, complex operation, large energy consumption, and large amount of pollutants produced in the prior art. , conducive to industrial production

Method used

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  • A kind of method for preparing 2-chloro-5-substituted pyridine
  • A kind of method for preparing 2-chloro-5-substituted pyridine
  • A kind of method for preparing 2-chloro-5-substituted pyridine

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0044] Example 1: Synthesis of N-propylene allylamine (R=methyl, R 1 =H)

[0045]

[0046] In a 500mL three-necked flask, add 57.7g (99.0%, 1.0mol, 1.0eq) of allylamine, cool the low temperature reaction bath to about 0°C, and slowly add 61.9g (98.5%, 1.05mol, 1.05eq) of propionaldehyde dropwise . After the dropwise addition was completed, 15 g of potassium hydroxide (85%, 0.23 mol, 0.23 eq) was added in batches after stirring at a temperature for 30 min, continued stirring for 2 h, and then allowed to stand for stratification. The water layer was separated to obtain 97.2 g of an organic layer (content 97%, yield 97%, 0.97 mol), which was a crude condensate product, pale yellow transparent liquid, which was directly used in the next reaction.

[0047] NMR data:

[0048] 1 H NMR (CDCl3) δ 1.03 (3H), 2.24 (2H), 3.90 (2H), 4.81-5.23 (2H), 5.58-6.26 (1H), 7.60 (1H).

[0049] With reference to the preparation method in Example 1, the following structural imines are prepared...

Embodiment 9

[0054] Example 9, Synthesis of N-allyl-N-propenylacetamide (R=methyl, R 1 =H, acetic anhydride)

[0055]

[0056] Add 70g (99.0%, 0.69mol, 0.7eq) of triethylamine and 121.2g (98.0%, 1.16mol, 1.2eq) of acetic anhydride to a 1000mL four-necked flask with a constant pressure dropping funnel, and cool the reaction bath at low temperature to At about 0°C, under stirring conditions, 97.0g (content 97%, 0.97mol, 1.0eq) of the crude condensate obtained in step 1 was slowly added dropwise to the reaction system, and the reaction was performed at about 25°C for 3h after the dropwise addition. After the reaction was completed, the low boiling point (the mixture of triethylamine and acetic acid) was removed by distillation under reduced pressure with a water pump, and the mixture was steamed until the internal temperature did not exceed 120°C. The distillation residue is the crude amide product, 135 g (content 90%, 0.87 mol, yield 87.4%), brown-red oil.

[0057] Referring to the meth...

Embodiment 16

[0061] Example 16, Synthesis of 2-chloro-5-methylpyridine (R=methyl, R 1 =H, the chlorinating agent is bis(trichloromethyl carbonate)

[0062]

[0063] 135g of crude amide product (content 90%, 0.87mol), 100mL of 1,2-dichloroethane, and 74.1g of DMF (99.0%, 1.0mol, 1.15eq) were successively added to a 1L reaction flask, stirred evenly, and a low temperature reaction bath was used. The temperature was lowered to about 0 °C, and then a solution of 191.2 g (99.0%, 0.64 mol, 0.73 eq) of bis(trichloromethyl carbonate) and 400 mL of 1,2-dichloroethane was slowly added dropwise with a constant pressure dropping funnel. In the process of adding, the internal temperature should not exceed 20 °C. After dripping, slowly heat up to about 40 °C for 2 hours, then remove most of the solvent by vacuum distillation, when the temperature in the kettle reaches about 100 °C (the solvent 1,2-dichloroethane has been distilled off at this time), Switch the receiving flask, collect 2-chloro-5-me...

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Abstract

The invention belongs to the technical field of chemical synthesis of pesticides, and in particular relates to a method for preparing 2-chloro-5-substituted pyridine, in particular for preparing 2-chloro-5-methylpyridine. In the present invention, the amide shown in formula C is used as a raw material, and the reaction is carried out in the presence of a chlorinating agent and nitrogen dimethylformamide, and the 5-substituted 2-chloropyridine shown in formula I is obtained by distillation after the reaction finishes. When the present invention adopts the compound of formula C structure to prepare the 5-substituted 2-chloropyridine, the by-product is allyl chloride (or its homologue) with a smaller molecular weight, and the difference with the boiling point of the product is obvious, not only the reaction conversion rate and yield It is higher than the prior art, and the by-products are easily separated from the products, and the by-product industry is more conducive to recovery; therefore, the preparation method of the present invention can greatly save equipment investment, reduce production costs, and simplify operation procedures; the use price in the route of the present invention Lower amine as starting material reduces production cost.

Description

technical field [0001] The invention belongs to the technical field of chemical synthesis of pesticides, in particular to a method for preparing 2-chloro-5-substituted pyridine. Background technique [0002] 2-Chloro-5-substituted pyridine is a class of important organic raw materials, of which the most representative structure is 2-chloro-5-methylpyridine, which can be used as an intermediate in the field of medicine (such as pirfenidone), and also as an intermediate. Key intermediates in the field of pesticides (such as imidacloprid, acetamiprid), etc. It mainly has the following synthetic methods: [0003] 1) Acetamide of a specific structure reacts with Vilsmeier reagent (prepared by the reaction of phosphorus oxychloride and DMF) to form a mixture of the corresponding 5-substituted 2-chloro and the corresponding pyridone (refer to J.Chem.Soc.Perkin Trans.I 1984 , 1173-1982), wherein pyridone is the main product; [0004] [0005] wherein R represents alkyl or aral...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D213/61C07C17/093C07C21/067C07C21/04C07C22/04
CPCC07D213/61C07C17/093C07C21/067C07C21/04C07C22/04
Inventor 丁洪海孟志
Owner 上海垚翀化工科技有限公司
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