A kind of synthetic technique of 2-hydrazinopyridine derivative

A technology for the synthesis of hydrazinopyridine, which is applied in the field of synthesis technology of 2-hydrazinopyridine derivatives, can solve the problems of low product yield, no safety protection, and many steps, and achieve improved selectivity and reaction rate, Guaranteed selectivity and efficiency, the effect of mild reaction conditions

Active Publication Date: 2020-03-20
江苏富比亚化学品有限公司
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  • Description
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  • Application Information

AI Technical Summary

Problems solved by technology

This method is difficult to prepare the reaction raw material 2-fluoro-3-chloropyridine, and there is no safety protection when using hydrazine hydrate for the reaction, and does not involve the recovery of the solvent
3-Chloro-2-hydrazinopyridine can also be prepared by the reaction of 2,3-dichloropyridine and hydrazine hydrate. However, the preparation of the reaction raw material 2,3-dichloropyridine generally uses nicotinamide and sodium hypochlorite to obtain 3 -Aminopyridine, obtained by chlorination reaction, diazotization and Sandmeyer reaction. This reaction process has many steps, which leads to low product yield and consumes a lot of labor costs, and diazotization, chlorination and reaction More extraction operations in the process will also produce a large amount of waste liquid and waste solid, which seriously pollutes the environment, restricts the industrial production scale of this product, and does not meet the requirements of my country's energy saving, emission reduction, and green production

Method used

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  • A kind of synthetic technique of 2-hydrazinopyridine derivative
  • A kind of synthetic technique of 2-hydrazinopyridine derivative
  • A kind of synthetic technique of 2-hydrazinopyridine derivative

Examples

Experimental program
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Effect test

Embodiment 1

[0088] (1) Synthesis of 2,3-dichloropyridine (using 2,3,6-trichloropyridine as raw material)

[0089] Add 500g of 2.3.6-trichloropyridine, 1800g of methanol, 20g of mixed catalyst (8%Pt / C:8%Pd / C=1:10) and 45g of pyridine into the reaction kettle, pass in hydrogen, and slowly drop 5 (weight)% sodium hydroxide methanol solution, maintain the pressure in the reactor to be 0.3Mpa, the temperature is 30 DEG C, after the hydrogenation is completed, replace the hydrogen, filter out the Pt / C and Pd / C catalysts for mechanical use, and receive the filtrate atmospheric pressure distillation Methanol is recovered, water is added to the remaining material, the temperature is lowered to crystallize, centrifuged and purified to obtain 2,3-dichloropyridine.

[0090] In step (1), the purity of 2,3-dichloropyridine is 97.6%, and the yield is 88.5%. After crystallization, the gas chromatogram without purification is as follows figure 1 shown.

[0091] (2) Synthesis of 3-chloro-2 hydrazinopyrid...

Embodiment 2

[0095] (1) Synthesis of 2,3-dichloropyridine

[0096] 450g of 2.3.6-trichloropyridine, 1600g of ethanol, 20g of mixed catalyst (8%Pt / C:8%Pd / C=10:1) and 45g of triethylamine were added to the reactor, and hydrogen was introduced while slowly Add dropwise 5 (weight)% sodium hydroxide ethanol solution, keep the pressure in the reactor as 0.25Mpa, and the temperature is 25 to 30°C. After the hydrogenation is completed, replace the hydrogen, filter out the Pt / C and Pd / C catalysts, and receive The filtrate is distilled at normal pressure to recover methanol, water is added to the remaining material, the temperature is lowered to crystallize, centrifuged and purified to obtain 2,3-dichloropyridine.

[0097] In step (1), the purity of 2,3-dichloropyridine is 96.8%, and the yield is 85%, and the gas chromatogram is as follows without purification after crystallization image 3 shown.

[0098] (2) Synthesis of 3-chloro-2 hydrazinopyridine

[0099] Mix 148g of 2,3-dichloropyridine and...

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Abstract

The invention discloses a synthetic process for a 2-hydrazinylpyridine derivative. The process includes the steps that a pyridine halide A, hydrazine hydrate and a solvent I are mixed for a reaction; and after the reaction and aftertreatment, a reaction product, namely the 2-hydrazinylpyridine derivative P is obtained. According to the process, the pyridine halide A can be obtained through a hydrogen substitution reaction of a precursor compound B under the conditions of bases and catalysts. N,N-dimethylpropanolamine in the solvent I plays the role of an acid-binding agent to a certain extent, and the reaction is promoted to the product generating direction; and in the hydrogen substitution reaction, the mixed catalysts are combined with compounding use of the strong base and the weak base, so that the selectivity of the hydrogen substitution reaction is improved, and the reaction speed of the hydrogen substitution reaction is increased.

Description

technical field [0001] The invention relates to the field of fine chemicals, in particular to a synthesis process of 2-hydrazinopyridine derivatives. Background technique [0002] 2-hydrazinopyridine derivatives are widely used as intermediates in the fields of medicine, pesticides, rubber and dyes. With the rapid development of my country's fine chemical industry, especially the rapid development of my country's pharmaceutical and pesticide industries, the demand for 2-hydrazinopyridine derivatives such as 3-chloro-2-hydrazinopyridine is increasing. [0003] At present, there are few reports on the industrial synthesis methods of 2-hydrazinopyridine derivatives, and only a small amount of research on the preparation methods of 3-chloro-2-hydrazinopyridines. For example, in Chinese patent CN103588705A, 2-fluoro-3-chloropyridine and hydrazine hydrate are mixed, and ethanol is used as a solvent to carry out the reaction at room temperature. The preparation of the reaction ra...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D213/77
CPCC07D213/77
Inventor 陈明光吴邦元施仲锋张文忠许军
Owner 江苏富比亚化学品有限公司
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