Synthetic process for 2-hydrazinylpyridine derivative

A synthetic process, the technology of hydrazinopyridine, applied in the direction of organic chemistry, can solve the problems of low product yield, no safety protection, and many steps, so as to improve selectivity and reaction rate, ensure selectivity and efficiency, and react The effect of mild conditions

Active Publication Date: 2017-04-26

江苏富比亚化学品有限公司

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AI-Extracted 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 r...

Method used

As a kind of improvement of above-mentioned embodiment, described catalyzer is selected from carrier catalyst, is preferably the catalyzer taking gac as carrier, more preferably palladium/carbon (Pd/C) and platinum/carbon (Pt/C) mixed catalyst. The production practice shows that the catalytic efficiency and selectivity of the mixed catalyst are higher than that of the Pd/C or Pt/C catalyst used alone.

[0039] Below by describing the present invention in detail, the features and advantages of the present invention will become clearer and clearer along with these descriptions.

[0054] The weight ratio of hydrazine hydrate and solvent I is 1:25 to 1:50, which satisfies the requirements of the reflux reaction, and simultaneously does not cause the reaction raw material concentration to be too low, reducing the react...

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.

Application Domain

Organic chemistry

Technology Topic

SolventSubstitution reaction +6

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Examples

Experimental program(2)
Comparison scheme(2)

Example Embodiment

[0087] Example 1

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

[0089] 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 were added to the reactor, hydrogen was introduced, and slowly dripped simultaneously 5 (weight) % sodium hydroxide methanol solution, maintaining the pressure in the reactor to be 0.3Mpa, the temperature is 30 ℃, after the hydrogenation is completed, replace the hydrogen, filter out Pt/C and Pd/C catalyst and apply mechanically, and receive the filtrate by atmospheric distillation Methanol is recovered, water is added to the remaining material, cooled for crystallization, centrifugation and purification to obtain 2,3-dichloropyridine.

[0090] In step (1), the purity of 2,3-dichloropyridine is 97.6%, and the yield is 88.5%. figure 1 shown.

[0091] (2) Synthesis of 3-chloro-2-hydrazinopyridine

[0092] Mix 148g of 2,3-dichloropyridine and 3700g of N,N-dimethylpropanolamine in the reaction kettle, add 105g of 80% hydrazine hydrate, replace the air in the kettle with nitrogen three times, then be warmed up to 130° C. The reaction was refluxed for 10 hours, the reaction was completed, cooled to 25 ° C for crystallization, then transferred to a centrifuge for centrifugation, and the centrifuged solid was washed with water, and the centrifuged mother liquor was put into the N,N-dimethylpropanolamine mother liquor tank for rectification. The solid was sent to a double cone dryer (-0.09MPa, 60°C) for drying to obtain the product 3-chloro-2-hydrazinopyridine.

[0093] In step (2), the purity of 3-chloro-2-hydrazinopyridine is 99.7%, the yield is 95%, and the liquid chromatogram is as follows figure 2 shown.

Example Embodiment

[0094] Example 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 into the reactor while slowly Add 5 (weight) % sodium hydroxide ethanol solution dropwise, maintain the pressure in the reactor to be 0.25Mpa, the temperature is 25~30 ℃, after the hydrogenation is completed, replace hydrogen, filter out Pt/C and Pd/C catalyst and apply mechanically, receive The filtrate is distilled at atmospheric pressure to recover methanol, water is added to the remaining material, cooled for crystallization, 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%. image 3 shown.

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

[0099] Mix 148g of 2,3-dichloropyridine and 4500g of N,N-dimethylformamide in the reaction kettle, add 110g of 80% hydrazine hydrate, replace the air in the kettle with nitrogen three times, then heat up to 130 ° C, keep under reflux The reaction was completed for 10 hours, the reaction was completed, cooled to 25°C for crystallization, then transferred to a centrifuge for centrifugation, and the centrifuged solid was washed with water. Dry in a double cone dryer (-0.09MPa, 60°C) to obtain the product 3-chloro-2-hydrazinopyridine.

[0100] In step (2), the purity of 3-chloro-2-hydrazinopyridine is 99.2%, the yield is 90%, and the liquid chromatogram is as follows Figure 4 shown.

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Classification and recommendation of technical efficacy words

mild reaction conditions
improve security

Synthetic process for 2-hydrazinylpyridine derivative

AI-Extracted Technical Summary

Problems solved by technology

Method used

Abstract

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Example Embodiment

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Description & Claims & Application Information

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