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Synthesis method of 2, 5-dibromopyridine

A synthetic method, the technology of dibromopyridine, applied in the direction of organic chemistry, etc., can solve the problems of low yield and long process route, and achieve the effect of high yield, short process route and easy availability of raw materials

Inactive Publication Date: 2019-05-14
丹阳市易通安全技术服务有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Benefits of technology

This patented technology has several benefits that make it useful for various industries such as manufacturing processes or production lines. It can be used at moderate temperatures with good yields but also makes things easier because there's no expensive material needed. Additionally, this new way allows products produced from these methods have fewer side reactions than traditional ways like producing them separately. Overall, this innovation offers technical advantages over existing technologies while reducing costs associated with their use.

Problems solved by technology

The technical problem addressed by this patented method described in the previous section relating to producing certain chemical products from pyridone rings involves high yields or complicated routes involved during manufacturing processes due to poor efficiency associated with existing techniques like reductive amination reaction between different starting materials (pyrrolidinium).

Method used

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  • Synthesis method of 2, 5-dibromopyridine

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Add 18.82g (0.2mol) of 2-aminopyridine and 30.63g (0.3mol) of acetic anhydride to a 200ml four-port oil bath and raise the temperature to reflux, follow the reaction with thin-layer chromatography until the reaction is complete, and wait until the temperature of the reaction solution drops to 20-25 At ℃, slowly add 35.2g (0.22mol) of liquid bromine dropwise, and react at 50℃ for 2.5 hours after dropping. Add water to the system until the solid is completely dissolved, slowly add 80ml of 40% sodium hydroxide solution dropwise, a large amount of solid is formed, continue the reaction for 30 minutes, filter with suction, dry, and recrystallize with ethanol to obtain 2-amino-5-bromopyridine 14.1 g, yield 65% (molar yield).

[0022] Add 50ml48% hydrobromic acid solution in the 200ml there-necked flask equipped with stirrer and thermometer, 6.9g (0.048mol) cuprous bromide is dissolved in the hydrobromic acid solution, keep temperature 0 ℃ in ice-water bath and slowly add 6g (...

Embodiment 2

[0024] Add 18.82g (0.2mol) of 2-aminopyridine and 20.4g (0.2mol) of acetic anhydride to a 200ml four-port oil bath and raise the temperature to reflux, follow the reaction with thin-layer chromatography until the reaction is complete, and wait until the temperature of the reaction solution drops to 20-25 At ℃, slowly add 35.2g (0.22mol) of liquid bromine dropwise, and react at 55℃ for 2 hours after dropping. Add water to the system until the solid is completely dissolved, slowly add 80ml of 40% sodium hydroxide solution dropwise, a large amount of solid is formed, continue the reaction for 30 minutes, filter with suction, dry, and recrystallize with ethanol to obtain 2-amino-5-bromopyridine 12.98 g, yield 60% (molar yield).

[0025] Add 50ml of 48% hydrobromic acid solution to a 200ml three-necked flask equipped with a stirrer and a thermometer, dissolve 7.5g (0.052mol) of cuprous bromide in the hydrobromic acid solution, and slowly add 6g in an ice-water bath to maintain the ...

Embodiment 3

[0027] Add 18.82g (0.2mol) of 2-aminopyridine and 40.8g (0.4mol) of acetic anhydride to a 200ml four-port oil bath and raise the temperature to reflux, follow the reaction with thin-layer chromatography until the reaction is complete, and wait until the temperature of the reaction solution drops to 20-25 At ℃, slowly add 35.2g (0.22mol) of liquid bromine dropwise, and react at 45℃ for 3 hours after dropping. Add water to the system until the solid is completely dissolved, slowly add 80ml of 40% sodium hydroxide solution dropwise, a large amount of solid is formed, continue the reaction for 30 minutes, filter with suction, dry, and recrystallize with ethanol to obtain 2-amino-5-bromopyridine 12.5 g, yield 62% (molar yield).

[0028] Add 50ml48% hydrobromic acid solution in the 200ml there-necked flask equipped with agitator and thermometer, 8.6g (0.06mol) cuprous bromide is dissolved in the hydrobromic acid solution, and slowly add 6g ( 0.04mol) 2-amino-5-bromopyridine, keep t...

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Abstract

The invention relates to the field of organic chemistry, in particular to a synthesis method of 2, 5-dibromopyridine. The method includes following steps: (1), adding 2-aminopyridine and acetic anhydride into a four-neck flask for backflow, and completing thin-layer chromatography tracking reaction; (2), when temperature of reaction liquid in the step (1) is lowered to 20-25 DEG C, dropwise addingliquid bromine, allowing reaction at 45-55 DEG C for 2-3h after dropwise adding is completed, adding water into a system until all solid is dissolved, dropwise adding a sodium hydroxide solution, continuing reaction for 30min when a lot of precipitate is generated, suction-filtering, drying, and recrystallizing to obtain 2-amino-5-bromopyridine; (3), adding 2-amino-5-bromopyridine into a hydrogenbromide solution, dropwise adding a sodium nitrate solution at the presence of cuprous bromide in a catalysis amount, controlling temperature to -5-15 DEG C, and allowing reaction for 2-5h to obtain2, 5-dibromopyridine. The method has the advantages of being mild in reaction condition, high in yield, easy-to-get in raw material, low in cost and few in byproduct and having industrialization prospect, and combine load of subsequent separation is reduced.

Description

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Claims

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Application Information

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Owner 丹阳市易通安全技术服务有限公司
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