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Synthesis method of 3,5-dimethyl-2,6-dibromopyridine

A technology of dibromopyridine and synthesis method, which is applied in the field of synthesis of 3,5-dimethyl-2,6-dibromopyridine, can solve problems such as low yield and long process route, and achieve high yield and process The effect of short route and easy access to raw materials

Inactive Publication Date: 2017-08-11
刘瑞海
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the synthetic method of reported 3,5-dimethyl-2,6-dibromopyridine has disadvantages such as low yield and long process route.

Method used

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  • Synthesis method of 3,5-dimethyl-2,6-dibromopyridine

Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0019] Using 3,5-dimethyl-2-aminopyridine as raw material, add 0.1mol of 3,5-dimethyl-2-aminopyridine and 0.13mol of acetic anhydride into a 250ml four-neck flask, heat the oil bath to reflux, Track the reaction with thin-layer chromatography. When the temperature of the reaction solution drops below 23°C, slowly add 0.11mol of liquid bromine dropwise. After the addition is complete, react at 40°C for 3 hours, then add water to the system until all solids are dissolved, then slowly add 40ml35 % sodium hydroxide solution, continue to react for 20 minutes after adding, suction filtration, drying, and recrystallization to obtain 3,5-dimethyl-2-amino-6-bromopyridine, the solvent used in the recrystallization is methanol, and the molar yield is 65%.

[0020] Add 50ml of 45% hydrobromic acid solution into a 200ml three-necked flask equipped with a stirrer and a thermometer, dissolve 0.048mol of cuprous bromide in the hydrobromic acid solution, and slowly add 0.04mol of 3 in an ice-w...

Embodiment approach 2

[0022] Using 3,5-dimethyl-2-aminopyridine as raw material, add 0.1mol of 3,5-dimethyl-2-aminopyridine and 0.21mol of acetic anhydride into a 250ml four-neck flask, heat the oil bath to reflux, Track the reaction with thin-layer chromatography. When the temperature of the reaction solution drops below 23°C, slowly add 0.11mol of liquid bromine dropwise. After the addition is complete, react at 55°C for 2 hours, then add water to the system until all solids are dissolved, then slowly add 40ml35 % sodium hydroxide solution, continue to react for 40 minutes after adding, suction filter, dry, and recrystallize to obtain 3,5-dimethyl-2-amino-6-bromopyridine, the solvent used in the recrystallization is methanol, and the molar yield is was 68%.

[0023] Add 50ml of 45% hydrobromic acid solution into a 200ml three-necked flask equipped with a stirrer and a thermometer, dissolve 0.068mol cuprous bromide in the hydrobromic acid solution, and slowly add 0.04mol of 3,5 -Dimethyl-2-amino6...

Embodiment approach 3

[0025] Using 3,5-dimethyl-2-aminopyridine as raw material, add 0.1mol of 3,5-dimethyl-2-aminopyridine and 0.16mol of acetic anhydride into a 250ml four-neck flask, heat the oil bath to reflux, Track the reaction with thin-layer chromatography. When the temperature of the reaction solution drops below 23°C, slowly add 0.11mol of liquid bromine dropwise. After the addition is complete, react at 48°C for 2.5 hours, then add water to the system until all solids are dissolved, and then slowly add 40ml of 35 % sodium hydroxide solution, continue to react for 30 minutes after adding, suction filtration, drying, and recrystallization to obtain 3,5-dimethyl-2-amino-6-bromopyridine, the solvent used in the recrystallization is methanol, and the molar yield is was 72%.

[0026] Add 50ml of 45% hydrobromic acid solution into a 200ml three-necked flask equipped with a stirrer and a thermometer, dissolve 0.068mol cuprous bromide in the hydrobromic acid solution, and slowly add 0.04mol of 3,...

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Abstract

The invention relates to the field of organic chemistry and particularly relates to a synthesis method of 3,5-dimethyl-2,6-dibromopyridine. The synthesis method comprises the steps of (1) adopting 3,5-dimethyl-2-aminopyridine as a raw material, adding the 3,5-dimethyl-2-aminopyridine and acetic anhydride to a four-mouth flask, raising the temperature until refluxing, and carrying out thin-layer chromatography tracking reaction; (2) when the temperature of a reaction liquid in the step (1) is reduced to below 23 DEG C, dropwise adding liquid bromine, reacting at 40-55 DEG C for 2-3h after dropwise adding, adding water to the system until all solids are dissolved, dropwise adding a sodium hydroxide solution, generating a lot of sediments and further reacting for 20-40min, carrying out suction filtration, drying and recrystallizing to obtain 3,5-dimethyl-2-amino-6-bromopyridine; and (3) adding the 3,5-dimethyl-2-amino-6-bromopyridine to a hydrogen bromide solution, dropwise adding a saturated sodium nitrite solution in the presence of a catalytic amount of cuprous bromide, controlling the temperature to be -3 DEG C to -4 DEG C and reacting for 2-3h to obtain the 3,5-dimethyl-2,6-dibromopyridine. The method is mild in reaction condition, high in yield, available in raw material, relatively low in cost and short in process route.

Description

technical field [0001] The invention relates to the field of organic chemistry, in particular to a synthesis method of 3,5-dimethyl-2,6-dibromopyridine. Background technique [0002] Pyridine and its derivatives are widely distributed in nature. Many plant components such as alkaloids contain pyridine ring compounds in their structures, which are the basis for the production of many important compounds, such as medicines, pesticides, dyes, surfactants, rubber additives, feed additives, food additives, adhesives, etc. Indispensable raw material in production. 3,5-Dimethyl-2,6-dibromopyridine is an important intermediate in organic synthesis, mainly used in pharmaceutical intermediates, organic synthesis, organic solvents, and can also be used in dye production, pesticide production and spices. Currently, the reported synthetic methods of 3,5-dimethyl-2,6-dibromopyridine have disadvantages such as low yield and long process route. Contents of the invention [0003] The te...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/61
CPCC07D213/61
Inventor 刘瑞海
Owner 刘瑞海