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Synthesis method of 3-bromo-5-methylpyridine

A kind of methylpyridine and synthetic method technology, applied in directions such as organic chemistry, can solve the problems of low yield, long process route, etc., and achieve the effects of high yield, short process route and mild reaction conditions

Inactive Publication Date: 2017-09-15
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-bromo-5-picoline has disadvantages such as low yield and long process route.

Method used

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  • Synthesis method of 3-bromo-5-methylpyridine

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Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0024] Diethyl malonate reacts with sodium to generate a salt, then adds dropwise a toluene solution of 3-nitro-5-chloropyridine for condensation reaction, and then decarboxylates under acidic conditions to obtain 3-nitro-5-methylpyridine; The molar ratio of diethyl diacid, alkali metal, and 3-nitro-5-chloropyridine is 5:1.1:1.

[0025] 3-nitro-5-methylpyridine was catalyzed by Pd / C, methanol was used as solvent, hydrogenated for reduction, suction filtered, and the filtrate was concentrated to obtain 3-amino-5-methylpyridine.

[0026] 3-Amino-5-picoline first forms a salt with an acid, cools to -10°C, adds liquid bromine dropwise, and then adds a sodium nitrite aqueous solution dropwise, after the dropwise addition, adjust the pH of the solution to be alkaline, then extract, dry, Concentration gave 3-bromo-5-methylpyridine.

Embodiment approach 2

[0028] Diethyl malonate reacts with sodium to generate a salt, then adds dropwise a toluene solution of 3-nitro-5-chloropyridine for condensation reaction, and then decarboxylates under acidic conditions to obtain 3-nitro-5-methylpyridine; The molar ratio of diethyl diacid, alkali metal, and 3-nitro-5-chloropyridine is 6:1.3:1;

[0029] 3-nitro-5-picoline is catalyzed by Pd / C, methanol is used as a solvent, hydrogenated for reduction, suction filtered, and the filtrate is concentrated to obtain 3-amino-5-picoline;

[0030] 3-Amino-5-methylpyridine forms a salt with an acid first, cools to 0°C, adds liquid bromine dropwise, and then adds a sodium nitrite aqueous solution dropwise, after the dropwise addition, adjust the pH of the solution to be alkaline, then extract, dry, and concentrate , in 3-bromo-5-methylpyridine.

Embodiment approach 3

[0032] Diethyl malonate reacts with potassium to generate a salt, then adds dropwise a toluene solution of 3-nitro-5-chloropyridine for condensation reaction, and then decarboxylates under acidic conditions to obtain 3-nitro-5-methylpyridine; The molar ratio of diethyl diacid, alkali metal, and 3-nitro-5-chloropyridine is 5.4:1.2:1;

[0033] 3-nitro-5-methylpyridine is catalyzed by Pd / C, methanol is used as a solvent, hydrogenated for reduction, suction filtered, and the filtrate is concentrated to obtain 3-amino-5-methylpyridine;

[0034] 3-Amino-5-picoline first forms a salt with an acid, cools to -4°C, adds liquid bromine dropwise, and then adds a sodium nitrite aqueous solution dropwise, after the dropwise addition, adjust the pH of the solution to be alkaline, then extract, dry, Concentration gave 3-bromo-5-methylpyridine.

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Abstract

The invention relates to the field of organic chemistry and particularly provides a synthesis method of 3-bromo-5-methylpyridine. The synthesis method includes the steps of: 1) performing a reaction to diethyl malonate and alkaline metal to generate a salt, and dropwise adding a toluene solution of 3-nitro-5-chloropyridine to perform a condensation reaction, and decarboxylating the product under an acidic condition to obtain 3-nitro-5-methylpyridine; 2) performing hydrogenation reduction to the 3-nitro-5-methylpyridine with Pd / C as a catalyst and methanol as a solvent, performing suction filtration and concentrating a filtrate to prepare 3-amino-5-methylpyridine; and 3) performing a reaction to the 3-amino-5-methylpyridine with an acid to generate a salt, and cooling the salt to -10 - 0 DEG C, dropwise adding liquid bromine, and then dropwise adding a sodium nitrite water solution, regulating the pH value of the solution to alkalinity and performing extraction, drying and concentration to obtain the 3-bromo-5-methylpyridine. The synthesis method is mild in reaction conditions, is high in yield, employs easy-to-obtained raw materials, is low in cost, is short in process route and has industrial prospect.

Description

technical field [0001] The invention relates to the field of organic chemistry, in particular to a method for synthesizing 3-bromo-5-picoline. 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-Bromo-5-picoline 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. At present, the reported synthetic methods of 3-bromo-5-picoline have disadvantages such as low yield and long process route. Contents of the invention [0003] The technical problem to be solved in the p...

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
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