Preparation method of 2-methyl-4-bromopyridine

A technology of bromopyridine and nitropyridine, which is applied in the field of preparation of 2-methyl-4-bromopyridine, can solve the problems of low yield and multiple routes, and achieve high yield, low production cost, and easy scale-up production Effect

Inactive Publication Date: 2015-10-14
陈吉美
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the invention is to overcome the technical deficiencies of many routes and low yield in the prior art, and provide a method for preparing 2-methyl-4-bromopyridine with high yield and suitable for industrialized production

Method used

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  • Preparation method of 2-methyl-4-bromopyridine

Examples

Experimental program
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Effect test

Embodiment 1

[0019] (1) Preparation of 2-methyl-4-nitropyridine: Heat a mixture of diethyl malonate (80ml, 0.5mol) and sodium (2.53g, 0.11mol) in an oil bath to 90°C, stir for 1h, After heating up to 120°C and stirring for 45 min, it was cooled to room temperature. A toluene solution of 2-chloro-4-nitropyridine (15.6 g, 0.1 mol) was added dropwise. After the addition was complete, the reaction solution was heated to 110° C. for 1.5 h, cooled to room temperature and stirred for 15 h. The solvent was evaporated under reduced pressure, 6N hydrochloric acid (100ml) was added, the temperature was raised to reflux for 3.5h and then cooled to room temperature. Adjust the pH to alkaline with saturated sodium carbonate solution, extract with ethyl acetate, combine the base phases, dry over anhydrous sodium sulfate, filter with suction, and concentrate to obtain 2-methyl-4-nitropyridine with a molar yield of 92 %.

[0020] (2) Preparation of 2-methyl-4-aminopyridine: Dissolve 2-methyl-4-nitropyrid...

Embodiment 2

[0023] (1) Preparation of 2-methyl-4-nitropyridine: heat up the oil bath of the mixture of diethyl malonate (80ml, 0.5mol) and sodium (2.76g, 0.12mol) to 90°C, stir for 1h, After heating up to 120°C and stirring for 45 min, it was cooled to room temperature. A toluene solution of 2-chloro-4-nitropyridine (15.6 g, 0.1 mol) was added dropwise. After the addition was complete, the reaction solution was heated to 110° C. for 1.5 h, cooled to room temperature and stirred for 15 h. The solvent was evaporated under reduced pressure, 6N hydrochloric acid (100ml) was added, the temperature was raised to reflux for 3.5h and then cooled to room temperature. Adjust the pH to alkaline with saturated sodium carbonate solution, extract with ethyl acetate, combine the base phases, dry over anhydrous sodium sulfate, and concentrate by suction filtration to obtain 2-methyl-4-nitropyridine with a molar yield of 95%. .

[0024] (2) Preparation of 2-methyl-4-aminopyridine: Dissolve 2-methyl-4-ni...

Embodiment 3

[0027] (1) Preparation of 2-methyl-4-nitropyridine: Heat a mixture of diethyl malonate (80ml, 0.5mol) and sodium (2.99g, 0.13mol) in an oil bath to 90°C, stir for 1h, After heating up to 120°C and stirring for 45 min, it was cooled to room temperature. A toluene solution of 2-chloro-4-nitropyridine (15.6 g, 0.1 mol) was added dropwise. After the addition was complete, the reaction solution was heated to 110° C. for 1.5 h, cooled to room temperature and stirred for 15 h. The solvent was evaporated under reduced pressure, 6N hydrochloric acid (100ml) was added, the temperature was raised to reflux for 3.5h and then cooled to room temperature. Adjust the pH to alkaline with saturated sodium carbonate solution, extract with ethyl acetate, combine the base phases, dry over anhydrous sodium sulfate, filter with suction, and concentrate to obtain 2-methyl-4-nitropyridine with a molar yield of 95 %.

[0028] (2) Preparation of 2-methyl-4-aminopyridine: Dissolve 2-methyl-4-nitropyrid...

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Abstract

The invention belongs to the field of organic synthesis and in particular relates to a preparation method of 2-methyl-4-bromopyridine. The preparation method comprises the following steps: (1) reacting diethyl malonate with alkali metal to generate salt, then dropwise adding a toluene solution of 2-chloro-4-nitropyridine to carry out condensation reaction, and then carrying out decarboxylation under the acidic condition to obtain 2-methyl-4-nitropyridine; (2) carrying out hydrogenation reduction on 2-methyl-4-nitropyridine in the presence of a catalyst Pd/C by using methanol as a solvent, carrying out suction filtration and concentrating filtrate to obtain 2-methyl-4-aminopyridine; (3) firstly reacting 2-methyl-4-aminopyridine with acid to generate salt, cooling the salt to minus 10-0 DEG C, dropwise adding bromine, dropwise adding a sodium nitrite water solution after completing dropwise adding bromine, regulating the pH value of the solution to alkalinity after completing dropwise adding the water solution, and then carrying out extraction, drying and concentration to obtain 2-methyl-4-bromopyridine. The preparation method has the beneficial effects that the preparation method is mild in reaction conditions, is easy to operate, is simple in after-treatment, easily achieves large scale production and is very suitable for industrial production; the catalytic effects are good and the yield is high; the raw materials are cheap and the production cost is low.

Description

technical field [0001] The invention belongs to the field of organic synthesis, and in particular relates to a preparation method of 2-methyl-4-bromopyridine. 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. 2-Methyl-4-bromopyridine is an important intermediate, mainly used as pharmaceutical intermediates, organic synthesis intermediates, organic solvents, and also used in the production of dyes, spices and pesticides. [0003] At present, the reported synthetic methods of 2-methyl-4-bromopyridine have disadvantages such as low yield and long process route. Contents of the invention [0004] The purpose of the pre...

Claims

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Application Information

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