Preparation method of 2-amino-3-bromopyridine

Abstract

The invention discloses a preparation method of 2-amino-3-bromopyridine. The method comprises the following steps: dissolving 2-aminopyridine in an organic solvent, stirring at 0 DEG C and adding half of the liquid bromine, heating by 10-20 DEG C, dropwise adding acetate, cooling to below 0 DEG C, then adding the other half of liquid bromine, rising the temperature and reacting for some time to obtain a mixed solution; adding sodium hydroxide solution to adjust the pH value to a neutral state, mixing the mixed solution with water, extracting three times, and carrying vacuum concentration to obtain 2-amino-bromopyridine. By the above way, the preparation method of 2-amino-3-bromopyridine provided by the invention can obtain high purity 2-amino-3-bromopyridine with a small amount of by-products, the product can be obtained by simple posttreatment, and a next step of reaction can be carried out directly. The preparation method has simple synthesis process and high yield, greatly reduces production cost and is applicable for mass production.

Description

technical field

[0001] The invention relates to the field of fine organic synthesis, in particular to a preparation method of 2-amino-3-bromopyridine. Background technique

[0002] Pyridine and its derivatives are a very important class of fine chemical products with a wide range of uses, especially in the fields of medicine and pesticides. Among pesticides, the herbicide paraquat is used in the largest amount, and niacin and niacinamide are used in the largest amount in medicine and animal feed. There are many kinds of pyridine special fine chemicals, some of which have high added value, and pyridine derivatives are widely used and have great development potential. 2-Amino-3-bromopyridine is an important pesticide intermediate, mainly used in the synthesis of plant growth regulators, and can be used to prepare drugs for neuron protection, analgesia, anti-drug dependence, and anti-Parkinson's disease. The traditional method for synthesizing 2-amino-3-bromopyridine has a lo...

Examples

Embodiment 1

[0013] A kind of preparation method of 2-amino-3-bromopyridine is provided, comprising the steps of:

[0014] (1) Dissolve 2-aminopyridine in an organic solvent, stir below 0°C and add half of the liquid bromine dropwise. The drop rate of the liquid bromine is 1 drop every 7 seconds, and then add acetic acid dropwise at 15°C. The dropping rate of the acetic acid is to add 1 drop every 3 seconds, drop the temperature below 0°C and then add the other half of the liquid bromine dropwise, raise the temperature to 57°C and react for 1.2 hours to obtain a mixed solution;

[0015] (2) Add sodium hydroxide solution to adjust the pH value to be neutral, then mix and extract the mixed solution with water three times, and concentrate under reduced pressure to obtain 2-amino-3-bromopyridine.

Embodiment 2

[0017] A kind of preparation method of 2-amino-3-bromopyridine is provided, comprising the steps of:

[0018] (1) Dissolve 2-aminopyridine in an organic solvent, stir below 0°C and add half of the liquid bromine dropwise. The drop rate of the liquid bromine is 1 drop every 6 seconds, and then add acetic acid dropwise at 17°C. The dropping speed of the acetic acid is to drop 1 drop every 4 seconds, drop the temperature below 0°C and then add the other half of the liquid bromine dropwise, raise the temperature to 53°C and react for 1 hour to obtain a mixed solution;

[0019] (2) Add sodium hydroxide solution to adjust the pH value to be neutral, then mix and extract the mixed solution with water three times, and concentrate under reduced pressure to obtain 2-amino-3-bromopyridine.

Embodiment 3

[0021] A kind of preparation method of 2-amino-3-bromopyridine is provided, comprising the steps of:

[0022] (1) Dissolve 2-aminopyridine in an organic solvent, stir below 0°C and add half of the liquid bromine dropwise. The drop rate of the liquid bromine is 1 drop every 5 seconds, and then add acetic acid dropwise at 14°C. The dropping speed of the acetic acid is to drop 1 drop every 4 seconds, drop the other half of the liquid bromine after cooling down to below 0°C, raise the temperature to 55°C and react for 0.5 hours to obtain a mixed solution;

[0023] (2) Add sodium hydroxide solution to adjust the pH value to be neutral, then mix and extract the mixed solution with water three times, and concentrate under reduced pressure to obtain 2-amino-3-bromopyridine.

technical field

[0001] The invention relates to the field of fine organic synthesis, in particular to a preparation method of 2-amino-3-bromopyridine. Background technique

[0002] Pyridine and its derivatives are a very important class of fine chemical products with a wide range of uses, especially in the fields of medicine and pesticides. Among pesticides, the herbicide paraquat is used in the largest amount, and niacin and niacinamide are used in the largest amount in medicine and animal feed. There are many kinds of pyridine special fine chemicals, some of which have high added value, and pyridine derivatives are widely used and have great development potential. 2-Amino-3-bromopyridine is an important pesticide intermediate, mainly used in the synthesis of plant growth regulators, and can be used to prepare drugs for neuron protection, analgesia, anti-drug dependence, and anti-Parkinson's disease. The traditional method for synthesizing 2-amino-3-bromopyridine has a lo...

Examples

Embodiment 1

[0013] A kind of preparation method of 2-amino-3-bromopyridine is provided, comprising the steps of:

[0014] (1) Dissolve 2-aminopyridine in an organic solvent, stir below 0°C and add half of the liquid bromine dropwise. The drop rate of the liquid bromine is 1 drop every 7 seconds, and then add acetic acid dropwise at 15°C. The dropping rate of the acetic acid is to add 1 drop every 3 seconds, drop the temperature below 0°C and then add the other half of the liquid bromine dropwise, raise the temperature to 57°C and react for 1.2 hours to obtain a mixed solution;

[0015] (2) Add sodium hydroxide solution to adjust the pH value to be neutral, then mix and extract the mixed solution with water three times, and concentrate under reduced pressure to obtain 2-amino-3-bromopyridine.

Embodiment 2

[0017] A kind of preparation method of 2-amino-3-bromopyridine is provided, comprising the steps of:

[0018] (1) Dissolve 2-aminopyridine in an organic solvent, stir below 0°C and add half of the liquid bromine dropwise. The drop rate of the liquid bromine is 1 drop every 6 seconds, and then add acetic acid dropwise at 17°C. The dropping speed of the acetic acid is to drop 1 drop every 4 seconds, drop the temperature below 0°C and then add the other half of the liquid bromine dropwise, raise the temperature to 53°C and react for 1 hour to obtain a mixed solution;

[0019] (2) Add sodium hydroxide solution to adjust the pH value to be neutral, then mix and extract the mixed solution with water three times, and concentrate under reduced pressure to obtain 2-amino-3-bromopyridine.

Embodiment 3

[0021] A kind of preparation method of 2-amino-3-bromopyridine is provided, comprising the steps of:

[0022] (1) Dissolve 2-aminopyridine in an organic solvent, stir below 0°C and add half of the liquid bromine dropwise. The drop rate of the liquid bromine is 1 drop every 5 seconds, and then add acetic acid dropwise at 14°C. The dropping speed of the acetic acid is to drop 1 drop every 4 seconds, drop the other half of the liquid bromine after cooling down to below 0°C, raise the temperature to 55°C and react for 0.5 hours to obtain a mixed solution;

[0023] (2) Add sodium hydroxide solution to adjust the pH value to be neutral, then mix and extract the mixed solution with water three times, and concentrate under reduced pressure to obtain 2-amino-3-bromopyridine.