Does anyone know the process for producing 2-chloro-5-chloromethylpyridine?
Thread Content
Does anyone know the process for producing 2-chloro-5-chloromethylpyridine? Let’s discuss it together.
Hehe. It should be called 2,5-dichloromethylpyridine ； It must be the route that uses methylpyridine as a starting material and achieves directional dichlorination at the position adjacent to the nitrogen atom on the ring.
Upstairs, there is 2-chloro-5-chloromethylpyridine, which can be used to synthesize various highly effective insecticides of heterocyclic type. It serves as an intermediate for compounds such as imidacloprid, acetamiprid, TI-304, thiamethoxam, and others. It can be synthesized using 3-methylpyridine as a starting material, through methods such as chloromethylation or ammonolysis of 3-methylpyridine. Nicotinic acid or 6-hydroxynicotinic acid can also be used as starting materials. In China, 3-methylpyridine is generally used as the starting material, with synthesis carried out via chloromethylation or N-oxidation. These methods involve fewer reaction steps and lower raw material costs, but the separation of the product is difficult, making it hard to obtain high-quality products. When 6-hydroxynicotinic acid or nicotinic acid is used as the starting material, the product purity is higher, but the reaction steps are more complex and the costs are higher.
2-Chloro-5-chloromethylpyridine is currently synthesized in China using dibicyclic dienes as a route, with monocyclic dienes serving as carriers; the yield of this synthesis is relatively low. There is a relatively large amount of waste
I was just about to add that, but I didn’t expect my friend to do it first – thanks! ! !
Yang Nong seems to be using the 3-methylpyridine route; the others seem to use cyclopentadiene
Dicyclopentadiene is first cleaved into monocyclopentadiene, which then reacts with acraldehyde and subsequently with acrylonitrile. After further cleavage, chlorination takes place, followed by cyclization with phosphorus trichloride to yield the target product. The product is purified by distillation to obtain colorless or pale yellow 2-chloro,5-chloromethylpyridine.
Who can give a detailed explanation of the cyclopentadiene route? Thank you.
The one on the 7th floor is the cyclopentadiene route! ! !