Improved preparation method of nitenpyram

Abstract

The invention relates to an improved preparation method of nitenpyram. The method comprises steps as follows: firstly, 1,1-dichloroethylene has a reaction with a nitration agent comprising hydrochloric acid and sodium nitrate to generate 1,1,1-trichlorine-2-nitroethane, and the 1,1,1-trichlorine-2-nitroethane has an elimination reaction with NaHCO3 to generate a 1,1-dichlorine-2-nitroethylene intermediate; secondly, 2-chlorine-5-chloromethylpyridine has a reaction with ethylamine, and an ethylamine intermediate is prepared; thirdly, the ethylamine intermediate has a reaction with 1,1-dichlorine-2-nitroethylene intermediate and monomethylamine, and the final product nitenpyram is generated. NaNO3 is used to replace traditional nitric acid to serve as a target phase transfer catalyst, the reaction selectivity is improved, the yield is higher, and the operation is safer.

Description

technical field

[0001] The invention belongs to the technical field of organic synthesis, and in particular relates to an improved method for preparing nitenpyram. Background technique

[0002] Nitenpyram (Nitenpyram) is another new type of nicotinamide insecticide following imidacloprid and acetamiprid. It has a nerve blocking effect on the synaptic receptors of pests. The effect of the method is unique systemic and osmotic action, excellent quick-acting and long-lasting effect, less dosage and low toxicity, so it is very important to study the synthesis process of nitenpyram. At present, nitenpyram The synthesis of generally mainly contains the following several synthetic routes.

[0003] Route 1:

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[0005] Route 2:

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[0007] Route 3:

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[0009] Route 4:

[0010]

[0011] Route 5:

[0012]

[0013] In summary, compared with 2-chloro-5-chloromethylpyridine, there are relatively few manufacturers of 2-chloro-5-aminomethylpyridine, ...

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