Synthesis method of 4-trifluoromethyl nicotinic acid

Abstract

The invention provides a synthesis method of 4-trifluoromethyl nicotinic acid, which comprises the following steps: step 1, carrying out heat preservation on 3-cyanopyridine, a solvent, tetramethylethylenediamine and butyl lithium at-40 DEG C to-30 DEG C to prepare a solution; step 2, introducing the solution into bromotrifluoromethane for reaction, and then raising the temperature to 0-10 DEG C for reaction to obtain 4-trifluoromethyl-3-cyanopyridine; 3, 4-trifluoromethyl-3-cyanopyridine and sodium hydroxide or potassium hydroxide are hydrolyzed in water at the temperature of 60-100 DEG C, reactants are separated out after being adjusted to be acidic through acid, and 4-trifluoromethyl-3-picolinic acid is obtained through filtering and drying. The raw materials adopted by the synthesis method are relatively cheap and easy to obtain, the method is simple and convenient to operate, the product in each step is easy to separate and purify, the yield is high, and the method is suitable for batch industrial production. The total yield of the synthesis method reaches 63%, and the purity is not less than 98%.

Description

technical field [0001] The invention belongs to the technical field of pesticide pharmacy and relates to 4-trifluoromethyl nicotinic acid, in particular to a synthesis method of 4-trifluoromethyl nicotinic acid. Background technique [0002] Flunicamid is a pyridinamide insect growth regulator insecticide developed by Ishihara Corporation of Japan. It has contact and stomach poisoning effects, and also has good neurotoxicity and rapid antifeedant effects. For piercing-sucking mouthparts pests such as aphids, after inhaling the plant juice with flonicamid, they will be quickly prevented from sucking the juice, there will be no excrement at all within 1 hour, and eventually they will die due to starvation. It is mainly used for cotton, pears and drupe fruits. It has the characteristics of high efficiency, low toxicity, systemic absorption, long-lasting effect and high safety. Fonicamid has good neurological effects and rapid Antifeedant activity, low dosage can control aphids...

AI Technical Summary

Problems solved by technology

[0004] The relevant 4-trifluoromethyl nicotinic acid preparation that is disclosed at home and abroad mainly contains following three kinds: by containing trifluoromethylpyridine compound in the presence of strong bases such as LDA and catalyzer and CO Reacidification preparation, but the raw material of this method Expensive, low yield and strict anhydrous conditions are required, it is difficult to realize industrial production; react with vinyl ethyl ether with trifluoroacetyl chloride or trifluoroacetic anhydride, then ammoniate, and then react with methyl 3-methoxyacrylate, Finally, the target product is obtained by ring-forming hydrolysis. The process route of this method is long and the total yield is low; using ethyl trifluoroacetoacetate and cyanoacetamide as raw materials, through cyclization, chlorination, cyanohydrolysis, and catalytic hydrogenolysis four One-step reaction to prepare 4-trifluoromethylnicotinic acid. At present, this route is not yet mature, and the yield is low during chlorination. The cyano group is easily reduced during catalytic hydrogenolysis, and the pyridine ring is easily partially reduced.

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