856965-66-7Relevant articles and documents
Preparation method of 4,5-dichloro-2-hydroxypyridine
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Paragraph 0022-0027, (2019/10/01)
The invention discloses a preparation method of 4,5-dichloro-2-hydroxypyridine. The method comprises the following steps that S1, chlorine-containing organic matter and 2,4,5-trihydroxy pyridine are added into a reaction bottle in sequence, heating reflux is conducted for 16-48 hours, concentration and extraction are conducted, organic phases are combined, a drying agent is added to the organic phases, filtering and rotary evaporation are conducted, and a solvent is removed for obtaining a 2,4,5-trichloropyridine crude product; S2, the 2,4,5-trichloropyridine crude product is dissolved in a polar solvent, an aqueous NaOH solution is added at 0-25 DEG C, a reaction is conducted for 1-6 hours at 0-25 DEG C, extraction is conducted, organic phases are combined, a drying agent is added to theorganic phases, filtering and rotary evaporation are conducted, and a solvent is removed for obtaining a 4,5-dichloro-2-hydroxypyridine crude product; S3, the 4,5-dichloro-2-hydroxypyridine crude product is subjected to recrystallization for obtaining a 2,4,5-trichloropyridine pure product. According to the preparation method of the 4,5-dichloro-2-hydroxypyridine, the raw materials are easy to obtain, the preparation process and purification steps are simple, and industrialization is conveniently achieved.