| 摘要 |
A 2-oxo-5-methyl-5,6-dihalopiperidine is contacted in a high boiling solvent, preferably trichlorobenzene, with a stoichiometric excess, up to 70 mole % excess, of a chlorinating agent, preferably phosphorus oxychloride or phosgene, at an elevated temperature between 80 DEG and 130 DEG C. The solution of 2-chloro-5-methylpyridine so obtained may be used directly for further chlorination to form 2-chloro-5-trichloromethylpyridine with, for example, chlorine gas in the presence of a free radical initiator. This chemical intermediate is useful in the synthesis of certain herbicidal compounds.
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