Processes for preparing 2-chloro-5-trifluoromethylpyridine

摘要

One process comprises the step of reacting an amount of 5-carboxy-2-pyridone directly with both a suitable chlorinating agent and a suitable fluorinating agent to selectively transform both the 5-carboxy group and the 2-positioned oxygen function of the ring. A second process comprises the steps of reacting an amount of 5-carboxy-2-pyridone with a suitable fluorinating agent to selectively transform the 5-carboxy group without altering the 2-positioned oxygen function of the ring and reacting the 5-trifluoromethyl-2-pyridone thereby formed with a suitable chlorinating agent to cause 2-chloro-5-trifluoromethylpyridine to form. A third process comprises the steps of reacting an amount of a 5-carboxy-2-pyrone compound with a suitable fluorinating agent to selectively transform the 5-carboxy group without altering the 2-positioned oxygen function of the ring, reacting the 5-trifluoromethyl-2-pyrone compound thereby formed with an ammonia-containing agent in the presence of a caustic material to cause 5-trifluoromethyl-2-pyridone to form, and reacting the 5-trifluoromethyl-2-pyridone thereby formed with a suitable chlorinating agent to cause 2-chloro-5-trifluoromethylpyridine to form.