The Preparation and Characterization of Some N-Chloro-2- and N-Chloro-4-Pyridones

2-Pyridone and 5-chloro-2-pyridone with NaOCl yield 1-chloro-2-pyridone and 1,5-dichloro-2-pyridone, respectively, which rapidly rearrange into 5-chloro- and 3,5-dichloro-2-pyridone. 3,5-Dichloro-2-pyridone with NaOCl yields 1,3,5-trichloro-2-pyridone which shows considerable stability. 4-Pyridone is similarly converted by NaOCl into 3,5-dichloro-4-pyridone via an unstable N-chloro derivative. 1,3,5-Trichloro-4-pyridone was obtained from 3,5-dichloro-4-pyridone and NaOCl.