Transformations of trichloromethyl groups during reactions of 3-trichloromethylpyridines with methoxide

When methoxide ion attacks an unsubstituted 2- or 6-position of a 3-trichloromethylpyridine, a hydrogen shift leads to a methoxy-substituted 3-dichloromethylpyridine. Further reaction of the dichloromethyl group with methoxide gives the corresponding acetal. This type of reaction has been applied to several chlorinated 3-trichloromethylpyridines and to 3-trichloromethylpyridine itself; a convenient synthesis of the latter is described.