Pyridine hydrochloride has been widely used in the cleavage of ethers. It is shown herein that this reagent is also efficient for the synthesis of chloro compounds starting from the corresponding bromo derivatives in π-deficient series such as pyridine and quinoline. Thus, for example, 7-bromo-8-hydroxyquinoline was almost quantitatively converted into 7-chloro- 8-hydroxyquinoline. The scope of the reaction has been studied.
