Pyridazines. Part 26: Efficient and Regioselective Pd-Catalysed Arylation of 4-Bromo-6-chloro-3-phenylpyridazine

The regioselective arylation at position 4 of 4-bromo-6-chloro-3-phenylpyridazine has been performed using a Suzuki cross-coupling reaction. This route allows access to a wide-ranging series of pharmacologically useful pyridazine derivatives and confirms the usefulness of chloropyridazines as a masking group for the carbonyl moiety in cross-coupling reactions involving 5-bromo-3(2H)-pyridazinones.