Introduction. Some years ago (1996) [1], we studied the relative ortho-directing power of the methoxy group and the chlorine atom for the metalation reaction in the diazine series. The substrate was 3-chloro-6-methoxypyridazine and various hindered alkylamides were used as metalat- ing agents. In this paper we have extended the compari- son to 2-chloro and -fluoro-6-methoxypyrazine and to 3-fluoro-6-chloropyridazine. At first we shall recall the main results in the benzene ...
