Recent Advances in the Chemistry of Condensed Pyridazines: Synthesis of Bi- and Tricyclic Systems by Annelation of Five-, Six-, and Seven-membered Rings to a Preformed 1,2-Diazine Nucleus

Abstract

Methods for the preparation of a wide variety of pyridazine-containing bi- and tricyclic ring systems, starting from appropriately substituted pyridazines are reviewed. The compilation comprises pyridazine-fused five-, six-, and seven-membered carbo- and heterocyclic systems. Particular interest is focused on compounds bearing no additional substituents in the 1,2-diazine moiety. In the syntheses discussed, diaroylpyridazines, aroylpyridazinecarboxylic acids, alkylpyridazinecarboxylic acids, aminopyridazinyl aryl ketones, and chloro- or alkylpyridazinecarbonitriles represent the key intermediates