Pyridazines 91. Synthesis of substituted tri- and tetracyclic compounds bearing a pyridazine core and their biological evaluation as antimycobacterial agents.

Starting from substituted 3,6-dichloropyridazine-4-carboxamides (2, 3) tri- and tetracyclic compounds (4, 5) could be smoothly prepared. Structural modifications of interest with regard to biological activity were performed by N-alkylation and reductive dehalogenation. The new substituted heterocyclic compounds were screened as antimycobacterial agents; the influence of the substitution pattern on activity is discussed.