Efficient synthesis and free-radical scavenging capacity of new 2,4-substituted tetrahydroquinolines prepared via BiCl3-catalyzed three-component Povarov reaction, using N-vinylamides.

Efficient synthesis of new structurally different 2-(het)aryl-4-amidyl-substituted tetrahydroquinolines 8-29 is reported. The synthesis based on BiCl(3)-catalyzed three-component Povarov reaction between anilines, (het)aryl aldehydes and enamides offers a fast, safe, and cheap way for efficient tetrahydroquinoline libraries construction. Using N-vinylamides (N-vinylpyrrolidin-2-one and N-vinylacetamide) in this reaction, it was possible to obtain two series of different cis tetrahydroquinolines with antioxidant properties. Among 14 tested compounds, 7 tetrahydroquinolines revealed a prominent anti-radical capacity, equal or higher than that of the commercial antioxidants. Being the most active molecule, the N-[2-(α-furanyl)-6-methoxy-1,2,3,4-tetrahydroquinolin-4-yl] acetamide 21 was ca. 2.2-fold more potent than the well-known antioxidant, vitamin E (α-tocopherol).

4-Aryl(benzyl)amino-4-heteroarylbut-1-enes as building blocks in heterocyclic synthesis. 4. Synthesis of 4, 6-dimethyl-5-nitro(amino)-2-pyridylquinolines and their antiparasitic activities.

New nitro- and aminoquinoline derivatives containing a pyridyl nucleus were synthesized from 6, 8-disubstituted 4-methyl-2-pyridylquinolines, which were prepared from N-pyridylmethylidenanilines. The anti-chagasic and trichomonacidal in vitro activity, as well as the cytotoxic properties towards macrophages of some of these compounds were evaluated. Although some of the compounds showed only moderate activity it was possible to establish some structure-activity relationships.