Synthesis of polycyclic quinolines using SiO₂/H₂SO₄ via Friedlӓnder synthetic method

An attention to the novel synthetic route for the polycyclic quinolines (3 & 5) from cyclic-diketones, cyclohexan-1,2-dione (2) / cyclohexan-1,3-dione (4) with o-aminoarylketones (1) in the presence of SiO₂/H₂SO₄ yielded via Friedlӓnder synthetic method. The catalytic efficiency of the SiO₂/H₂SO₄ was discussed through their utilization in the synthesis of biologically active substituted polycyclic quinoline derivatives (3 & 5) and the mechanism has been proposed. The SiO₂/H₂SO₄ was found as a effective catalyst for the Friedlӓnder reaction and gave considerable isolated yield of the targeted products under the mild reaction condition. The synthesized polycyclic quinolines (3 & 5) were characterized through diverse analytical techniques like FT-IR, NMR spectroscopy and single crystal X-ray diffraction studies.