Ionic Liquid-Promoted Regiospecific Friedlander Annulation: Novel Synthesis of Quinolines and Fused Polycyclic Quinolines
Sanjay S. Palimkar, Shapi A. Siddiqui, Thomas Daniel, Rajgopal. J. Lahoti, and Kumar V. Srinivasan*
*Division of Organic Chemistry, Technology, National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India, Email: kvsridalton.ncl.res.in
S. S. Palimkar, S. A. Siddiqui, T. Daniel, R. J. Lahoti, K. V. Srinivasan, J. Org. Chem., 2003, 68, 9371-9378.
DOI: 10.1021/jo035153u (free Supporting Information)
On screening, 1-butylimidazolium tetrafluoroborate [Hbim]BF4 was found to be the best ionic liquid for the Friedlander heteroannulation reaction. The reactions proceed very well under relatively mild conditions without any added catalyst. The ionic liquid acts as a promoter for this regiospecific synthesis and can be recycled.
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