Collect. Czech. Chem. Commun. 1979, 44, 3141-3148

Reduction of 3-substituted quinolines with triethylammonium formate

Miloslav Ferles and Oldřich Kocián

Department of Organic Chemistry, Prague Institute of Chemical Technology, 166 28 Prague 6


Reduction of 3-substituted quinoline derivatives, containing electron donating substituents (Ia-Id), as well as of the quaternary salts VIb and VIc, with triethylammonium formate afforded mainly the corresponding 1-formyl-1,2,3,4-tetrahydroquinolines II or their 1-methyl derivatives. Analogous reductions of quinoline derivatives, containing electron withdrawing groups (e.g. Im) gave 1,4-dihydroquinolines IV in addition to 1,2,3,4-tetrahydroquinoline derivatives. Quaternary salts of 3-substituted derivatives with electron withdrawing substituents (e.g. VId) were reduced exclusively to 1-alkyl-1,4-dihydroquinolines IV.