Palladium catalysis in reductive alkyl group transfer from trialkylamines to nitroarenes followed by cyclization

Nitroarenes having electron donating and withdrawing substituents are reductively cyclized with an array of trialkylamines in the presence of a catalytic amount of Pd/C along with tin(II) chloride at 120 °C in a toluene/H2O medium to afford quinolines in moderate to good yields. The product yield depends on the position of the substituent of nitroarenes and the chain length of trialkylamines. The addition of tin(II) chloride is essential for the formation of quinolines and toluene/H2O is the solvent of choice.