A recyclable copper catalysis in modified Friedländer quinoline synthesis

2-Aminobenzyl alcohol reacts with ketones in dioxane at 100 °C in the presence of a catalytic amount of a copper catalyst along with KOH and MS 4A under O₂ atmosphere to afford the corresponding quinolines in good yields. The catalytic system could be recovered and reused 10 times without any loss of catalytic activity. A similar catalytic system using copper catalyst/PEG-2000 is also effective for this coupling and cyclization with a similar catalytic potential. 2-Aminobenzyl alcohol is also coupled and cyclized with secondary alcohols under the CuCl₂/MS 4A catalytic system to give quinolines in moderate to good yields.