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.

Graphical abstract2-Aminobenzyl alcohol is oxidatively cyclized with ketones and secondary alcohols under a recyclable copper catalytic system (copper catalyst/MS 4A or PEG-2000) to give quinolines.Figure optionsDownload full-size imageDownload as PowerPoint slide