One-Pot Synthesis of Highly Functionalized Indole in Choline Chloride/Oxalic Acid as a Deep Eutectic Solvent

An efficient protocol for the synthesis of some functionalized indole derivatives has been achieved through a one-pot three-component reaction of aniline derivatives, arylglyoxals, and 1,3-dicarbonyl compounds in choline chloride/oxalic acid as a deep eutectic solvent (DES). The use of biodegradable materials, short reaction time, and high yields of products introduced this protocol as an efficient, environmentally friendly method. The DES could be easily recovered and reused four times with satisfying catalytic activity.