One-pot multi-component process for the synthesis of 4-azaphenanthrene-3,10-dione, 1,8-dioxo-octahydroxanthene and tetrahydrobenzo[b]pyran derivatives catalyzed by the deep eutectic solvent choline chloride-oxalic acid

Abstract

An effective method based on choline chloride (ChCl)-oxalic acid (Ox) deep eutectic solvent was proposed for the synthesis of 4-azaphenanthrene-3,10-dione, 1,8-dioxo-octahydroxanthene and tetrahydrobenzo[b]pyran derivatives. The eutectic mixture worked as both the solvent and acidic catalyst for conversion. The impacts of different variables, including the composition and volume of ChCl-Ox, and temperature, on reaction yield were studied for optimization. The crucial advantages of this process are simplicity of the experimental procedure, high yields, short reaction times, high recyclability, and the use of safe and inexpensive components.