Transition-Metal-Free Synthesis of Quinoxalines from o-Phenylenediamines and Arylacetaldehydes under Basic Conditions

A novel method for the synthesis of quinoxalines via transition-metal-free cyclization of o -phenylenediamine and aryl­acetaldehyde in a one-pot procedure has been developed. In this process, an inorganic base (K 2 CO 3 ) is the only reagent required, and it proceeds smoothly in the absence of adding transition metal catalysts. The reaction appears to be very general and suitable for the construction of a variety of quinoxalines.