Chromenes and quinolines are recognized as important scaffolds in medicinal chemistry. Herein, the efficient use of chromene- and quinoline-3-carbaldehydes to synthesize other valuable heterocycles is described. These carbaldehydes are obtained in excellent yields through the Vilsmeyer-Haack reaction of flavanones and azaflavanones. Protocols towards the synthesis of new heterocycles, such as 3H-chromeno[3-c]quinolines, (Z/E)-2-aryl-4-chloro-3-styryl-2H-chromenes, and (E)-2-aryl-4-chloro-3-styrylquinoline-1(2H)-carbaldehydes were established. Altogether, we demonstrate the value of chromene- and quinoline-3-carbaldehydes as building blocks.
Keywords: 3-styryl-2H-chromenes; 3-styrylquinoline-1(2H)-carbaldehydes; 3H-chromeno[3,4-c]quinolines; Wittig reaction; chromene-3-carbaldehydes; quinoline-3-carbaldehydes.