Bioorganopromoted green Friedländer synthesis: a versatile new malic acid promoted solvent free approach to multisubstituted quinolines

Abstract

The discovery of a new, malic acid promoted, eco-friendly Friedländer approach to varied multisubstituted quinolines is disclosed. To the best of our knowledge, this is the first report on the use of malic acid, classified as one of the 12 biobased hot molecules by the US Department of Energy, as an organopromoter in organic synthesis and includes many benefits like wide substrate scope, solvent free ambient reaction conditions, short reaction times, operational simplicity, cost effectiveness, high atom economy, good to excellent yields, and recylability of the organopromoter, making it a valuable green alternative to the existing methods. The versatility and practicability of the developed method was further established by its successful application towards the targeted synthesis of some important quinoline molecules and successful scale up.