Greener Synthesis of N-heterocyclic compounds In deep eutectic solvent under mild reaction conditions

Deep eutectic solvents (DESs), as an advanced ionic liquid (ILs), obtained by the simple complexion of quaternary ammonium salts and the most frequently choline chloride with hydrogen bond donors (e.g. Urea, amide, acid, or polyol [1]. Multicomponent reactions (MCRs) are not only a powerful tools in organic, combinatorial and medicinal chemistry; they also represent an excellent framework of green chemistry [2]. Operationally simple, atom economical, and scalable synthesis of imidazoles from 1,2- diketones, aldehydes and amines and indolo[3,2-a] carbazoles from 1,2-diketones and indoles is shown to proceed readily in deep eutectic solvent with good yield. The scope of the reaction is quite broad; a variety of aromatic and aliphatic, activated and unactivated aldehydes as well as amines and indoles have all been shown to be viable substrates for this reaction.