Catalyst- and solvent-free synthesis of highly functionalized octahydro-imidazo[1,2-a]quinolin-6-ones via a one-pot sequential four-component reaction in melt conditions
An efficient one‐pot four‐component protocol for the synthesis of imidazo[1,2‐a]pyridines was developed by condensing ethane‐1,2‐diamine (2), 1,1‐bis(methylthio)‐2‐nitroethene (1), aldehydes 3, and activated methylene compounds in EtOH under reflux conditions (Tables 1–3). The features of this procedure are operational simplicity, good yields of products, in situ preparation of heterocyclic ketene