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

This is a report of an innovative, one-pot, catalyst-free, four-component synthesis of octahydro-imidazo[1,2-a]quinolin-6-ones from aromatic aldehydes, cyclic 1,3-diones, diamines, and nitro ketene dithioacetal in stoichiometric melt conditions. The protocol avoids the use of expensive catalysts, toxic organic solvents and anhydrous conditions, and affords potentially bioactive compounds in excellent to high yields.