One-pot multicomponent cascade reaction of N,S-ketene acetal: solvent-free synthesis of imidazo[1,2-a]thiochromeno[3,2-e]pyridines.

Unprecedented imidazo[1,2-a]thiochromeno[3,2-e]pyridines have been synthesized via a three-component cascade reaction under solvent-free conditions. This one-pot transformation involving multiple steps and not requiring the use of transition metal catalysts constructs three new C-C bonds, two C-N bonds, one C-S bond, and three new rings with all reactants efficiently utilized.