Sustainable and efficient synthesis of oxazolidinones using a unique deep eutectic solvent (DES)

A quaternary diammonium salt and urea (1 : 2)-containing deep eutectic solvent (DES) is introduced as a simple and promising catalytic medium for the atom-economic synthesis of oxazolidinone compounds from epoxides and isocyanates. This DES is an economical, reclaimable, and environmentally gentle medium. In this protocol, no other supplementary catalyst or organic solvent is used since the DES plays the twofold roles of solvents and catalysts in the reaction. An extensive variety of oxazolidinone compounds were synthesized in good-to-excellent yields using this procedure. This protocol has a low E-factor (0.11), high atom economy (AE = 100%), excellent reaction mass efficiency (RME = 90.1%), and great process mass intensity (PMI = 1.11).