Glycerol as a promoting and recyclable medium for catalyst-free synthesis of linear thioethers: new antioxidants from eugenol

We describe herein the use of glycerol as an efficient and recyclable solvent for the addition of thiols to nonactivated alkenes. The catalyst-free reactions take place easily using glycerol at room temperature or heating and the corresponding linear thioethers were obtained in good to excellent yields. The method was used to synthesize new sulfur-containing eugenols, which were tested for their antioxidant activities. The semisynthetic thio-derivatives were more effective in inhibition of induced lipid peroxidation compared to the precursor eugenol and the synthetic antioxidant butylated hydroxyanisole.