Simple synthesis of furfuryl sulfides via extrusion of COS from the xanthates and its mechanistic aspects

Abstract

Heating of O-furfuryl S-alkyl dithiocarbonates (xanthates) gave furfuryl alkyl sulfides together with S-furfuryl S-alkyl dithiocarbonates. The crossover reaction using differently substituted furfuryl xanthates in polar solvents indicates that the reaction proceeds intermolecularly, whereas the reaction in non-polar solvents showed intramolecular reaction behaviour. The reaction is first-order and the rates are considerably affected by a change in the solvent polarity. The activation enthalpy and entropy for the extrusion of O-furfuryl S-methyl xanthate in xylene are 28.0 ± 1.3 kcal mol^–1 and –2 ± 4 cal K^–1 mol^–1, respectively. Based on these findings together with the MO calculation data, the mechanism for the conversion reaction of furfuryl xanthates to furfuryl alkyl sulfides is discussed.