PUMMERER REARRANGEMENTS OF ETHYL ETHYLTHIOMETHYL SULPHOXIDE

Abstract

Abstract Some Pummerer rearrangements, in which ethyl ethylthiomethyl sulphoxide (I) is supposed to react initially as a nucleophile, were investigated in connection with the observed decrease of basicity in this compound, due to electronic interaction between α-sulphur atom and sulphinyl group. In fact, it proved to be quite resistant to the acetic anhydride induced rearrangement, being totally recovered under conditions in which DMSO reacts. In more drastic condition, or when triethyloxonium tetrafluoroborate and sodium acetate was substituted for acetic anhydride, instead of the normal Pummerer product, ethyl orthotrithioformate (II) was produced. Although ethyl ethylthiomethyl sulphoxide appeared to be susceptible, in mild condition, to acqueous acid, instead of Pummerer reaction, hydrolysis to formaldehyde and diethyl disulphide took place. The suppression of the Pummerer rearrangement was also found to occur in the reaction with thionyl chloride, to afford ethyl chloromethyl sulphide (III). However,...