Some Aspects of the Chemistry of Sulphur Halides and Oxyhalides

Abstract

The reactions between thionyl chloride and ketones containing at least one alpha proton, have been shown to give a variety of products depending upon the applied conditions and the structure of the adjacent groups. This work partly deals with the reactions of thionyl chloride with 1,3-diketones which afforded sulphides and o-chlorides. Typically, dimedone gave di-2-hydroxy-4,4-dimethyl- ~6-oxocyclohex-1-enyl sulphide and 2-chloro-5,5-dimethylcyclohexane- -1,3-dione,whereas 1,1-dibenzoyl ethane gave a mixture of products containing an α-sulphinyl chloride, which upon treatment with ethanol gave a disulphide, a trisulphide, or a thiosulphinate according to the conditions employed. A number of possible intermediates were investigated in an attempt to establish the conditions and structural requirements necessary for the formation of the above products. A novel synthesis of β-ketosulphinyl chlorides was developed which afforded excellent yields in a simple one stage process. Certain of the chemical and spectral properties of this new class of compounds were examined in an effort to elucidate the role of sulphinyl chlorides as intermediates in the reaction of 1,3- -diketones with thionyl chloride. Ethyl isopropyl ketone afforded a 3~thietanone upon treatment with thionyl chloride, a reaction which possibly involved a sulphinyl chloride intermediate. Lastly a number of partly saturated cyclic compounds suitably activated by carbonyl groups, were shown to be readily oxidised by thionyl chloride to give aromatic systems.