Dithiazoles and related compounds. Part 3. Preparation of 5H-1,4,2-dithiazoles via 1,3-dipolar cycloadditions between nitrile sulphides and thiocarbonyl compounds, and some conversions into 3,5-diaryl-1,4,2-dithiazolium salts

Abstract

Thermolysis of 1,3,4 -oxathiazol-2-ones 3 in the presence of thiocarbonyl compounds gives modest to good yields of the little-known 5H-1,4,2-dithiazoles 1, the reaction being successful with diaryl, aryl alkyl and dialkyl ketones, and thiono esters, but failing with dithio esters and tertiary thioamides. The influence of substituents is discussed. Solvolysis of 5-ethoxy-5H-1,4,2-dithiazoles, derived from thiono esters, with perchloric acid in acetic anhydride gives high yields of 3,5-diaryl-1,4,2-dithiazolium salts 9.