Reaction of ortho-Azidohetarenecarbaldehydes with Bis(trimethylsilyl) sulfide. A Novel Route to Fused Isothiazoles.

o-Azidohetarenecarbaldehydes react with bis(trimethylsilyl)sulfide and hydrochloric acid to give fused isothiazoles in yields strongly dependent upon the nature of the heteroaromatic ring through intramolecular cyclization reaction of presumable intermediate o-azidocarbothialdehydes.