CONVERSION OF AMIDES AND LACTAMS TO THIOAMIDES AND THIOLACTAMS USING HEXAMETHYLDISILATHIANE

Amides and lactams were converted to their corresponding thioamides an d thiolactams employing a new protocol using hexamethyldisilathiane (T MS(2)S). Oxophilic promoters were employed to generate Vilsmeier-type intermediates, the most efficient reagents being phosphorus oxychlorid e, triphosgene, and oxalyl chloride. Thionation of intermediate chloro iminium ions was accomplished in situ with TMS(2)S. Yields were good to excellent for secondary and tertiary amides and lactams while yield s for primary systems were poor.