Novel Annulation of the Thiete Ring on Imidazole Nucleus and Lil-Catalysed Expansion of the Thiete Ring with Carbon Bisulfide

摘要

One-pot annulation of 5-arylidene-2-thiohydantoins (3a-f) with O,O-diethyl hydrogen dithiophosphate (4) yields 3,5-dihydrothieto[2,3-d]imidazole-2(lH)-thiones (6a-f) which undergo LiI-catalysed facile expansion of their thiete ring with carbon disul-fide to afford the corresponding dihydro[l,3]dithiino[4,5-d]imida-zole-2,5(lH)-dithiones (7a-f).