1,4‐Dithiafulvene aus der Umsetzung von 4,4‐disubstituierten 1,3‐Thiazol‐5(4 H )‐thionen mit Acetylenderivaten

1,4‐Dithiafulvenes, Products of the Reaction of 4,4‐Disubstituted 1,3‐Thiazol‐5(4 H )‐thiones and Acetylenic Compounds On heating in toluene, 4,4‐disubstituted 1,3‐thiazol‐5(4 H )‐thiones 1 and acetylenecarboxylates or acetylenecarbonitriles 2 undergo a cyclosubstitution reaction to yield 2‐methylidene‐1,3‐dithiol derivatives 3 (1,4‐dithiafulvenes) and a nitrile. Further heating of 3a and 3b in the presence of excess 2a leads to the isomeric 2,3‐dihydrothiophene‐2‐thiones 4a and 4b , respectively. The benzodithiafulvene 14 has been formed in a similar reaction from 1a and in situ generate benzyne.