THIOACYLTHIOKETENES BY PYROLYSIS OF 1,3-DITHIETHANES AND 1,2-DITHIOLEDERIVATIVES

Thioacylthioketenes are formed by flash vacuum pyrolysis (FVP) of 1.3- dithiethanes 6, 1,2-dithiole-3-thiones 11, 14, 15, 3-indo-1,2-dithioly lium iodide 9, 3-methylthio-1,2-dithiolylium iodides 16, 17 and 1,2-di thiol-3-one tosylhydrazone sodium salt 10. They show IR absorption in the region 1754-1700 cm(-1) due to the C=C=S grouping. It is proposed based on the results obtained that 1,2-dithiol-3-ylidenes (1,2-dithiol e carbenes) rearrange to give thioacylthioketenes which further rearra nge forming thiete-2-thiones. The latter finally fragment into carbon disulfide and alkynes. Formation of C3S2 has been observed in the pyro lysis of the dithiethanes and 1,2-dithiole-3-thione.