406480-97-5Relevant academic research and scientific papers
Diisothiocyanates as heterodienophiles or dipolarophiles in the presence of α-thioxothioamides or mesoionic thiazoles
Morel, Georges,Marchand, Evelyne
, p. 617 - 624 (2007/10/03)
Reactions of α-thioxothioamides (1) with diisothiocyanates were carried out in the hope of generating the N,N′-bis(1,3-thiazoline-2-thiones) (A). Although that purpose could not be achieved, we succeeded in preparing the monocycloadducts 7 from the phenylene-1,2-diisothiocyanate (4). The benzimidazole derivatives 8 and 9 were also characterized and a mechanism was assumed to account for this intramolecular process. On the other hand, the regioselective synthesis of the N,N′-biimidazole (13) containing the phenylene bridge was performed by the treatment of the 5-aminothiazolium chloride (2) with the diisothiocyanate (4) in a basic medium. The mesoionic derivative 13 probably arises from the monoimidazolium-4-thiolate (12) which was shown to react with the salt 2 under similar conditions to give the primary cycloadduct 14 as an intermediate towards the bis(imidazolium) (13).
