Palkó Roberta, Riedl Zsuzsanna, Egyed Orsolya, Fábián László, Hajós György
Chemical Research Center, Hungarian Academy of Sciences, H-1025 Budapest, Pusztaszeri út 59, Hungary.
J Org Chem. 2006 Sep 29;71(20):7805-12. doi: 10.1021/jo061361l.
2-Arylsulfanyl- and benzylsulfanylpyridinium N-arylimides (2), easily available from tetrazolo[1,5-b]pyridinium salts (1), participate in 1,3-dipolar cycloaddition with aryl isothiocyanates and aryl isocyanates to result in formation of fused thioxo- and oxo[1,2,4]triazolium salts (5 and 12), respectively. This transformation is interpreted as a regular 1,3-cycloaddition followed by spontaneous elimination of the aryl- or benzylsulfanyl group. Formation of these triazolium salts can be followed--under appropriate reaction conditions--by ring-opening reactions to afford some new triazolyldienes (6). Recognition of the intermediate participation of the thiolate anion along the pathway 1 --> 5 allowed elaboration of a simple procedure to 5 implying a tandem reaction sequence.
2-芳硫基和苄硫基吡啶鎓N-芳基酰亚胺（2）可容易地从四唑并[1,5-b]吡啶鎓盐（1）制得，它们与芳基异硫氰酸酯和芳基异氰酸酯发生1,3-偶极环加成反应，分别生成稠合的硫代和氧代[1,2,4]三唑鎓盐（5和12）。这种转化被解释为常规的1,3-环加成反应，随后自发消除芳基或苄硫基。在适当的反应条件下，这些三唑鎓盐的形成之后会发生开环反应，得到一些新的三唑基二烯（6）。认识到硫醇盐阴离子在1→5途径中的中间参与，使得可以设计出一种制备5的简单方法，这意味着串联反应序列。
