Tellurium-Containing Heterocycles with N-Bridged Atoms

Tellurium-Containing Heterocycles with N-Bridged Atoms 

N-Bridged tellurium-containing heterocycles are exemplified by derivatives of l,4-tellurazine[2,3-g/j]carbazole 107 and heterocycle 108. One-pot reaction of 7V-propargylcarbazole with tellurium tetrahalides under conditions of the two-phase tellurohalogenation (Section II,B, I) leads to halogenomethylene derivatives 107 (90KGS126). The reaction proceeds as the spontaneous electrophilic cycliza-tion of initially formed tellurium trihalides 109. 

Heterocycle 108 was obtained in 45% yield by the reaction of dilithiated A-ethynylpyrrole 110 with elemental tellurium followed by a treatment of the reaction mixture with hexamethylphosphorus triamide [95JOM(493)271j. 

This work has been supported by Russian Fund for Basic Research (grants 00-15-97320 99-03-33132a). V.I.M. gratefully acknowledges the support of the Alexander von Humboldt Foundation 

60MI1 L. Pauling, The Nature of the Chemical Bond, 3 ed. Cornell University 

---

VI. Tellurium-Containing Heterocycles with N-Bridged Atoms... 

---