Heterocycles with One Te Atom and Two N Atoms

Derivatives of three of the four possible structural types of these aromatic heterocycles have been synthesized. 

A similar approach provided a synthesis of phenanthro[9,10-c]l,2,5-telluradia-zole 73 in 35% yield [87ZN(B)84]. 

The Te,Te-dichloro derivative 74 was prepared in 85% yield by heating phenanthro-9,10-bis(trimethylsilyl)imine with TeCU (87MI1). 

Because of the lower stability of Se(IV) compounds as compared with their Te(IV) analogues (95UK527), the reaction of the disilyldiimine with SeCU ends up in phenanthro[9,10-c]-l,2,5-selenadiazole. 3,4-(2,4-Di-ferr-butylbenzo)-l,2,5-telluradiazole 75 was obtained by a treatment of the tellurium diimide 76 with a lithium salt of tris(rerr-butyl)anihne. Dimer 77 is an intermediate in this reaction (96IC9). 

Reactions of telluradiazoles 69 and their analogues 73 and 75 were not studied in detail. Compounds 69 are stable with respect to air and moisture, but decompose when exposed to sunlight. Acidic hydrolysis of telluradiazoles gives dicarbonyl compounds, ammonium salts, Te, and H2Te03. 

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