With Removal of Tellurium from the Ring

Tellurophene is decomposed by strong mineral acids. Tetrachlorotellurophene Te,Te-dichloride is rapidly converted by aqueous base to l,2,3,4-tetrachloro-l,3-butadiene and tellurous acid s. 2,5-Diphenyltellurophene reacted with butyl lithium in hexane in the presence of tetramethylethylenediamine at 20 to give l,4-dilithio-l,4-diphenyl-l,3-butadicne, a compound that can be used as a starting material for the synthesis of 1,4-disubstituted butadienes . 

Grignard reagents remove tellurium from the tellurophene ring in refluxing benzene in the presence of nickel-phosphine complexes.  

A solution of 2-phenyltellurophene in diethyl ether kept in a Pyrex container eliminates tellurium upon irradiation with light from a 300 nm lamp and produces 1-phenylbut-l-yn-3-ene . 

However, 2,5-diphenyltellurophene, when irradiated in diethyl ether solution with a 450-watt Hanovia medium pressure mercury arc lamp equipped with a Pyrex filter, was recovered quantitatively.  

Bicyclic 2,5-diphenyltellurophenes lost tellurium when their chloroform solutions were exposed to light from mercury lamps or to day light.  

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Bis[trifluoromethyl] Ditellurium An apparatus for irradiation consisting of a reaction vessel, a low-temperature (— 25°) cooler with argon adapter, and an external mercury high-pressure lamp (Heraeus, TQ 150) is assembled. Under an atmosphere of argon 2.65 g (10 mmol) bis[trifluoromethyl] tellurium, 13.6 g (200 mmol) furan, and several glass rings are plaeed into the reaction vessel. The mixture is irradiated for 54 h and stirred to remove the tellurium mirror from the walls of the reaction vessel. The solvent is distilled at atmospheric pressure until the bath temperature reaches 80°. The residue is distilled at 0.001 torr by increasing the temperature slowly from — 78° to + 25° yield 43% b.p. 120°/760 torr. 

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