From Diorgano Ditellurium Derivatives

Diaryl ditellurium formed aryl 2-carboxyethanethio tellurium compounds upon reaction with 2-carboxyethanethiol in ethanol at 20°. 

2-Carboxyethylthio Phenyl Tellurium A solution of 1.06 g (10 mmol) of 2-carboxyethanethiol in 25 ml of ethanol is added to a solution of 2.05 g (5 mmol) of diphenyl ditellurium in 175 ml of ethanol. The resultant mixture is stirred at 20° for 24 h and then concentrated to a volume of 50 ml. Water is added to the concentrate until the mixture becomes cloudly and the mixture is cooled overnight. The precipitated solid is collected and dried yield 1.1 g (35%) m.p. 40°. 

2-Carboxyethylthio 4-methylphenyl tellurium (m.p. 50°) was similarly prepared in 45% yield .  

Methyl trifluoromethylthio tellurium could not be obtained in pure form from the reaction of dimethyl ditellurium with bis[trifluoromethyl] disulfide. At 20° the product is in equilibrium with the reactants  

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Whether the nickel complexes formed from diorgano ditellurium derivatives and cyclopentadienyl(cyclopentadiene)nickel tetrafluoroborate in diethyl ether at 20° contain an intact diorgano ditellurium ligand or two tellurolato ligands is not known4. 

Lithium benzenetellurolate8,9 and lithium ethanetellurolate10 were more conveniently obtained from the corresponding diorgano ditellurium compounds and lithium at room temperature with anhydrous diethyl ether or tetrahydrofuran as reaction medium. The reductions are complete when the orange-red color of the ditellurium derivatives has faded to pale yellow. 

A promising method for the synthesis of unsymmctrical diorgano tellurium compounds uses carboxylic acid derivatives and diaryl ditellurium as starting materials. The carboxylic acid chloride, prepared in quantitative yield from the acid and oxalyl chloride is added slowly to a mixture of a diary] ditellurium and the sodium salt of 2-mercaptopyridine N-oxide in toluene at 35°. Under normal laboratory light the aryl tellurium radicals... 

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