Indirect Electrolytic Oxidation of Thioamides Using Organotellurium as a Mediator

Article abstract of DOI:10.1246/bcsj.61.2117

Bis(p-methoxyphenyl) telluride (1) electrochemically reacted with supporting electrolytes such as tetrabutylammonium acetate and tetraethylammonium tosylate under anhydrous conditions to give tellurium(IV) diacetate 2a and ditosylate 2b, respectively.On the other hand, 1 was electrolyzed in the presence of water to give telluroxide 3.It has turned out that the tellurium compounds 2a and 2b like telluroxide 3 are mild oxidizing agents, but 2b behaves differently in a reaction towards thioamide.Thus 2a and 3 converted it into nitrile, while 2b did it into 1,2,4-thiadiazole.An indirect electrolytic oxidation of thioamides with 1 as a mediator was examined under various conditions.As a result, nitriles or 1,2,4-thidiazoles could be chemoselectively formed, depending on the intermediacy of 2a or 3 as an active species for the formed and 2b for the latter.