Regenerable Radical-Trapping Tellurobistocopherol Antioxidants

Tellurobistocopherols 9-11 were prepared by lithiation of the corresponding bromotocopherols, reaction with tellurium tetrachloride and reductive workup. Compounds 9-11 quenched linoleic-acid-derived peroxyl radicals much more efficiently than α-tocopherol in a chlorobenzene/water two-phase system. N-Acetylcysteine or tris(2-carboxylethyl)phosphine as co-antioxidants in the aqueous phase could regenerate the tellurobistocopherols and increase their inhibition times. Antioxidant 11 inhibited peroxidation for 7-fold longer than that recorded with α-tocopherol. Thiol consumption in the aqueous phase was monitored and found to be inversely related to the inhibition time.