A Facile, Sustainable One-Pot Synthesis of the Spiro-Dimers of α-Tocopheramine and Its N-Methyl Derivative

alpha-Tocopheramine and N-methyl-alpha-tocopheramine are used as stabilizers in the spinning of cellulosic fibers from solutions in 1,3-dialkylimidazolium ionic liquids. Upon aging, they form chromophoric degradation products, among which the spiro-dimers are major components. These compounds have proved to be otherwise inaccessible so far, although they are urgently needed as chromatographic standards in spinning baths and fiber analysis. In this work, the spiro-dimers of alpha-tocopheramine and N-methyl-alpha-tocopheramine have been synthesized. Extensive optimization of reaction conditions, solvents and oxidants resulted in a sustainable one-pot protocol that provided quantitative yields without the need for product purification and with the easy recycling of the solvent.