Studies on the Inhibition of the Autoxidation of Oils and Fats

Part 13. Syntheses of Some ω, ω'-bis-(2, 3, 4-trihydroxyphenyl) Alkanes and their Antioxidant Activity

Abstract

Succeeding to the fact that some of ω, ω'-bis-(3, 4-dihydroxyphenyl) alkanes showed marked antioxidant activity⁽²⁾⁽³⁾ ω, ω'-bis-(2, 3, 4-trihydroxyphenyl) hexane and decane were prepared and their activity was examined in the present paper.
The syntheses of the alkanes: Pyrogallol trimethylether was condensed with adipyl chloride in the presence of AlCl₃ to give 1, 4-bis-(2-hydroxy-3, 4-dimethoxybenzoyl) butane (IV), which. was reduced by WOLFF-KISHNER Method to 1, 6-bis-(2-hydroxy-3, 4-dimethoxyphenyl) hexane (VI). (VI) was then demethylated with HI to yield 1, 6-bis-(2, 3, 4-trihydroxyphenyl) hexane (VIII). 1, 10-Bis-(2, 3, 4-trihydroxyphenyl) decane (IX) was prepared, in the same way using sebacyl chloride and pyrogallol trimethylether as the starting materials.
The antioxidant activity of the alkanes: The activity of the compounds, (VIII) and (XI), was examined by the Active Oxygen Method using lard as the substrate. It was found that their activity was superior to those of NDGA and some ω, ω'-bis-(3, 4-dihydroxyphenyl) alkanes as shown in Table 1.
The authors wish to express their appreciation to Professor Dr. Y. SUMIKI for his guidance and advice.