Studies on Antioxidants. IV. : Syntheses of ω, ω'-Bis-p-aminophenol Derivatives and Their Antioxidant Activities

Abstract

Following the systeinatic syntheses of various phenol derivatives and examination of a relation the kind, number, and position of their substituents to the antioxidant action of these compounds, systematic syntheses were carried out to obtain compounds having an amino group with marked electrondonating nature. The compounds synthesized were p-aminophenol derivatives of ω, ω'-bis(2-hydroxy-5-aminophenyl)alkanes (A), ω, ω'-bis(2-hydroxy-5-dimethylaminophenyl)alkanes (C), ω, ω'-bis(2-hydroxy-4-methyl-5-aminophenyl)-alkanes (D), and ω, ω'-bis(2-hydroxy-3, 4-dimethoxy-5-aminophenyl)alkanes (E), with 5, 7, and 10 carbons in the alkanes. Compounds of (A), (D), and (E) series were obtained by deriving the corresponding phenols to azo compounds and reduced with sodium thiosulfate. Compounds of (B) series were obtained by formylation of (A) compounds and reduction of its products with lithium aluminum hydride. Compounds of (C) series were obtained by catalytic reduction of (A) compounds in the presence of formaldehyde. Examination of the antioxidant activity of these compounds was examined as in the preceding work, and all the compounds showed a fairly good antioxidant effect, especially those of the (B) series.