Studies on the Inhibition of the Autoxidation of Oils and Fats

Part 7. The Synthese of Some ω, ω'-Bis- (3, 4-dihydroxyphenyl) Alkanes. (2)

Abstract

In the present paper, several ω, ω'-(3, 4-dihyhroxyphenyl) alkanes were synthesized to find the relation between the chemical structure and antioxidant property as well as in the previous pape⁽¹⁾.
4-Iodoveratrol (I) was prepared by the treatment of veratrol with iodine and mercuric oxide. Heating of (I) with Cu powder in C0₂ gave 3, 4, 3', 4'-tetramethoxybiphenyl (II), which was demethylated with HI to yield 3, 4, 3', 4'-tetrahydroxydbiphenyl (III), mp. 225_??_227°.
Veratroyl chloride was condensed with veratrol in the presence of A1C1₃ to give veratroylveratrol (IV), which was reduced with Na-alcoholate to 3, 4, 3', 4'-tetramethoxybiphenylmethane (V), mp. 70°. Demethylation of (V) with HI gave 3, 4, 3', 4'-tetrahydroxybiphenylmethane (VI), mp. 145°. It-had been reported by C_ARO⁽⁴⁾ that 3, 4, 3', 4'-tetrahydroxybiphenylmethane, mp. 220 (decompn.) was obtained when a solution of 5 parts of catechol in 50 parts of H₂O was boiled with 40% HCHO solution and a few drops of HC1 or H₂S0₄. This experiment was repeated by the authors in various conditions, but such a compound was never obtained. Therefore, it should be conclued that C_ARD's report concerned with (VI) is errornous.
Diveratralacetone (VI) prepared from veratric aldehyde and acetone in NaOH solution was reduced by the catalytic hydrogenation and CLEMMENSEN reduction successively, and demethyl-ation of the resulting product with HI gave 1, 5-bis-(3, 4-dihydroxyphenyl) pentane(X), mp. 128_??_129°.
1, 8-Diveratroyloctane (XI), mp. 106_??_107°, the intermediate for the. preparation of 1, 10-bis-(3, 4-dihydroxyphenyl) decane was obtained by the treatment of sebacyl chloride with veratrol in the presence of AlC1₃, instead of the condensation of . sebacic polyanhydride with veratrol⁽¹⁾.
The authors wish to express their appreciation to Professor Dr. Y S_UMIKI for his guidance and advice.