Chemistry of Ubiquinone Related Compounds

Abstract

Many ubiquinone related compounds have been obtained photochemically, chemically, metabolically from ubiquinone-7 (Q-7) and isolated from natural sources. Their structures and the reaction mechanisms have been elucidated : Irradiation of Q-7 with sunlight results in the reduction of the quinone ring, the demethylation of the methoxyl group, the isomerization and oxidation of the isoprenoid side chain. The reduction of Q-7 and its hydroquinone compound with LiAlH_4 leads to the demethylation. The acetate of ubichromenol-6 (UC-6) undergoes cleavage of the chromene ring by the same reaction to give several quinones. Treatment of UC-6 with Na in ethanol results in the reduction and cleavage of the chromene ring. Metabolites of Q-7 in which the isoprenoid side chain was oxidized were isolated from the urine, adrenals and ovaries of animals dosed with Q-7; the possible metabolic pathway are discussed. Compounds having an epoxy group in the side chain were obtained from the heart muscle of the whale as well as cells of Pseudomonas sp. Some new observations are also reported on the behavior of the ubiquinone related compounds in teh NMR, mass spectra and in gas liquid chromatography. The ubiquinone related compounds were assayed to determine their ability to restore the activity of acetone-treated mitochondria in the succinate oxidase system.