THE KETO-ENOL-TAUTOMERISM AND THE REDOX CONVERSIONS OF ALPHA-KETOL FATTY-ACIDS

main conversions of alpha-ketol fatty acids (18:2 and 18:3), accompany ing their redox interactions with 2,6-dichlorophenolindophenol (DCPIP) and copper(II) acetate, were studied. The highest rates of oxidation with DCPIP were observed in the alkaline water solutions. In the acidi c aqueous media or in organic solvents, reaction with DCPIP proceeded much more slowly. The presence of oxygen significantly altered the dir ection but not the kinetics of reaction. The predominant products of a erobic reaction with DCPIP under alkaline conditions were alpha-ketol hydroperoxides. Similar incubations under argon atmosphere, excluding hydroperoxide formation, afforded 9,13-dihydroxy-12-oxo and 9,12-dioxo -13-hydroxy acids. The latter was also the main product of reaction wi th copper acetate, along with 9-acetoxy-12-oxo-13-hydroxy acid. The fr ee radical mechanism of the observed conversions is proposed.