Polarographic reduction of 5-hydroxy-7-methoxy flavanone

Abstract

Reduction of 5-hydroxy-7-methoxy flavanone in 50% ethanolic buffers pH 1.8–14 follows a similar pattern as that of acetophenones and other aryl carbonyl compounds. The irreversible wave of protonated form occurring in acidic media is replaced by a wave of the unprotonated flavanone in the medium pH-range. Decrease of the two-electron wave at pH greater than about 8 is due to a decrease in rate of protonation of the radical anion formed in the first electron uptake. At pH greater than about 10 alkaline cleavage of the flavanone in the bulk of the solution resulted in formation of substituted chalcone, manifested by formation of a more positive polarographic wave and a new absorption band in electronic spectra at 355 nm.