Synthesis, biological activity, and metabolism of 8′,8′,8′-trideuteroabscisic acid

Abstract

An 8′,8′,8′-trideuterated analog of abscisic acid (ABA) was diastereoselectively synthesized as a new analog of ABA that is resistant to 8′-hydroxyIation, the first metabolic reaction of ABA, owing to the primary kinetic isotope effect. (+)-8′,8′,8′-Trideutero-ABA showed long-term activity in the rice elongation assay. The rate of metabolism of this analog in rice cell suspension culture was about two fold slower than that of (+)-ABA. The concentration of 8′,8′-dideuterophaseic acid produced was about 1/3 that of phaseic acid converted from (+)-ABA. This result indicated that the long-lasting activity of the (+)-trideutero-ABA in the rice assay was the result of the delayed 8′-hydroxylation as expected. © 1997, Taylor & Francis Group, LLC. All rights reserved.