164854-69-7

Upstream product

• 164854-67-5 (+)-3'-fluoroabscisic acid 
• 164854-68-6 (+)-3'-fluoro-8'-hydroxyabscisic acid 

Relevant academic research and scientific papers

Analysis of isomerization process of 8'-hydroxyabscisic acid and its 3'- fluorinated analog in aqueous solutions

8'-Hydroxyabscisic acid (8'-HOABA), the first metabolite of abscisic acid (ABA) in plants, is spontaneously isomerized to low bioactive phaseic acid (PA). We investigated thermodynamic and kinetic properties of the isomerization process in aqueous solution buffered at the various pHs, along with the effects of 3'-fluorine. The 8'-HOABA/PA ratio at equilibrium was 2:98 at 25°C, while the 3'-fluoro-8'-HOABA/3'α-fluoro-PA ratio was 16:84, indicating that introduction of a fluorine at C-3' thermodynamically reduced isomerization of 8'-HOABA to PA. The isomerization became more rapid as pH increased; the rate constant at pH 10 was higher than that at pH 3 by a factor of 2000. Introduction of a fluorine at C-3' reduced the reaction rate by raising the activation enthalpy. This indicated that 8'-HOABA was also kinetically stabilized by the 3'-fluorine. These findings suggested that the control of pH and modification of the enone moiety of the ring would be useful to manipulate the catabolic inactivation rate of ABA. (C) 2000 Elsevier Science Ltd.

Synthesis and biological activity of 3'-chloro, -bromo, and - iodoabscisic acids, and biological activity of 3'-fluoro-8'-hydroxyabscisic acid

(+)-3'-Chloro, -bromo and -iodoabscisic acids were synthesized, and their biological activities and metabolism were examined, as well as that of (+)-3'-fluoroabscisic acid. This was in order to estimate the effects of altered electron density at the C-2' position of abscisic acid on both biological activity and metabolic stability. The biological activities of (+)-3'-chloro and bromoabscisic acids were similar to, or higher than, those of (+)-abscisic acid in four bioassays, while (+)-3'-iodoabscisic acid was more potent in two bioassays and less potent than (+)-abscisic acid in the other two bioassays. The biological activities of 3'-haloabscisic acids seem to be dependent on the 3'-halogens, but not on the electron density at C-2'. The metabolism of (+)3'-haloabscisic acids to ca. 50% of their original levels in the media of rice cell suspension culture was similar to that of (+)abscisic acid. Metabolites from (+)-3'-chloro, -bromo and -iodoabscisic acids were not found in the culture media and cells, while (+)-3'- fluoroabscisic acid gave (+)-3'-fluoro-8'-hydroxyabscisic acid as a stable metabolite. (+)-3'-fluoro-8'-hydroxyabscisic acid showed biological activities lower than (+)-3'-fluoroabscisic acid, but higher than (-)-3'α- Fluorophaseic acid. These findings suggested that the biological activity of (+)-8'-hydroxyabscisic acid is intermediate between those of (+)abscisic acid and (-)-phaseic acid. Abscisic acid may be inactivated in a stepwise manner by metabolism in plants.

Synthesis, Biological Activity and Metabolism of (S)-(+)-3'-Fluoroabscisic Acid

(S)-(+)-3'-Fluoroabscisic acid (5a) was synthesized as an analogue of abscisic acid that can resist the metabolic cyclization of 8'-hydroxyabscisic acid to phaseic acid due to increased electron density at C-2'.The inhibitory activity of 5a was slightly h