THE STABILITY OF THE 1',4'-DIOLS OF ABSCISIC ACID

Article abstract of DOI:10.1016/0031-9422(88)83093-0

The 1',4'-cis and 1',4'-trans-diols of abscisic acid (ABA) are unstable in acidic conditions: they interconvert and oxidize to ABA.When the diols were held in acidic (pH 4) <18O>H2O the oxygen atoms of both the 1'- and 4'-hydroxyl groups exchanged with the medium with retention and inversion of configuration.Thus the (+)-<2-14C>-trans-diol was epimerized to the (+)-<2-14C>-cis-diol and to the (-)-<2-14C>-cis-diol.Similarly, the <1'-18O>cis and <1'-18O>trans-diol lost 18O during epimerization.The trans-diol was the more stable by about 30percent and was also less prone to oxidation to ABA.Significant epimerization of the cis-diol occurred below pH 6 while an equivalent reaction of the trans-diol occurred below pH 5.Key Word Index - 1',4'-trans-diol of ABA; 1',4'-cis-diol of ABA; 1',4'-dihydroabscisic acid; epimerization; abscisic acid.