| Popis: |
Several compounds having the basic α-ionylideneacetic acid structure were tested in Cercospora rosicola resuspensions. At 100 μm, all the compounds inhibited abscisic acid (ABA) biosynthesis. Time studies with unlabelled and deuterated (2Z,4E)- and (2E,4E)-α-ionylideneacetic acids showed rapid conversions into both (2Z,4E)- and (2E,4E)-4′-keto-α-ionylideneacetic acids as major products. Incorporation of the label into ABA was specific for the 2Z,4E-isomer. Minor products, identified by GC-MS, were (2Z,4E)- and (2E,4E)-4′-hydroxy-α-ionylideneacetic acids and (2Z,4E)-1′-hydroxy-α-ionylideneacetic acid. The conversion to (2Z,4E)-l′-hydroxy-α-ionylideneacetic acid has not been previously reported and was specific for the 2Z,4E-isomer. A time study for the conversion of methyl esters of [2H3]-(2Z,4E)- and [2H3]-(2E,4E)-4′-keto-α-ionylideneacetates showed a slow introduction of the l′-hydroxyl group and specificity for 2Z,4E-isomer. Conversion of the ethyl esters of (2Z,4E)- and (2E,4E)-l′-hydroxy-α-ionylidenea... |
