Synthesis and biological activity of 4′-methoxy derivatives of abscisic acid

Replacing the 4′-carbonyl group of abscisic acid with a methoxy group does not affect the abscisic acid (ABA)-like activities of the product in barley aleurone protoplasts, although the reduction of ABA to 4′-hydroxyl derivatives significantly reduces the ABA-like activity of the products. This suggests that methoxy derivatives of abscisic acid might be used to produce probes for ABA binding proteins.