Synthesis and Plant Growth Regulatory Activity of 6α,7β-Dihydroxyvouacapan-17β-oic Acid Derivatives.

Five new derivatives of 6α,7β-dihydroxyvouacapan-17β-oic acid were prepared. The effect of these new furan diterpenes on the radicle growth of Sorghum bicolor L. and Cucumis sativus L. was evaluated. All compounds, at a concentration of 100 ppm, showed an inhibitory effect (40–63%) on the radicle growth of S. bicolor L. and a small stimulatory growth effect (3–15%) on the radicle of C. sativus L. None of the compounds had any effect on the germination rate of both plants.