The synthesis of several analogues of 8-oxabicyclo[3.2.1]oct-6-en-3-one is reported. The effect of these compounds and 4-oxohexanoic acid on the germination and radicle growth of Sorghum bicolor was evaluated. At 100 ppm compounds 3-(methoxycarbonylmethyl)-8-oxabicyclo[5.3.0]dec-4-ene-2,9-dione (13) and 4-oxohexanoic acid (17) showed 33-35% stimulatory radicle growth, and at 1000 ppm a 29% (13) and 80.2% (17) inhibition was observed. All the other compounds showed an inhibitory effect on the radicle growth at 100 and 1000 ppm. None of the compound had a clear effect on the germination rate.
germination; growth inhibition; lactones; [3+4]; cycloaddition
