SYNTHESIS OF SPIROTHIOHYDANTOIN ANALOGS OF HYDANTOCIDIN

Synthesis of spirothiohydantoin derivatives of hydantocidin is describ ed. The key feature of the synthesis was spirothiohydantoin ring forma tion through an iminophosphorane intermediate. Spirothiohydantoin deri vative 2 maintained comparable herbicidal activity to that of the natu ral compound except against fall panicum, when applied through a folia ge of weeds at 1000 ppm. Surprisingly, its epimer 15 also demonstrated good herbicidal activity under the same condition, while 5-epi-hydant ocidin 16 displayed fair activity.