Hisao Ishikawa

SYNTHESES AND HERBICIDAL ACTIVITIES OF SULFUR CONTAINING CYCLOHEXANEDIONE DERIVATIVES

To find out a compound which possesses potent herbicidal activities against not only annual grass weeds but also perennial ones for the control of them in soybean fields, exhaustive synthetic studies have been made. In the last analysis of the structure-activity correlation the synthetic approach was directed toward introduction of sulfur containing substituents at the 5-position on the cyclohexane molecule. In order to introduce such substituents into the molecule at an appropriate stage several synthetic methods were attempted using aldehydes or γ-bromocrotonic acids as starting materials. In the preparation of 2-acylcyclohexanediones, direct acylation and the Fries rearrangement of the corresponding O-acylated substances were attempted contrasting with known methods. Herbicidal activities of the newly prepared compounds were also discussed.