Bioactive Chemical Bond Systems in Safeners and Prosafeners*

Ferenc Dutka Department for Pesticide Research, Central Research Institute for Chemistry, Hungarian Academy of Sciences, P.O. Box 17, H-1525 Budapest, Hungary Z. Naturforsch. 46c, 805 — 809 (1991); received March 26, 1991 Safeners, Prosafeners, Acetals, Ketals, MG-191 Acetals and ketals involving a dichloromethyl group on their central carbon atom were found to be active or highly active as safeners of corn against thiocarbamate and chloroacetanilide herbicide injury. A mechanism for the biotransformation of these compounds as pro­ safeners to the actual dichloroacetic ester safeners is proposed. Similarly, Sand N-analogues of the cyclic acetals (ketals) which show safener activity can also be considered as prosafeners because they can be converted in the biophase by the same mechanism into actual safeners such as dichloroacetic thiolesters or dichloroacetamides sup­ porting the bioactivation hypothesis. Characteristic bioactive chemical bond systems in safeners and prosafeners are suggested.