Kuni Matsuya

STRUCTURE-ACTIVITY RELATIONSHIP OF CYCLIC IMIDE HERBICIDES

Abstract N-Aryl-3,4,5,6-tetrahydrophthalimides (I) and other two series of cyclic imide types of compounds (II & III) have been found active as pre-emergence or early post-emergence herbicides. The compounds showed activity at low rates on many grassy and broadleaf weeds and were exceptionally phytotoxic to hairy galinsoga, common purslane and toothcup. Futher biological and biochemical studies showed that these cyclic imide herbicides belonged to the category of diphenylether herbicides having 0-substituent(s) such as CNP or nitrofen in their mechanism of action. In the context of development of cyclic imide herbicides, an information has been obtained on the structural characteristics required for herbicidal activity and a hypothesis that the alkylene ring, the electrondonating moiety, the imide ring and p-substituted ary ring are the prerequisite for activity is presented.

Structure-activity Relationship of Cyclic Imide Herbicides I. N-Substituted Phenyl-3,4,5,6-tetrahydrophthalimides and Related Compounds

In the course of the development of new herbicide (MK–616: N-(p-chlorophenyl)-3,4,5,6-tetrahydrophthalimide), the structure-activity relationship of cyclic imide herbicides was investigated. Sixty N-substituted phenyl-3,4,5,6-tetrahydrophthalimides and related compounds were prepared and their herbicidal activity were examined. The results indicate that, for high inhibitory activity, lipophilic tetramethylene moiety, double bond or nitrogen atom (s) in bridgehead position and N-(p-substituted)phenyl moiety are essential in these cyclic imides. New 4-(p-chlorophenyl)-1,2-tetramethyleneurazole and 3 (-p-chlorophenyl)-1,5-tetramethylenehydantoin were found to be herbicidally active.