Synthesis and herbicidal activity of 1H-1,4-benzodiazepine-2,5-diones

A series of 1H-1,4-benzodiazepine-2,5-diones, which have been found to inhibit photosystem II electron transport, were evaluated for their herbicidal activity. Many of the analogues tested exhibited moderate to good herbicidal activity both preemergence and postemergence. The structure-activity relationships were probed by substitution in both the benzene and diazepine ring. Among the variations investigated, it was found that maximal herbicidal activity was obtained by substitution at C-7 and C-9 in the aromatic portion and by bulky aliphatic substitution at N-4 while leaving N-1, C-6, and C-8 unsubstituted.