Ab initio molecular orbital theory has been used to study in detail the C2H20 potential energy surface. Equilibrium structures and transition structures have been explicitly identified by using gradient techniques and the split-valence 4-31G basis set. Improved relative energies have been obtained by using the split-valence

The asymmetric synthesis of the antibacterial natural product, streptophenazine G, has been achieved by employing asymmetric alkylation and asymmetric aldol reactions using chiral oxazolidinones as the key steps. The originally proposed structure for streptophenazine G has been revised, and its absolute configuration has been determined to be 1'S,2'R,6'S. The asymmetric total synthesis of 6'-epi-streptophenazine G is also described.

A total synthesis of both diastereomers of the originally proposed structure for streptophenazine A (1) has been achieved. However, both synthetic compounds are different from the natural product. Re-examination of NMR data reported for streptophenazine A and a concise total synthesis of both diastereomers of 17 (17a and 17b) led to the structural revision of streptophenazine A to 17b. Asymmetric synthesis of (-)-streptophenazine A was also conducted, and its absolute configuration was determined to be 1'S,2'R.

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.

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