Abstract The synthesis and properties of new heterocyclic systems are described: isomeric 2, 3-dioxo-2, 3-dihydro-1H-benzo [b] thiopheno [2, 3-g]-, 1, 2-dioxo-1, 2-dihydro-1H-benzo [b] thiopheno [3, 2-e]-, and 2, 3-dioxo-2, 3-dihydro-1H-benzo [b] thiopheno [2, 3-f] indoles. The reduction of the latter to the corresponding unsubstituted benzo [b] thiophenoindoles depends on both the nature of the reducing agent and the reaction conditions.
