Synthesis and X-ray analysis of isomeric diazadithia-pentacenes.
The isomeric diazadithiapentacenes (3) and (4) were obtained in reactions of 2-chloro-3-bromoquinoline (5) with selected sulfur reagents in various conditions. The 1,4-dithiin ring opening in diazadithiapentacene (3) led to 2,3’-diquinolinyl sulfide or (via the Smiles rearrangement stage of the S→S type) to 3,3’-diquinolinyl sulfide or to diazadithiapentacene (4) depending on reaction conditions.