A More Efficient Access to Tetraaza-pentacenes

Significance

Tetraazapentacenes are promising candidates for applications in organic electronics. They can usually be obtained in good yields via condensation of an aromatic diamine with an ortho-dichloroarene. However, when the diamine carries substituents ortho to the amino groups (e.g. 1) this approach results in low yields. The ­authors present a palladium-catalyzed route that affords the dihydrotetraazapentacenes (3a-c) in 80-90% yield. Subsequent oxidation with MnO₂ leads to the conjugated compounds 4a-c.