Synthesis and characterization of S,N-heterotetracenes

• Astrid Vogt,
• Florian Henne,
• Christoph Wetzel,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2020, 16, 2636–2644, doi:10.3762/bjoc.16.214

• nitrogen heteroatoms were synthesized in multistep synthetic routes. A Buchwald–Hartwig amination of brominated precursors, thermolysis of azide precursors, and a Cadogan reaction of nitro-substituted precursors were successfully applied to eventually build-up pyrrole rings to stable and soluble fused

• derivatives by Cadogan reaction of nitro-substituted precursors. Another possibility for the preparation of fused pyrrole rings is established by the Cadogan reaction [40]. Well-known examples are the reductive cyclization of 2-nitro-1,1’-biphenyls with triethyl phosphite or phosphanes as reducing agent to

• provide carbazoles covering a wide substrate and functional group spectrum [41]. Moreover, penta- and heptafused heteroacenes were prepared by the Cadogan reaction by annulation of nitrophenyl or nitrobenzothienyl precursors [42][43][44][45]. In this respect, we recently reported a Cadogan cyclization of