The insertion and extrusion of heterosulfur bridges. XIV. Synthesis of nitrotriphenyleno[1,12‐bcd]thiophenes

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Abstract
Sulfur bridging to form triphenyleno[1,12‐bcd]thiophene (2) in ca. 46% yield has been effected at 540° by direct addition of crystalline triphenylene (1) or dodecahydrotriphenylene (4) to a heterogeneous catalyst in a stream of hydrogen sulfide. Treatment of a reaction mixture of 1 and 2 with hydrogen peroxide‐glacial acetic acid gives 2 sulfone 2d and 1,4‐triphenylenoquinone (3). Reduction of 2d with lithium aluminum hydride in tetrahydrofuran leads back to 2 (80%), while reductive acetylation of 3 produces 1,4‐diacetoxytriphenylene. Treatment of 2 with nitric acid in acetic anhydride at 65° gives a mixture of 1‐nitro (30%), 3‐nitro (47%), and 1,7‐dinitro (11%) derivatives, separable by chromatography on alumina. Structures of these derivatives are assigned on the basis of ultraviolet‐visible absorption and proton magnetic resonance spectra, as well as the chemical conversion 1‐nitro‐2 → 1,7‐dinitro‐2. The substitution pattern in 2 is correlated with Hückel molecular orbital calculations on reactivity and with substitution in analogous polycyclic, condensed aromatic compounds.