Triphenyleno[1,12‐bcd]:4,5‐b′c′d′]dithiophene (3) is synthesized in low yield (2.5% maximum) from a mixture of triphenylene (1) and triphenyleno[4,5‐bcd]thiophene or from 1 alone by means of heterogeneously catalyzed sulfur bridging by hydrogen sulfide at 500–550°. Compound 3 is characterized by spectral and other properties. Hückel molecular orbital calculations for the formation and reaction of 3 are presented.
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.
Reaction of 1‐nitrotriphenylene (7a) with triethylphosphite (Cadogan reaction) produces 4H‐naphtho[1,4‐def]carbazole, a likely component of fossil fuels. Surprisingly 7a and its 2‐isomer are obtained from treatment of triphenylene with sulfuric acid/trifluoroacetic anhydride in nitromethane. Correlation between ultraviolet spectra and substitution reactions in peri‐condensed pyrroles and thiophenes is presented.
Reaction of m‐terphenyl with 20% oleum at 100° gives both disulfonation and double sulfonyl bridging to yield benzo[1]thieno[2,3‐b]dibenzothiophene‐3,9‐disulfonic acid 5,5,7,7‐tetraoxide, isolated as the disodium salt (24%) and convertible (via the disulfonyl chloride) to the bis‐sulfonanilide (44%) and the bis‐N‐butylsulfonamide (40%). Analogously, reaction of m‐terphenyl with chlorosulfonic acid at 100° gives disulfonation plus only single sulfonyl bridging to produce 2‐(4‐chlorosulfonyl)‐7‐chlorosulfonyldibenzothiophene 5,5‐dioxide (80%), convertible to the corresponding bis‐sulfonanilide (63%) and the bis‐N‐butylsulfonamide (45%).
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