New molecular arrangements of perconjugated systems

Under oxidation conditions (electrochem. or chem.), starting from substituted benzenes or derivatives, triphenylene structures (benzo[l,2 3,4 5,6]tris[arylenes] are formed, e.g.  

If pheynlsulfonic acid (I) is used as a counterion (current density [/] 10 mA/cm ), the trisulfonic acid of triphenylene is formed to some extent [23]. 

Another simple and convincing experiment is the conversion (trimerization) of o-dimethoxybenzene (III) to the analogous triphenylene ether (IV) [41]. 

Imporved procedure 120 g FeCls was suspended in 500 ml H2SO4 (70%), and 30 ml o-dimethosybenzene added under stirring. After 18 hours of stirring, 500 g ice was added and the precipitate filtered off. Washing with 1000 ml H2O, 500 ml ethanol and 300 ml xylene and crystallization from trifluoroacetic acid yielded 13.8 g (46%) of 2,3,6,7,10,11-hexamethoxytripheny-lene, mp 300°C. 

All these phenomena are in accordance with the proposed macrocyclic structure and not with a linear one. 

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