Synthesis of substituted triphenylenes useful for discotic liquid crystals

摘要

Substituted triphenylenes, required in the synthesis of polymeric discotic liquid crystals, are made using an oxidising agent (eg FeCl3 or NOBF4) to couple suitably substituted benzenes with suitably substituted benzenes or biphenyls. The coupling is followed by treatment with a reducing agent (eg methanol). For example, iron (III) chloride in organic solvent at room temperature may be used to effect the oxidative coupling of 1,2-dialkoxybenzenes to 3,3',4,4'-tetraalkoxybiphenyls. The same oxidation-reduction protocol also proves effective in the trimerisation of 1,2-dialkoxybenzenes.