A 1,4-benzoquinone with counteracting inductive donor and acceptor substituents

Investigation of a published route to produce 3,5-di- tert-butylphenol, starting from commercial 3,5-di- tert-butylbenzoic acid via 3,5-di- tert-butylanlinium hydrogen sulfate, unexpectedly yielded 2,6-dintitro-3,5-di- tert-butylphenol. Attempts to increase the yield of the latter resulted, instead, in the previously unreported 2,6-dinitro-3,5-di- tert-butylcyclohexa-2,5-dien-1,4-dione. Single-crystal X-ray diffraction structures are reported for the anilinium salt, the nitrated phenol, and the quinone. Voltammetry of the quinone shows two chemically reversible reductions in anhydrous solution and the radical anion produced from the first reduction step has been characterized by electron paramagnetic resonance spectroscopy. This compound fits well to the middle range of electron-poor quinones, indicating that the inductive effects of the tert-butyl and nitro groups counteract each other. This conclusion is also supported by the infrared spectroscopic data where the ν(C=O) and ν(C=C) bands are of very similar energy to those of 2,3,5,6-tetrachloro-1,4-benzoquinone.