4,11-BISANTHENEQUINONE AND 10,10′-BIANTHRONE: SIMPLE ONE-STEP SYNTHESES FROM ANTHRONE

Irradiation of a dichloromethane/benzene solution of anthrone and molecular bromine promotes a cascade of events that continues all the way to 4,11-bisanthenequinone, which precipitates as a yellow solid from the solution as it is formed. Alternatively, treatment of anthrone in the dark with molecular iodine and diazabicyclo[5.4.0]undecene (DBU) at room temperature in dichloromethane gives 10,10′-bianthrone. These new procedures represent particularly convenient methods for preparing the title compounds, each in just one step from commercially available anthrone. Diprotonation of 4,11-bisanthenequinone with triflic acid in CDCl3 generates a red solution of the dication, the 1H NMR spectrum of which is reported here for the first time: δ (ppm) 10.00 (d, J = 8.0 Hz, 4 H), 9.82 (d, J = 8.0 Hz, 4 H), 8.76 (t, J = 8.0 Hz, 4 H).