Dibenzotetrathiafulvalene was prepared from 2,2'-Bi-1,3-benzodithiol under reaction conditions with 2,3-dicyano-5,6-dichloro-p-benzoquinone and dichloromethane. The specific method of operation is described below:
General procedure: Dithioacetal (0.1 mmol) and DDQ (68 mg, 0.30 mol) were dissolved in CH2Cl2 (3 mL). The resultant dark blue mixture was stirred at room temperature for 16 h and was then washed with a saturated NaOH aqueous solution (2 mL) and CH2Cl2 (10 mL). The orange organic phase was dried over anhydrous Na2SO4, filtered, and then evaporated under reduced pressure. The crude solid was recrystallized from hexane to give the corresponding dibenzotetrathiafulvalene derivative. Dibenzotetrathiafulvalene (2a)22. Yield: 30 mg (99%); orange solid; mp 239.8-243.0 °C. 1H NMR (500 MHz, CDCl3): δ = 7.27-7.24 (m, 4 H), 7.13-7.10 (m, 4 H). 13C NMR (125 MHz, CDCl3): δ = 136.6, 125.9, 121.9, 110.6. MS (FAB): m/z = 304 [M+]. HRMS (FAB): m/z calcd for [M]+ (C14H8S4): 303.9509; found: 303.9519.