2,3-dicyano-5,6-dichloro-p-benzoquinone in benzene 16 h; Ambient temperature;

1: 68 percent / Cu2Br2, Na2CO3 / various solvent(s) / 5.5 h / 170 °C 2: 81 percent / 2,3-dichloro-5,6-dicyano-1,4-benzoquinone / benzene / 6 h / Heating View Scheme