1: 2,3-dichloro-5,6-dicyanobenzoquinone; molecular sieves 4 Angstroem / benzene / 1 h / 60 °C 2: aq. HCl / diethyl ether / 6 h View Scheme

4 A molecular sieve; 2,3-dicyano-5,6-dichloro-p-benzoquinone in benzene T=60°C; 1 h;