cyclohexa-1,4-diene in chlorobenzene T=190°C; 8 h; Yields of byproduct given;

aluminum oxide T=500°C; Cyclization; Dehydrogenation; P=2 Torr;

T=800°C; P=0.01 Torr;

1: 79 percent / diethyl ether; methanol 2: 85 percent / 2,3-dichloro-5,6-dicyano-1,4-benzoquinone / chlorobenzene / 10 h / Heating 3: 68 percent / lithium hydroxide monohydrate / H2O; 1,2-dimethoxy-ethane / 18 h / Heating 4: 68 percent / acetic anhydride / 11 h / 90 °C 5: 0.67 h / 860 °C / 0.07 Torr / flash vacuum pyrolysis View Scheme

1: 68 percent / lithium hydroxide monohydrate / H2O; 1,2-dimethoxy-ethane / 18 h / Heating 2: 68 percent / acetic anhydride / 11 h / 90 °C 3: 0.67 h / 860 °C / 0.07 Torr / flash vacuum pyrolysis View Scheme

1: 85 percent / 2,3-dichloro-5,6-dicyano-1,4-benzoquinone / chlorobenzene / 10 h / Heating 2: 68 percent / lithium hydroxide monohydrate / H2O; 1,2-dimethoxy-ethane / 18 h / Heating 3: 68 percent / acetic anhydride / 11 h / 90 °C 4: 0.67 h / 860 °C / 0.07 Torr / flash vacuum pyrolysis View Scheme

1: 68 percent / acetic anhydride / 11 h / 90 °C 2: 0.67 h / 860 °C / 0.07 Torr / flash vacuum pyrolysis View Scheme

oxalic acid

sodium tetrahydroborate; aluminium trichloride; oxalic acid; sodium chloride Yield given. Multistep reaction. Yields of byproduct given. Title compound not separated from byproducts;

T=860°C; P=0.07 Torr; 0.666667 h; Yield given. Yields of byproduct given. Title compound not separated from byproducts;