2-Iodo-3-nitrotoluene

Typical procedure (synthesis of 2,2’-diamino-6,6’-dimethylbiphenyl (2)): 2-Iodo-3-nitrotoluene (78.9 g), fine copper powder (80.0 g) and DMF (500 ml) are added to a 1L round bottomed flask. The reaction vessel is purged with nitrogen and the reaction mixture is heated to reflux and stirred for 4 hours. The solution gradually change color from yellow to dark brown. Another batch of copper powder (20 g) is added to the reaction mixture which is stirred for a further 3 hours. On cooling the solution is filtered and washed with diethylether which is added to the filtrate. The filtrate is concentrated to 200 mL, it is then dissolved in diethylether (750 mL). The ethereal solution is washed with water (3 x 250 mL) and brine (1 x 250 mL). The organic solvents are removed on an evaporator to give (1) as a biscuit colored brown solid, and dried in a vacuum oven at 40 °C (37.6 g, 92 %). The biphenyl (1) (31.3 g) is dissolved in ethyl acetate (400 ml), and placed in a hydrogenation bottle. A 5% palladium on carbon (2.3 g) is added and the reaction mixture was mechanically shaken under an atmosphere of hydrogen gas (3 atm) for 3 days or until there is no more uptake of hydrogen. The solution is filtered through a bed of Celite to remove the catalyst and the filtrate is evaporated to dryness to give (2) as a light brown colored solid (24.4 g, 100 %)