3,3′-Dibromo-4,4′-bipyridine (3). To a solution of lithium diisopropylamide (15 mmol) in tetrahydrofuran (50 mL), 3-bromopyridine 2 (2.37 g, 15 mmol) was added dropwise at -85°C, without letting the temperature get over -80°C.  The orange suspension was stirred for 1 h at that temperature and CuCl2 (4.90 g, 36 mmol) added.  The mixture was allowed to come to rt, air was allowed into the reaction flask and stirring was continued overnight.  The volatiles were removed under reduced pressure and the brown solid taken up in H2O (30 mL), NH4OH (25 %, 15 mL) and NH4Cl (sat., 15 mL).  This mixture was extracted three times with chloroform, the combined organic phases were dried over Na2SO4 and concentrated to give a brown oil, which was separated by column chromatography (SiO2, hexanes/ethyl acetate, 2:1) to give 1.03 g (44 %) of the title product 3 as off-white powder. 1H NMR (CDCl3, 400 MHz): δ = 8.85 (d, 2 H, 5J(H,H)=0.6 Hz, 2,2′-H), 8.62 (d, 2 H, 3J(H,H)=4.9 Hz, 6,6′-H), 7.16 (dd, 2 H, 3J(H,H)=4.9 Hz, 5J(H,H)=0.6 Hz, 5,5′-H); 13C{1H} NMR (CDCl3, 100.6 MHz): δ = 154.4, 148.3, 146.6, 124.5, 120.6 ppm; MS (EI): m/z 314 (M+), 233 ([M – Br]+), 154 ([M – 2 Br]+); elemental analysis calcd (%) for C10H6Br2N2: C 38.25, H 1.93, N 8.92; found: C 38.36, H 1.77, N 8.88.