phosphorus tribromide in chloroform T=0 - 60°C; 2 h; Inert atmosphere;

acetyl-bromide in acetic acid 24 h; Inert atmosphereReflux;

acetyl-bromide; phosphorus tribromide; acetic acid in chloroform

acetyl-bromide; acetic acid 4 h; Inert atmosphereReflux;

1: 13.48 g / magnesium monoperoxyphthalate / ethanol / 5 h / Heating 2: 49 percent / HNO3; H2SO4 / 31 h / 100 °C 3: acetyl bromide 4: PBr3 View Scheme

1: 16 percent / KNO3; H2SO4 / 24 h / 100 °C 2: 64 percent / CH3COBr; glacial AcOH / 2 h / Heating 3: 60 percent / PBr3 / CHCl3 / 1.25 h / Heating View Scheme

bromine 1.) 1,2-dichlorobenzene, 180 deg C, 16 h; 2.) CHCl3, -60 deg C; Yield given. Multistep reaction;

n-butyllithium in tetrahydrofuran; hexane (Ar, Schlenk) n-C4H9Li in hexane was added to the soln. of bipyridine-compound and borate at -78°C over 25 min, stirred for 30 min, allowed to warm to -20°C followed by addn. of 1 N HCl soln., room temp.; extd. with ethyl acetate, the aq. layer was collected, pH 7 (aq. NaOH), the solid was filtered, washed with CH3CN, dried in vac.; elem. anal.;

1: n-butyllithium; 4-bromo-2,2'-bpy in diethyl ether; hexane T=-110 - -100°C; Metallation; 0.5 h; 2: boric acid trimethyl ester in diethyl ether; hexane T=-110 - -100°C; Substitution; 1 h;

1.1: n-BuLi / diethyl ether; hexane / 1 h / -78 °C 1.2: 15.1 percent / diethyl ether; hexane / 1 h / -78 °C 2.1: 83 percent / MnO2 / CHCl3 / 1 h / Heating View Scheme