156492-30-7

87330-27-6

156492-30-7

1,10-Phenanthroline-4,7(1H,10H)-dione (73c, 4.2 g, 20 mmol) was used as a feedstock and mixed with tribromophosphine (14.3 g, 50 mmol) in anhydrous chloroform. The reaction mixture was refluxed for 6 hours under nitrogen protection. Upon completion of the reaction, the reaction solution was washed with water followed by saturated brine three times. The organic layer was dried with anhydrous magnesium sulfate and the solvent was removed by evaporation. Finally, the crude product was purified by silica gel column chromatography to afford 4,7-dibromo-1,10-phenanthroline (73d, 4.7 g, 13.9 mmol) in 70% yield.