Tetrafluoroboric acid → 2,5-Dibromo-3-fluoropyridine

Participants

Reaction Conditions

Reaction Steps

37.00 g (146.87 mmol) of 3-amino-2,5-dibromopyridine are diazotized in 50 ml of aqueous HBF4 (35% strength) at -10° C. using 11.10 g (160.87 mmol) of sodium nitrite in 20 ml of water. After the reaction mixture has been stirred for a further half an hour at -10° C., it is heated at 50° C. for 30 minutes, poured into ice water, neutralized using sodium hydrogencarbonate and extracted three times with dichloromethane. The organic phase is washed twice with water, dried over sodium sulfate, filtered and freed from solvent. Chromatographic purification (silica gel/dichloromethane) gives 11.10 g of 2,5-dibromo-3-fluoropyridine. ##STR13##

Provenance & Evidence