Tetrafluoroboric acid → 2,5-Dibromo-3-fluoropyridine
Reaction equation
N[C:2]1[C:3]([Br:9])=[N:4][CH:5]=[C:6]([Br:8])[CH:7]=1.N([O-])=O.[Na+].C(=O)([O-])O.[Na+].[H+].[B-](F)(F)(F)[F:21]>O>[Br:9][C:3]1[C:2]([F:21])=[CH:7][C:6]([Br:8])=[CH:5][N:4]=1Participants
6
Reactant 4
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- -10 °C
Procedure
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##
Workup
- temperatureit is heated at 50° C. for 30 minutes
- extractionextracted three times with dichloromethane
- washThe organic phase is washed twice with water
- dry with materialdried over sodium sulfate
- filtrationfiltered
- customChromatographic purification (silica gel/dichloromethane)
Sources & evidence
- ORD record
- ord-4eb7cdc948b64563a3d1c53ed7e68712
- Source dataset
- uspto-grants-1995_08
- Patent number
- US05445763
Reaction notes
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