Hydrochloric Acid → 5-Bromo-3-fluoropyridine-2-carboxylic acid
Reaktionsgleichung
[Br:1][C:2]1[CH:3]=[C:4]([F:11])[C:5]([C:8](N)=[O:9])=[N:6][CH:7]=1.Cl.[OH-:13].[Na+]>>[Br:1][C:2]1[CH:3]=[C:4]([F:11])[C:5]([C:8]([OH:13])=[O:9])=[N:6][CH:7]=1Komponenten
4
Versuchsvorschrift
A solution of crude 5-bromo-3-fluoropyridine-2-carboxamide (40.50 g, 184.9 mmol) in HCl (12N, 539.4 mL, 6.472 mol) was heated to 120° C. for 1 hour. The reaction was cooled to room temperature, and NaOH (20%) was added slowly to pH˜6. The solution was concentrated in vacuo, and azeotroped 3×with toluene. The residue was extracted thoroughly with 40% MeOH/CHCl3 and filtered. This was repeated three times. The combined filtrates were concentrated and azeotroped 3×with toluene to provide 5-bromo-3-fluoropyridine-2-carboxylic acid that gave a mass ion (ES+) of 218.1 for M+H+(79Br).