Boron tribromide → 2-Fluoroquinoline-4-carboxylic acid
Reaction equation
C[O:2][C:3]([C:5]1[C:14]2[C:9](=[CH:10][CH:11]=[CH:12][CH:13]=2)[N:8]=[C:7]([F:15])[CH:6]=1)=[O:4].B(Br)(Br)Br>ClCCl>[F:15][C:7]1[CH:6]=[C:5]([C:3]([OH:4])=[O:2])[C:14]2[C:9](=[CH:10][CH:11]=[CH:12][CH:13]=2)[N:8]=1Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
A solution of 2-fluoroquinoline4-carboxylic acid methyl ester (0.08 g) in dichloromethane (4 ml) was cooled to −50° C. and boron tribromide (0.08 ml) was added. After the addition of boron tribromide the reaction was warmed to room temperature and stirred for 1.5 h. The mixture was re-cooled to −50° C., quenched with water (10 ml), diluted with dichloromethane:water (1:1, 60 ml), the organic phase separated and solvent removed at reduced pressure to give 2-fluoroquinoline-4-carboxylic acid (0.02 g) after trituration with dichloromethane/petroleum ether. 1H NMR δ: 7.70-7.76 (2H, m), 7.85-7.96 (2H, m), 8.65 (1H, d), 14.24 (1H, brs). m/z (API−): 190 (MH+).