Boron tribromide → 2-Fluoroquinoline-4-carboxylic acid

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Reaktionsschritte

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+).

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