反应详情

To the solution of KMnO4 (284 mg, 1.8 mmol) in H2O (50 mL) was added 2-fluoro-5-methylpyridine (100 mg, 0.9 mmol) at room temperature. The reaction mixture was then heated to 100° C. for 4 h. The resulting precipitate was filtered and discarded. The aqueous solution was washed with 3:2, hexane: ethyl acetate (2×20 mL), acidified with 2N HCl, then extracted with ethyl acetate (3×20 mL). The organic extracts were combined and washed with H2O and brine, dried over anhydrous Na2SO4. The solvent was evaporated in vacuo to give 6-fluoronicotinic acid (30 mg) as a white solid. The title compound was prepared from 6-fluoronicotinic acid and 4-ethoxy-2-nitroaniline as a yellow solid as described in Example 15. 1H NMR (CDCl3): 11.09 (bs, 1H), 8.88 (d, J=2.4, 1H), 8.81 (d, J=9.3, 1H), 8.42-8.35 (m, 1H), 7.74 (d, J=3.3, 1H), 7.33-7.29 (m, 1H), 7.13-7.10 (m, 1H), 4.11 (q, J=7.2, 2H), 1.47 (t, J=7.2, 3H).