4-Fluoroaniline → Methyl 1-(4-fluorophenyl)-2-oxo-1,2-dihydropyridine-3-carboxylate

Beteiligte Stoffe

Reaktionsschritte

To a solution of methyl 2-oxo-2H-pyran-3-carboxylate (2.31 g, 15 mmol, Aldrich) in THF (40 mL) and DMF (10 mL) at rt was added 4-fluoroaniline (1.67 g, 15 mmol), and the reaction mixture was stirred for 2.5 h. To the 4-fluoroaniline intermediate formed via a Michael addition was added EDCI.HCl (3.85 g, 20 mmol) and DMAP (120 mg) at rt. The reaction mixture was stirred at rt overnight. To the reaction mixture were added 1 N aq. HCl (50 mL) and EtOAc (150 mL). The EtOAc layer was separated, and the aqueous layer was washed with EtOAc (150 mL). The combined EtOAc layers were dried over MgSO4 and concentrated in vacuo to obtain a semi-solid material (˜4.4 g). The crude product was dissolved in ether (100 mL) and methanol (15 mL), and the solid which formed after stirring was filtered off. The filtrate was concentrated in vacuo to afford the desired product (2.95 g, 80%) as a semi-solid, which was sufficiently pure to use in the next step without further purification. 1H NMR (DMSO-d6) δ 8.23 (dd, 1H, J=7.2, 2.2 Hz), 7.57 (dd, 1H, J=6.6, 1.7 Hz), 7.32–7.34 (m, 2H), 7.17 (t, 2H, J=8.8 Hz), 6.32 (t, 1H, J=7.1 Hz), 3.89 (s, 3H); MS(ESI+) m/z 248.2 (M+H)+.

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