[F:1][C:2]1[CH:7]=[CH:6][C:5]([CH2:8][C:9](=[O:16])[CH2:10][C:11]([O:13][CH2:14][CH3:15])=[O:12])=[CH:4][CH:3]=1.[CH3:17]C[O-].[Na+].[N:21]1[CH:26]=CC=NN=1>CCO.N1C=CC=NN=1>[F:1][C:2]1[CH:3]=[CH:4][C:5]([C:8]2[C:9](=[O:16])[C:10]([C:11]([O:13][CH2:14][CH3:15])=[O:12])=[CH:17][NH:21][CH:26]=2)=[CH:6][CH:7]=1
To a solution of ethyl 4-(4-fluorophenyl)-3-oxobutanoate (4.6 g, 21 mmol) in absolute EtOH (45 mL) was added NaOEt solution (21% NaOEt solution in EtOH, 7.7 mL) and triazine (1.67 g, 21 mmol). The resulting mixture was heated to 85° C. for 1.5 h, cooled to room temperature and treated with an additional portion of triazine (0.08 g, 1 mmol) and NaOEt solution (21% NaOEt solution in EtOH, 0.4 mL). The reaction mixture was heated for an additional hour and concentrated in vacuo. The residue was treated with 1N HCl until the pH of the reaction was about 2. The precipitate was collected to give the desired ester intermediate, ethyl 5-(4-fluorophenyl )-4-oxo-1,4-dihydropyridine-3-carboxylate (4.5 g, 83%) as a yellow solid. MS (ESI+) m/z 262 (M+H)+.
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