[O:1]=[C:2]([NH:9][C:10]1[CH:15]=[CH:14][CH:13]=[C:12]([C:16]([F:19])([F:18])[F:17])[CH:11]=1)[CH2:3][C:4]([O:6]CC)=[O:5].C[O-].[Na+].CO[CH:25]=[CH:26][C:27](=O)[CH3:28].[OH-].[Na+]>CCO.O>[CH3:25][C:26]1[N:9]([C:10]2[CH:15]=[CH:14][CH:13]=[C:12]([C:16]([F:17])([F:18])[F:19])[CH:11]=2)[C:2](=[O:1])[C:3]([C:4]([OH:6])=[O:5])=[CH:28][CH:27]=1
To a solution of ethyl 3-oxo-3-{[3-(trifluoromethyl)phenyl]amino}propanoate (19.2 g, 70 mmol) and sodium methoxide (7.6 g, 140 mmol) in EtOH (250 ml) was added 4-methoxybut-3-en-2-one (90%) (7.72 g, 77 mmol). After the addition, the reaction mixture was refluxed for 2 h and then cooled. Water (50 ml) and 2M NaOH were added and the mixture was stirred at RT overnight. The organic solvents were removed and the reaction mixture was extracted (washed) with EtOAc. The water phases were acidified with hydrochloric acid to pH 3 to 4, an orange coloured precipitate appeared and was filtered off, washed with water and dried. Recrystallisation twice from heptane/EtOAc (4:1) afforded 6-methyl-2-oxo-1-[3-(trifluoromethyl)phenyl]-1,2-dihydropyridine-3-carboxylic acid (12 g, 58%) as a white powder.
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