[N+:1]([CH:3](S(C1C=CC(C)=CC=1)(=O)=O)[CH3:4])#[C-:2].[F:15][C:16]1[C:23]([F:24])=[C:22]([C:25]([F:28])([F:27])[F:26])[CH:21]=[CH:20][C:17]=1[CH:18]=[O:19].C([O-])([O-])=O.[K+].[K+].O>CO>[F:15][C:16]1[C:23]([F:24])=[C:22]([C:25]([F:28])([F:26])[F:27])[CH:21]=[CH:20][C:17]=1[C:18]1[O:19][CH:2]=[N:1][C:3]=1[CH3:4]A mixture of 1-(1-isocyanoethylsulfonyl)-4-methylbenzene (1 0.0 g, 47.8 mmol), 2,3-difluoro-4-(trifluoromethyl)benzaldehyde (9.68 g, 46.1 mmol), and K2CO3 (13.1 g, 95.0 mmol) in MeOH (240 mL) was heated to reflux. After 2 hr, the reaction mixture was cooled to ambient temperature, water (700 mL) was added, and the product was extracted with EtOAc (700 mL). The organic layer was washed with brine and dried over Na2SO4, filtered, and concentrated to an orange oil. The crude product was purified by chromatography on silica gel in five batches (Analogix® SF40-240G column, 100% CH2Cl2, 65 mL/min) to afford 7.22 g (60%) of the title compound as a light yellow liquid. 1H NMR (300 MHz, DMSO-d6) δ 8.56 (s, 1H), 7.78-7.69 (m, 1H), 7.68-7.59 (m, 1H), 2.30 (d, J=2.5, 3H). MS (DCI+) m/z 264 (M+H).
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