P(Cl)(Cl)([Cl:3])=O.N1C2C(=CC=CC=2)C=CC=1.[N+:16]([C:19]1[C:20](O)=[N:21][CH:22]=[C:23]([C:25]([F:28])([F:27])[F:26])[CH:24]=1)([O-:18])=[O:17].C([O-])([O-])=O.[Na+].[Na+]>O>[Cl:3][C:20]1[C:19]([N+:16]([O-:18])=[O:17])=[CH:24][C:23]([C:25]([F:28])([F:27])[F:26])=[CH:22][N:21]=1To a solution of phosphoryl chloride (2.0 mL, 21.2 mmol) and quinoline (1.30 mL, 10.8 mmol) was added solid powder 3-nitro-5-(trifluoromethyl)pyridin-2-ol (4.00 g, 18.3 mmol) (95% purity). The resulting dark brown thick suspension was heated to reflux for 4 h and gradually turned into a very cloudy dark brown solution. After cooling to 100° C., water (11 mL) was slowly added to the mixture which was further cooled to room temperature and neutralized carefully with Na2CO3. The resulting solution was extracted with EtOAc three times. The extracts were combined, dried over MgSO4, filtered, and evaporated in vacuo. The residue was purified by flash chromatography on silica gel (EtOAc/hexanes 30:70) to afford 2.28 g of desired product.
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