Pyridine → 5-(Pyridin-2-yl)-4-(trifluoromethyl)isoxazole-3-carbonyl fluoride
Reaction equation
[N:1]1[CH:6]=[CH:5][CH:4]=[CH:3][C:2]=1[C:7]1[O:11][N:10]=[C:9]([C:12](O)=[O:13])[C:8]=1[C:15]([F:18])([F:17])[F:16].N1C=CC=CC=1.N1C(F)=NC(F)=NC=1[F:27]>ClCCl>[N:1]1[CH:6]=[CH:5][CH:4]=[CH:3][C:2]=1[C:7]1[O:11][N:10]=[C:9]([C:12]([F:27])=[O:13])[C:8]=1[C:15]([F:18])([F:17])[F:16]Participants
Procedure
To a solution of 5-(pyridin-2-yl)-4-(trifluoromethyl)isoxazole-3-carboxylic acid (54.3 mg, 0.210 mmol) and pyridine (0.037 mL, 0.463 mmol) in dichloromethane (2 mL) was added cyanuric fluoride (0.021 mL, 0.252 mmol). The reaction mixture was stirred at room temperature for 2 hrs., diluted with dichloromethane (2 mL), and washed with ice water (1 mL). The aqueous layer was extracted with dichloromethane (2×1 mL), and the combined organic layers were washed with brine (1 mL) and dried over anhydrous sodium sulfate. Concentration under reduced pressure afforded 5-(pyridin-2-yl)-4-(trifluoromethyl)isoxazole-3-carbonyl fluoride (0.048 g, 0.185 mmol, 88% yield). The product had an HPLC retention. time=2.50 min. (The product reacted readily with methanol and a small portion was characterized as the methyl ester)—Column: YMC S5 COMBISCREEN® 4.6×50 mm (4 min.); Solvent A=10% MeOH, 90% H2O, 0.1% TFA; Solvent B=90% MeOH, 10% H2O, 0.1% TFA.
Workup
- washwashed with ice water (1 mL)
- extractionThe aqueous layer was extracted with dichloromethane (2×1 mL)
- washthe combined organic layers were washed with brine (1 mL)
- dry with materialdried over anhydrous sodium sulfate
- concentrationConcentration under reduced pressure
Sources & evidence
- ORD record
- ord-f9780144861d44efb19b8775afd9a67e
- Source dataset
- uspto-grants-2013_03
- Patent number
- US08404672B2
Reaction notes
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