Isopropanol → 1236188-80-9

To a solution of (3-phenyl-4-(trifluoromethyl)isoxazol-5-yl)methanol (5.24 g, 21.6 mmol) in acetone (75 mL) at room temperature (immersed in a water bath) was added Jones' Reagent (43.8 mL, 53.9 mmol) via addition funnel slowly over 1.5 h. The dark reaction mixture was stirred at room temperature overnight. By HPLC, the reaction was 93% complete. An additional 0.5 equivalents (9 mL) of the Jones' Reagent was added. After 1 h, the reaction was 95% complete. After an additional 3h, the reaction was 96% complete. An additional 0.5 equivalents (9 mL) of the Jones' Reagent was added. The reaction mixture was stirred for an additional 2.5 h. By HPLC, the reaction was 97% complete. Isopropyl alcohol (6 mL) was added, and the mixture was stirred for 90 min, resulting in a dark green precipitate. The mixture was diluted with ether (600 mL), washed with a 2% aqueous solution of sodium hydrogen sulfite (5×100 mL), and the organic layer was collected. The aqueous layer was back-extracted with ether (2×100 mL). By HPLC, there was no additional product in the aqueous layer. The combined organic layers were washed with water (100 mL), washed with a saturated aqueous solution of brine (100 mL), and dried over anhydrous sodium sulfate. The aqueous layer was back-extracted with ether (100 mL), and the organic layer was added to the previous organic layers. The solution was concentration under reduced pressure to give 3-phenyl-4-(trifluoromethyl)isoxazole-5-carboxylic acid as an off-white solid. The solid was diluted with dichloromethane (200 mL), washed with a 2% aqueous solution of sodium hydrogen sulfite, washed with brine, and dried over anhydrous sodium sulfate. Concentration under reduced pressure afforded 3-phenyl-4-(trifluoromethyl)isoxazole-5-carboxylic acid (3.84 g, 14.93 mmol, 69.3% yield) as a pale yellow solid. The product was 96% pure by HPLC with a ret. time=1.60 min.-Column: CHROMOLITH® SpeedROD 4.6×50 mm (4 min.); Solvent A=10% MeOH, 90% H2O, 0.1% TFA; Solvent B=90% MeOH, 10% H2O, 0.1% TFA. LC/MS M+1=258.2.

1. additionvia addition funnel slowly over 1.5 h
2. customThe dark reaction mixture
3. waitAfter 1 h
4. stirringThe reaction mixture was stirred for an additional 2.5 h
5. stirringthe mixture was stirred for 90 min
6. customresulting in a dark green precipitate
7. washwashed with a 2% aqueous solution of sodium hydrogen sulfite (5×100 mL)
8. customthe organic layer was collected
9. extractionThe aqueous layer was back-extracted with ether (2×100 mL)
10. washThe combined organic layers were washed with water (100 mL)
11. washwashed with a saturated aqueous solution of brine (100 mL)
12. dry with materialdried over anhydrous sodium sulfate
13. extractionThe aqueous layer was back-extracted with ether (100 mL)
14. additionthe organic layer was added to the previous organic layers
15. concentrationconcentration under reduced pressure

ORD record

ord-111dff6843f54fbd91e786cdeea38fc6

Source dataset

uspto-grants-2014_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08835470B2