Sulfuric Acid → (2R)-5,5,5-Trifluoro-2-hydroxypentanoic acid

Temperature

0 °C

To a cool (0° C.), stirred solution of (2R)-2-amino-5,5,5-trifluoropentanoic acid (4.09 g, 23.90 mmol) (U.S. Pat. No. 2009/0111858 A1) and H2SO4 (2.8 mL, 52.5 mmol) in water (95 mL) was added a solution of sodium nitrite (9.89 g, 143 mmol) in water (30 mL) dropwise via addition funnel over 60 min. The reaction mixture was allowed to slowly warm to room temperature and stirred overnight. The reaction mixture was diluted with Et2O, the aqueous phase was separated and extracted with Et2O (3×). The combined organics were dried (Na2SO4), filtered and concentrated under reduced pressure to provide Intermediate S-3A (4.1551 g, >99%) as an amber oil: 1H NMR (400 MHz, CDCl3) δ ppm 4.33 (1H, dd, J=8.03, 4.27 Hz), 2.09-2.42 (3H, m), 1.88-2.02 (1H, m).

1. additiondropwise via addition funnel over 60 min
2. temperatureto slowly warm to room temperature
3. customthe aqueous phase was separated
4. extractionextracted with Et2O (3×)
5. dry with materialThe combined organics were dried (Na2SO4)
6. filtrationfiltered
7. concentrationconcentrated under reduced pressure
8. customto provide Intermediate S-3A (4.1551 g, >99%) as an amber oil

ORD record

ord-84d73495319e4ff8ae8cadf41ffc8603

Source dataset

uspto-grants-2015_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09187434B2