Hydrogen Bromide → (2R)-2-bromo-4-methylpentanoic acid

Temperature

0 °C

While stirring, D-leucine (76.6 g, 584 mmol, 1.0 eq) was dissolved into 920 mL of aq. 3.0 M HBr (2.8 mol, 4.7 eq) and cooled to 0° C. A solution of NaNO2 (64.5 g, 934 mmol, 1.6 eq) in 200 mL water was slowly added over 20 minutes and the mixture was stirred at 0° C. for 3 hours. The mixture was extracted 2× with 500 mL EtOAc, washed with saturated aqueous NaCl, dried over MgSO4, filtered, and concentrated under reduced pressure, to yield (R)-2-bromo-4-methylpentanoic acid as a yellow oil (103 g). 1H-NMR (DMSO) δ (ppm): 0.9 (m, 6H), 1.6-1.7 (m, 1H), 1.7-1.9 (m, 2H), 4.3 (t, 1H).

1. stirringthe mixture was stirred at 0° C. for 3 hours
2. extractionThe mixture was extracted 2× with 500 mL EtOAc
3. washwashed with saturated aqueous NaCl
4. dry with materialdried over MgSO4
5. filtrationfiltered
6. concentrationconcentrated under reduced pressure

ORD record

ord-a3f8ff9f50a9479f817804fa54b52c3e

Source dataset

uspto-grants-2014_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08895755B2