Hydrochloric Acid → N-Acetyl-L-valine

Temperature

0 °C

L-Valine (200 g, 1.7 mol eq) is dissolved in water (500 mL) followed by the addition of NaOH (30%, 170 mL).The mixture is cooled to 0°–5° C. followed by the addition of acetic anhydride (32 ml, 1.4 eq.). Sodium hydroxide (30%, 34 mL) is added while keeping the temperature at 0°–5° C. Acetic anhydride and 30% NaOH alternate additions are repeated six time while keeping the temperature (acetic anhydride, 6×32 mL; 30% NaOH 6×34 mL). After all the additions are completed, the mixture is stirred for an additional two hours at 0° C. Hydrochloric acid (32%, 380 mL) is added to lower the pH below 3 while keeping the temperature at 0° C. The resulting slurry is granulated for 12 hours, filter and the cake washed with HCl (0.1 N, 100 mL). The wet N-acetyl-L-valine was dried to produce 233 g (86% yield).

1. temperatureis cooled to 0°–5° C.
2. customat 0°–5° C
3. customat 0° C
4. waitThe resulting slurry is granulated for 12 hours
5. filtrationfilter
6. washthe cake washed with HCl (0.1 N, 100 mL)
7. dry with materialThe wet N-acetyl-L-valine was dried
8. customto produce 233 g (86% yield)

ORD record

ord-b38140935c3f4342afa92e3c8e8b753f

Source dataset

uspto-grants-2006_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07026345B2