Hydrochloric Acid → N-Acetyl-L-valine

Participants

Reaction Conditions

Reaction Steps

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).

Provenance & Evidence