Citric Acid → Citric Acid

Participants

Reaction Steps

Aqueous citric acid was prepared by dissolving citric acid (7.35 g, 38.25 mmol) in water (100 mL). The aqueous citric acid solution was added to a reaction vessel containing ({3[(1S)-2-tert-butoxy-1-methylethoxy]-5-[4-(methylsulfonyl)phenoxy]benzoyl}oxy)(tert-butyl)ammonium (10 g at 94.6% w/w, 19.13 mmol) and MTBE (80 mL). The two-phase mixture was stirred for 30 minutes at ambient temperature. The two phases were separated, and the aqueous phase was extracted with MTBE (80 mL). The two organic phases were combined and washed three times with brine (3×80 mL), followed by water (2×80 mL). The combined MTBE extract was distilled down to low volume, fresh MTBE (80 mL) was added and the mixture was distilled down to low volume. Acetonitrile (120 mL) was added and the mixture was distilled down to low volume at 50° C., 209 mbar. This azeodrying was repeated once more to provide a dry acetonitrile solution of the title compound, which was used directly in the next stage.

Provenance & Evidence