(-)-2-amino-1butanol D-(-)-mandelate → (-)-Mandelic acid

Participants

Reaction Conditions

Reaction Steps

A portion of the (-)-2-amino-1-butanol D-(-)-mandelate wet cake (155 grams "as is"--90.3% pure; 0.58 mole) from resolution A is dissolved in water (125 mls) at 50°-55° C. and the resulting solution is distilled under vacuum to remove 48.5 mls of methanol and water. The concentrated solution is treated with 37% hydrochloric acid (60 mls) and the acidified solution is cooled to -5° C. over about 5 hours to crystallize D-(-)-mandelic acid from the solution. The crystals are isolated by filtration, washed twice with ice cold (0°-5° C.) water (20 mls), twice with hexane (20 mls), and dried at 60° C. to obtain 64.1 grams of D-(-)-mandelic acid (72.6% of theoretical; m.p. 131°-133° C.; [α]D25 =-154.1° (C=2. H2O)).

Provenance & Evidence