Hydrochloric Acid → methyl (3S)-3-amino-2-hydroxybutanoate

Participants

Reaction Steps

Into a suspension of (3S)-3-amino-2-hydroxybutanoic acid (1.0 g, 8.4 mmol) in methanol (25 ml) was bubbled anhydrous hydrogen chloride gas until a solution resulted. After a solution resulted, the reaction was cooled in an ice bath and saturated with hydrogen chloride. The cooling bath was removed and the reaction stirred at room temperature for 3.5 hours. The solvent was removed on a rotary evaporator at ambient temperature and the resultant residue dissolved in methanol (25 ml), cooled in an ice bath and saturated with hydrogen chloride gas. Warming of the reaction solution to room temperature and removal of the solvent on a rotary evaporator gave an oil. To this oil was added triethylamine (15 ml) followed by the minimum amount of methanol (about 15 ml) needed to dissolve the initial gummy solid. The solution was cooled in an ice bath and ether (75 ml) added in portions with stirring. The precipitated triethylamine hydrochloride was filtered and the filtrate evaporated to give methyl (3S)-3-amino-2-hydroxybutanoate.

Provenance & Evidence