Hydrochloric Acid → (2S)-2-hydroxy-3-(trifluoroacetamido)propanoic acid

Participants

Reaction Steps

To a stirred solution of sodium methoxide in methanol, 11 ml (1 eq., 24.8% w/w solution) was added 5 g of (S)-isoserine. The mixture was stirred at room temperature for 15 minutes until a homogeneous solution was obtained. Ethyltrifluoroacetate, 7 ml (1.25 eq.) was added. The mixture was stirred for 30 minutes after the addition. The completeness of the reaction was monitored by 1H-NMR. The mixture was concentrated under reduced pressure to as low a volume as possible. To the residue 50 ml ethylacetate was added The mixture was cooled to 0°-5° C. 25 ml of 2N HCl (1 eq.) was added, followed by 5 g of solid sodium chloride. The organic layer was separated. The aqueous layer was reextracted with 50 ml of ethylacetate. The combined organic extracts were dried (over 5 g of anhydrous magnesium sulfate), filtered and concentrated under reduced pressure to 20 ml. To it 50 ml heptane was added with stirring in an ice-bath for 30 minutes. The product was filtered and dried to yield 8.86 g (93%) of N-trifluoroacetyl-(S)-isoserine; m.p. 142°-143° C.; [a]D20 : +12.4 (1%, H2O); 1H-NMR (D2O) w 3.78 (d, 2H, J=5.48 Hz), 4.53 (t, 1H, J=5.48 Hz).

Provenance & Evidence