Trifluoroacetic acid methylene chloride → (2S,3R)-2-amino-3-azido-butyric acid methylester hydrochloride

Participants

Reaction Steps

A solution of Trt-Azido-Thr-OMe (3) (4.8 g, 12.0 mmol) was dissolved in a 95% TFA/DCM solution (60 ml) at rt with stirring. After 2.5 h, the reaction was complete by LCMS. The bright yellow solution was diluted with 0.5 N aq. HCl (300 ml). The aqueous layer was extracted with DCM (2×30 ml) and then lyophilized to dryness. The white solid was dissolved in AcCN/water (50:50) (100 ml) and again lyophilized to dryness to produce a consistent powder and remove as much of the TFA as possible. The azido-Thr product (4), 2.26 g (97% yield, 95% pure) of a white solid, was obtained as the HCl salt.

Provenance & Evidence