Hydrochloric Acid → Fmoc-D-allo-Thr-OH

Participants

Reaction Steps

All Fmoc amino acids were synthesized from the corresponding free amino acids by the following general procedure. To a solution of D-allo-Thr (25) (1.62 g, 13.6 mmol) and NaHCO3 (3.4 g, 41 mmol) in H2O (60 mL) was added a solution of Fmoc-OSu (4.58 g, 13.6 mmol) in dioxane (60 mL) and the turbid reaction mixture stirred at RT overnight. The mixture was then diluted with H2O, acidified to pH≤4 by addition of 37% HCl and extracted with ethyl acetate (3×100 mL). The combined ethyl acetate extracts were washed with saturated NaCl (2×100 mL), dried (MgSO4) and taken to dryness by rotary evaporation to give a colorless oil which was crystallized from ethyl acetate/hexane, yielding Fmoc-D-allo-Thr (26) as white crystals (3.7 g, 80%), mp 152°-153° C. Anal. (C19H19NO5) C, H, N.

Provenance & Evidence