(2R)-3-fluoro-2-[(2-methylpropan-2-yl)oxycarbonylamino]propanoic acid

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 150 mg (R)-tert-butoxycarbonylamino-3-fluoropropionic acid in 2 ml DMF were added 115 mg 1-ethoxycarbonylpiperazine, 0.18 ml N-ethylmorpholine and 238 mg TOTU. After stirring for 12 h it was diluted with ethyl acetate and extracted with aqueous LiCl (4% w/w), aqueous NaHCO3, 0.1 M HCl and brine. The organic layer was dried over MgSO4 and concentrated to furnish the crude coupling product which was deprotected by using 10 equivalents TFA in dichloromethane. After stirring for 12 h it was concentrated and codistilled twice with toluene. Yield: 216 mg colorless oil. extracted with aqueous LiCl (4% w/w), aqueous NaHCO3, 0.1 M HCl and brine The organic layer was dried over MgSO4 concentrated to furnish the crude coupling product which After stirring for 12 h it was concentrated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 150 mg (R)-2-tert-Butoxycarbonylamino-3-fluoro-propionic acid were added 0.18 ml N-ethylmorpholine, 237 mg TOTU and 115 mg 1-butoxycarbonylpiperazine. After stirring for 12 h the reaction mixture was diluted with ethyl acetate and washed with aqueous LiCl (4%), 0.1 M HCl, saturated aqueous NaHCO3 and brine. The crude product obtained was used without further purification. Yield: 230 mg. washed with aqueous LiCl (4%), 0.1 M HCl, saturated aqueous NaHCO3 and brine

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 150 mg (R)-2-tert-Butoxycarbonylamino-3-fluoro-propionic acid were added 0.18 ml N-ethylmorpholine, 237 mg TOTU and 115 mg 1-ethoxycarbonylpiperazine. After stirring for 12 h the reaction mixture was diluted with ethyl acetate and washed with aqueous LiCl (4%), 0.1 M HCl, saturated aqueous NaHCO3 and brine. The crude product obtained was used without further purification. Yield: 160 mg. washed with aqueous LiCl (4%), 0.1 M HCl, saturated aqueous NaHCO3 and brine