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Di-tert-Butyl dicarbonate (243.0 g, 1.1 mol) was added dropwise to a suspension of (R)-3-amino-4-methyl pentanoic acid (commercially available) (133.0 g, 1.0 mol) and Na2C03 (212 g, 2.0 mol) in acetone (1 L) and water (1 L) with stirring at room temperature. The reaction mixture was stirred overnight and the organic solvent was removed under reduced pressure. The residue was diluted with water (1 L) and washed with EtOAc (500 mL x3). The aqueous phase was acidified with 2N HC1 solution to pH=3 and the resulting mixture was extracted with EtOAc (800 mL x3). The combined extracts were washed with brine (800 mL xl), dried (anhydrous Na2S04) and concentrated to give compound (T2) (224.0 g, 97% yield) as an oil, which was used in the next step without further purification.
97%
With sodium carbonate; In water; acetone; at 20℃;
Compound T2 [0575] B0C2O (243.0 g, 1.1 mol) was added dropwise to a suspension of (R)-3-amino-4- methyl pentanoic acid (commercially available) (133.0 g, 1.0 mol) and Na2C03 (212 g, 2.0 mol) in acetone (1 L) and water (1 L) with stirring at room temperature. The reaction mixture was stirred overnight and the organic solvent was removed under reduced pressure. The residue was diluted with water (1 L) and washed with EtOAc (500 mL x3). The aqueous phase was acidified with 2N HCl solution to pH=3 and the resulting mixture was extracted with EtOAc (800 mL x3). The combined extracts were washed with brine (800 mL xl), dried (Na2S04) and concentrated to give compound (T2) (224.0 g, 97% yield) as an oil, which was used in the next step without further purification.
97%
With sodium carbonate; In water; acetone; at 18 - 25℃;
Boc2O (243.0 g, 1.1 mol) was added dropwise to a suspension of (R)-3-amino-4-methyl pentanoic acid (commercially available) (133.0 g, 1.0 mol) and Na2CO3 (212 g, 2.0 mol) in acetone (1 L) and water (1 L) with stirring at room temperature. The reaction mixture was stirredovernight and the organic solvent was removed under reduced pressure. The residue was diluted with water (1 L) and washed with EtOAc (500 mL x3). The aqueous phase was acidified with 2N HC1 solution to pH=3 and the resulting mixture was extracted with EtOAc (800 mL x3). The combined extracts were washed with brine (800 mL x 1), dried (Na2SO4) and concentrated to give compound (2) (224.0 g, 97% yield) as an oil, which was used in the next step withoutfurther purification.