Water → (S)-2-(tert-butoxycarbonyl-amino)-3-methyl-butyric acid N-[2-(4-hydroxy-3-methoxy-phenyl)-ethyl]-amide

Participants

Reaction Steps

To a mixture of BOC-L-Valin (48 g), 4-(2-Amino-ethyl)-2-methbxy-phenol hydrochloride (45 g) and diethyl-isopropylamine (64.6 g) in dimethylformamide (900 ml) is added benzotriazol-1-yloxy-tris(dimethylamino)phosphonium hexafluorophosphate (97.8 g) in one portion. The reaction mixture is stirred for 4 hours at room temperature. Water (1000 ml) is then added. The mixture is extracted with ethyl acetate (2×500 ml). The organic layers organic layers are washed with brine (2×400 ml), dried (MgSO4) and evaporated. The residue is purified by flash column chromatography on silica gel (ethyl acetate/hexane 1:2). (S)-{1-[2-(4-Hydroxy-3-methoxy-phenyl)-ethylcarbamoyl]-2-methyl-propyl}-carbamic acid tert.-butyl ester is obtained.

Provenance & Evidence