Diisopropylethylamine → {(2S,3S)-3-hydroxy-2-[2-(4-trifluoromethyl-1H-benzoimidazol-2-yl)-acetylamino]-hex-4-ynyl}-carbamic acid benzyl ester

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Reaction Steps

The compound [(2S,3S)-2-amino-3-hydroxy-hex-4-ynyl]-carbamic acid benzyl ester (70 mg, 0.19 mmol, prepared as described in WO PCT 0250019) was dissolved in 5 mL of 2:1 CH2Cl2/DMF. The resultant solution was charged sequentially with the lithium salt of (4-trifluoromethyl-1H-benzoimidazol-2-yl)-acetic acid (46 mg, 0.19 mmol, see procedure 28a), N,N-diisopropylethylamine (0.16 mL, 0.94 mmol) and HATU (85 mg, 0.22 mmol). The mixture was stirred for 12 h at RT, concentrated in vacuo, and partitioned between EtOAc and sat. NH4Cl. The aqueous phase was extracted with EtOAc (1×). The combined organic extracts were washed with sat. NaHCO3 and brine, dried (Na2SO4), filtered, and concentrated in vacuo. The residue was purified by flash chromatography to provide {(2S,3S)-3-hydroxy-2-[2-(4-trifluoromethyl-1H-benzoimidazol-2-yl)-acetylamino]-hex-4-ynyl}-carbamic acid benzyl ester (87 mg, 95% yield). MS found: (M+Na)+=511.3.

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