Diisopropylethylamine → Benzyl (2s,3s)-2-(2-(2-(tert-butoxycarbonylamino)-5-(trifluoromethoxy)benzamido)acetamido)-3-hydroxyhex-4-ynylcarbamate

Participants

Reaction Steps

A solution of benzyl (2S,3S)-2-[2-(tert-butoxycarbonylamino)acetamido]-3-hydroxyhex-4-ynylcarbamate (700 mg; see WO-02/50019 for preparation) in methylene chloride (12 mL) was cooled to 0° C. and charged with trifluoroacetic acid (4 mL). The mixture was allowed to warm to RT and stirred for 45 min before being concentrated in vacuo. The residue was dissolved in methylene chloride and the resultant solution concentrated; this was repeated twice more to afford the TFA salt of benzyl (2S,3S)-2-(2-aminoacetamido)-3-hydroxyhex-4-ynylcarbamate, MS found: (M+H)+=320.6. A solution of this amine in 1:1 CH2Cl2/DMF (10 mL) was charged successively with N,N-diisopropylethylamine (0.84 mL), 2-(tert-butoxycarbonylamino)-5-(trifluoromethoxy)benzoic acid (322 mg, see WO-02/50019), and HATU (544 mg). The reaction was stirred for 14 h at RT before being partitioned between EtOAc and water. The organic phase was washed with sat. NH4Cl, water, and brine before being dried (Na2SO4), filtered, and concentrated in vacuo. The residue was purified by flash chromatography to afford benzyl (2S,3S)-2-(2-(2-(tert-butoxycarbonylamino)-5-(trifluoromethoxy)benzamido)acetamido)-3-hydroxyhex-4-ynylcarbamate (182 mg). MS found: (M+H)+=623.3.

Provenance & Evidence