Diisopropylethylamine → 4-[(S)-4-tert-Butoxycarbonyl-2-({5-[2-((S)-4,4-difluoro-2-methoxycarbonyl-pyrrolidin-1-yl)-2-oxo-ethoxy]-1-phenyl-1H-pyrazole-3-carbonyl}-amino)-butyryl]-piperazine-1-carboxylic acid ethyl ester

Participants

Reaction Steps

To a solution of 1.2 g 4-{(S)-4-tert-Butoxycarbonyl-2-[(5-carboxymethoxy-1-phenyl-1H-pyrazole-3-carbonyl)-amino]-butyryl}-piperazine-1-carboxylic acid ethyl ester in 35 ml DMF were added 278 mg HOAt, 1.6 g EDC, 1.1 ml DIPEA and 684 mg (S)-4,4-Difluoro-pyrrolidine-2-carboxylic acid methyl ester hydrotrifluoroacetate. After 36 h the mixture was diluted with ethyl acetate and subsequently extracted with aqueous LiCl (4% w/w), 0.1 M HCl and saturated aqueous NaHCO3. The organic layer was dried over MgSO4 and the solvent was removed under reduced pressure. The crude product thus obtained was purified by chromatography on silica using heptan/ethyl acetate 40/60 to 33/67 as eluent.

Provenance & Evidence