1-Hydroxybenzotriazole → 4-[(S)-2-({5-[(1-Benzyloxycarbonyl-cyclobutylcarbamoyl)-methoxy]-1-phenyl-1H-pyrazole-3-carbonyl}-amino)-4-tert-butoxycarbonyl-butyryl]-piperazine-1-carboxylic acid ethyl ester

Participants

Reaction Steps

To a solution of 4.9 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 1.3 g HOBt, 1.6 g EDC, 2.7 ml DIPEA and 1.7 g 1-Amino-cyclobutanecarboxylic acid benzyl ester. After 12 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 used in the subsequent reaction. Yield: 4.7 g

Provenance & Evidence