1-Hydroxybenzotriazole → (S)-N-((S)-1-Cyclohexyl-2-{(S)-2-[2-(2,3-dihydro-indol-1-yl)-pyridin-4-yl]-pyrrolidin-1-yl}-2-oxo-ethyl)-2-methylamino-propionamide

Participants

Reaction Steps

A solution of Boc-N-methyl-L-α-alanine (53 mg, 0.26 mmol), HOBt (39 mg, 0.29 mmol) and HBTU (108 mg, 0.29 mmol) in DMF (10 mL) is stirred at room temperature for 30 min. Then a solution of (S)-2-Amino-2-cyclohexyl-1-{(S)-2-[2-(2,3-dihydro-indol-1-yl)-pyridin-4-yl]-pyrrolidin-1-yl}-ethanone in DMF (10 mL) is added, followed by diisopropylethylamine (153 mg, 1.19 mmol). The mixture is stirs at room temperature for 2 h, then diluted with water and extracted with EtOAc. The combined organic layers are washed with water, sat. NaHCO3, brine, dried over Na2SO4, filtered and concentrated down. The crude product is dissolved in dichloromethane (5 mL). TFA (5 mL) is added. The resulting mixture is stirred at room temperature for 1 h and concentrated down to give a crude product, which is purified by prep. reverse phase HPLC (Column: Waters Sunfire Prep C18 OBD 5 μM 30×100 mm; Gradient: AcCN/water with 0.1% TFA: 10%˜70%) to give (S)—N—((S)-1-Cyclohexyl-2-{(S)-2-[2-(2,3-dihydro-indol-1-yl)-pyridin-4-yl]-pyrrolidin-1-yl}-2-oxo-ethyl)-2-methylamino-propionamide (72 mg, 42%) as a TFA salt. M/Z=490.2 [M+1].

Provenance & Evidence