Diisopropylethylamine → N-[(9H-fluoren-9-ylmethoxy)carbonyl]-2-methylalanyl-N-{(3R,4S,5S)-3-methoxy-1-[(2S)-2-{(1R,2R)-1-methoxy-2-methyl-3-oxo-3-[(2-phenylethyl)amino]propyl}pyrrolidin-1-yl]-5-methyl-1-oxoheptan-4-yl]-N-methyl-L-valinamide

Participants

Reaction Steps

To a solution of #24 (104 mg, 0.256 mmol, 1 eq.) in dichloromethane (10 mL, 0.094 M) were added #32 (156 mg, 0.256 mmol, 0.9 eq.), diisopropylethylamine (135 μL, 0.768 mmol, 3 eq.) and HATU (120 mg, 0.307 mmol, 1.2 eq.). After stirring for 18 hours, the mixture was concentrated in vacuo and the residue was diluted with ethyl acetate (10 mL), washed with 1 M aqueous hydrochloric acid solution (2×5 mL) and with brine, dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was diluted with dichloromethane and filtered. The filtrate was concentrated under reduced pressure onto silica and purified by silica gel chromatography (Gradient: 0% to 100% ethyl acetate in heptane) to give #55 (44 mg, 19%) as a white solid. LC-MS: m/z 884.5 [M+2H+], retention time=1.04 minutes.

Provenance & Evidence