Hydrochloric Acid → (S)-5-(3-(2-((((9H-fluoren-9-yl)methoxy) carbonyl)amino)-3-oxo-3-(piperidin-1-yl)propyl)phenyl)pentanoic acid

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Reaction Steps

tert-Butyl (S)-5-(3-(2-((tert-butoxycarbonyl)amino)-3-oxo-3-(piperidin-1-yl)propyl)phenyl)pentanoate (Compound SP431) (4.70 g, 9.62 mmol) was dissolved in DCM (30.0 ml), trifluoroacetic acid (15.0 ml, 195 mmol) was added and the mixture was stirred for 50 minutes at room temperature, after which the reaction solution was concentrated under reduced pressure. The resulting residue was dissolved in dioxane (34 ml) and a 10% aqueous sodium carbonate solution (68 ml), N-(9-fluorenylmethoxycarbonyloxy)-succinimide (3.15 g, 9.33 mmol) was added and the mixture was stirred at room temperature for 3 hours. The reaction solution was made acidic by adding a 5 N aqueous HCl solution and then extracted with ethyl acetate. The ethyl acetate layer was dried over anhydrous Na2SO4, and then filtered and concentrated under reduced pressure, and the resulting residue was purified by silica gel column chromatography (hexane:ethyl acetate=100:0-30:70) to afford the title compound (Compound SP432) (4.65 g, 87%).

Provenance & Evidence