Trifluoroacetic acid → (R)-4-biphenyl-4-yl-3-(3-carboxy-propionylamino)-butyric acid ethyl ester

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Reaction Steps

To a solution of (R)-4-biphenyl-4-yl-3-tert-butoxycarbonylamino-butyric acid ethyl ester (400 mg, 1.04 mmol) in DCM (10 mL) at room temperature is added TFA (2.009 mL, 26.1 mmol) and the mixture is stirred at room temperature for 1 hour. The mixture is concentrated under reduced pressure. To the obtained TFA salt in DCM (10 mL) at ice bath temperature is added succinic anhydride (125 mg, 1.25 mmol) and followed by TEA (0.363 mL, 2.61 mmol). The reaction is stirred at room temperature for 16 hours. The mixture is concentrated under reduced pressure. The obtained residue is purified by flash chromatography (silica gel, 2% to 5% EtOH/DCM) give (R)-4-biphenyl-4-yl-3-(3-carboxy-propionylamino)-butyric acid ethyl ester (200 mg). HPLC retention time=1.53 minutes (condition C); MS=384 (m+1).

Provenance & Evidence