3-Aminopropionitrile → (R)-4-biphenyl-4-yl-3-[3-(2-cyano-ethylcarbamoyl)-propionylamino]-butyric acid ethyl ester

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Reaction Steps

Next, to a solution of (R)-4-biphenyl-4-yl-3-(3-carboxy-propionylamino)-butyric acid ethyl ester (200 mg, 0.522 mmol) in THF (10 mL) at room temperature is added EDC HCl (120 mg, 0.626 mmol) and HOBT (96 mg, 0.626 mmol). The reaction is stirred at room temperature for 10 minutes then added 3-aminopropionitrile (0.046 ml, 0.626 mmol) and TEA (0.087 ml, 0.626 mmol). After 1 hour, 0.5 equivalent of EDC HCl, HOBT, and 3-aminopropionitrile are added and stirred for 16 hours. The reaction mixture is quenched by brine and is extracted with ethylacetate. The combined organic layer is washed with brine and dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The obtained residue is purified by flash chromatography (silica gel, 2% to 5% EtOH/DCM) to give (R)-4-biphenyl-4-yl-3-[3-(2-cyano-ethylcarbamoyl)-propionylamino]-butyric acid ethyl ester (218 mg, 96% yield). HPLC retention time=0.77 minutes (condition E); MS=436 (m+1).

Provenance & Evidence