Ethyl Acetate → (2R,4S)-5-biphenyl-4-yl-2-methyl-4-(2-thiophen-2-yl-acetylamino)-pentanoic acid

Participants

Reaction Steps

Next, to a solution of (2R,4S)-5-biphenyl-4-yl-2-methyl-4-(2-thiophen-2-yl-acetylamino)-pentanoic acid ethyl ester (0.287 mmol) in ethanol (10 mL) is added aqueous 1M NaOH (2 mL, 6.97 mmol) and the mixture is stirred at room temperature for 18 hours. The mixture is poured into ethyl acetate and is washed with aqueous 1M HCl, the organic phase is dried over magnesium sulfate and the solvent is removed under reduced pressure. The residue is purified by preparative HPLC using a gradient of MeCN/water (0.1% TFA). The proper fractions are lyophilized to furnish (2R,4S)-5-biphenyl-4-yl-2-methyl-4-(2-thiophen-2-yl-acetylamino)-pentanoic acid. HPLC Retention time 1.23 minutes (condition A); MS 408.3 (M+1); 1H NMR (400 MHz, MeOD-d4) δ ppm 1.16 (d, J=7.07 Hz, 3H), 1.50 (m, 1H), 1.96 (m, 1H), 2.52 (m, 1H), 2.72 (dd, J=7.71 Hz, 7.58 Hz, 1H), 2.84 (dd, J=5.81 Hz, 5.66 Hz, 1H), 3.64 (d, J=1.26 Hz, 2H), 4.20 (m, 1H), 6.82 (m, 1H), 6.89 (m, 1H), 7.21 (m, 3H), 7.32 (m, 1H), 7.42 (m, 2H), 7.46 (m, 2H), 7.57 (m, 2H), 7.95 (d, J=8.59 Hz, 1H).

Provenance & Evidence