To a solution of 2-(S)-amino-N,N-dimethyl-3-phenylpropionamide hydrochloride (Preparation 8, 0.0135 g, 0.059 mmol) in DMF (anhydrous, 3 mL) was added DIPEA (0.031 mL, 0.177 mmol) then carboxylic acid (Preparation 60, 0.010 g, 0.054 mmol). To the stirred solution was added HOBt.H2O (0.008 g, 0.059 mmol) then, after 10 min, EDCI (0.012 g, 0.065 mmol). The reaction mixture was stirred for 18 h then all volatiles were removed in vacuo. The residue was partitioned between ethyl acetate (30 mL) and water (20 mL). The layers were separated and the aqueous layer extracted with ethyl acetate (3×20 mL). The combined organics were washed with brine (30 mL), dried (MgSO4), filtered and concentrated in vacuo. The residue was dissolved in methanol then adsorbed onto silica gel. Purification via flash column chromatography (SiO2, CH2Cl2:MeOH, 19:1, v/v) gave the title compound as an off-white solid. δH (CD3OD): 2.88 (3H, s), 2.89 (3H, s), 3.00–3.23 (2H, m), 3.50 (1H, s), 5.27 (1H, t), 7.10–7.37 (6H, m), 7.86 (1H, s), 8.70 (1H, s). m/z (ES+)=361 [M+H]+; RT=2.65 min.
