To a solution of 2-(S)-amino-N,N-dimethyl-3-phenylpropionamide hydrochloride (Preparation 8, 0.023 g, 0.100 mmol) in DMF (anhydrous, 4 mL) was added DIPEA (0.052 mL, 0.300 mmol) then carboxylic acid (Preparation 62, 0.017 g, 0.091 mmol). To the stirred solution was added HOBt.H2O (0.0135 g, 0.100 mmol) then, after 10 min, EDCI (0.021 g, 0.109 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 ethyl acetate then adsorbed onto silica gel. Purification via flash column chromatography (SiO2, ethyl acetate:isohexane, 1:1, v/v) gave the title compound as a pale brown solid. δH (CDCl3): 2.77 (3H, s), 2.96 (3H, s), 3.08-8.20 (2H, m), 5.23-5.41 (1H, m), 6.99 (1H, s), 7.14-7.36 (5H, m), 7.65 (1H, d), 8.01 (1H, s), 8.87 (1H, s), 10.01 (1H, s); m/z (ES+)=362 [M+H]+; RT=3.11 min.
