A mixture of (S)-ethyl N-({6-[(3-methyl-1-{4-[5-(trifluoromethyl)pyridin-2-yl]phenyl}butyl)amino]pyridin-3-yl}carbonyl)-beta-alaninate (60.9 g, 115 mmol) was dissolved in methanol (230 ml) and tetrahydrofuran (115 ml) and treated with aqueous lithium hydroxide (115 ml, 0.230 mol, 2.0M). The reaction was heated to 50° C. for 30 minutes. The solution was concentrated in vacuo, and the resulting residue was diluted with water (approximately 500 ml). The mixture was then acidified with aqueous 1.0M hydrochloric acid (230 ml, to approximately pH 4.0). The precipitated solid was collected by filtration and washed with water (2×100 ml). Air was pulled through the filter cake over 12 hours to affect drying of the product. The crude solid was transferred into a 2-liter flask with a stirbar and the solid was suspended in ethyl acetate (approximately 1.5 L). Sodium sulfate (approximately 500 g) was added and the mixture was stirred vigorously for a further 1 hour. The cloudy mixture was filtered through a plug of celite, resulting in a clear solution. The solution was concentrated in vacuo and the remaining solid was suspended in diethyl ether (1 L) and concentrated in vacuo (the process was repeated twice). The resulting solid was pulverized with a mortar and pestel, and dried in a vacuum oven for 12 hours at 60° C. The final product (50.1 g, 87%) was obtained as a off-white solid. 1H NMR (400 MHz, DMSO-d6, δ): 9.01 (s, 1H), 8.39 (d, J=1.2 Hz, 1H), 8.26 (dd, J=8.4, 2.0 Hz, 2H), 8.15 (d, J=8.4 Hz, 1H), 8.10 (d, J=8.2 Hz, 2H), 7.84 (d, J=6.7 Hz, 1H), 7.55 (d, J=8.2 Hz, 2H), 6.66 (br. s., 1H), 5.15 (br. s., 1H), 3.33-3.43 (m, 2H), 2.45 (t, J=7.0 Hz, 2H), 1.74-1.86 (m, 1H), 1.62-1.72 (m, 1H), 1.51-1.62 (m, 1H), 0.95 (d, J=6.5 Hz, 3H), 0.92 (d, J=6.5 Hz, 3H). MS (M+1): 501.4.
