To a solution of methyl 5-[{4-[(4-butylphenyl)ethynyl]benzyl}(hexyl)amino]-2-hydroxybenzoate in MeOH (400 mL) and water (40 mL) was added an aqueous solution of NaOH (6.0 mL, 5N). The reaction mixture was sired at 60° C. overnight. Then an aqueous solution of HCl (10 mL, 5N) was added and the solvents were removed under reduced pressure. The residue was taken up in water and extracted with Et2O (3×). The combined organic layers were dried over MgSO4 and the solvent was removed under reduced pressure to give a yellow solid. Precipitation from a DCM/MeOH mixture gave 2.17 g (53%, stop e and f) of the title compound as a beige powder. HPLC, Rt: 4.8 min purity: 99.7%). LC/MS, M+(ESI): 484.4, M−(ESI): 482.2. 1H NMR (CDCl3/CD3OD (15/1)) δ: 7.39 (m, 4H), 7.18-7.09 (m, 5H), 6.87 (dd, J=9.0, 3.0 Hz, 11), 6.78 (d, J=9.0 Hz, 1H), 4.38 (s, 2H), 3.22 (t, J=7.5 Hz, 2H), 2.57 (t, J=7.8 Hz, 2H), 1.55 (m, 4H), 1.34-1.21 (m, 8H), 0.90-0.75 (m, 6H).
