Reaction Steps
A solution of (3-{3-[(2,2-Diphenyl-ethyl)-(2,3-difluoro-benzyl)-amino]-propoxy}-phenyl)-acetic acid methyl ester (4b). (0.83 g, 0.0016 mol) in methanol (7.5 mL) was treated with 2N NaOH (5.0 ml) and the mixture stirred overnight at ambient temperature. After concentration to dryness, the residue was dissolved in EtOAc (25 mL) and water was added (10 mL), the solution acidified to pH 3 with concentrated hydrochloric acid, then extracted into EtOAc (3×20 mL). The combined organic extracts were dried over Na2SO4, and then concentrated in vacuo to provide the carboxylic acid as waxy oil. Solidification of the waxy oil from EtOAc gave white solid (5a) 0.73 g in 88% yield, mp: 148.4° C. 1H NMR (CD3OD) δ 7.18 (m, 1H), 6.99 (m, 1H), 6.81 (d, 2H), 6.76 (m, 1H), 6.72 (s, 1H), 6.55 (d, 1H), 4.17 (t, 1H), 3.67 (s, 2H), 3.55 (s, 2H), 3.54 (d, 2H), 3.07 (d, 2H), 2.62 (t, 2H), 1.77 (t, 2H); 13C NMR (CD3OD) δ 175.6, 160.5, 152.7, 151.5, 149.5, 149.4, 145.1, 137.3, 130.3, 130.1, 129.1, 127.6, 125.0, 124.9, 122.4, 129.3, 116.6, 114.1, 66.0, 60.9, 52.2, 51.3, 51.1, 42.2, 28.0. Anal. Calcd for C32H31F2NO3.21/2H2O: C, 68.55; H, 5.57; N, 2.50; F, 6.77. Found: C, 68.62; H, 5.27; N, 2.28; F, 6.52.
