To a solution of ethyl 5-(4-(2-(5-amino-8-methylbenzo[f][1,7]naphthyridin-2-yl)ethyl)phenoxy)pentanoate (1.0 equiv.) (from Example 139) in ethanol (0.10 M) was added anhydrous sodium hydroxide (2.0 equiv.) and the resulting mixture was allowed to stir at 80° C. for 2 hours. After cooling to ambient temperature, the mixture was diluted with ethyl acetate and water. The biphasic layers were separated and the aqueous layer was washed twice with ethyl acetate. The combined organic layers were dried over anhydrous Na2SO4 and the volatiles were removed in vacuo. The resulting residue was purified by a COMBIFLASH® system (ISCO) using 0-10% methanol in dichloromethane to furnish 5-(4-(2-(5-amino-8-methylbenzo[f][1,7]naphthyridin-2-yl)ethyl)phenoxy)pentanoic acid as a solid. 1H NMR (Methanol-d4): δ 8.61 (s, 1H), 8.57 (s, 1H), 8.20 (d, 1H), 7.40 (s, 1H), 7.20 (d, 1H), 7.07 (d, 2H), 6.81 (d, 2H), 3.93 (t, 2H), 3.18 (t, 2H), 3.00 (t, 2H), 2.48 (s, 3H), 2.25 (t, 2H), 1.74-1.81 (m, 2H), 0.86-0.96 (m, 2H). LRMS [M+H]=430.2
