To a degassed suspension of 2-hydroxybenzoic acid (2.4 g, 15.8 mmol) and Cs2CO3 (7.72 g, 23.7 mmol) in NMP (13 mL), 2,2,6,6-tetramethyl-heptane-3,5-dione (0.41 mL, 1.97 mmol) and compound 14p (2.0 g, 7.90 mmol) was added followed by small amount of NMP for rinsing. The resulting mixture was degassed again with nitrogen and then CuCl (0.39 g, 3.95 mmol) was added and reaction again degassed. The mixture was heated to 140-150° C. After mixing for 22 hours, the reaction mixture was poured into ether/H2O. The two layers were separated and the aqueous layer (pH 11) was washed with ether. The aqueous layer was acidified to pH 7 and extracted with ether (4×) and the combined organic layers were dried over anhydrous Na2SO4. The solvent was removed under reduced pressure. The precipitate was formed gradually in a small volume of a mixed solvent of ether/hexane/DCM and collected through filtration to obtain the desired compound (15p) (0.93 g, 36% isolation yield). 1H NMR (400 MHz, CDCl3) δ 7.87 (br s, 1H), 7.38-7.28 (m, 2H), 7.25-7.17 (m, 2H), 7.13 (d, J=9.39 Hz, 1H), 7.10-7.03 (m, 1H), 6.79 (d, J=8.61 Hz, 1H), 4.15 (br s, 2H), 3.79 (s, 2H), 2.40-2.27 (m, 1H), 0.93 (s, 3H), 0.92 (s, 3H); MS (APCI+) m/z 325 (M+H), MS (APCI−) m/z 322.8 (M−H) and 646.8 (2M−H) detected.
