Reaction Steps
(see, e.g., Neres, J., et al., J Med Chem 2013, 56, 2385-405). A solution of ester 51 (40 mg, 0.08 mmol) and 1N NaOH (3.5 mL, 3.5 mmol) in THF (1.5 mL) was refluxed for 3 h. Reaction mixture was diluted with water (10 mL) and washed with EtOAc (10 mL×2). Aqueous layer was acidified with 1N HCl and extracted with EtOAc (10 mL×2). Combined organic extracts were washed with brine, dried (Na2SO4) and filtered. The solvent was removed under reduced pressure to give the title compound (22 mg, 61%) as an orange solid. 99% pure by HPLC. 1H NMR (500 MHz, DMSO-d6) δ 7.79 (t, J=5.1 Hz, 1H), 7.54 (s, 1H), 7.34 (t, J=7.6 Hz, 2H), 7.27 (d, J=8.1 Hz, 2H), 7.10 (t, J=6.8 Hz, 1H), 6.95 (d, J=7.9 Hz, 2H), 6.90 (d, J=8.3 Hz, 2H), 6.86 (s, 1H), 6.33 (s, 1H), 6.25 (s, 1H), 5.35 (s, 2H), 4.57 (d, J=5.2 Hz, 2H), 2.41 (s, 3H). 13C NMR (125 MHz, DMSO-d6) δ 167.35, 157.85, 157.05, 156.29, 153.26, 152.02, 142.37, 140.38, 135.41, 133.48, 130.46, 130.44, 130.08, 123.85, 118.98, 118.97, 110.81, 107.38, 103.37, 49.09, 37.87, 15.96. ESI MS: m/z 455.0 (M+H)+.
