Example 19
To a mixture of Intermediate 12 (19.5 mg, 0.046 mmol) in MeOH (0.8 mL) was added NaOMe (25 wt % in methanol, 0.084 mL, 0.37 mmol). The mixture was heated at 120° C. under microwave irradiation for 1 h. An additional portion of NaOMe (25 wt % in methanol, 0.08 mL) was added and the mixture was then heated at 130° C. for 2 h. The mixture was cooled to room temperature, acidified by addition of 1 M HCl in ether and subjected to SCX purification (GENERAL METHOD 3-1, 1 g SiliaBond Propylsulfonic Acid® cartridge). The crude product was further purified by preparative reverse-phase HPLC to obtain the title compound as a white solid (8 mg). LC/MS Rt=0.39 min. MS (M+1)=422.3. 1H NMR (METHANOL-d4) δ 8.50 (s, 1H), 8.47 (d, J=5.6 Hz, 1H), 8.14 (d, J=10.1 Hz, 1H), 7.25 (s, 1H), 7.24 (d, J=10.1 Hz, 1H), 6.74 (d, J=5.6 Hz, 1H), 5.07 (t, J=12.1 Hz, 1H), 4.02 (s, 3H), 2.94 (s, 3H), 1.58-1.70 (m, 2H), 1.46-1.58 (m, 2H), 1.32 (s, 6H), 1.16 (s, 6H).
