Reaction Steps
In a 100 mL round bottom flask, Compound D of Example 6 (100 mg, 0.21 mmol) was dissolved in THF (10 mL). LiOH (500 mg, 20 mmol) in water (5 mL) was added to the reaction solution. The reaction mixture was stirred at room temperature overnight. Ethyl acetate (100 mL) was added to the reaction mixture. The reaction mixture was acidified by 1 N HCl solution (pH=4.0). The organic portion was separated and dried over Na2SO4, concentrated and purified by HPLC (40 mg, 41%) to yield Compound G. 1H-NMR (500 MHz, MeOH-d4): δ 1.62 (bs, 6H), 1.69 (s, 3H), 1.70 (s, 3H), 1.99 (m, 2H), 2.08 (m, 6H), 2.51 (t, J=6.5, 2H), 2.79 (dd, J=7.0, 14.0 Hz, 1H), 2.93 (dd, J=4.5, 8.1 Hz, 1H), 3.17 (dd, J=7.0, 13.0 Hz, 1H), 3.28 (dd, J=9.0, 15.0 Hz, 1H), 3.40 (t, J=6.5 Hz, 3H), 4.50 (dd, J=5.0, 6.5 Hz, 1H), 5.11 (m, 2H), 5.23 (t, J=7.5, 1H). 13C-NMR (125 MHz, MeOH-d4): δ 16.1, 16.2, 17.8, 26.0, 27.4, 27.8, 30.5, 34.4, 35.7, 36.8, 40.8, 40.9, 54.1, 121.7, 125.2, 125.5, 132.1, 136.3, 140.5, 160.3, 175.1, 175.7; ES-MS: mass calcd for Chemical Formula: C22H36N2O5S 440.6. Found (M+Na) m/z 463.3.
