Reaction Steps
To a stirred solution of benzyl((7S,10R,11R)-2-((4-fluorobenzyl)carbamoyl)-3-hydroxy-10,12,12-trimethyl-4-oxo-6,7,8,9,10,11-hexahydro-4H-7,10-methanopyrimido[1,2-a]azocin-11-yl)carbamate hydrochloride salt (0.025 g, 0.055 mmol) and diisopropyl-ethylamine (0.175 mL, 1 mmol) in CH2Cl2 (3 mL) was added acetyl chloride (0.036 mL, 0.5 mmol). After 4 h, 2M Me2NH/methanol (1 mL) was added and stirring continued at room temperature. After 16 h, the reaction mixture was concentrated and purified by preparative-HPLC using methanol/water (0.1% trifluoroacetic acid) to afford the title compound (0.0188 g, 0.038 mmol, 69% yield) as a white solid. 1H NMR (500 MHz, CDCl3) δ: 11.99 (1H, s), 7.56 (1 H, t, J=5.8 Hz), 7.33 (2 H, dd, J=8.5, 5.2 Hz), 7.04-7.09 (2 H, m), 6.42 (1 H, d, J=9.2 Hz), 5.52 (1 H, d, J=9.2 Hz), 5.17 (1 H, dd, J=15.4, 8.7 Hz), 4.54-4.66 (2 H, m, J=14.8, 14.6, 14.6, 6.0 Hz), 3.70 (1 H, d, J=15.3 Hz), 3.48 (3H, s, from CH3OH), 2.09 (1 H, t, J=8.1 Hz), 1.94 (3 H, s), 1.78-1.87 (1 H, m), 1.41-1.49 (1 H, m), 1.38 (3 H, s), 1.30-1.37 (1 H, m), 0.99 (3 H, s), 0.95-0.98 (1 H, m), 0.94 (3 H, s). LCMS (M+H) calcd for C24H30FN4O4: 457.23; found: 457.27. Purity: >98%.
