Reaction Steps
A 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 (0.0367 g, 0.081 mmol), 2-(dimethylamino)-2-oxoacetic acid (9.53 mg, 0.081 mmol), O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate (HATU) (0.031 g, 0.081 mmol) and diisopropyl-ethylamine (0.014 mL, 0.081 mmol) in DMF (3 mL) was stirred at room temperature for 24 h. After this the crude reaction mixture was purified by preparative-HPLC using methanol/water (0.1% trifluoroacetic acid) to afford the title compound (0.0301 g, 0.059 mmol, 72% yield) as a purple solid. 1H NMR (500 MHz, CDCl3) δ: 12.01 (1H, s), 8.76 (1 H, t, J=6.0 Hz), 8.21 (1 H, d, J=9.8 Hz), 7.36-7.41 (2 H, m), 6.99-7.05 (2 H, m), 5.27 (1 H, d, J=9.8 Hz), 5.18 (1 H, dd, J=15.6, 8.9 Hz), 4.50-4.63 (2 H, m), 3.65 (1 H, d, J=15.6 Hz), 3.34 (3 H, s), 2.95 (3 H, s), 2.14 (1 H, t, J=8.2 Hz), 1.83-1.94 (1 H, m), 1.47-1.52 (1 H, m), 1.41 (1 H, dd, J=9.5, 5.2 Hz), 1.36 (3 H, s), 1.06 (1 H, dd, 9.8, 4.6 Hz), 1.03 (3 H, s), 0.97 (3 H, s). LCMS (M+H) calcd for C26H33FN5O5: 514.25; found: 514.29.
