To a solution of 10-amino-N-(4-fluorobenzyl)-3-hydroxy-4-oxo-4,6,7,8,9,10-hexahydro-7,10-ethanopyrimido[1,2-a]azepine-2-carboxamide (25 mg, 0.067 mmol) in CH2Cl2 (2 mL) was added Et3N (0.047 mL, 0.336 mmol) followed by dimethylsulfamoyl chloride (0.036 mL, 0.336 mmol) and the resulting mixture was stirred at room temperature overnight. The reaction mixture was concentrated to give crude product which was dissolved in methanol (2 mL) and treated with sodium ethoxide (0.2 ml, 21 wt % in ethanol) and the heated at 70° C. overnight. The mixture was then cooled, concentrated and purified by preparative HPLC to afford the title compound as a white solid (3.5 mg, 11% yield). 1H NMR (500 MHz, CDCl3) δ: 12.00 (s, 1H), 8.90 (s, 1H), 7.34 (dd, 2H, J=8.39 & 5.34 Hz), 7.01 (t, 2H, J=8.55 Hz), 4.53 (d, 2H, J=6.41 Hz), 4.15 (d, 2H, J=3.97 Hz), 2.77 (s, 6H), 2.50 (s, 1H), 2.12 (t, 4H, J=7.63 Hz), 1.85-1.97 (m, 2H), 1.64-1.73 (m, 2H). LCMS (M+H)=480.21. HPLC purity: >95%.
