Reaction Steps
To 3:1 mixture of 4-(5-chloropyridin-3-yl)-7-fluoro-2-[(4aR,7aR)-hexahydrocyclopenta[b][1,4]oxazin-4(4aH)-yl]-N′-hydroxy-3-[(trans-4-methylcyclohexyl)methyl]-3H-imidazo[4,5-c]pyridine-6-carboximidamide and 7-chloro-4-(5-chloropyridin-3-yl)-2-[(4aR,7aR)-hexahydrocyclopenta[b][1,4]oxazin-4(4aH)-yl]-N′-hydroxy-3-[(trans-4-methylcyclohexyl)methyl]-3H-imidazo[4,5-c]pyridine-6-carboximidamide (33 mg, 0.06 mmol) in acetonitrile (2 mL) was added 1,1′-carbonyldiimidazole (19.7 mg, 0.122 mmol) and 1,8-diazabicyclo[5.4.0]undec-7-ene (0.037 mL, 0.244 mmol). The reaction was stirred at room temperature for 1 hour and then concentrated. The residue was purified by mass triggered reverse phase HPLC(C-18) eluting with acetonitrile/water+0.1% TFA to afford pure 3-{4-(5-chloropyridin-3-yl)-7-fluoro-2-[(4aR,7aR)-hexahydrocyclopenta[b][1,4]oxazin-4(4aH)-yl]-3-[(trans-4-methylcyclohexyl)methyl]-3H-imidazo[4,5-c]pyridin-6-yl}-1,2,4-oxadiazol-5(4H)-one (TFA salt). MS ESI calc'd for C28H31ClFNγO3 [M+H]+=568. found=568. 1H NMR (600 MHz, DMSO-d6) δ 12.83 (s, 1H), 8.91 (d, J=1.8 Hz, 1H), 8.79 (d, J=2.4 Hz, 1H), 8.43 (m, 1H), 3.94 (d, J=9.6 Hz, 1H), 3.78-3.87 (m, 2H), 3.63 (dd, J=14.4, 3.6 Hz, 1H), 3.56 (d, J=12.6 Hz, 1H), 3.39 (m, 1H), 3.04 (m, 1H), 2.84 (m, 1H), 2.27 (m, 1H), 1.86 (m, 1H), 1.69 (m, 1H), 1.51-1.64 (m, 2H), 1.32-1.41 (m, 2H), 1.12 (m, 1H), 1.04 (m, 1H), 0.80 (m, 1H), 0.63-0.74 (m, 6H), 0.47 (m, 1H), 0.29-0.42 (m, 2H).
