The 6-(2,4-difluorophenyl)-5-(6-hydrazinylpyridazin-3-yl)imidazo[2,1-b]oxazole (0.300 g, 0.914 mmol, Example #40, Step B, was dissolved in MeOH (15 mL) at about ambient temperature before addition of Na2CO3 (0.112 g, 1.371 mmol). Cyanogen bromide (3M in DCM, 0.305 mL, 0.914 mmol) was added and the resulting mixture was stirred at about ambient temperature for about 1 h. The crude mixture was partitioned between water and DCM. The organics were dried over MgSO4, filtered, concentrated under reduced pressure to give a yellow solid that was triturated with Et2O and filtered to give the title compound (0.185 g, 57%): LC/MS (Table 1, Method g) Rt=1.65 min.; MS m/z: 354.07 (M+H)+.
