To a solution of 4-(4-bromo-2-fluorophenylamino)-1H-indazole-5-carboxylic acid (115 mg, 0.33 mmol) and O-(2-vinyloxy-ethyl)-hydroxylamine (51 mg, 0.49 mmol) in DMF (3 mL) was added EDCI (69 mg, 0.36 mmol), HOBt (49 mg, 0.36 mmol) and DIPEA (61 μL, 0.36 mmol). The reaction mixture was stirred at room temperature for 4 hours before being concentrated in vacuo. The resultant residue was dissolved in ethyl acetate (10 mL), washed with aqueous saturated sodium bicarbonate solution (10 mL) and the aqueous fraction extracted twice with ethyl acetate (2×10 mL). The combined organic extracts were washed with brine (20 mL), dried (MgSO4) and concentrated in vacuo. The resultant residue was subjected to flash chromatography (Si—SPE, gradient 0-10% methanol in DCM) to yield the title compound as a pale yellow solid (96 mg, 67%). LCMS (Method B): RT=3.43 min, [M−H]−=433/435.
