To a solution of 4-(2-fluoro-4-iodo-phenylamino)-1-(toluene-4-sulfonyl)-1H-indazole-5-carboxylic acid (0.58 g, 1.05 mmol) in DMF (10 mL) was added EDCI (0.22 g, 1.1 mmol) followed by HOBt (0.16 g, 1.1 mmol) and the reaction mixture stirred at room temperature for 10 minutes. O-(2-vinyloxy-ethyl)-hydroxylamine (0.12 g, 1.1 mmol) and DIPEA (0.2 mL, 1.1 mmol) were added and the reaction stirred for 16 hours before being concentrated in vacuo. The resultant residue was dissolved in ethyl acetate (10 mL), washed with an aqueous saturated sodium bicarbonate solution (10 mL) before the aqueous fraction was 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—PPC, gradient 0-100% ethyl acetate in cyclohexane) to yield the title compound as a pale brown solid (439 mg, 66%). LCMS (Method B): RT=4.40 min, [M+H]+=637.
