Trifluoroacetic acid → 4-(4-bromo-2-fluorophenylamino)-1H-indazole-5-carboxylic acid

Participants

Reaction Steps

To a solution of 4-(4-bromo-2-fluorophenylamino)-indazole-1,5-dicarboxylic acid di-tert-butyl ester (420 mg, 0.83 mmol) in DCM (5 ml) was added TFA (1.2 mL, 16.2 mmol). The reaction mixture was stirred at room temperature for 16 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 with ethyl acetate (2×10 mL). The combined organic extracts were washed with brine (20 mL), dried with 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 an off-white solid (232 mg, 80%). LCMS (Method B): RT=3.22 min, [M+H]+=350/352.

Provenance & Evidence