To a solution of methyl 6-amino-5-({3-[(3-methyl-2-furoyl)amino]phenyl}ethynyl)nicotinate, (1.82 g, 4.85 mmol, 1 eq) in MeOH—H2O (100 mL, 3:1) at RT was added potassium hydroxide (2.72 g, 10 eq) with stirring. The mixture was heated at 65° C. for 2 hours and a brown solution was observed at this time. The reaction mixture was concentrated to remove most of the methanol. The resulting solution was cooled to 0° C. and concentrated HCl was added until the pH was around 3 at which time a white precipitates formed. The solid which had formed was collected by filtration, rinsed with water, and dried to give the title compound as a white solid (1.75 g).
