To a solution of 4-[2-(4-azetidin-1-yl-3-benzofuran-2-yl-but-2-enoylamino)ethoxy]-benzoic acid methyl ester (158 mg, 0.362 mmol) in THF (4 ml), a solution of hydroxylamine in 50% water (2.78 ml) and 1N NaOH (0.1 ml) were added. Methanol was added dropwise until a homogeneous solution was obtained. The reaction mixture was stirred overnight at rt. After cooling the mixture at 0° C., 6 N HCl was added until pH 7 was reached. The solid was separated by filtration and the crude solid purified by HPLC to give the title compound (25 mg) as a white solid.
