To a stirred solution of 6-phenylamino-nicotinic acid (0.1 g, 0.00047 mol) in DMF (2 mL), was added DIPEA (0.181 g, 0.001401 mol), HOBt (0.0756 g, 0.00056 mol) and EDCI.HCl (0.107 g, 0.00056 mol) at ambient temperature. After 2 minutes glycine ethyl ester hydrochloride (0.0782 g, 0.00056 mol) was added and the resulting mixture was stirred overnight. The reaction mixture was then diluted with cold water. The resulting precipitate was isolated by filtration and purified by column chromatography using silica gel 60-120 mesh (60% ethyl acetate in hexane) to afford 0.135 g (97%) of [(6-phenylamino-pyridine-3-carbonyl)-amino]-acetic acid ethyl ester. LCMS: 299.13 (M+1)+, 99%. To a stirred solution of [(6-phenylamino-pyridine-3-carbonyl)-amino]-acetic acid ethyl ester (0.135 g, 0.00045 mol) in a mixture of THF (5 mL), methanol (7 mL) and H2O (2 mL) was added LiOH.H2O (0.0568 g, 0.00135 mol) at ambient temperature and the resulting mixture was stirred for 2 hours. Volatiles were then evaporated and the resulting residue was diluted with water, acidified with 10% aqueous HCl solution. The resulting precipitate was isolated by filtration and dried to afford 0.078 g (64%) of [(6-phenylamino-pyridine-3-carbonyl)-amino]-acetic acid.
