Beta-Alanine → 3-{[1-Benzyl-5-(5-fluoro-pyridin-3-yl)-8-hydroxy-2-oxo-1,2-dihydro-[1,6]naphthyridine-7-carbonyl]-amino}-propionic acid

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Reaction Steps

A mixture of 1-benzyl-5-(5-fluoro-pyridin-3-yl)-8-hydroxy-2-oxo-1,2-dihydro-[1,6]naphthyridine-7-carboxylic acid methyl ester (23 mg, 0.056 mmol), β-alanine (495 mg, 5.6 mmol) and NaOMe solution (9 mL, 4.4 mmol) was refluxed for 16 h. After cooling to r.t., solvent was evaporated. The residue was partitioned between EtOAc and water. 1 M HCl was added with vigorous stilling until pH about 3. The organic layer was dried over MgSO4 and concentrated. The crude product was purified by silica gel chromatography (0-40% EtOAc/hexanes+2% AcOH). The product isolated was then dissolved in saturated NaHCO3 and washed several times with ether. The aqueous layer was acidified to pH about 2 with 4 M HCl, and the resulting precipitate was isolated by filtration to give 10 mg of the title compound. MS: (+) m/z 463.35 (M+1).

Provenance & Evidence