Tetrahydrofuran → (S)-2-(2-Oxo-2H-pyridin-1-yl)-propionic acid

A stirred mixture of (S)-2-(2-Oxo-2H-pyrid-1-yl)-propionic acid ethyl ester (364 mg, 1.87 mmol), THF (2 ml), water (1 ml) and sodium hydroxide (90 mg, 2.24 mmol) was kept at room temperature for 1 h, then concentrated under reduced pressure. The residue was dissolved in ether and the resulting solution washed with water. The organic layer was discarded and the aqueous layer was acidified with concentrated HCl then extracted several times with ethyl acetate. The combined organic extracts were dried (MgSO4), filtered and concentrated. The residue was triturated with ether to afford the title compound as a colorless solid (84 mg, 27%): [α]31D=−50° (c=0.2, CH3OH); 1H NMR (400 MHz, DMSO) δ 1.5 (3H, d), 5.1 (1H, q), 6.2 (1H, t), 6.4 (1H, d), 7.4 (1H, m), 7.6 (1H, d).