Acetic Anhydride → (S)-N-[3-(3-Fluoro-4-iodo-phenyl)-2-oxo-oxazolidin-5-ylmethyl]-acetamide

Participants

Reaction Conditions

Reaction Steps

A suspension of (5S)-5-aminomethyl-3-(3-fluoro-4-iodo-phenyl)-oxazolidin-2-one (1022, 16.0 g, 47.6 mmol) in CH2Cl2 (150 mL) was treated with triethylamine (TEA, 9.62 g, 13.2 mL, 95.2 mmol, 2.0 equiv) at 25° C., and the resulting reaction mixture was cooled down to 0-5° C. before being treated with acetic anhydride (Ac2O, 7.29 g, 6.75 mL, 71.4 mmol, 1.5 equiv) and 4-N,N-dimethylaminopyridine (DMAP, 58 mg, 0.5 mmol, 0.01 equiv) at 0-5° C. under N2. The resulting reaction mixture was subsequently stirred at 0-5° C. for 2 h. When TLC and HPLC showed that the reaction was complete, the reaction mixture was quenched with H2O (100 mL). The two layers were separated, and the aqueous layer was then extracted with CH2Cl2 (2×50 mL), and the combined organic extracts were washed with H2O (2×100 mL) and saturated NaCl aqueous solution (100 mL), dried over MgSO4, and concentrated in vacuo. The residue was further dried in vacuo to afford the crude, (5S)-N-[3-(3-fluoro-4-iodo-phenyl)-2-oxo-oxazolidin-5-ylmethyl]-acetamide (1010, 17.36 g, 17.99 g theoretical, 96.5%) as white powders, which were found to be essentially pure and was directly used in the subsequent reactions without further purifications. For 1010: 1H NMR (300 MHz, DMSO-d6) δ 1.63 (s, 3H, NHCOCH3), 3.25 (t, 2H, J=5.4 Hz), 3.56 (dd, 1H, J=6.4, 9.2 Hz), 3.95 (t, 1H, J=9.1 Hz), 4.58 (m, 1H), 5.16 (t, 1H, J=5.7 Hz, OH), 7.02 (dd, 1H, J=2.4, 8.2 Hz), 7.38 (dd, 1H, J=2.4, 10.8 Hz), 7.66 (t, 1H, J=7.5, 8.4 Hz), 8.08 (t, 1H, J=5.8 Hz, NHCOCH3); C12H12FIN2O3, LCMS (EI) m/e 379 (M++H).

Provenance & Evidence