N-[3-(3-Fluoro-4-{4-[2-(2-nitro-6,7-dihydro-5H-imidazo[2,1-b][1,3]oxazin-6-yloxy)-acetyl]-piperazin-1-yl}-phenyl)-2-oxo-oxazolidin-5-ylmethyl]-acetamide. A mixture of (2-nitro-6,7-dihydro-5H-imidazo[2,1-b][1,3]oxazin-6-yloxy)-acetic acid (53 mg, 0.22 mmol), N-[3-(3-fluoro-4-piperazin-1-yl-phenyl)-2-oxo-oxazolidin-5-ylmethyl]-acetamide (73 mg, 0.228 mmol) (prepared as described by Barbachyn et al, U.S. Pat. No. 5,547,950) and TBTU (114 mg, 0.35 mmol) is dissolved in DMF (5 ml) and treated with Et3N (0.122 ml, 0.88 mmol) and stirred at room temperature for 12 hours. The mixture was diluted with EtOAc and water. The organic layer was washed with water, dried over sodium sulfate and concentrated. The residue was purified by preparative TLC to give 13 mg (10%) of the titled product as a tan solid. ESI MS m/z 562 (M+H+); 1H NMR (400 MHz, CDCl3) δ 7.50 (d, J=11.6 Hz, 1H), 7.44 (s, 1H), 7.21-7.02 (m, 1H), 7.00-6.85 (m, 1H), 5.99-5.92 (m, 1H), 4.76-4.67 (m, 2H), 4.44-4.22 (m, 4H), 4.05-4.01 (m, 1H), 3.79-3.44 (m, 4H), 3.49 (s, 2H), 3.10-2.62 (m, 4H), 2.02 (s, 3H), 1.24 (s, 3H).
