Reaction Steps
The Standard Procedure 2 was followed by use of 9a (72.2 mg, 0.160 mmol, 1.0 equiv), sodium methoxide (19.1 mg, 0.353 mmol, 2.2 equiv), and 4-nitroimidazole (6a, 36.3 mg, 0.321 mmol, 2.0 equiv). After workup and purification with column chromatography (80% EtOAc in hexanes as eluant), 10a (50.3 mg, 0.104 mmol) was obtained in 65% yield as white solids: mp (recrystallized from methanol) 98.3-98.8° C.; 1H NMR (CDCl3, 400 MHz) δ 0.80 (d, J=6.8 Hz, 3H, CH3), 0.83 (d, J=6.8 Hz, 3H, CH3), 1.74 (m, 2H, 2×CH), 2.22-2.34 (m, 2H, 2×ArCH), 2.69-2.76 (m, 2H, 2×ArCH), 3.81 (s, 3H, OCH3), 3.83 (s, 3H, OCH3), 3.84 (s, 3H, OCH3), 4.25 (t, J=4.8 Hz, 2H, CH2N), 4.37 (t, J=4.8 Hz, 2H, CH2O), 6.62-6.68 (m, 4H, 4×ArH), 6.71-6.78 (m, 2H, 2×ArH), 7.60 (d, J=1.4 Hz, 1H, nitroimidazole C5-H), 8.13 (d, J=1.4 Hz, 1H, nitroimidazole C2-H); 13C NMR (CDCl3, 100 MHz) δ 16.03, 16.16, 38.70, 38.93, 39.06, 39.25, 47.92, 55.61, 55.73, 55.82, 68.38, 110.98, 112.23, 112.78, 114.90, 120.62, 120.85, 120.93, 134.26, 136.55, 137.02, 144.90, 146.99, 147.98, 148.61, 149.66; IR (neat) 2957 (s), 2933 (s), 1590 (w), 1543 (s), 1516 (m), 1456 (w), 1337 (s), 1262 (m), 1235 (s), 1031 (s) cm−1; HRMS (FAB) m/z calcd for C26H34N3O6 (M+H)+: 484.2448. found: 484.2444.
