[H-].[Na+].[NH:3]1[CH:7]=[C:6]([C:8]([O:10][CH3:11])=[O:9])[N:5]=[CH:4]1.Cl[CH2:13][O:14][CH2:15][CH2:16][Si:17]([CH3:20])([CH3:19])[CH3:18]>CN(C=O)C>[CH3:18][Si:17]([CH3:20])([CH3:19])[CH2:16][CH2:15][O:14][CH2:13][N:3]1[CH:7]=[C:6]([C:8]([O:10][CH3:11])=[O:9])[N:5]=[CH:4]1To a stirred suspension of sodium hydride (572 mg, 23.8 mmol, 94%) in dry DMF (50 mL) at 0° C. was added methyl 1H-imidazole-4-carboxylate (3.0 g, 23.8 mmol) in DMF (90 mL) and was allowed to warm up to room temperature over 30 min. The reaction mixture was cooled to 0° C. and was treated dropwise with (2-(chloromethoxy)ethyl)trimethylsilane (Aldrich, 4.77 g, 28.6 mmol). The cold bath was removed and the mixture was stirred for 16 h. The reaction mixture was quenched by the addition of ice-flakes and then by water, and extracted with EtOAc (3×). The combined organic layers were washed with brine, dried over Na2SO4 and concentrated in vacuo to give crude product. The crude material was purified by flash chromatography (gradient from 2 to 5% MeOH/CH2Cl2) to provide the title compound (4.46 g, 73%). 1H NMR (CDCl3) δ 7.72 (s, 1H), 7.61 (s, 1H), 5.29 (s, 2H), 3.90 (s, 3H), 3.49 (t, J=8.0 Hz, 2H), 0.90 (t, J=8.0 Hz, 2H), 0.01 (s, 9H); MS(ESI+) m/z 257.2 (M+H)+.
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