[N+:1]([C:4]1[CH:8]=[CH:7][NH:6][N:5]=1)([O-:3])=[O:2].[Si:9]([O:16][CH2:17][CH2:18]Br)([C:12]([CH3:15])([CH3:14])[CH3:13])([CH3:11])[CH3:10].C(=O)([O-])[O-].[Cs+].[Cs+].CN(C=O)C>C(Cl)Cl.O>[Si:9]([O:16][CH2:17][CH2:18][N:6]1[CH:7]=[CH:8][C:4]([N+:1]([O-:3])=[O:2])=[N:5]1)([C:12]([CH3:15])([CH3:14])[CH3:13])([CH3:11])[CH3:10]
A 100-mL single-neck round-bottomed flask equipped with a reflux condenser and magnetic stirrer was purged with nitrogen and charged with 3-nitro-1H-pyrazole (500 mg, 4.42 mmol), 2-(tert-butyldimethylsilyloxy)-1-bromoethane (2.12 g, 8.85 mmol), cesium carbonate (5.76 g, 17.7 mmol) and anhydrous DMF (5 mL). After heating at 70° C. for 1 h, the mixture was cooled to room temperature and diluted with methylene chloride (50 mL) and water (30 mL). The organic layer was separated, and the aqueous layer was extracted with methylene chloride (2×30 mL). The combined organic layers were dried over sodium sulfate and concentrated under reduced pressure. The residue was purified by column chromatography to afford an 85% yield (1.02 g) of 119a as a white solid: mp 76-77° C.; 1H NMR (500 MHz, CDCl3) δ 7.52 (d, 1H, J=2.5 Hz), 6.87 (d, 1H, J=2.5 Hz), 4.29 (t, 2H, J=5.0 Hz), 3.98 (t, 2H, J=5.0 Hz), 0.84 (s, 9H), −0.44 (s, 6H).
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