[NH:1]1[CH:5]=[CH:4][N:3]=[CH:2]1.[Li][CH2:7][CH2:8][CH2:9]C.CN([CH:14]=[O:15])C>C1COCC1>[CH:8]([N:1]1[CH:5]=[CH:4][N:3]=[C:2]1[CH:14]=[O:15])([CH3:9])[CH3:7]A solution of the imidazole (890 mg, 8.08 mmol) in THF (10 mL) under nitrogen was cooled to −78° C. and n-BuLi (2.5M in hexanes, 4.5 mL, 11.3 mmol) was added. The bright yellow solution was stirred at 0° C. for 25 minutes, then DMF (1.5 mL, 19 mmol) was added. The reaction was stirred at room temperature for one hour, then was quenched by the addition of saturated aqueous NH4Cl (10 mL). The layers were separated and the aqueous solution was extracted with EtAOc (10 mL×2). The combined organic solution was dried (Na2SO4), filtered and concentrated under reduced pressure. Purification by flash column chromatography on silica (hexane/EtOAc, 1:1) gave the aldehyde as a pale yellow solid (731 mg, 5.29 mmol, 65%). 1H NMR (CDCl3) δ 1.46 (d, 6H, J=6.6 Hz), 5.46 (septet, 1H, J=6.8 Hz), 7.29 (s, 1H), 7.31 (s, 1H), 9.81 (s, 1H).
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