[H-].[Na+].[I:3][C:4]1[CH:5]=[C:6]([CH:9]=[O:10])[NH:7][CH:8]=1.Br[CH2:12][C:13]([O:15][CH2:16][CH3:17])=[O:14]>O1CCCC1>[CH:9]([C:6]1[N:7]([CH2:12][C:13]([O:15][CH2:16][CH3:17])=[O:14])[CH:8]=[C:4]([I:3])[CH:5]=1)=[O:10]Sodium hydride (1.62 g, 60% w/w dispersion in mineral oil, 67.9 mmol) was added to a solution of 4-iodo-1H-pyrrole-2-carbaldehyde (5.0 g, 22.6 mmol) in tetrahydrofuran (30 mL) over 10 min. The reaction mixture was stirred for 15 min, then ethyl bromoacetate (7.56 g, 45.2 mmol) was added and the mixture stirred for 2 h at ambient temperature. The reaction was quenched with methanol and concentrated in vacuo. The crude compound was then extracted into ethyl acetate. The organic layer washed with water, brine, dried over anhydrous sodium sulfate, filtered and concentrated under in vacuo to afford the crude compound. Purification by column chromatography over silica gel (100-200 mesh) using 2% ethyl acetate in petroleum ether afforded ethyl 2-(2-formyl-4-iodo-pyrrol-1-yl)acetate (3.4 g, 49%).
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