CC(C)([O-])C.[K+].[C:7]1([C:13]2[CH:14]=[C:15]([C:18]([O:20][CH2:21][CH3:22])=[O:19])[NH:16][CH:17]=2)[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=1.[C:23]([O:27][CH2:28][CH3:29])(=[O:26])[CH:24]=[CH2:25]>C(O)(=O)C>[CH2:28]([O:27][C:23](=[O:26])[CH2:24][CH2:25][N:16]1[CH:17]=[C:13]([C:7]2[CH:8]=[CH:9][CH:10]=[CH:11][CH:12]=2)[CH:14]=[C:15]1[C:18]([O:20][CH2:21][CH3:22])=[O:19])[CH3:29]Potassium tert-butoxide (100 mg, 0.90 mmol), ethyl 4-phenyl-1H-pyrrole-2-carboxylate (1.0 g, 4.65 mmol) and ethyl acrylate (50 mL) were heated at reflux for 90 min. The reaction mixture was allowed to cool to room temperature and neutralized with acetic acid (1 mL). Excess ethyl acrylate was evaporated in vacuo, the residue diluted with water and extracted with chloroform. The organic layer was dried over anhydrous sodium sulfate, filtered and concentrated in vacuo to give the crude compound. Purification by column chromatography over neutral alumina using 5% ethyl acetate in petroleum ether as eluent gave ethyl 1-(3-ethoxy-3-oxo-propyl)-4-phenyl-pyrrole-2-carboxylate (1.0 g, 69%) as an oil.
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