[CH2:1]([O:3][C:4]([C:6]1[NH:10][C:9]2[CH:11]=[CH:12][S:13][C:8]=2[CH:7]=1)=[O:5])[CH3:2].[N+:14]([C:17]1[CH:22]=[CH:21][C:20](O)=[C:19](I)[CH:18]=1)([O-:16])=[O:15].C([O-])(=O)C.[Na+].Cl>CC(N(C)C)=O.C(OCC)(=O)C>[CH2:1]([O:3][C:4]([C:6]1[NH:10][C:9]2[CH:11]=[C:12]([C:20]3[CH:21]=[CH:22][C:17]([N+:14]([O-:16])=[O:15])=[CH:18][CH:19]=3)[S:13][C:8]=2[CH:7]=1)=[O:5])[CH3:2]
The resulting fused thiophene-pyrrole product, 4H-thieno[3,2-b]pyrrole-5-carboxylic acid ethyl ester (250 mg, 1.28 mmol) and 4-nitro-iodophenol (266 mg, 1.07 mmol) were dissolved in dimethylacetamide (10 ml). Sodium acetate (209.6 mg, 1.6 mmol) and tetrakis-(triphenylphosphine)palladium (61.8 mg, 0.005 mmol) were added thereafter and the reaction mixture was heated at 150° C. while stirring for 24 hours. A solution of HCl 0.1 M (50 ml) and ethyl acetate (20 ml) was then added, the organic and aqueous phases were separated, and the aqueous phase was extracted with ethyl acetate (3×20 ml). The combined organic phase was dried over Na2SO4 and the organic solvents were evaporated under reduced pressure. The crude product was purified by silica gel flash chromatography to give 105.5 mg of pure 2-(4-nitro-phenyl-4H-thieno[3,2-b]pyrrole-5-carboxylic acid ethyl ester (yield 31.2%).
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