[C:1](Cl)(=O)[C:2]([Cl:4])=[O:3].[CH2:7]([C:11]1[O:12][C:13]2[CH:22]=[CH:21][CH:20]=[CH:19][C:14]=2C=1C(O)=O)[CH2:8][CH2:9][CH3:10].CN(C=O)C>C(Cl)Cl>[CH2:7]([C:11]1[O:12][C:13]2[CH:22]=[CH:21][CH:20]=[CH:19][C:14]=2[C:1]=1[C:2]([Cl:4])=[O:3])[CH2:8][CH2:9][CH3:10]Oxalyl chloride (6 mL, 68.8 mmol) was added under nitrogen at room temperature to a solution of 2-butyl-benzofuran-3-carboxylic acid (3.00 g, 13.7 mmol), prepared in the previous step, in 40 mL of methylene chloride. After the addition 10 μL of DMF was added and the reaction stirred at room temperature for 3 h. The solvent and the excess oxalyl chloride were removed under reduced pressure. To remove any residual oxalyl chloride the residue was taken up in benzene and then concentrated under reduced pressure to give 2-butyl-benzofuran-3-carbonyl chloride (3.00 g, 92%) as a white solid that was used in the next step without additional purification.
Wird geladen…
