Efficient and Convenient Method for Synthesis of Benzofuran-3-acetic Acids and Naphthafuran-acetic Acids

Herein, we report an efficient and convenient method for synthesis of benzofuran-3-acetic acids and naphthafuran-acetic acids 5a–p by the reaction of substituted-4-bromomethylcoumarins with aqueous sodium hydroxide at refluxing temperature. The obtained products are characterized by infrared, ¹H NMR, ¹³C NMR, and mass spectral data. Structures 5a and 5e are confirmed by their single x-ray diffraction studies. The advantages of this method are good yields, easy workup, and no chromatographic purifications.