Studies On The Synthesis Of Fully Substituted Benzofuran Derivatives

The benzofurans presenting in a wide variety of natural products and synthetic compounds have attracted considerable attention owing to their biophysical and pharmacological activities. As medicine and synthesis intermediates, the benzofurans and their derivatives have been extensively investigated in the selection of medical intermediates and other fields. Because of the structure of a-oxoketene-S, S-acetals give the diversity of chemical reactions of these compounds, they can be extensively investigated in organic synthesis.Combining with the special properties of α-oxo ketenedithioacetals. we have succeeded in exploring a new kind of benzofurans. This work mainly based on the following two aspects:1. By reported, we synthesised a series of a-oxoketene-S, S-acetals in water. The simple procedure, mild conditions, easy separation, high yields, and especially that in relation to the current environmental concerns make this protocol much attractive. Dithioacetals were prepared in high yields via the deacetylation reaction in the presence of concentrated sulfuric acid.2. Benzofurans were synthesized from a-oxoketene-S, S-acetals and para benzoquinone. In presence of BF3·OEt2, we successfully synthesized a series of benzofurans at room temperature. These compounds were characterized via IR and NMR.The reaction was readily performed with good yield, mild conditions and readily available starting materials. This method was offered the reactions of choice in large and industrial scale reactions.