Synthesis
5-Acetyl-2,3-dihydrobenzo(b)furan is prepared from o-bromophenol as the starting material, using water as the solvent, in the presence of the phase-transfer catalyst benzyl-tributyl ammonium chloride, by alkylation with 1,2-dichloroethane, sodium hydroxide and sodium bisulphite under reflux conditions to yield intermediate compound 1. Subsequently, in anhydrous tetrahydrofuran, 1,2-dibromoethane and magnesium are added to carry out an alkylation reaction, thereby yielding 2,3-dihydrobenzofuran (intermediate 2). Finally, acetyl chloride and aluminium trichloride were added to intermediate 2 to carry out the reaction and prepare the final product. The yield reached 76.6%. The reaction route is as follows:
Uses
1-(2,3-Dihydro-5-benzofuranyl)ethanone is used to prepare tricyclic [1,2,4]triazine 1,4-dioxides as hypoxia selective cytotoxins. It is also used to synthesize N-(1-benzo[1,3]dioxol-5-yl)ethyl-, N-[1-(2,3-dihydro-benzofuran-5-yl)ethyl-, and N-[1-(2,3-dihydro-1H-indol-5-yl)ethylacrylamides with KCNQ2 opener activities.
