Syntheses of Licoisoflavone a and 5′-Alkenyl Isomer

Abstract

2′,4′,5,7-Tetrahydroxyisoflavone was partially benzoylated with benzoyl chloride to give 7-benzoyloxy-2′,4′,5-trihydroxyisoflavone. The condensation of 7-benzoyloxyisoflavone with 2-methyl-3-buten-2-ol, followed by the hydrolysis of the resultant 3′-(3-methyl-2-butenyl)isoflavone afforded licoisoflavone A. Its 5′-(3-methyl-2-butenyl) isomer was also synthesized from 5-benzoyloxyisoflavone.