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

No 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.

The condensation of 6',7-dibenzoyloxy-2',4'-dimethOxyisoflavone with 2-methyl-3-buten-2-01. followed by the hydrolysis of the resultant 3'-13-methyl-2-buteny1)isaflavone afforded licoricone. Its isomer, 5'-(3-methyl-2-buteny1)isoflavone, was also synthesized from 7-benzoyloxy or 6',7-dibenzoyl-

Kondensation der cyclischen Verbindung (I) mit den Aldehyden (II) gibt die hauptsächlich E‐konfigurierten Alkylidenderivate (III); das Z‐Isomere (IV) von (IIIa) ist bekannt.