Synthesis of isoflavones. Part V. Irigenin and tectorigenin
Abstract
The general ethoxalylation procedure for the synthesis of isoflavones has been applied to the synthesis of irigenin (VII) and tectorigenin (XVI). This synthetic route also yields the isomers, ψ-irigenin (XI) and ψ-tectorigenin (XX). Information concerning the product ratio in certain ethoxalylation reactions and the relative thermodynamic stabilities of 5,6,7- and 5,7,8-trisubstituted isoflavones is discussed.