CHAPTER 5: Chemistry and Synthesis of Daidzein and its Methylated Derivatives: Formononetin, Isoformononetin, and Dimethyldaidzein

The existence of polyphenols within the plant kingdom was originally thought primarily to function in plant pigmentation and flavor; however, in recent years, these compounds have garnered considerable attention not only for their antioxidant properties but also for their ability to modulate a number of significant biological processes. Of particular interest, daidzein, a naturally occurring isoflavone, has been shown to have a key antagonistic role in the progression of carcinogenesis, neurodegeneration, and osteoporosis, in addition to its already well-known antioxidant and estrogenic activity. While these preliminary findings highlight their potential in these areas, the limited quantities of daidzein has hampered the preclinical development of this agent, thus making daidzein and its derivatives worthy of more efficient and practical syntheses. The synthesis of isoflavones has seen numerous advances over the past 80 years. Both the efficiency and applicability of the syntheses of daidzein and other isoflavones has grown in leaps and bounds. With the application of Suzuki coupling to the synthesis of isoflavones in the late 1980's, it has added yet another dimension to produce daidzein in a very selective and efficient manner.