Novel reaction products from the hypervalent iodine oxidation of hydroxylated stilbenes and isoflavones.

Abstract

Novel reaction pathways for the hypervalent iodine-mediated oxidation of bioactive phenols containing extended conjugated pi-systems are described. Oxidation of 4-hydroxystilbenes in methanol using a hypervalent iodine-based oxidant led to the formal 1,2-addition of methoxy groups across the central stilbene double bond. Treatment of the structurally related 4-hydroxyisoflavone with di(trifluoroacetoxy)iodobenzene leads to the surprising formation of 2,4'-dihydroxybenzil. Potential mechanisms for these new reaction pathways are discussed, and the X-ray crystal structure of 2,4'-dihydroxybenzil is presented. In contrast, oxidation of the corresponding 3-hydroxystilbenes and 3-hydroxyisoflavone led to conventional dienone oxidation products. The antitumour implications of these oxidation processes are briefly highlighted; the novel 4-substituted phenolic oxidation products were found to be inactive in terms of in vitro antitumour cellular activity, whereas the 3-substituted phenol products gave novel agents with potent and enhanced antitumour activity in the HCT 116 cancer cell line.

• Authors: Cedric J Lion, David A Vasselin, Carl H Schwalbe, Charles S Matthews, Malcolm F G Stevens, Andrew D Westwell
• Journal: Organic & biomolecular chemistry (Org Biomol Chem) Vol. 3 Issue 21 Pg. 3996-4001 (Nov 07 2005) ISSN: 1477-0520 [Print] England
• PMID: 16240020 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antineoplastic Agents
• Isoflavones
• Phenols
• Stilbenes
• Iodine

Topics

• Antineoplastic Agents (chemical synthesis)
• Cell Line, Tumor
• Humans
• Iodine (chemistry)
• Isoflavones (chemical synthesis, pharmacology)
• Phenols
• Stilbenes (chemical synthesis, pharmacology)
• Structure-Activity Relationship