Synthesis of quinone and xanthone analogs of rhein

• Published in: Tetrahedron Vol. 57; no. 44; pp. 9131 - 9135
• Main Authors: Fonteneau, Nadia, Martin, Philippe, Mondon, Martine, Ficheux, Hervé, Gesson, Jean-Pierre
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 29-10-2001
• Subjects: anthraquinones; rhein; xanthone analogs; xanthone analogs; rhein; anthraquinones
• ISSN: 0040-4020; 1464-5416
• DOI: 10.1016/S0040-4020(01)00918-8

A new strategy based on carbonylation of aryl triflates has been developed to prepare 7-methyl rhein from emodin and new xanthone analogs of rhein. This approach avoids the oxidation step of methyl derivatives with toxic chromium salts. Although possessing the same structural arrangement of phenol and carboxylic acid functions as found in rhein, these new xanthone derivatives have no activity against IL-1. Thus, the quinone moiety of rhein appears to be essential for activity.
Carbonylation of anthraquinone or xanthone triflates a new and efficient route towards title compounds, thereby avoiding oxidation with toxic chromium salts. In contrast to rhein, xanthone derivatives are not IL-1 inhibitors.