Synthesis of ferrocenyl quinones and polyquinanes

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Edebiyat Fakültesi, Kimya Bölümü, Türkiye

Tezin Onay Tarihi: 2005

Öğrenci: TUĞÇE ERALP

Danışman: METİN ZORA

Özet:

With the discovery of antitumor activity of ferrocene derivatives, research on new ferrocene derivatives have gained importance. For this purpose, we have investigated the synthesis of ferrocenyl quinones starting from squaric acid. Several quinone derivatives are known to have antitumor and antibiotic activities. In this research, by combining ferrocene and quinone moieties, we have targeted ferrocenyl quinones which are supposed to have enhanced potential antitumor activity. Thermolysis of ferrocenyl-substituted 4-alkynyl cyclobutenones, which have been prepared from ferrocenyl cyclobutenediones and alkynyllithiums, leads to the formation of ferrocenyl quinones and besides also cyclopentendiones are observed. Ferrocenyl cyclobutenediones have been prepared from known cyclobutenediones by nucleophilic addition of ferrocenyllithium followed by hydrolysis. A mechanism for the formation of ferrocenyl substituted quinones, involving first electrocyclic ring opening of alkynyl substituted cyclobutenone to ketene intermediate and then ring closure, has been proposed. Polyquinanes are widely found in nature and proved to have biological activity such as antibiotic activity. For the synthesis of ferrocenyl polyquinanes, starting from squaric acid, ferrocenyl substituted cyclobutenediones were prepared and reacted with alkenyllithium, and hydrolyzed to afford ferrocenyl substituted polyquinanes. A mechanism has been proposed that involves first the formation of cis- and trans-divinyl substituted cyclobutenes that produce cyclooctatriene-dienolate, upon hydrolysis of this dienolate, aldol-type transannular ring closure reaction takes place, producing polyquinanes.