Spectroscopic and Computational Study of Hydrate vs. Hemiacetal Equilibria in 6,7-Epoxy-6,7-Dihydroquinoline-5,8-Dione

Year 2025, Volume: 29 Issue: 3, 651 - 656, 25.12.2025

Raşit Çalışkan , Ozlem Sari

https://doi.org/10.19113/sdufenbed.1794752

Abstract

The hydration of carbonyl compounds and the formation of hemiacetals have been a topic of interest in organic chemistry. Hydration plays an important role in biological processes. Quinoline derivatives are also biologically active molecules with many applications. Equilibrium between 6,7-epoxy-6,7-dihydroquinoline-5,8-dione and its hydrate or hemiacetal form was investigated in aqueous and alcoholic solutions by NMR spectroscopy. Interestingly, no equilibrium was detected for the hydrocarbon counterpart. It was presumed that the existence of this equilibrium is highly dependent on the electronic structure of the molecule. To further understand the difference in reactivity to such systems, density functional theory (DFT) calculations were performed.

Keywords

Quinoline , Quinone , Hydration , Hemiacetal

Supporting Institution

TÜBİTAK and Süleyman Demirel University

Project Number

TÜBİTAK 109T910

Thanks

The authors thank to TÜBİTAK 109T910 (Scientific and Technological Research Council of Turkey) for financial support. We also thank Prof. Metin Balci and Prof. Dr. Akın Akdağ at Middle East Technical University for helpful discussions.

6,7-Epoksi-6,7-Dihidrokinolin-5,8-Dion'da Hidrat ve Hemiasetal Dengelerinin Spektroskopik ve Hesaplamalı Çalışması

Abstract

Karbonil bileşiklerinin hidratasyonu ve hemiasetallerin oluşumu organik kimyada ilgi çekici bir konu olmuştur. Hidratasyon biyolojik işlemlerde özellikle de ilaç salınımında önemli bir rol oynar. Kinolin türevleri de birçok uygulama alanına sahiptir ve çok geniş spektrumda biyolojik olarak aktif moleküllerdir. Bir kinolin türevi olan 6,7-epoksi-6,7-dihidrokinolin-5,8-dion ile hidrat veya hemiasetal formu arasındaki denge, sulu ve alkollü çözeltilerde NMR spektroskopisi ile incelendi. İlginç bir şekilde, hidrokarbon analoğu için bir denge tespit edilmedi. Bu dengenin varlığının molekülün elektronik yapısına (azot atomu molekülün elektronik yapısını değiştirdiğinden) büyük ölçüde bağlı olduğu varsayıldı. Bu tür sistemlere karşı reaktiflikteki farkı daha iyi anlamak için yoğunluk fonksiyonel teorisi (DFT) hesaplamaları yapıldı.

Keywords

Kinolin , Kinon , Hidratasyon , Hemiasetal

Supporting Institution

TÜBİTAK ve Süleyman Demirel Üniversitesi

Project Number

TÜBİTAK 109T910

Thanks

Yazarlar, finansal destekleri için TÜBİTAK 109T910'a (Türkiye Bilimsel ve Teknolojik Araştırma Kurumu) teşekkürlerini sunarlar. Ayrıca, faydalı tartışmaları için Orta Doğu Teknik Üniversitesi'nden Prof. Metin Balcı ve Prof. Dr. Akın Akdağ'a teşekkür ederiz.

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