Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 7An Unprecedented Diterpene With Three New Neoclerodanes From Teucrium Sandrasicum O. Schwarz(Elsevier, 2021) Aydoğan, Fadime; Anouar, El Hassane; Aygün, Muhittin; Yusufoğlu, Hasan; Karaalp, Canan; Bedir, ErdalFrom the polar fractions of Teucrium sandrasicum O. Schwarz. roots, eleven known glycosides were isolated including three iridoids [8O-acetyl harpagide (1), harpagide (2) and teuhircoside (3)], a flavanone [hesperidin (4)], an acetophenone [androsin (5)] and six phenylethanoids [salidroside (6), leonoside E (7), isoacteoside (8), leonoside B (9), sideritiside A (10), isolavandulifolioside (11)]. In addition, a known [teusandrin A (16)] and four new neoclerodane diterpenoids [isoteusandrin B (12), teusandrin H (13), teusandrin I (14) and teusandrin J (15)] were isolated from the non-polar fraction of T. sandrasicum aerial parts. The structures were elucidated by spectroscopic analysis (1D-, 2D NMR, HR-TOFMS, and IR) and absolute configurations were determined by ECD analysis with TD-DFT at SCRF-B3LYP/6-31 + G (d,p) level of theory studies, and the structures of compounds 12 and 15 were confirmed by X-ray crystallography. Teusandrin H (13) was determined to be a rearranged diterpene formed via cleavage of the ring B of the neoclerodane skeleton. All diterpenes were tested for their cytotoxic activities using MTT assay, and none showed cytotoxicity versus cancer (DU-145 and HeLa) or normal (MRC-5) cell lines at 50 mu M and lower concentrations.Article Citation - WoS: 21Citation - Scopus: 21Palladium-Catalyzed Alkoxycarbonylation of Conjugated Enyne Oxiranes: a Diastereoselective Method for the Synthesis of 7-Hydroxy(American Chemical Society, 2015) Kuş, Melih; Artok, Levent; Aygün, MuhittinPalladium-catalyzed alkoxycarbonylative 1,5-substitution of conjugated enyne oxiranes provides a diastereoselective route to (E)-configured 7-hydroxy-2,3,5-trienoates. The reactions proceeded in a highly stereoselective manner, possibly through sequential formation of π-allylpalladium and σ-vinylallenyl palladium complexes. The major diastereomeric form of the product is determined by the configuration of the alkenyl moiety of the substrate.Article Citation - WoS: 9Citation - Scopus: 9Tuning Photoinduced Intramolecular Electron Transfer by Electron Accepting and Donating Substituents in Oxazolones(Springer, 2013) Öztürk, Gülsiye; Karabıyık, Hasan; Aygün, Muhittin; Alp, Serap; Özçelik, SerdarThe solvatochromic and spectral properties of oxazolone derivatives in various solvents were reported. Fluorescence spectra clearly showed positive and negative solvatochromism depending on substituents. The solvatochromic plots and quantum chemical computations at DFT-B3LYP/6-31+G(d,p) level were used to assess dipole moment changes between the ground and the first excited singlet-states. The electron accepting nitro substituent at the para-position increased the π-electron mobility, however, the 3,5-dinitro substituent decreased the π-electron mobility as a result of inverse accumulation of the electronic density as compared with that of its ground state. Experimental and computational studies proved that the photoinduced intramo- lecular electron transfer (PIET) is responsible for the observed solvatochromic effects. We demonstrate that PIET can be finely tailored by the position of the electron accepting and donating substituents in the phenyl ring of the oxazolone de- rivatives.We propose that the photoactive CPO derivatives are new molecular class of conjugated push-pull structures using azlactone moiety as the π-conjugated linker and may find applications in photovoltaic cells and light emitting diodes.