Browsing by Author "Gul, Sergen"

Now showing 1 - 4 of 4

Design and Synthesis of Esipt-Based Imidazole Derivatives for Cell Imaging
(Amer Chemical Soc, 2024) Gul, Sergen; Acikgoz, Eda; Cakir, Mustafa; Menges, Nurettin
Excited-state intramolecular proton transfer (ESIPT)-based fluorescent molecules offer several exciting applications and are utilized most frequently as a cell imaging agent. Because of this, four distinct imidazole derivatives with ESIPT emission have been synthesized, and their fluorescence characteristics have been assessed in a variety of settings. Measurements using fluorescence spectroscopy have shown a promising candidate for cell staining, and potential candidate was specifically investigated for cell imaging uses in HT-29, MDA-MB-231, and HaCaT. Cytotoxicity of candidate molecule (1d) was analyzed using HT-29 and HaCaT cell lines, and at a dosage of 160 mu M, HT-29 and HaCaT cell lines showed no signs of important cell toxicity. When spectroscopically measured, compound 1d showed no fluorescence ability in phosphate-buffered saline (PBS) solution. However, after 8 h of incubation in several cell lines, excellent fluorescence characteristics were seen in the green and red filters.
Single-Step Approach for Synthesis of a Novel Tetracyclic Skeleton: Investigation of X-Ray Analysis, Fluorescence Spectra, Td-Dft Calculations and Biological Activities
(Elsevier, 2023) Kuzu, Burak; Gul, Sergen; Tan-Uygun, Meltem; Donmez, Mesude Figen; Menges, Nurettin
Tetracyclic molecules show important properties such as biological activities and fluorescence sensors. Hence, in this study, we have reported unknown tetracyclic skeleton. N -propargylated C-2 and C-4 disubstituted imidazole derivatives were reacted by 2-aminomethyl piperidine without using any transition metal. The reaction unveiled 16 different imidazo[1,2-a]pyrido[1 ' ,2 ' :3,4]imidazo[2,1-c]pyrazine skeletons. Cyclization reaction tolerated phenyl, naphthyl, bi-phenyl, 2-thienyl, and many substituents on the benzene ring such as OMe, CF 3 , and halogens. We have uncovered the exact structure of the tetracyclic skeleton using single-crystal X-ray analysis. Significant fluorescence emission of tetracyclic molecules was investigated, and derivatives bearing electron-withdrawing groups, CF 3 , and the 2-thienyl group possessed a bathochromic effect (shift to longer wavelength) which was confirmed by not only steady-state experiments but HOMOs and LUMOs calculations. The antimicrobial effects of the synthesized molecules on six different or ganisms were tested. Considerable activities of molecules 5p and 5n on many organisms were determined. Docking modeling and Lipinski, Ghose, and Veber compatibility studies of two different molecules were performed.
Synthesis of Indolizines by Dimerization of N-Propargylated Pyrroles Via Allene Intermediates
(Wiley-v C H verlag Gmbh, 2021) Kuzu, Burak; Gul, Sergen; Tan, Meltem; Menges, Nurettin; Balci, Metin
Ten different N-propargyl pyrrole derivatives having various substituents at the C-2 position were synthesized. These derivatives were converted into indolizine derivatives by the [2+2] cycloaddition reaction of pyrrole N-allene, forming in situ, by heating in PrOH in basic medium. The structures were characterized by NMR and X-ray crystallography. The N-propargylated derivatives smoothly underwent intermolecular cyclizations to produce indolizine derivatives in good yields. We proposed a radical mechanism for the dimerization. Reaction of an allene product with butylated hydroxytoluene (BHT), a radical scavenger, did not give any dimerization product. This result supports the radical reaction.
Tbacn-Promoted Regioselective Cyanofunctionalization and Benzannulation: Enabling Access To Cyanoindolizine Scaffolds Via Alkyne Cyclization
(Amer Chemical Soc, 2025) Gul, Sergen; Amudi, Karina S. I.; Kuzu, Burak; Menges, Nurettin
A novel and regioselective cyanofunctionalization-benzannulation cascade reaction has been developed, utilizing tetrabutylammonium cyanide (TBACN) as a practical and efficient cyanide source. This transformation provides streamlined access to a structurally diverse array of cyano-substituted indolizine scaffolds, which are valuable intermediates in the synthesis of nitrogen-containing heterocycles with potential pharmaceutical applications. The methodology employs readily available N-propargyl pyrrole derivatives as starting materials and proceeds under relatively mild reaction conditions, enabling the synthesis of 20 structurally distinct cyanoindolizine derivatives. The reaction exhibits remarkable regioselectivity in the installation of the cyano group, a feature that was not initially anticipated. This unexpected regioselective outcome was elucidated through a combination of control experiments, by-product analysis, and intermediate isolation, shedding light on the underlying mechanistic pathway. Furthermore, the reaction displays a broad substrate scope, demonstrating high functional group tolerance with respect to both electronic and steric variations on the pyrrole ring and the propargyl substituents. The versatility of the methodology is further highlighted by the potential for downstream transformations of the cyano group into other functional groups, such as amide moieties, which expand the synthetic utility of the obtained scaffolds. Importantly, this work represents the first reported example of a TBACN-mediated benzannulation of propargyl units, marking a significant advancement in the field of heterocyclic chemistry. The strategy not only provides a novel route to access complex indolizine frameworks but also offers valuable mechanistic insights and synthetic opportunities for the design and development of biologically relevant heterocycles.