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Öğe Synthesis of a novel N,N?,N?-tetraacetyl-4,6-dimethoxyindole-based dual chemosensor for the recognition of Fe3+ and Cu2+ ions(Elsevier Science Sa, 2019) Senkuytu, Elif; Bingul, Murat; Saglam, Mehmet F.; Kandemir, Hakan; Sengul, Ibrahim F.A novel N,N'N',1-tetraacetyl-4,6-dimethoxy-1H-indole-2-carbohydrazide 5, bearing four N-acetyl groups (N-COCH3) as cation binding sites was successfully synthesized by the reaction of readily available 4,6-dimethoxy-1H-indole-2-carbohydrazide 4 with acetic anhydride in dimethyl formamide in the presence of triethylamine. The structure of the acetyl indole 5 was confirmed using H-1 NMR, C-13 NMR, FT-IR, mass spectrometry and single crystal X-ray diffraction techniques. The colorimetric sensing ability of targeted compound 5 was investigated by monitoring UV-Vis and fluorescence spectroscopy spectral changes upon addition of different cations. The compound 5 demonstrated selective recognition toward the Fe+3 and Cu+2 ions over other cations examined such as Li+, Na+, K+ Mg2+, Ca2+, Ba2+, Mn2+, Fe2+, Cr3+, Co2+, Ni2+, Ag+, Cd2+, Al3+, Hg (+), Zn2+. The complex stoichiometry of the compound 5 and Cu2+/Fe3+ ions were determined as 2:1 (ligand/metal) by fluorescence titrations (Job's plot). This is the first report showing 4,6-dimethoxyindole moiety represents a dual chemosensor capable of detecting the Cu2+ and Fe2+ ions.Öğe Synthesis of indole-2-carbohydrazides and 2-(indol-2-yl)-1,3,4-oxadiazoles as antioxidants and their acetylcholinesterase inhibition properties(Springer Wien, 2019) Bingul, Murat; Saglam, Mehmet F.; Kandemir, Hakan; Boga, Mehmet; Sengul, Ibrahim F.A range of novel 4,6-dimethoxy-1H-indole-2-carbohydrazides was prepared starting from methyl 4,6-dimethoxy-1H-indole-2-carboxylate which underwent cyclodehydration to generate the corresponding 2-(indol-2-yl)-1,3,4-oxadiazole scaffolds in the presence of N,N-diisopropylethylamine and p-toluenesulfonyl chloride in acetonitrile. All novel compounds were fully characterized by H-1 NMR, C-13 NMR, FT-IR, and high-resolution mass spectroscopic data. Biological importance of the designated compounds was identified by employing three different antioxidant property determination assays, namely DPPH free radical scavenging, ABTS cationic radical decolarization, and cupric reducing antioxidant capacity (CUPRAC). The anticholinesterase properties were also evaluated by the acetylcholinesterase and butyrylcholinesterase enzyme inhibition assays. According to the results, the indole compounds possessing carbohydrazide functionality were found to be more promising antioxidant targets than the 2-(indol-2-yl)-1,3,4-oxadiazole systems. N'-Benzoyl-4,6-dimethoxy-1H-indole-2-carbohydrazide, a member of the dimethoxyindole-2-carbohydrazide group, demonstrated a better inhibition performance than the standards. Additionally, extremely important results were obtained in the anticholinesterase enzyme inhibition assays in the case of 2-(indol-2-yl)-1,3,4-oxadiazole derivatives. [GRAPHICS] .Öğe Synthesis, characterization, UV-Vis absorption and cholinesterase inhibition properties of bis-indolyl imine ligand systems(Elsevier, 2020) Saglam, Mehmet F.; Bingul, Murat; Senkuytu, Elif; Boga, Mehmet; Zorlu, Yunus; Kandemir, Hakan; Sengul, Ibrahim F.A number of bis-indolyl imine helical structures has successfully been synthesized employing Schiff base reaction conditions starting from 4,6-dimethoxy-2,3-diphenylindole with different o-phenyl diamines as pi-spacer bridged. The structures of targeted compounds were identified by FT-IR, mass, H-1 and C-13 NMR spectroscopy along with single crystal X-ray diffraction techniques. The ground state absorption properties of the bis-indolyl compounds were also investigated utilizing UV-Vis absorption spectroscopy. As the biological aspect of the synthesized compounds, the anticholinesterase potency was investigated towards the acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. The highest inhibition was determined in the presence of compound 9 with the values of 89.21 and 96.06, better than standard Galantamine, for AChE and BChE, respectively. (C) 2020 Elsevier B.V. All rights reserved.Öğe Synthesis, in vitro and in silico evaluation of indole linked carbohydrazides and 1,3,4-oxadiazoles as new α-glycosidase inhibitors(Elsevier, 2025) Kocaman, Kubra; Bingul, Murat; Ceyhan, Sadik M.; Sahin, Hasan; Saglam, Mehmet F.; Kandemir, Hakan; Sengul, Ibrahim F.The Hemetsberger indole reaction afforded 6-methyl and methoxy substituted indole-2-carboxylates 8 which were then reacted with an excess of hydrazine hydrate in ethanol to produce indole-2-carbohydrazides 9. Treatment of the compounds 9 with a range of commercially available benzoyl chlorides generated new indole linked diacyl hydrazines 10-15 and the corresponding cyclodehydration reaction in the presence of N,N-diisopropylethylamine (DIPEA) and p-toluenesulfonyl chloride (p-TsCl) in acetonitrile gave the targeted indole linked 1,3,4-oxadiazoles 16-21. The antidiabetic properties of the newly synthesized compounds were evaluated by employing alpha-glycosidase and alpha-amylase enzyme inhibition assays and the targeted compounds showed a range of inhibitory activities against alpha-glycosidase and alpha-amylase. The study revealed that the compounds selectively inhibit alpha-glycosidase enzyme. The detection of selective inhibition behaviours for alpha-glycosidase enzyme increased the novelty of the study and most of the IC50 values against the designated enzyme were found to be better than the standard acarbose. The structure-activity relation study illustrated that the oxadiazole ring with the methyl substituted indole and nitro substituted benzene rings demonstrated the best inhibition towards the alpha-glycosidase enzyme. The detected IC50 value for the identified compound 21 was found to be better (>25-fold) than the standard acarbose.Öğe Synthesis, photophysical and antioxidant properties of carbazole-based bis-thiosemicarbazones(Springer, 2019) Bingul, Murat; Senkuytu, Elif; Saglam, Mehmet F.; Boga, Mehmet; Kandemir, Hakan; Sengul, Ibrahim F.Utilizing Schiff base condensation of the 9-ethylcarbazole-3,6-dicarbaldehyde and thiosemicarbazides, four new N-ethylcarbazole-based bis-thiosemicarbazone compounds 4a-d were successfully synthesized in high yields. The photophysical properties of the targeted compounds 4a-d were investigated using UV-vis absorption and fluorescence emission spectroscopy. The antioxidant properties of targeted compounds 4a-d were determined by DPPH radical scavenging, ABTS Cation Radical Decolarization and CUPRAC Cupric Reducing Antioxidant Capacity assay methods. Moreover, the anti-cholinesterase properties of designated compounds were investigated by the Acetylcholinesterase (Ach) and Butyrylcholinesterase (BCh) enzyme inhibition assays. The compound 4a was determined as a valuable candidate to be a potent antioxidant agent for the DPPH and ABTS assays. The compound 4d was found to be a target compound for the kinetic measurements to identify the mechanism of action in the area of anticholinesterase activity assay.Öğe Synthesis, photophysical and antioxidant properties of pyrrolo[3,2-c]carbazole and dipyrrolo[3,2-c:2,3-g]carbazole compounds(Springer, 2019) Bingul, Murat; Senkuytu, Elif; Boga, Mehmet; Uslu, Tugce Nur; Kandemir, Hakan; Sengul, Ibrahim F.The synthesis of (6-ethyl-1,6-dihydropyrrolo[3,2-c]carbazol-2-yl)methanol 5 and (6-ethyl-6,11-dihydro-1H-dipyrrolo[3,2-c:2,3-g]carbazole-2,10-diyl)dimethanol 6 were achieved via the reduction of methyl pyrrolo carbazole carboxylate 3 and methyl dipyrrolo carbazole carboxylate 4, respectively. The structures of hydroxymethyl-pyrrolocarbazoles 5 and 6 were supported by FT-IR, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, H-1 and C-13 NMR spectroscopy. The photophysical properties of the targeted compounds 3-6 were investigated by employing absorption and fluorescence spectroscopy in different common organic solvents. Also, the fluorescence lifetime ((F)) of the compounds was measured utilizing a time-correlated single-photon counting technique in tetrahydrofuran. Antioxidant activities of compounds 3-6 were determined by employing three different assays, namely DPPH radical scavenging, ABTS cation radical decolarization and cupric reducing antioxidant capacity. The results revealed that the ABTS cationic scavenging activity assay was found to be the most sensitive method for the determination of inhibition values.
