Aydın Aktaş

Novel NHC Precursors: Synthesis, Characterization, and Carbonic Anhydrase and Acetylcholinesterase Inhibitory Properties

Three series of imidazolidinium ligands (NHC precursors) substituted with 4‐vinylbenzyl, 2‐methyl‐1,4‐benzodioxane, and N‐propylphthalimide were synthesized. N‐Heterocyclic carbene (NHC) precursors were prepared from N‐alkylimidazoline and alkyl halides. The novel NHC precursors were characterized by 1H NMR, 13C NMR, FTIR spectroscopy, and elemental analysis techniques. The enzymes inhibition activities of the NHC precursors were investigated against the cytosolic human carbonic anhydrase I and II isoenzymes (hCA I and II) and the acetylcholinesterase (AChE) enzyme. The inhibition parameters (IC50 and Ki values) were calculated by spectrophotometric method. The inhibition constants (Ki) were found to be in the range of 166.65–635.38 nM for hCA I, 78.79–246.17 nM for hCA II, and 23.42–62.04 nM for AChE. Also, the inhibitory effects of the novel synthesized NHCs were compared to acetazolamide as a clinical CA isoenzymes inhibitor and tacrine as a clinical cholinergic enzymes inhibitor.

Palladium catalyzed Mizoroki–Heck and Suzuki–Miyaura reactions using naphthalenomethyl-substituted imidazolidin-2-ylidene ligands in aqueous media

Naphthalenomethyl-substituted imidazolidinium salts (1a-g) were prepared and characterized by conventional spectroscopic methods, 1H NMR, 13C NMR, FTIR, and elemental analysis techniques. The in situ prepared three component systems naphthalenomethyl-substituted imidazolidinium salts, Pd(OAc)2, and K2CO3 catalyzed quantitatively the Mizoroki–Heck and Suzuki–Miyaura coupling of aryl halides under mild conditions in aqueous media.

Novel N-propylphthalimide- and 4-vinylbenzyl-substituted benzimidazole salts: Synthesis, characterization, and determination of their metal chelating effects and inhibition profiles against acetylcholinesterase and carbonic anhydrase enzymes

The novel N‐propylphthalimide‐substituted and 4‐vinylbenzyl‐substituted N‐heterocyclic carbene (NHC) precursors were synthesized by N‐substituted benzimidazolium with aryl halides. The novel N‐propylphthalimide‐substituted and 4‐vinylbenzyl‐substituted NHC precursors have been characterized by using 1H NMR, 13C NMR, FTIR spectroscopy, and elemental analysis techniques. They were tested for the inhibition of AChE and hCA enzymes and demonstrated efficient inhibition profiles with Ki values in the range of 351.0–1269.9 nM against hCA I, 346.6–1193.1 nM against hCA II, and 19.0–76.3 nM against AChE. On the other hand, acetazolamide, a clinically used molecule, utilized as CA inhibitor, obtained a Ki value of 1246.7 nM against hCA I and 1407.6 nM against hCA II. Additionally, tacrine inhibited AChE and obtained a Ki value of 174.6 nM.

Erratum to: N-Propylphthalimide-Substituted Silver(I) N-Heterocyclic Carbene Complexes and Ruthenium(II) N-Heterocyclic Carbene Complexes: Synthesis and Transfer Hydrogenation of Ketones

This study deals with the synthesis of N-propylphthalimide substituted Ag(I)–N-heterocyclic carbene (NHC) complexes and N-propylphthalimide substituted Ru(II)–NHC complexes in the transfer hydrogenation of ketones. The Ag(I)–NHC complexes were synthesized from the imidazolium salts and Ag2O in dichloromethane at room temperature. The Ru(II)–NHC complexes have been prepared from Ag(I)–NHC complexes using transmetallation method. The six N-propylphthalimide substituted Ag(I)–NHC complexes and six N-propylphthalimide substituted Ru(II)–NHC complexes have been characterized by spectroscopic techniques and elemental analyses. N-propylphthalimide substituted Ru(II)–NHC complexes have been analyzed as catalysts for the transfer hydrogenation of ketones and exhibit activity in this reaction. This study deals with the synthesis of N-propylphthalimide substituted Ag(I)-N-heterocyclic carbene (NHC) complexes and N-propylphthalimide substituted Ru(II)–NHC complexes in the transfer hydrogenation of ketones. The Ag(I)–NHC complexes were synthesized from the imidazolium salts and Ag2O in dichloromethane at room temperature. The Ru(II)–NHC complexes have been prepared from Ag(I)–NHC complexes using transmetallation method. The six N-propylphthalimide substituted Ag(I)–NHC complexes and six N-propylphthalimide substituted Ru(II)–NHC complexeshavebeencharacterizedbyspectroscopictechniquesandelementalanalyses. N-propylphthalimide substituted Ru(II)–NHC complexes have been analyzed as catalysts for the transfer hydrogenation of ketones and exhibit activity in this reaction.

4-Vinylbenzyl-substituted silver(I) N-heterocyclic carbene complexes and ruthenium(II) N-heterocyclic carbene complexes: synthesis and transfer hydrogenation of ketones

Abstract4-Vinylbenzyl-substituted Ag(I) N-heterocyclic carbene (NHC) complexes and Ru(II) NHC complexes have been synthesized. The Ag(I) complexes were synthesized from the imidazolium salts and Ag2O in dichloromethane at room temperature. The Ru(II) complexes were prepared from Ag(I) NHC complexes by transmetallation. The six 4-Vinylbenzyl-substituted Ag(I) NHC complexes and six 4-Vinylbenzyl-substituted Ru(II) NHC complexes have been characterized by spectroscopic techniques and elemental analyses. The Ru(II) NHC complexes show catalytic activity for the transfer hydrogenation of ketones.

Synthesis, Characterization and Crystal Structure of New 2-Morpholinoethyl-Substituted Bis-(NHC)Pd(II) Complexes and the Catalytic Activity in the Direct Arylation Reaction

This paper contains the synthesis of the new 2-morpholinoethyl substituted bis-(NHC)Pd(II) complexes and their catalytic activity in direct arylation reaction. The new bis-(NHC)Pd(II) complexes have been prepared from Ag(I)NHC complexes by using transmetallation method. The new bis-(NHC)Pd(II) complexes have been characterized by using 1H NMR, 13C NMR, FTIR spectroscopy and elemental analysis techniques. Molecular and crystal structure of the complex 1a and its ligand (N-benzylbenzimidazole) were obtained by single crystal X-ray diffraction method. The new bis-(NHC)Pd(II) complexes exhibit activity in the reaction after being examined as catalysts in the direct arylation (C–H activation) reaction.Graphical Abstract

Synthesis, characterization, crystal structure, and antimicrobial studies of 2-morpholinoethyl-substituted benzimidazolium salts and their silver(I)- N -heterocyclic carbene complexes

This article describes synthesis of N-morpholinoethylbenzimidazole (1), 2-morpholinoethyl-substituted benzimidazolium salts (NHC precursors, 2a–c), and their Ag(I) N-heterocyclic carbene (NHC) complexes (3a–c). All compounds were characterized by 1H and 13C Nuclear Magnetic Resonance (NMR), Fourier Transform Infrared Spectroscopy (FTIR), and elemental analysis, and their antimicrobial effects examined. The molecular structure of the NHC precursor 2a1 was established by single-crystal X-ray diffraction analysis. Minimum Inhibition Concentration (MIC) values were determined to evaluate their antimicrobial activity against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus bacterial strains and Candida albicans fungal species. All tested samples were compared with silver nitrate. All the compounds exhibited strong antimicrobial activity.

N -Propylphthalimide-substituted bis-(NHC)PdX 2 complexes: synthesis, characterization and catalytic activity in direct arylation reactions

Palladium-catalyzed direct arylation of heteroaromatics has become a popular method for producing carbon–carbon bonds via C–H bond activation. A wide diversity of heteroaromatics such as furan, thiophenes and thiazoles can be used for this reaction. This paper reports the synthesis of N-propylphthalimide-substituted bis-(NHC)PdX2 complexes (NHC = N-heterocyclic carbene), and their catalytic activity in direct arylation reactions. The complexes have been prepared from Ag(I)NHC precursors by transmetallation and characterized by spectroscopy and elemental analysis. The bis-(NHC)PdX2 complexes show excellent activity as catalysts in the direct arylation reactions of 2-n-butylfuran, 2-n-butylthiophene and 2-isopropylthiazole.

meta-Cyanobenzyl substituted benzimidazolium salts: Synthesis, characterization, crystal structure and carbonic anhydrase, α-glycosidase, butyrylcholinesterase, and acetylcholinesterase inhibitory properties

meta‐Cyanobenzyl‐substituted N‐heterocyclic carbene (NHC) precursors were synthesized by the reaction of a series of N‐(alkyl)benzimidazolium with 3‐bromomethyl‐benzonitrile. These benzimidazolium salts were characterized by using 1H NMR, 13C NMR, FTIR spectroscopy, and elemental analysis techniques. The molecular and crystal structures of 2f and 2g complexes were obtained by using the single‐crystal X‐ray diffraction method. The derivatives of these novel NHC precursors were effective inhibitors of α‐glycosidase (AG), the cytosolic carbonic anhydrase I and II isoforms (hCA I and II), butyrylcholinesterase (BChE), and acetylcholinesterase (AChE) with Ki values in the range of 1.01–2.12 nM for AG, 189.56–402.44 nM for hCA I, 112.50–277.37 nM for hCA II, 95.45–352.58 nM for AChE, and 132.91–571.18 nM for BChE. In the last years, inhibition of the CA enzyme has been considered as a promising factor for pharmacologic intervention in a diversity of disturbances such as obesity, glaucoma, cancer, and epilepsy.

Management of Acute Sleeve Gastrectomy Leaks by Conversion to Roux-en-Y Gastric Bypass: a Small Case Series

Management of early sleeve gastrectomy leak remains challenging. The recommended approach is endoscopic stenting and abdominal drainage. Conversion to a Roux-en-Y gastric bypass (RYGB) is a common procedure used for late fistulas with distal obstruction. Here, we have presented three cases of early staple line leaks treated by conversion to RYGB. These patients had uncontrolled abdominal infections despite intensive medical treatments, and surgery was elected for abdominal drainage as well as to control the source of sepsis. All the patients were discharged without problems, and successful weight loss processes continued. Conversion to RYGB of a sleeve gastrectomy leak in an acute setting can be a feasible method in the case of inevitable surgical drainage for abdominal sepsis.