Beyhan Yiğit

Synthesis and antimicrobial studies of 1-methyl-2-dimethylaminoethyl-substituted benzimidazolium salts and N-heterocyclic carbene–silver complexes

The synthesis and antimicrobial studies of 1-methyl-2-dimethylaminoethyl-substituted carbene precursors and silver complexes are reported. The carbene precursors (1a–d) have been prepared from 1-methyl-2-dimethylaminoethyl-substituted benzimidazole and various alkyl halides. The silver–NHC complexes (2a–d) were synthesized from the benzimidazolium salts and Ag2O in dichloromethane at room temperature. The new compounds were characterized by 1H NMR, 13C NMR, FT-IR, and elemental analyses. The new carbene precursors and Ag-complexes were tested for their in vitro antimicrobial activity against a variety of Gram-positive and Gram-negative bacteria, as well as for their antifungal activities against Candida albicans and Candida tropicalis.

Synthesis of ruthenium(II) N-heterocyclic carbene complexes and their catalytic activities in transfer hydrogenation of ketones

Three RuCl2(η6-arene, η1-carbene) and two RuCl2(NHC)(arene) complexes have been prepared by the reaction of bis(1,3-dialkylperhydrobenzimidazol-2-ylidene) (1) and bis(1,3-dialkyl-4-methylzimidazolin-2-ylidene) (3) with [RuCl2(arene)]2 in toluene and characterized by elemental analysis, 1H NMR, 13C NMR and IR spectroscopy. The catalytic activities of these complexes were examined in the transfer hydrogenation of aromatic ketones using 2-propanol as hydrogen source.

THE SYNTHESIS OF SOME BENZIMIDAZOLIUM SALTS AND USE AS CARBENE PRECURSORS IN THE HECK AND SUZUKI REACTIONS

Novel 1-(2-diisopropylaminoethyl)-3-alkylbenzimidazolium salts as N-heterocyclic carbene precursors 2a-g were prepared by quartemazition of 1-(2-diisopropylaminoethyl)benzimidazoles in DMF with alkyl halides. The salts were characterized spectroscopically and in situ formed complexes from Pd(OAc) 2 and 2 have been tested as catalyst in homogenous Heck and Suzuki reactions.

The synthesis and catalytic properties of imidazolinium salts and their palladium(II) complexes

Three 1,3-dialkylimidazolinium chloride salts and their palladium(II) complexes have been synthesized and characterized by elemental analysis, 1H NMR, 13C NMR and IR spectroscopy. The catalytic activities of the 1,3-dialkylimidazolinium chloride salts and their complexes in the Heck and Suzuki coupling reactions were investigated.

Schiff bases and their amines: Synthesis and discovery of carbonic anhydrase and acetylcholinesterase enzymes inhibitors

Three series of symmetrical Schiff bases were synthesized from 1,2‐diaminoethane, 1,3‐diaminopropane and 1,4‐diaminobutane and substituted benzaldehydes, and reduced by sodium borohydride to the corresponding benzylic diamines 4–6. All of the compounds obtained were characterized using elemental analysis, FT‐IR, 1H NMR, and 13C NMR spectroscopy. The enzyme inhibitory properties of these compounds were tested and the influence of the alkane chain length and the substituents on the phenyl group on the enzyme inhibition activity were examined. The novel Schiff bases and their amine derivatives (1a–d, 2a–d, 3b–d, 4a–c, 5a–c, 6a, 6c, 6d) were effective inhibitors of the cytosolic carbonic anhydrase I and II isoforms (hCA I and II), and acetylcholinesterase (AChE) with Ki values in the range of 159.43 ± 30.03 to 563.73 ± 115.30 nM for hCA I, 104.88 ± 18.44 to 524.32 ± 95.03 nM for hCA II, and 3.95 ± 0.74 to 30.83 ± 6.81 nM for AChE.