Rza Abbasoglu

Synthesis of a new 1,2,3,4,5-pentasubstituted cyclohexanol and determining its stereochemistry by NMR spectroscopy and quantum-chemical calculations

The presence of substituents in cyclohexane can influence to the ratio of conformers; for some cases, the boat form is preferable. The new six‐membered cyclohexanol derivative 2 has been obtained by the synthesis of (E)‐1‐(bromophenyl)‐3‐phenylpropen‐2‐one (1). The NMR and quantum‐chemical conformational analysis for the 2 have carried out, and its possible mechanism of formation was given. Copyright

Low and high temperature bromination of 2,3-dicarbomethoxy and 2,3-dicyano benzobarrelene: unexpected substituent effect on bromination

The bromination of 2,3-dicarbomethoxy benzobarrelene yielded the dibromide regio- and stereospecifically arising from the aryl shift where the bromine exclusively attacks the double bond from the exo face of the double bond. High temperature bromination of this compound yielded aryl-shift products. From the low temperature bromination of 2,3-dicyano benzobarrelene, non-rearranged products were obtained along with the rearranged products. Surprisingly, we observed that the yield of non-rearranged products decreased on increasing the temperature. A possible role of the substituent was discussed using DFT calculations on model compounds.

A quantum chemical investigation of electrophilic addition reaction of bromine to benzonorbornadiene

Abstract The molecular complexes formed by the treatment of bromine with benzonorbornodiene have been studied by the AM1 semiempirical method and their stable configurations and also stabilization energies have been determined. It has been found that the molecular complexes formed by the attack of bromine on the double bond of benzonorbornadiene, from the exo direction are more stable than those formed from the endo direction. Possible various cations and radical intermediates of the electrophilic addition reaction of bromine to benzonobornadiene have been investigated by MNDO and ab initio methods. The nonclassical delocalized bromocarbonium cation is the most stable among these cations according to both methods, and the ionic addition reaction occurs via this cation.

DFT and MP2 study on the electrophilic addition reaction of bromine to exo-tricyclo[3.2.1.02.4]oct-6-ene

The geometry and electronic structure of exo-tricyclo[3.2.1.02,4]oct-6-ene (exo-TCO) was investigated using DFT methods. The two faces of the endo-pyramidalised double bond of the molecule are not equivalent. The exo face of the double bond has regions with high electron density (qi,HOMO) and greater negative potential. Molecular complexes of exo-TCO with bromine were investigated using the B3LYP/6-311++G(d,p) method; the exo-TCO . . . Br2(exo) molecular complex was found to be relatively more stable than the exo-TCO . . . Br2(endo) complex. The cationic intermediates of the reaction were studied by DFT and MP2 methods. The solvent effect was evaluated using the self-consistent isodensity polarised continuum model (SCI-PCM). The exo-bromonium cation was found to be more stable than the endo-bromonium cation. Exo-facial selectivity due to electronic and steric factors was observed upon addition of bromine to exo-TCO. The multicentre nonclassical delocalised bromocarbonium cation IV and the exo-bridged-bromonium cation I are more stable than the rearrangement cation V. The reaction products are formed via exo-bridged-bromonium I and nonclassical IV cations, which are the most stable intermediates and whose stabilities barely differ. The mechanism of the addition reaction is also discussed.

Investigation of DNA cleavage activities of new oxime-type ligand complexes and molecular modeling of complex-DNA interactions

Nucleolytic activities of some new oxime-type ligand complexes were investigated by neutral agarose gel electrophoresis. Analysis of the cleavage products in agarose gel indicated that all complexes used converted supercoiled pUC18 plasmid DNA to its nicked or linear form. It was found that nucleolytic activities of the complexes depend on the complex concentration, reaction time and the presence of a cooxidant (magnesium monoperoxyphthalate, MMPP) in the reaction mixture. However, the complexes cleaved pUC18 plasmid DNA at all investigated pH values. Nucleolytic activities of complexes were investigated for different complex concentrations (0.1–100 μmol L−1), pH values (6.0–10.0) and reaction times (0–60 min). Molecular modeling studies performed by the Hyperchem Software together with DNA-binding studies showed that planar sites of the complexes intercalated into double stranded DNA. It can be concluded that all oxime-type ligand complexes used can be evaluated as nuclease mimics.