European Reviews of Chemical Research

42-50

Authors: Abdelilah Benallou, Zouhair Lakbaibi, Habib El Alaoui El Abdallaoui, Hocine Garmes

The mechanism nature of the 32CA reaction involving zwitterionic species has been performed; and thus, the changes of electron density associated with the O-C and C-C bond formation along IRC are characterized. Conceptual DFT analyses of the most favorable adduct, Endo-mode α; shows that the electronic flux will takes place from nitrone to methacrylonitrile moiety. Furthermore, ELF topological analysis based on the electron density predicts that C-C bond is formed by the coupling of two pseudoradical centers generated at the most significant atoms of the molecules, while O-C bond is formed by the donation of the some electron density given by the lone pair. Two-stage one-step is the most probably mechanism of this reaction, the first stage aims for the formation of C2-C3 σ bond while the second stage aims for the formation of O1-C1 σ bond. In general, the observed asynchronicity of this 32CA reaction can be related mainly to the asymmetric reorganization of the electron density at the most attractive centers.

59-66

Authors: M. El Idrissi, A. El Haib, Y. Hakmaoui, M. Zoubir, M. El Ghozlani, S. Mouatarif, N. Ourhriss, R. El Ajlaoui

The mechanism and regioselectivity of the epoxidation reaction of the methyl 2-((2R,4aR)-4a,8-dimethyl-1,2,3,4,4a,5,6,7-octahydronaphthalen-2-yl)acrylate 1 by m-CPBA, have been theoretically studied at the DFT/ B3LYP/6-31(d) computational level. The possible 1/2/3 regioselective and sterioselective channels were explored and characterized, the energies analysis associated with the different reaction pathways indicates that this epoxidation reaction is highly regioselective, in good conformity with the experimental observations.

75-85

Authors: H.A. Shindy, M.A. El-Maghraby, M.M. Goma, N.A. Harb

Novel acyclic merocyanine dyes and cyclic merocyanine dyes derived from the nucleus of furo[(3,2-d)pyrazole;(3',2'-d)oxazole] were prepared. The electronic visible absorption spectra of all the new synthesized acyclic and cyclic merocyanine dyes were examined in 95 % ethanol solution to evaluate their spectral sensitization properties. Studying the electronic visible absorption spectra of cyanine dyes in 95 % ethanol solution have a great practical value and is very important study in the case of cyanine dyes because the extensive uses and applications of these dyes as photographic sensitizers for silver halide emulsion in photosensitive material industry for coloured and non coloured (black and white) films (cyanine dyes were originally used, and still are, to increase the sensitivity range of photographic emulsions, i.e. to increase the range of wavelengths which will form an image on the film). Structural characterization and identification was carried out via elemental analysis, visible spectra, mass, IR and 1H NMR spectroscopic data.