Bellara Nedjar-Kolli

Synthesis and in silico biological activity evaluation of new N-substituted pyrazolo-oxazin-2-one systems.

Cyclisation of pyrazolo-beta-enaminones 3 readily obtained from 4-aceto acetyl pyrazol 2 with triphosgene led to the formation of N-substituted pyrazolo-1,3-oxazin-2-ones 4 in good yields. Estimation of pharmacotherapeutic potential, possible molecule mechanisms of action, toxic/side effects and interaction with drug-metabolizing enzymes were made for synthesised compounds on the basis of prediction of activity spectra for substances (PASS) prediction results and their analysis by PharmaExpert software. COX inhibition predicted by PASS was confirmed by experimental evaluation.

Synthesis of Imidazoles from Ketimines Using Tosylmethyl Isocyanide (TosMIC) Catalyzed by Bismuth Triflate

The preparation of a series of 1,5-disubstituted-4-methyl imidazoles is reported, based on an unprecedented re- action between an acetimine and TosMIC in the presence of tert-butylamine and catalytic amounts of bismuth(III) triflate. The mechanism is believed to involve formation of an imidazoline intermediate, followed by the methyl group migration, and subsequent aromatization to the imidazole ring.

Copper(II) and nickel(II) complexes derived from a carbothioamide-5-pyrazolone ligand: synthesis, characterization, crystal structures, electrochemical, potentiometric and DNA-binding studies

The synthesis of a 5-pyrazolone derivative (H2L) bearing a carbothioamide group at N1, N-ethyl-4-(2-hydroxyethyl)-3-methyl-5-oxo-2,5-dihydro-1H-pyrazole-1-carbothioamide, using a Keggin catalyst (H4SiW12O14·nH2O), is described. Complexes of copper(II) and nickel(II) have been prepared with this potential ligand and studied by potentiometry. Processing the pH-metric titrations revealed remarkable chelation ability of the ligand and high stability constants for the complexes. The complexes have been characterized by IR, UV/visible, electrochemistry, magnetic measurements, Electron Paramagnetic Resonance (EPR) and single-crystal X-ray diffraction. The structures are [Cu(HL)2H2O]·2H2O and [Ni(HL)2H2O]·2H2O, where the metal is five coordinate in an almost perfect trigonal bipyramidal geometry (D3h). The pyrazolone derivative (H2L) is a NS bidentate negative ligand, which coordinates to the metal through sulfur and amine nitrogen of the pyrazolone ring. The electronic results and the EPR of the complexes have been carefully studied in this (D3h) crystal field with a special emphasis on the energy levels. DNA-binding experiments have been conducted by UV spectroscopy and electrochemistry. The results reveal an interaction between the complexes and DNA and suggest an intercalative binding mode. UV titrations allowed determination of the binding constants Kb and revealed that the nickel(II) complex binds more strongly.

The first example of an unusual rearrangement in the van Leusen imidazole synthesis

The synthesis of an 1,4-disubstituted 5-methylimidazole is reported by reacting toluenesulfonylmethyl isocyanide with an enaminic tautomeric form of a secondary ketimine in the presence of catalytic amounts of bismuth(III) triflate. A possible mechanism involving a tosyl substitution on the imidazoline intermediate is proposed. This work represents a novel application for the versatile reagent toluenesulfonylmethyl isocyanide that expands its use to the preparation of imidazole starting from ketimine compounds.