Synthèse et criblage antiplasmodial de quelques benzimidazolyl-chalcones

Une série d’hybrides de chalcones (6a-6g) associant le noyau benzimidazole et le groupement arylpropénone a été synthétisée par condensation entre des méthylcétones à support benzimidazole et des arylaldéhydes. L’analogue cyclohexénone (6h) a par ailleurs été préparé à l’aide de l’acétoacétate d’éthyle. Les structures chimiques des composés ont été déterminées par spectrométries RMN et de masse ESI. Leur criblage antiplasmodial vis-à-vis d’isolats de P. falciparum chloroquino-sensible et chloroquino-résistant montrent que la benzimidazolyl-chalcone est un excellent pharmacophore antiplasmodial. Les activités étaient paradoxalement toutes plus efficaces sur les isolats de P. falciparum chloroquino-résistants que chloroquinosensibles. Leur amélioration serait assujettie à l’introduction d’un chlore en C5 du benzimidazole et ne serait pas nécessairement liée, ni à la nature de l’azote pyrrolique du benzimidazole ni à la cyclisation de la propénone en cyclohexénone. La benzimidazolyl-chalcone (6e) avec une valeur de CI50 de 5,63 μM, avait le meilleur profil antiplasmodial sur l’isolat de P. falciparum chloroquino-sensible. Le composé 6f avec des valeurs de CI50 de 10,65 et 0,78 μM s’est révélé être la meilleure chalcone antiplasmodiale quel que soit le statut des isolats de P. falciparum. Ce dernier pourrait constituer une tête de série pour le développement de nouveaux agents antipaludiques.Mots clés : Benzimidazole, Chalcone, Activité antiplasmodiale, Chloroquino-résistance, Plasmodium falciparum

Etude théorique de la cyclocondensation [4+2] de N,N-diméthyl- N-(3-oxo-cyclohexe-1-enyl)-formamidine avec les 9H-carbazole 1,4-dione substitués et activés par le brome

Theoretical study of [4+2] cyclocondensation of N,N-dimethyl-N-(3-oxocyclohexe-1-enyl)-formamidine with substituted and bromo-activated 9Hcarbazole1,4-dioneA theoretical study of hetero-Diels-Alder reaction between N,N-diméthyl-N-(3-oxocyclohexe-1-enyl)-formamidine (aza-diene) and substituted 9H-carbazole-1,4-dione. This reaction is regioselective and is an effective method for synthesizing calothrixin B and its analogues. The rich-electron substituted dienophiles permit to acces to the major adducts. The theoretical results are consistent with experience

Inhibitive effects of 2-mercaptobenzimidazole (MBI) and 2-thiobenzylbenzimidazole (TBBI) on copper corrosion in 1 M nitric acid solution

The inhibitive actions of 2-mercaptobenzimidazole (MBI) and 2-thiobenzylbenzimidazole (TBBI) on copper corrosion in 1M HNO3 medium were studied, using weight loss method, at 25 to 65°C and concentrations of 5.10-5M to 10-3M. The results showed that the two compounds had fairly good inhibiting properties for copper corrosion in the medium, with efficiencies of 90.0% for TBBI and 87.7% for MBI at 25°C and concentration of 10-3M. Modified Langmuir isotherm was found to provide an accurate description of the behavior of the two compounds. The thermodynamic functions of adsorption (ΔG°ads,Qads) and the activation energy (Ea) were calculated. Negative values of changes in free energies were obtained, indicating the spontaneity of the adsorption process. From thermodynamic adsorption and dissolution functions, both physisorption and chemisorption were proposed. Quantum chemical parameters such as highest occupied molecular orbital energy (EHOMO), lowest unoccupied molecular orbital energy (ELUMO), energy gap (ΔE) and dipole moment (μ) were calculated for these compounds, using DFT/B3LYP/6-31G (d,p) method in order to discuss the correlation between theoretical data and experimental results. It was found that theoretical data support the experimental results.Key words: Corrosion Inhibitor, inhibition efficiency, adsorption isotherm, free adsorption energy, adsorption heat, theoretical calculation, dipole moment

Synthesis and anthelmintic activity of some hybrid Benzimidazolyl-chalcone derivatives

Purpose: To synthesize hybrid benzimidazolyl-chalcone derivatives, evaluate their anthelmintic activity, and establish some structural elements which could lead to induction and enhancement of this activity.Methods: A series of 1-(1H-benzimidazol-2-yl)-3-aryl-2-propen-1-one compounds (6a-z) was synthesized by condensation reaction of 2-acetylbenzimidazole with aryl and heteroaryl aldehyde derivatives. The physicochemical characterization of these benzimidazolyl-chalcones was carried out by nuclear magnetic resonance spectroscopy (1H and 13C NMR) and mass spectroscopy (MS). All compounds were screened in vitro for their nematicidal activity against Haemonchus contortus in larval development assay. The anthelmintic activities obtained were compared with those of anthelmintic reference drugs (fenbendazole and ivermectin); 1,3-diphenyl-2-propen-1-one also used as reference for chalcone.Results: Compounds 6a, 6g, 6w and 6y showed good nematicidal activity (LC100) at 0.002 and 0.0092 μg/ml. The activity of these four benzimidazolyl-chalcones is nearly equal to that of fenbendazole. It is also interesting to know that these compounds have anti-haemonchus activity which is equal or more efficient than ivermectin. Four other compounds (6d, 6h, 6o and 6t) possess interesting anthelmintic activities at 0.68 and 0.16 μg/ml.Conclusion: Preliminary structure-activity relationship studies revealed that arylpropenone group in position 2 of the benzimidazole ring can be considered as new pharmacophore for nematicidal activity.Keywords: Benzimidazole, Chalcone, Anthelmintic activity, Haemonchus contortu

1-(2-Methyl­imidazo[1,2-a]pyridin-3-yl)-3,3-bis­(methyl­sulfan­yl)prop-2-enone monohydrate

The title compound, C13H14N2OS2·H2O, appears in the form of bimolecular aggregate in which mol­ecular components are linked by O—H⋯N hydrogen bonding. The nine-membered imidazo[1,2-a]pyridine system is almost planar, with a mean deviation of 0.026 (1) Å. An intra­molecular C—H⋯O hydrogen bond forms within the imidazo[1,2-a]pyridine system. The crystal packing is consolidated by O—H⋯O and C—H⋯O hydrogen bonds, forming a supra­molecular structure consisting of perpendicular infinite mol­ecular chains running along the a and c axes

Synthesis of a calothrixin B isomer with a novel 7H-indolo[2,3-j]phenanthridine-7,13(8H)-dione structure

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