Facile Synthesis of 1,2-Disubstituted Benzimidazoles Usingp-Toluenesulfonic Acid through Grinding
Method
摘要:
An efficient synthetic method for the highly selective synthesis of pharmacologically active 1,2-disubstituted benzimidazole derivatives fromo-phenylenediamine and various aromatic aldehydes catalyzed byp-toluenesulfonic acid through grinding under solvent-free condition is described. The reaction requires the catalyst only during the conversion of intermediateN,N '-dibenzylidene-o-phenylenediamine into the desired product. The products were obtained within a short time with good yields by using only a mortar and pestle, which makes the proposed method convenient and cost-effective.
Synthesis of functionalized benzimidazoles and quinoxalines catalyzed by sodium hexafluorophosphate bound Amberlite resin in aqueous medium
作者:Pranab Ghosh、Amitava Mandal
DOI:10.1016/j.tetlet.2012.09.045
日期:2012.11
for the selective synthesis of 1,2-disubstitutedbenzimidazoles and quinoxalines in water–methanol (1:1) mixture with the aid of resin bound hexafluorophosphate ion as catalyst is reported. The method is also effective for the incorporation of quinoxaline nucleus at the A ring of pentacyclic triterpenoid, friedelin. A plausible mechanism for the formation of disubstituted benzimidazole has also been suggested
Chitosan-supported Fe3O4 nanoparticles: a magnetically recyclable heterogeneous nanocatalyst for the syntheses of multifunctional benzimidazoles and benzodiazepines
作者:Ali Maleki、Nakisa Ghamari、Maryam Kamalzare
DOI:10.1039/c3ra47366j
日期:——
An environmentally benign and clean biopolymer-based heterogeneous nanocatalyst was prepared and its properties and morphology were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). Then, its catalytic activity was investigated in two important organic reactions. In these reactions, efficient and selective syntheses of 1,2-disubstituted benzimidazole and 1,5-benzodiazepine derivatives were carried out using 1,2-diamines and aldehydes or ketones in the presence of a catalytic amount of magnetically recoverable chitosan-supported iron oxide nanoparticles (Fe3O4/chitosan), as a biodegradable nanocomposite, in ethanol at ambient temperature in high yields. The Fe3O4/chitosan nanocatalyst can be recovered easily and reused without any significant loss of the catalytic activity.
ZrO<sub>2</sub>-β-cyclodextrin catalyzed synthesis of 2,4,5-trisubstituted imidazoles and 1,2-disubstituted benzimidazoles under solvent free conditions and evaluation of their antibacterial study
作者:Yarabhally R. Girish、Kothanahally S. Sharath Kumar、Kuntebommanahalli N. Thimmaiah、Kanchugarakoppal S. Rangappa、Sheena Shashikanth
DOI:10.1039/c5ra13891d
日期:——
A series of 2,4,5-trisubstituted imidazoles and 1,2-disubstituted benzimidazoles catalyzed by ZrO2-supported-β-cyclodextrin (ZrO2-β-CD) under solvent free conditions have been synthesized and characterized by spectral methods.
2-Substituted and 1,2-disubstited benzimidazoles were prepared efficiently from o -phenylenediamines and aryl aldehydes using p -toluenesulphonic acid (5 mol%)-on-silica gel as a cheap and environmentally benign catalyst.
2‐Aryl‐1‐arylmethyl‐1H‐benzimidazoles were prepared in excellent yields by the condensation of o‐phenylenediamine with aldehydes under mechanically activated solvent‐free conditions in ballmill using FeCl3·6H2O as the catalyst.