An Efficient and Green Synthesis of Benzimidazole Derivatives Using SBA-15 Supported Cobalt Nanocatalysts

Abstract

Benzimidazole derivatives have attracted a significant attention in recent years because of their medicinal applications as antiviral, antiulcer, antifungal, antihypertensive, anticancer, and antihistamine compounds. The one-pot synthesis of benzimidazole derivatives via oxidative condensation of aromatic aldehydes with o-phenylenediamines under mild conditions was successfully accomplished using a cobalt(II) supported on mesoporous silica-type material. The supported cobalt catalyst could be easily recovered after reaction completion and reused seven times with an excellent durability and without any noticeable loss in activity. Graphical Abstract

Enhanced Catalytic Properties of Molybdenum Promoted Mesoporous Cobalt Oxide: Structure‐Surface‐Dependent Activity for Selective Synthesis of 2‐Substituted Benzimidazoles

“…Among these systems, the condensation reaction of o‐ phenylenediamines and aldehydes under oxidative condition turned out to be the most facile method to synthesize 2‐substituted and 1,2‐disubstituted benzimiazole derivatives. This method is preferred in terms of applications as a wide range of 2‐substituted benzimidazole derivatives could be obtained due to the availability of a high variety of aldehydes . However, these reactions require either stoichiometric amounts of hydrogen acceptors or strong bases in order to achieve efficient and selective benzimidazole yields, which has been an issue of high interest …”

“…This method is preferred in terms of applications as a wide range of 2-substituted benzimidazole derivatives could be obtained due to the availability of a high variety of aldehydes. [7] However, these reactions require either stoichiometric amounts of hydrogen acceptors or strong bases in order to achieve efficient and selective benzimidazole yields, which has been an issue of high interest. [8][9][10] An alternative protocol is the one-pot tandem synthesis from amines in the presence of a bifunctional catalyst, where amines are in situ oxidized to aldehydes followed by cyclocondensation with amine compounds.…”

Copper(II) Oxide Nanoparticles Impregnated on Melamine‐Modified UiO‐66‐NH2 Metal–Organic Framework for C–N Cross‐Coupling Reaction and Synthesis of 2‐Substituted Benzimidazoles

“…The performance of the catalyst for the synthesis of benzimidazoles was compared with results reported in the literature (Table S2) for homogeneous and heterogeneous catalytic systems. For example, the current catalytic system offered milder conditions in the reaction temperature and time (RT, 0.5 h) in comparison with the Co and Ni catalysts supported on SBA‐15 (60°C, 4 h) and MCM‐41 (90°C, 4 h), respectively. Although these inorganic porous materials (e.g.…”

“…Although these inorganic porous materials (e.g. SBA‐15 , MCM‐41 , zeolite , and alumina ) possess high thermal and mechanical stabilities, their preparations require soft or hard templates as structural‐directing agents to ensure the pore formation. Moreover, they are prepared via a multistep energy‐consuming process: solvothermal reaction (e.g.…”

Recent Trends in the Synthesis of Benzimidazoles From o‐Phenylenediamine via Nanoparticles and Green Strategies Using Transition Metal Catalysts

“…The reaction took 10-45 min under solvent-free conditions and gave 73-98% yield (Scheme 8, Table 3, entry 5) [38]. Contemporary, Co/SBA-15, a new nanocatalyst, was prepared and evaluated by Rajabi et al to synthesize these compounds in an eco-friendly manner [39]. The reaction was carried out by mixing reactants in ethanol at 60°C for 4 h in the presence of catalyst and atmospheric oxygen that gave the products in 85-98% yield (Scheme 8, Table 3, entry 6).…”