Development of bioactive 2-substituted benzimidazole derivatives using an MnOx/HT nanocomposite catalyst

Benzimidazole is a vital moiety found in a wide range of naturally and pharmacologically active molecules. We prepared a proficient and facile manganese oxide-supported magnesium and aluminium-based nanocomposite catalytic framework using the deposition-precipitation method and characterised it with XRD, XPS, SEM, TEM, and TGA techniques. Following that, the catalyst was used in the green synthesis of highly functional 2-substituted benzimidazole derivatives in an ethanol-water solvent system at room temperature using various assorted benzaldehydes and o-phenylenediamine as substituents. The synthesised catalyst operates efficiently and is applicable to a wide range of electron-withdrawing and electron-donating substrates, resulting in good to excellent yields. The advantages of this process include the use of a greener solvent, high yield, high conversions, no use of additives or bases, a good TOF, and a shorter reaction time.

Copper nanoparticles catalyzed carbon–heteroatom bond formation and synthesis of related heterocycles by greener procedures

A variety of procedures for the carbon–nitrogen, carbon–oxygen, carbon–sulfur and carbon–selenium bond formation using copper nanoparticles in greener conditions have been highlighted. The synthesis of several heterocyclic compounds of biological importance has also been reported using these protocols.

Al2O3/CuI/PANI nanocomposite catalyzed green synthesis of biologically active 2-substituted benzimidazole derivatives

This work is generally focused on the synthesis of an efficient, reusable and novel heterogeneous Al2O3/CuI/PANI nanocatalyst, which has been well synthesized by a simple self-assembly approach where aniline is oxidized into PANI and aniline in the presence of KI also acts as a reductant. The nanocatalyst was well characterized by XRD, FTIR, SEM, EDX, TEM, BET and XPS techniques. In this study, the fabricated material was employed for the catalytic one-pot synthesis of 2-substituted benzimidazoles via condensation between o-phenylenediamine and aldehydes in ethanol as a green solvent. The present method is facile and offers several advantages such as high % yield, less reaction time, and no use of additive/bases. Also, the catalyst showed better values of green metrics including low E-factor: 0.17, high reaction mass efficiency: 85.34%, high carbon efficiency: 94%, and high process mass intensity: 1.17.

Metal–organic framework mediated expeditious synthesis of benzimidazole and benzothiazole derivatives through an oxidative cyclization pathway

Herein, we report facile synthesis of various benzimidazoles and benzothiazoles by using the NH₂-MIL-125(Ti) MOF as an efficient oxidant-free heterogeneous catalyst with good yield.

Extending the Hierarchy of Heterogeneous Catalysis to Substituted Derivatives of Benzimidazole Synthesis: Transition Metals Decorated CNTs

A simple and practical procedure has been adopted for one pot synthesis of benzimidazole derivatives under mild reaction conditions, starting from cinnamyl alcohol (COH) with bimetallic nanoparticles (BNPs) and supported bimetallic nanoparticles of Cu, Ti, Zn, Mn, Ag, and Co. All the catalysts were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), X-Ray Diffractometry (XRD), Brunauer Emmett-Teller (BET) surface area, and pore size analyzer. The products were identified/quantified with 1HNMR, FT-IR, and MS. 98% yield of substituted derivatives of benzimidazole was obtained with Cu–Ti supported on FMWCNTs in ethanol with excellent selectivity. Quantum chemical calculations of molecular reactivity of substituted cinnamaldehyde (CHO) and ortho phenylenediamine (OPD) have good consistency with experimental results. The returns of this work were the use of readily available catalysts, high yield, short reaction time, and simplicity of the process.

A nanoscopic icosahedral {Mo72Fe30} cluster catalyzes the aerobic synthesis of benzimidazoles

In this study, the catalytic efficiency of amorphous {Mo₇₂Fe₃₀} nanocapsules as a safe Keplerate polyoxometalate in organic synthesis was exploited. The easy-made solid catalyst exhibited high efficiency using a very low dosage (0.02–0.05 mol%) in the catalyzed condensation of various aromatic 1,2-diamines and aldehydes for the aerobic synthesis of benzimidazoles with very small E-factor values (0.11–0.33). The superior catalytic activity of amorphous nanoclusters compared to that of its crystalline counterpart was demonstrated. The high activity and recyclability of heterogeneous catalysts in a green reaction media under oxygen atmosphere, make this environmentally benign organic process appropriate for our applied goals.

Catalytic activity of amorphous {Mo₇₂Fe₃₀} nanoclusters as a safe Keplerate polyoxometalate in aerobic synthesis of benzimidazoles was described.

Efficient and Site-Specific 125I-Radioiodination of Bioactive Molecules Using Oxidative Condensation Reaction

In this report, the novel and site-specific radioiodination of biomolecules by using aryl diamine and alkyl aldehyde condensation reaction in the presence of a Cu²⁺ catalyst under ambient conditions was reported. ¹²⁵I-labeled alkyl aldehyde was synthesized using a tin precursor with a high radiochemical yield (72 ± 6%, n = 5) and radiochemical purity (>99%). The utility of the radioiodinated precursor was demonstrated through aryl diamine-installed c[RGDfK(C)] peptide and human serum albumin (HSA). Radioiodinated c[RGDfK(C)] peptide and HSA protein were synthesized with high radiochemical yields and purity. ¹²⁵I-HSA protein showed excellent in vivo stability and negligible thyroid uptake as compared with directly radioiodinated HSA by using the tyrosine group. Excellent reaction kinetics and the in vitro and in vivo stabilities of ¹²⁵I-labeled alkyl aldehyde have suggested the usefulness of the strategy for the radioiodination of bioactive molecules.

CuI nanoparticle-catalyzed synthesis of tetracyclic benzo[e]benzo[4,5]imidazo[1,2-c][1,3]thiazin-6-imine heterocycles by SNAr-type C-S, C-N bond formation from isothiocyanatobenzenes and benzimidazoles

In this paper, a simple and practical synthesis of benzo[e]benzo[4,5]imidazo[1,2-c][1,3]thiazin-6-imine tetracyclic heterocycles via a CuI nanoparticle-catalyzed intramolecular C(sp2)-S coupling reaction is presented. This strategy provides a straightforward method for synthesizing analogs of the anti-HIV drug 3,4-dihydro-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine (PD 404182). The reaction rate and yield were increased by employing CuI nanoparticles.

The synthesis of benzimidazoles via a recycled palladium catalysed hydrogen transfer under mild conditions

An efficient synthesis of benzimidazoles was developed by virtue of a recycled palladium catalyzed hydrogen transfer.