3878-23-7

Upstream product

• 95-54-5 1,2-diamino-benzene 
• 1003-29-8 2-pyrrole aldehyde 
• 88-74-4 2-nitro-aniline 
• 634-97-9 pyrrole-2-carboxyl acid 
• 28144-70-9 anthranilic acid amide 
• 1172625-18-1 2-(bromomethyl)-1H-pyrrole 

Downstream Products

• 73725-25-4 1-methyl-2-(2'-pyrrolyl)benzimidazole 

Relevant academic research and scientific papers

Bis(pyrrole-benzimidazole) conjugates as novel colorimetric sensor for anions

Abstract: Novel bis(pyrrole-benzimidazole) (PYBI) conjugates were investigated as colorimetric anion recognition motif by employing multiple donor sites. In this regard, PYBI derivatives where pyrrole unit is connected to the C2 position of benzimidazole via its α-position were synthesized and their anion recognition behavior were evaluated by UV-Vis, fluorescence and 1H NMR spectroscopy. PYBI selectively interacts with fluoride ion, whereas introduction of nitro group on the benzimidazole moiety enhances the binding affinity by at least one order, albeit at the expense of the selectivity. Bridging of two PYBIs led to interesting cooperative effect between the two subunits, which gets enhanced upon changing the spacer between the two from non-conjugating type (sp3-C) to conjugating one (quinoxaline). This also affects the way they interact with anions, with the latter moiety displaying very interesting stepwise double deprotonation of benzimidazole protons upon addition of fluoride ions with strong colorimetric as well as fluorometric response. Further, acidity of the H-bond donor sites was found to play pivotal role in the anion complexation mechanism and selectivity. Graphical abstract?: SYNOPSIS Novel bis(pyrrole-benzimidazole) (PYBI) conjugates where pyrrole units are connected to the C2 position of benzimidazole via its α-position were synthesized and their anion recognition behavior were evaluated. Anion selectivity and mode of interaction was found to depend on the nature of the substituent and the spacer between the two PYBI units. [Figure not available: see fulltext.].

Oxidative NHC catalysis for base-free synthesis of benzoxazinones and benzoazoles by thermal activated NHCs precursor ionic liquid catalyst using air as oxidant

A reusable thermal activated NHC precursor ionic liquid catalyst ([BMIm]2[WO4]) has been prepared and developed for the synthesis of nitrogen-containing heterocycles such as benzoxazinones and benzoazoles through imines activation. [BMIm]2[WO4] exhibited the good activity for the base-free condensation and oxidative NHC catalysis tandem under air atmosphere. The catalyst can be recovered and reused for at least five runs in gram scale synthesis without any decrease in catalytic activity. Furthermore, the control experiments demonstrated that the reaction involved formation of aromatic aldimines, NHC-catalyzed oxidative formation of imidoyl azoliums and intramolecular cyclization to generate the product.

Skin damages—Structure activity relationship of benzimidazole derivatives bearing a 5-membered ring system

In the search for scaffolds for multifunctional compounds we investigated the structure activity relationship of a class of benzimidazole derivatives bearing 5-membered ring. The newly synthesized and the already known compounds were divided into three cl

Metal-free selective synthesis of 2-substituted benzimidazoles catalyzed by Br?nsted acidic ionic liquid: Convenient access to one-pot synthesis of N-alkylated 1,2-disubstituted benzimidazoles

A novel efficient method for the selective synthesis of 2-substituted benzimidazoles is described through condensation reaction of o-phenylenediamines with a wide rang of aliphatic, aromatic and heteroaromatic aldehyde substrates using Br?nsted acidic ionic liquid as a reusable catalyst under metal-free conditions at ambient temperature. Notably, Dodecylimidazolium hydrogen sulfate ([DodecIm][HSO4]) is the most efficient catalyst for good to excellent yields of the corresponding products (up to 98%). Subsequently, this protocol was successfully applied for the preparation of N-alkylated 1,2-disubstituted benzimidazoles in high to excellent yields via sequential one-pot reaction. In addition, catalysts are recycled at least four times without significant loss in activity.

Revisiting the fluoride binding behaviour of dipyrrolylquinoxaline in aqueous medium: a copper ion mediated approach

An ion detection methodology employing synergistic interaction between copper(ii) ions and fluoride with 2,3-dipyrrol-2′-yl-quinoxaline (SR1) is investigated with a particular target to detect fluoride in an aqueous environment. The theme of this work simultaneously exploits the H-bonding and metal-ligand interactions of SR1 in the presence of fluoride and Cu(ii) ions in a DMSO/water mixture. The cooperative ion detection event in the presence of SR1 and fluoride reveals in situ reduction of Cu(ii) to Cu(i) species, which causes a sharp colorimetric change from green to red differentiable to the naked eye. The mechanism of the reaction is comprehensively investigated using UV-Vis, 1H NMR, 19F NMR, EPR spectroscopy and Differential Pulse Voltammetry (DPV) techniques, and is further justified by DFT study and subsequent NBO analysis. The limit of detection (LOD) is found to be 0.15 ppm, which is below the limit set by WHO for the fluoride content in drinking water. The real time application of the protocol is also tested in groundwater samples collected from a fluoride affected area and toothpaste samples.

Sulfonic-acid-functionalized activated carbon made from tea leaves as green catalyst for synthesis of 2-substituted benzimidazole and benzothiazole

Abstract: A simple and efficient procedure for synthesis of 2-substituted benzimidazole and benzothiazole has been developed by using sulfonic-acid-functionalized activated carbon as heterogeneous catalyst. The activated material was prepared from matured tea leaf in presence of phosphoric acid as activating agent. The final catalyst was prepared by anchoring –SO3H group on the surface of the activated carbon. The catalyst could be easily recovered and reused for more than three catalytic cycles without significant loss in catalytic activity. The catalytic performance of the catalyst was found to be superior to that of a similar catalyst prepared from montmorillonite K10. Graphical Abstract: [Figure not available: see fulltext.].

I2/TBHP promoted oxidative C–N bond formation at room temperature: Divergent access of 2-substituted benzimidazoles involving ring distortion

A new ‘one pot’ tandem synthesis of 2-substituted benzimidazoles has been developed from 2-aminobenzyl alcohol/2-aminobenzamide and different coupling partners (nitriles, aldehydes and 1,3-diketones) via iodine and TBHP promoted oxidative ring contraction. The present strategy involves sequential C–N bond formation, cyclization, subsequent ring contraction and dehydrogenation to afford various medicinally important benzimidazole derivatives in moderate to good yields. This operationally simple synthetic approach proceeds at room temperature under base-free condition, broadly applicable to a wide array of nitriles and aldehydes bearing oxidation prone functional groups and noteworthy to mention that various acyclic 1,3-diketones undergo selective C–C bond cleavage leading to 2-alkyl benzimidazoles under mild condition.

Direct conversion of alkyl halides into benzimidazoles using pyridine-N-oxide and 1,2-diaminobenzenes

Benzimidazole heterocycles were obtained from halogenated compounds and aromatic 1,2-diamines. A mild oxidizing reagent such as pyridine N-oxide (PyO) is required to produce the benzimidazole core. The method is solvent free and provides products without the need for chromatography. Good yields, moderate reaction temperature, fast reaction rates are important advantages of this procedure. {figure presented}.

Simple and efficient one-pot synthesis of 2-substituted benzimidazoles from θ-diaminoarene and aryl aldehydes

An easy and efficient one-pot condensation method for the synthesis of substituted benzimidazoles from θ-phenylenediamines with aryl aldehydes using urea hydrogen peroxide (UHP) and I2 in dimethylsulfoxide (DMSO) provides wide substrate scope with good to excellent yields and simple and quick isolation of the products.

DBSA mediated chemoselective synthesis of 2-substituted benzimidazoles in aqueous media

An efficient synthetic method has been developed for the facile synthesis of 2-substituted benzimidazoles in organized aqueous media in the presence of a surfactant (viz. DBSA) as catalyst and I2 as co-catalyst. The method described has the advantages of operational simplicity, excellent yields, high chemoselectivity, and clean and green reaction profile.