Zirconocene catalyzed synthesis of 2-substituted benzimidazole derivatives

Karhale, Shrikrishna; Patil, Kiran N.; Bhenki, Chandrakant; Rashinkar, Gajanan; Helavi, Vasant

doi:10.1007/s11164-016-2534-7

Cited by 18 publications

(5 citation statements)

References 48 publications

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“…The most popular route for synthesis of 2-substituted benzimidazoles contains the reaction of o-phenylenediamine with diverse aryl aldehydes. As a result, array of catalysts has been reported to catalyze this transformation using the aforementioned route [40][41][42][43][44][45][46][47][48]. However, there are notable challenges such as tedious synthetic methods, use of corrosive solvents, high reaction time, lack of simplicity in experimental procedure, and so on, are still viable to be overcome for further research particularly towards developing an adaptable protocol using robust heterogeneous catalyst.…”

Section: Determination Of Aciditymentioning

confidence: 99%

Cellulose-based surface-modified heterogeneously feasible novel solid acid catalyst to access bioactive heterocycles

Karhale,

Kadam

2023

Preprint

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Surface-modified cellulose-based heterogeneously active catalyst was prepared by covalent anchoring of chlorosulphonic acid on amino-functionalized cellulose (SA@Cell-AEPC). The structure of synthesized catalyst was confirmed by analytical methods such as FT-IR, FE-SEM, EDX, TGA and CP/MAS 13C-NMR spectroscopy. The catalytic effect was evaluated for the formation of oxygen and nitrogen heterocycles. Reusability, shorter reaction time, high conversion, wide substrate scope, easy work-up procedure are noteworthy measures of this synthetic route.

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Section: Determination Of Aciditymentioning

confidence: 99%

Cellulose-based surface-modified heterogeneously feasible novel solid acid catalyst to access bioactive heterocycles

Karhale,

Kadam

2023

Preprint

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“…Recently, Ru, 25 Mn, 26 Co, 27,32 Cu, 28 Zr, 29 Fe 30 and Ir 31 organometallic complexes have been used to catalyze the synthesis of benzimidazoles, and the recycle times of catalysts were increased obviously. That provided a new idea for designing catalysts to catalyze the synthesis of benzimidazoles.…”

Section: Introductionmentioning

confidence: 99%

CO2 Improved Synthesis of Benzimidazole with the Catalysis of a New Calcium 4-Amino-3-hydroxybenzoate

Gao¹,

Gao²,

Zhu³

et al. 2021

ACSi

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In this paper, we explored the synthesis of benzimidazole by the reaction of DMF and o-phenylenediamine. In the process of catalyst screening, we found that 4-amino-3-hydroxybenzoic acid, benzoic acid, and benzene-1,3,5-tricarboxylic acid could catalyze the reaction. Moreover, the calcium 4-amino-3-hydroxybenzoate and CO2 could more effectively catalyze the reaction, the synergistic effect of CO2 and 4-amino-3-hydroxybenzoic acid calcium salt can increase the yield of benzimidazole from 28% to 94%.

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“…Organometallic Lewis acids play an important role in green chemistry and sustainable development [4]. Recently, Cp 2 ZrCl 2 has been explored for the synthesis of carbonyl group transformation reactions [5], bis(indole)methanes [6], intramolecular coupling of alkyne, EtMgBr (ethylene or CO) [7], quinozolin-4(3H)ones [8], 1-amidoalkyl-2-naphthols [9], and benzimidazoles [10]. In addition, Cp 2 ZrCl 2 has also been employed for acetylation of phenols/ alcohols/amines [11], coupling of terminal alkynes, and intramolecular coupling of amines and alkynes.…”

Section: Introductionmentioning

confidence: 99%

Cp2ZrCl2: AN EFFICIENT CATALYST FOR MULTICOMPONENT SYNTHESIS OF CAROTENOID DEHYDROSQUALENE SYNTHASE INHIBITING PYRANO[2,3-d]PYRIMIDINEDIONES

Sonawane¹,

Sonawane

et al. 2019

Asian J Pharm Clin Res

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Objectives: The present protocol deals with zirconocene dichloride (Cp2ZrCl2) catalyzed synthesis of pyrano[2,3-d]pyrimidinediones through one-pot multicomponent reactions of aromatic aldehydes with malononitrile and barbituric acid at ambient temperature. All the synthesized compounds were characterized and evaluated for antibacterial, antifungal, and antioxidant activities. Furthermore, a molecular docking was carried out to reveal the atomic insights between synthesized compounds and carotenoid dehydrosqualene synthase (PDB ID: 3ACX). Methods: All the synthesized compounds were evaluated for their in vitro antimicrobial activity by diffusion method. Antioxidant activities such as 1,1-diphenyl-2-picrylhydrazyl and radical scavenging activity. A mixture of barbituric acid 1 (1 mmol), malononitrile 2 (1 mmol), benzaldehyde 3a (1 mmol), ethanol (5 mL), and Cp2ZrCl2 (5 mol %) was stirred at ambient temperature for specified time. After completion of reaction as indicated by thin-layer chromatography, the obtained crude product was filtered and purified by column chromatography on silica gel (Merck, 60–120 mesh) using ethyl acetate:pet. ether to afford pure product which was then characterized by spectroscopic methods such by FTIR, nuclear magnetic resonance (1H NMR), 13C NMR, and mass spectroscopy. Results: All the synthesized pyrano[2,3-d]pyrimidinediones were characterized by spectroscopic analysis. The results revealed that pyrano[2,3-d] pyrimidinediones (4 a-k) displayed the zone of inhibition in the range of 3–13 mm. The most active compound 4b displayed largest zone of inhibition of 13 mm for Escherichia coli (NCIM-2832) and 9 mm for Bacillus subtilis (NCIM-2635). The antifungal and antioxidant activity of all synthesized pyrano[2,3-d]pyrimidinediones (4a-k) showed moderate to good activity. Molecular docking studies suggest that pyrano[2,3-d]pyrimidinediones might inhibit the carotenoid dehydrosqualene synthase activity. Conclusion: All the synthesized pyrano[2,3-d]pyrimidinediones display moderate to good antibacterial, antifungal, and antioxidant activity. This molecular docking studies supported that pyrano[2,3-d]pyrimidinediones might inhibit the carotenoid dehydrosqualene synthase (PDB ID: 3ACX).

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Zirconocene catalyzed synthesis of 2-substituted benzimidazole derivatives

Cited by 18 publications

References 48 publications

Cellulose-based surface-modified heterogeneously feasible novel solid acid catalyst to access bioactive heterocycles

Cellulose-based surface-modified heterogeneously feasible novel solid acid catalyst to access bioactive heterocycles

CO2 Improved Synthesis of Benzimidazole with the Catalysis of a New Calcium 4-Amino-3-hydroxybenzoate

Cp2ZrCl2: AN EFFICIENT CATALYST FOR MULTICOMPONENT SYNTHESIS OF CAROTENOID DEHYDROSQUALENE SYNTHASE INHIBITING PYRANO[2,3-d]PYRIMIDINEDIONES

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