Bentonite Supported NiTiO3 Composite as Heterogeneous Catalyst for Synthesis 2,4-Disubstituted Benzo[4,5]imidazo[1,2-a]pyrimidine

被引：0
作者：
Periasamy Vinoth Kumar [1 ]
Selvaraj Mohana Roopan [1 ]
Gunabalan Madhumitha [1 ]
机构：
[1] Chemistry of Heterocycles and Natural Product Research Laboratory, Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Tamil Nadu, Vellore
来源：
Catalysis Letters | 2025年 / 155卷 / 5期
关键词：
Imidazo-pyrimidines; Microwave Synthesis; NiTiO[!sub]3[!/sub]/bentonite;
D O I：
10.1007/s10562-025-05016-6
中图分类号：
学科分类号：
摘要：
In this study, an eco-friendly synthesis of 2,4-disubstituted benzo [4,5]imidazo[1,2-a]pyrimidine analogs was developed using a microwave approach, utilizing Carissa edulis fruit extract stabilized NiTiO3 nanoparticles decorated with a bentonite clay (NiTiO3/bentonite) composite as an effective heterogeneous catalyst. A facile ultrasonication method was employed to prepare different loading of NiTiO3/bentonite composites (5%, 10%, 15%, 20%, and 25%). Owing to its high surface area and active sites the NiTiO3/bentonite composite was demonstrated to be an effective heterogeneous catalyst that provides high yields of 2,4-disubstituted benzo [4,5]imidazo[1,2-a]pyrimidine. The moderate surface area and active sites, chemical states, high thermal stability, and purity of the NiTiO3/bentonite composites were confirmed using BET, XPS, TGA, XRD, and FT-IR. FE-SEM and elemental mapping were performed. HR-TEM analysis revealed that the NiTiO3 nanoparticles had an aggregated spherical shape with an average particle size of 22 nm and a d-spacing of 0.21 nm. Various optimization parameters, including solvent, catalyst type, catalyst loading, temperature, microwave power was explored for synthesis of 2,4-disubstituted benzo [4,5]imidazo[1,2-a]pyrimidine. Mechanistic investigation reveals that initially, the aldehyde and ketone produce α, β-unsaturated ketone through Claisen-Schmidt condensation. Resulting intermediate reacts with 2-aminobenzimidazole followed by intramolecular cyclization and dehydrogenation process yielding the final product. The optimal NiTiO3/bentonite catalyst achieved up to 94% yield with high turnover number and turnover frequency. Remarkably, the prepared heterogenous catalyst shows high catalytic activity, offering excellent yields even after six recycling cycles. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2025.
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  • [1] Goel R., Luxami V., Paul K., Recent advances in development of imidazo[1,2-a]pyrazines: synthesis, reactivity and their biological applications, Org Biomol Chem, 13, pp. 3525-3555, (2015)
  • [2] Olszewski T.K., Boduszek B., Synthesis of new thiazole-2, -4, and– 5-yl-(amino)methylphosphonates and phosphinates: unprecedented cleavage of thiazole-2 derivatives under acidic conditions, Tetrahedron, 66, pp. 8661-8666, (2010)
  • [3] Kerru N., Bhaskaruni S.V.H.S., Gummidi L., Et al., Recent advances in heterogeneous catalysts for the synthesis of imidazole derivatives, Synth Commun, 49, pp. 2437-2459, (2019)
  • [4] Butler A.J.E., Thompson M.J., Maydom P.J., Et al., Regioselective synthesis of 3-aminoimidazo[1,2-a]-pyrimidines under continuous flow conditions, J Org Chem, 79, pp. 10196-10202, (2014)
  • [5] Damont A., Medran-Navarrete V., Cacheux F., Et al., Novel pyrazolo[1,5-a]pyrimidines as translocator protein 18 kda (TSPO) ligands: synthesis, in vitro biological evaluation, [18 F]-labeling, and in vivo neuroinflammation PET images, J Med Chem, 58, pp. 7449-7464, (2015)
  • [6] Cherukupalli S., Karpoormath R., Chandrasekaran B., Et al., An insight on synthetic and medicinal aspects of pyrazolo[1,5-a]pyrimidine scaffold, Eur J Med Chem, 126, pp. 298-352, (2017)
  • [7] Tully W.R., Gardner C.R., Gillespie R.J., Westwood R., 2-(Oxadiazolyl)- and 2-(thiazolyl)imidazo[1,2-a]pyrimidines as agonists and inverse agonists at benzodiazepine receptors, J Med Chem, 34, pp. 2060-2067, (1991)
  • [8] Goel R., Luxami V., Paul K., Synthetic approaches and functionalizations of imidazo[1,2-a]pyrimidines: an overview of the decade, RSC Adv, 5, pp. 81608-81637, (2015)
  • [9] Humphries A.C., Gancia E., Gilligan M.T., Et al., 8-Fluoroimidazo[1,2-a]pyridine: synthesis, physicochemical properties and evaluation as a bioisosteric replacement for imidazo[1,2-a]pyrimidine in an allosteric modulator ligand of the GABAA receptor, Bioorg Med Chem Lett, 16, pp. 1518-1522, (2006)
  • [10] Shaaban M.R., Saleh T.S., Mayhoub A.S., Farag A.M., Single step synthesis of new fused pyrimidine derivatives and their evaluation as potent Aurora-A kinase inhibitors, Eur J Med Chem, 46, pp. 3690-3695, (2011)
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