Efficient cascade C N coupling reactions catalyzed by a recyclable MoOx/Nb2O5 nanomaterial for valuable N-heterocycles synthesis

Singh, Nittan and Kalbande, Pavan Narayan and Umbarkar, Shubhangi and Sudarsanam, Putla (2022) Efficient cascade C N coupling reactions catalyzed by a recyclable MoOx/Nb2O5 nanomaterial for valuable N-heterocycles synthesis. Molecular Catalysis, 532. pp. 1-13. ISSN 2468-8231

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Abstract

The efficient cascade synthesis of pharmaceutically valuable N-heterocycles at solvent-free conditions was achieved using a robust, recyclable MoOx/Nb2O5 nanocatalyst. The results of catalyst screening revealed that the MoOx/Nb2O5 nanorods, calcined at 500 C (MoNb5), exhibit excellent catalytic activity in the oxidative coupling of benzylamine with 96.5% conversion and >99.6% selectivity to the desirable imine product. The uniform dispersion of Mo-oxide nanoparticles (average particle size: 5.2 ± 0.5 nm) on shape-controlled Nb2O5 nanorods (width: 5.3 ± 0.5 nm and length: 23–38 nm) in MoNb5 catalyst led to improved structural and acid properties, beneficial for the cascade C[sbnd]N bond construction. The shape-controlled MoNb5 catalyst showed versatile activity in various cascade C[sbnd]N coupling reactions to obtain 2-phenylbenzimidazole, 2-phenylquinaxoline, and 2-phenyl-2,3-dihydroquinazolin-4(1 h)-one with good to excellent yields at solvent-free conditions. The optimum ratio of Lewis/Brønsted acid sites, the unique structure of Nb2O5 nanorods, and the strong MoO3[sbnd]Nb2O5 interaction are the key reasons for the higher activity of MoNb5 catalyst. The efficient reusability of MoNb5 catalyst, its remarkable activity in diverse N-heterocycles synthesis, and efficient gram-scale synthesis emphasize its practical application for the cascade C[sbnd]N coupling reactions under benign conditions. © 2022 Elsevier B.V.

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IITH Creators:

IITH Creators	ORCiD
Sudarsanam, Putla	UNSPECIFIED

Item Type:

Article

Additional Information:

N.S. and P.N.K. acknowledge the Council of Scientific and Industrial Research (CSIR), New Delhi, for research fellowships.

Uncontrolled Keywords:

Acid sites optimization; Cascade C-N bond formation; Diverse nitrogenous chemicals; Heterogeneous nanosized catalyst; MoO3-Nb2O5 interaction; Nb2O5 nanorods

Subjects:

Chemistry

Divisions:

Department of Chemistry

Depositing User:

. LibTrainee 2021

Date Deposited:

28 Oct 2022 11:52

Last Modified:

28 Oct 2022 11:52

URI:

http://raiithold.iith.ac.in/id/eprint/11090