Chemistry - Research Publications

Permanent URI for this collectionhttps://kr.cup.edu.in/handle/32116/37

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Author: search.filters.author.Borah, Biplob

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    Br�nsted acid catalyzed mechanochemical�domino multicomponent reactions by employing liquid assisted grindstone chemistry
    (Nature Research, 2023-01-25T00:00:00) Borah, Biplob; Swain, Sidhartha; Patat, Mihir; Kumar, Bhupender; Prajapat, Ketan Kumar; Biswas, Rathindranath; Vasantha, R.; Chowhan, L. Raju
    Here, we have demonstrated a metal-free energy-efficient mechanochemical approach for expedient access to a diverse set of 2-amino-3-cyano-aryl/heteroaryl-4H-chromenes, tetrahydrospiro[chromene-3,4?-indoline], 2,2?-aryl/heteroarylmethylene-bis(3-hydroxy-5,5-dimethylcyclohex-2-enone) as well as tetrahydro-1H-xanthen-1-one by employing the reactivity of 5,5-dimethylcyclohexane-1,3-dione/cyclohexane-1,3-dione with TsOH?H2O as Br�nsted acid catalyst under water-assisted grinding conditions at ambient temperature. The ability to accomplish multiple C�C, C=C, C�O, and C�N bonds from readily available starting materials via a domino multicomponent strategy in the absence of metal-catalyst as well as volatile organic solvents with an immediate reduction in the cost of the transformation without necessitates complex operational procedures, features the significant highlights of this approach. The excellent yield of the products, broad functional group tolerances, easy set-up, column-free, scalable synthesis with ultralow catalyst loading, short reaction time, waste-free, ligand-free, and toxic-free, are other notable advantages of this approach. The greenness and sustainability of the protocol were also established by demonstrating several green metrics parameters. � 2023, The Author(s).
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    Direct Michael addition/decarboxylation reaction catalyzed by a composite of copper ferrite nanoparticles immobilized on microcrystalline cellulose: an eco-friendly approach for constructing 3,4-dihydrocoumarin frameworks
    (Royal Society of Chemistry, 2022-10-27T00:00:00) Kumar, Bhupender; Borah, Biplob; Babu, J. Nagendra; Chowhan, L. Raju
    A composite of copper ferrite oxide nanoparticles immobilized on microcrystalline cellulose (CuFe2O4@MCC) was synthesized. The synthesized composite was characterized by FESEM with EDS-Mapping, TEM, P-XRD, TEM, and BET analysis and investigated for its catalytic activity toward Tandem Michael addition and decarboxylation of coumarin-3-carboxylic acid with cyclic 1,3-diketones to obtain novel 3,4-dihydrocoumarin derivatives. This protocol was established with wide substrate scope and significant yield. The significant characteristics of this methodology are mild reaction conditions, easy setup procedure, non-toxic, and cost-effectiveness. A gram-scale synthesis with low catalyst loading was also demonstrated. � 2022 The Royal Society of Chemistry.
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    Acetyl oxime/azirine 1, 3-dipole and strategy for the regioselective synthesis of polysubstituted pyrroles via [3 + 2] cycloaddition with alkyne utilizing Fe2O3@cellulose catalyst
    (Elsevier B.V., 2021-09-27T00:00:00) Dwivedi, Kartikey Dhar; Kumar, Bhupender; Reddy, Marri Sameer; Borah, Biplob; Nagendra Babu, J.; Chowhan, L. Raju
    Fe2O3@cellulose catalyzed regioselective [3 + 2] cycloaddition of acetyl oxime with alkynes via 2H?azirines intermediate generated in situ in an aqueous ethanolic medium is described. The methodology is highly regioselective for the synthesis of polysubstituted pyrroles in good yield. The products were isolated without using any column chromatography. The catalyst could be separated by using an external magnet and the recovered catalyst could be reused for four consecutive cycles with negligible loss in its catalytic activity. Broad functional group tolerance, mild reaction condition, easily accessible starting materials, utilization of green reaction medium, recyclability of the catalyst up to further reaction without affecting the outcome of the reaction, gram-scale synthesis are some of the salient features of this strategy. � 2021 The Author(s)