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1.
J Org Chem ; 89(13): 9666-9671, 2024 Jul 05.
Article in English | MEDLINE | ID: mdl-38877990

ABSTRACT

A cobalt catalyst, under oxidative conditions, facilitates the single electron transfer process in N-pyridyl arylacetamides to form α-carbon-centered radicals that readily react with molecular oxygen, giving access to mandelic acid derivatives. In contrast to the known benzylic hydroxylation approaches, this approach enables chemo- and regioselective hydroxylation at a benzylic position adjacent to (N-pyridyl)amides. Mild conditions, broad scope, excellent selectivity, and wide synthetic practicality set up the merit of the reaction.

2.
J Org Chem ; 88(21): 14847-14859, 2023 Nov 03.
Article in English | MEDLINE | ID: mdl-37867455

ABSTRACT

Herein, we report metal- and photocatalyst-free room-temperature amidation for α-ketoamide synthesis from feedstock phenacyl bromides and amines using molecular oxygen as an oxidant as well as a source of oxygen in the amide segment. Visible light-mediated base-promoted one-pot sequential C-N/C═N/C═O bond formation takes place in a tandem manner to afford the desired product. Functional group tolerance (benzylic alcohol, keto, cyano, nitro, halo, etc.), a broad substrate scope, and gram-scale synthesis make this synthetic methodology more attractive. We have observed that electron-rich aromatic amines, aliphatic amines, and phenacyl bromide derivatives proceeded the present transformation with marginally superior reactivity in comparison to electron-deficient aromatic amines and phenacyl bromide derivatives. Moreover, several control experiments, in situ isolation of secondary amine and imine as key intermediates, and 18O-labeling experiments provide complete insight into the mechanism of the tandem pathway.

4.
Environ Sci Pollut Res Int ; 29(5): 6698-6709, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34462857

ABSTRACT

Magnetite (Fe3O4) nanoparticles coated with dextrose and gluconic acid possessing both super-paramagnetism and excellent optical properties have been productively synthesized through a straightforward, efficient and cost-efficient hydrothermal reduction route using Fe3+ as sole metal precursor acquired from accumulated iron ore tailings-a mining waste that usually represents a major environmental threat. Fe3O4/C nanocomposites were fully elucidated by FEGSEM and TEM, revealing a combination of platelets (<1 µm) capped by particles (<10 nm) and magnetite which was verified by XPS, which demonstrated also oxygen deficiency. A dextrose/gluconic acid coating was elucidated by Fourier transform-infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA). The Fe3O4/C nanocomposites were found to be superparamagnetic at room temperature. Meanwhile, their optical properties were investigated by UV-visible diffuse reflectance spectroscopy (UV-vis DRS) and photoluminescence (PL) spectroscopy; an Eg of 1.86 eV was determined, and emissions at 612 and 650 nm (ex. 250 nm) were consistent with the XPS identification of oxygen vacancies. The efficacy of the as-synthesized magnetically recoverable magnetite/carbon (Fe3O4/C) nanocomposites has been exhibited in the photocatalytic degradation of the toxic textile (industrial) dye bodactive red BNC-BS.


Subject(s)
Ferrosoferric Oxide , Nanocomposites , Carbon , Catalysis , Iron , Light , Spectroscopy, Fourier Transform Infrared
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