Oxindoles have been successfully α-alkylated under Cp*Co III catalysis by a vast array of secondary alcohols, including cyclic, acyclic, symmetrical, and unsymmetrical, to produce C-alkylated oxindoles. This protocol was also extended to the α-alkylation of N,N-dimethyl barbituric acid and benzyl cyanides. The kinetic profile and other preliminary mechanistic investigations suggest a first order reaction rate in oxindole and catalyst. A plausible catalytic cycle is proposed on the basis of the kinetic profile, of other preliminary mechanistic investigations and of previous mechanistic studies on similar transformations, while DFT calculations provide insight into the nature of the active species..
Herein, we demonstrate an efficient protocol for transfer hydrogenation of ketones using methanol as practical and useful liquid organic hydrogen carrier (LOHC) under Ir(III) catalysis. Various ketones, including electron‐rich/electron‐poor aromatic ketones, heteroaromatic and aliphatic ketones, have been efficiently reduced into their corresponding alcohols. Chemoselective reduction of ketones was established in the presence of various other reducible functional groups under mild conditions.
Sucrose chelated Bismuth ferrite (BiFeO 3 ) nanoparticles as a novel heterogeneous catalyst was synthesized by an auto combustion route. Different calcination temperatures (150°C, 450°C, 550°C, 650°C, 750°C and 850°C) have been employed to obtain single phased BiFeO 3 nanoparticles. The perovskite structure formation and disappearance of organic phase (sucrose) was obtained by Fourier transform infrared spectroscopy (FT-IR). Phase determination and structural characterization was carried out by powder X-ray diffraction (XRD). The magnetic properties were analyzed by vibrating sample magnetometer (VSM) whereas surface area/pore volume was obtained by Brunauer-Emmett-Teller (BET). Transmission electron microscope (TEM) analyzed the particles size and morphology. Thermal stability was investigated by thermogravimetric analysis (TGA) and determination of constituent elements was carried out by X-ray Photo-Electron Spectroscopy (XPS). Raman spectroscopy confirmed the perovskite structure of the synthesized materials. The BiFeO 3 nanoparticles so obtained were employed as heterogeneous catalyst for the synthesis of polyhydroquinoline derivatives. All the polyhydroquinoline derivatives were characterized by Fourier transform infrared spectroscopy (FT-IR) and Nuclear magnetic resonance spectroscopy ( 1 H NMR). For the very first time ever we have used BiFeO 3 as a recyclable magnetic nanocatalyst in the one-pot four component cyclization reaction of benzaldehyde, ethylacetoacetate/methylacetoacetate, dimedone/cyclohexane-1,3-dione, and ammonium acetate for the synthesis of polyhydroquinoline derivatives without solvent under refluxing conditions to provide excellent yields of products. BiFeO 3 nanocatalyst (without any functionalization/surface coatings) shows easy magnetic separation, recyclability, reusability along with excellent yield of polyhydroquinoline derivatives in an economic and benign way.
The described system offers a ideal, user-friendly protocol for the chemoselective homogeneous hydrogenation of α,β-unsaturated ketones at room temperature using methanol as liquid organic hydrogen carriers. Excellent yields were achieved...
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