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A cost-effective and step-economic synthesis of pharmaceutically important 1,2-disubstituted benzimidazoles and 2,3-dihydro-1H-perimidine derivatives is accomplished without the assistance of external ligands. An environmentally friendly biogenic strategy for the synthesis of single phase δ-MnO2 NPs using the Pongamia pinnata leaf extract was adopted. The phytochemicals detected in the extract of Pongamia pinnata leaves might be responsible for the reduction of Mn(VII) to Mn(IV), which provides stability to the metal centre. The synthesized catalyst was tested for the synthesis of pharmaceutically important benzimidazole and perimidine analogues. In addition, mechanistic experiments and the plausible mechanism were discussed. The δ-MnO2 NP catalyst exhibited superior catalytic activity and high durability in the dye removal study. [ABSTRACT FROM AUTHOR]

The sustainable and environmentally benign biogenic synthesis of manganese‐oxide nanoparticles (MnO2 NPs) in a single crystalline δ‐phase and its subsequent synthetic utility have been described. The synthesized δ‐MnO2 NPs were characterized using scanning electron microscopy (SEM), energy dispersive X‐ray (EDX), and X‐ray diffraction (XRD) analysis techniques. The detailed analysis envisages the reduction of Mn(VII) to Mn(IV) was facilitated by various phytochemicals present in the aq. mango leaves extract, avoiding the use of external ligand source. The synthesized δ‐MnO2 NPs were perceived in a single delta (δ) monoclinic crystalline phase, wherein a spherical agglomerated morphology was displayed with a particle size of <5 nm. Further, the utility of newly developed δ‐MnO2 NPs was showcased for alpha‐keto‐alkylation and quinoline synthesis via hydrogen autotransfer and the acceptorless dehydrogenative coupling strategy. Moreover, a series of control experiments, mechanistic elucidation, catalyst recyclability, and a dye removal study were demonstrated. [ABSTRACT FROM AUTHOR]

Environmentally amiable biogenic strategy for in‐situ one‐step synthesis of Pd‐NPs decorated on carbon nanotubes (CNTs) and its synthetic utility for C−H activation of benzamides to access isoquinolones has been reported for the first time. The phytochemicals present in Gliricidia sepium leaves extract was found to be serve as a reducing agent to reduce Pd (II) to Pd (0) and subsequently acts as a stabilizing agent. The formation of Pd@CNTs was confirmed by P‐XRD, FE‐SEM, EDX and ICP‐OES analysis technique with active Pd content 42.82 % w/w. In addition, DFT study of phytochemicals found in Gliricidia sepium leaves extract were conducted. The catalytic activity was showcased for the cost‐effective, step and atom economic synthesis of isoquinolones via C−H and N−H bond activation without the aid of external ligands. A series of isoquinolone derivatives were synthesized in good to excellent yields under air as a sole oxidant. In addition, catalyst recyclability and mechanistic experiments were deliberated. The Pd@CNTs unveiled superior catalytic activity and high durability towards hydrogen evolution reaction in acidic media. The Pd@CNTs attains the current density of 10 mA/cm2 at an over potential of 127 mV with a small Tafel slope of 41 mV/dec. [ABSTRACT FROM AUTHOR]

A sustainable and environmentally benign biogenic technique for one-step synthesis of Ni-NPs (NiC2O4·2H2O-NPs) using Portulaca oleracea (purslane) leaf extract has been disclosed for the first time. The phytochemicals found in Portulaca oleracea leaf extract were found to serve as a reducing agent and subsequently act as a stabilizing agent. The various analytical and spectroscopic techniques confirm the formation of Ni-NPs. The catalytic potential of Ni-NPs was investigated to achieve cost-effective, sustainable, atom and step economic synthesis of pharmaceutically important quinazoline, 2-aminoquinoline, and N-(alkyl amino) quinoline via hydrogen auto transfer and acceptorless dehydrogenative annulation without the aid of external ligand and additives. Importantly, the photophysical property studies of the synthesized N-heterocycles are deliberated and gram-scale synthesis was achieved. Moreover, catalyst recyclability, control experiments, and mechanistic elucidation were elaborated. [ABSTRACT FROM AUTHOR]

An eco-friendly green method for a one-step synthesis of palladium nanoparticles and their synthetic utility are reported. Phytochemicals like amines, alcohols, and phenols present in the Areca Nut Husk extract facilitate the reduction of Pd(II) to Pd(0). The phytochemicals serve as stabilising agents and ligands for palladium reduction and the need for an external ligand is avoided. The Field Emission Scanning Electron Microscopy and Transmission Electron Microscopy of newly synthesized palladium nanoparticles revealed a spherical morphology. The catalytic activity of the nanoparticles was tested for 1,2-difunctionalization of ynamides, Heck coupling, denitrogenative coupling of phenylhydrazine and C–H arylation of indole. Moreover, catalyst recyclability, control experiments, mechanistic elucidation, and gram-scale synthesis are elaborated. [ABSTRACT FROM AUTHOR]