One-pot sequential multi-component reaction: Synthesis of 3-substituted indoles

Green synthesis of some 3-(α,α-diarylmethyl)indoles by bio-nanocomposite from embedding L-histidinium trichloroacetate ionic liquid on functionalized magnetite (L-His+CCl3CO2-@PEG@SiO2-nano Fe3O4)

In this research, a new multilayered magnetized bio-nanocomposite has been prepared. At first, the amino acid-based ionic liquid was obtained from L-histidine and trichloroacetic acid (L-His⁺CCl₃CO₂^-), embedded on the polyethylene glycol-functionalized silicated-nanomagnetite, to prepare the final nanostructure (L-His⁺CCl₃CO₂^-@PEG@SiO₂-nano Fe₃O₄). The bio-nanocomposite was characterized by several techniques such as FT-IR, FESEM, TGA/DTG, EDAX, TEM, VSM, and XRD. The catalytic activity of the core-shell nanostructure was examined in one-pot three-component reaction between aryl aldehydes, indoles, and β-naphthol/phenols to get some new 3-(α,α-diarylmethyl)indoles under solvent-free conditions at 75 °C. Eco-friendly protocol in the absence of hazardous solvents, no observation of by-products such as bis(indolyl)methanes (BIMs), in addition to recovery and reusability of the nanostructure within 3 runs without activity loss are some highlighted notable features of the work. The reused bio-nanocomposite was also characterized through FESEM technique.

Convenient Synthesis of Functionalized Cyclopropa[c]coumarin-1a-carboxylates

A simple method has been developed for the synthesis of cyclopropa[c]coumarins, which belong to the donor-acceptor cyclopropane family and, therefore, are promising substrates for the preparation of chromene-based fine chemicals. The method, based on the acetic acid-induced intramolecular transesterification of 2-arylcyclopropane-1,1-dicarboxylates, was found to be efficient for substrates containing hydroxy group directly attached to the aromatic ring.