Sabari Ghosh

Direct amide bond formation from carboxylic acids and amines using activated alumina balls as a new, convenient, clean, reusable and low cost heterogeneous catalyst

For the first time, we have used activated alumina balls (3–5 mm diameter) for amide synthesis from carboxylic acids (unactivated) and amines (unactivated) under neat reaction conditions that produce no toxic by-products and has the advantages of being low-cost, easily available, heterogeneous, reusable and environmentally benign with no troublesome/hazardous disposal of the catalyst.

Synthesis of 2-alkyl substituted benzimidazoles under microwave irradiation: Anti-proliferative effect of some representative compounds on human histiocytic lymphoma cell U937

The objective of this research was the synthesis of 2-alkyl substituted benzimidazoles under microwave irradiation using 62% aqueous hexafluorophosphoric acid (10 mol%) as catalyst. Some of the newly synthesised compounds were tested for their potential to inhibit proliferation of cancer cells (histiocytic lymphoma cell U937) by cell viability assay.

Recognition of steric factor in external association of xanthenocrown-5 and bis-napthalenocrown-6 with bis(benzimidazolium)propane borontetrafluoride.

This is the first report of charge transfer band for crown-axel H-bonding interaction in acetonitrile medium. Monte Carlo simulation established external association of small cavity crown with BBIM-propane dication axels. Resonance energy, binding constant and ratiometric detection of association of xanthenocrown-5 (1) and bis-napthalenocrown-6 (2) with bis-(benzimidazolium)propane borontetrafluoride (3a-3d) in acetonitrile determined the effect of steric factor towards association.

The new threading system 2-benzyl-5,6-dimethyl-1H-benzo[d]imidazolium – dibenzo-24-crown-8: a model for Monte Carlo calculations incorporating an anion for the first time in threaded structures

A new [2]pseudorotaxane containing a benzimidazolium hydrogen-bonding station for a dibenzo-24-crown-8 (DB24C8) macrocycle is described. The structure of the [2]pseudorotaxane formed is established by 1H NMR spectroscopy, 2D NOESY and a Monte Carlo protocol (including an anion for the first time).