Sourav Jana

Catalyst-free selenylation of imidazoheterocycles

A simple, efficient, and practical method for the phenylselenylation of imidazo[1,2-a]pyridines via electrophilic substitution employing readily available phenylselenium bromide has been developed in aqueous media at room temperature. A library of 3-phenylselenylimidazo[1,2-a]pyridines has been synthesized employing this methodology with high yields. The present protocol is also applicable for the phenylselenylation of imidazo[2,1-b]thiazole and benzo[d]imidazo[2,1-b]thiazole.

(Diacetoxy)iodobenzene-Mediated Oxidative C–H Amination of Imidazopyridines at Ambient Temperature

(Diacetoxy)iodobenzene (PIDA)-mediated direct oxidative C-H amination for the synthesis of 3-amino substituted imidazopyridines has been achieved under metal-free conditions at room temperature in short reaction times. This methodology is also applicable for the regioselective amination of indolizines. Experimental results suggest that the reaction likely proceeds through a radical pathway.

Copper-Catalyzed Regioselective Synthesis of Multisubstituted Furans by Coupling between Ketones and Aromatic Olefins

A regioselective synthesis of multisubstituted furan derivatives has been developed via Cu(II)-catalyzed intermolecular annulation of aryl ketones with a wide range of aromatic olefins under ambient air in good yields. This protocol is applicable to both cyclic and acyclic aryl ketones.

Visible Light Organic Photoredox-Catalyzed C–H Alkoxylation of Imidazopyridine with Alcohol

The visible light-mediated C-3 alkoxylation of imidazopyridines with alcohols has been achieved using rose bengal as an organic photoredox catalyst at room temperature. Widely abundant air acts as the terminal oxidant that avoids the use of a stoichiometric amount of peroxo compounds. A wide range of functional groups could be tolerated under the reaction conditions to produce C(sp2)-H alkoxylated products in high yields.

Metal-free C–H arylation of imidazoheterocycles with aryl hydrazines

A simple and efficient metal-free arylation of imidazo[1,2-a]pyridines at the C-3 position with arylhydrazine has been achieved at room temperature under ambient air conditions. Various 2,3-disubstituted imidazopyridines and imidazothiazoles were synthesized with high yields. The present methodology demonstrates the usefulness of commercially available aryl hydrazine as an arylating agent.

tert-Butyl nitrite mediated azo coupling between anilines and imidazoheterocycles

A tBuONO mediated practical and efficient method for the synthesis of azo imidazoheterocycles with broad functionalities has been achieved by the reaction between imidazoheterocycles and anilines at room temperature in goods yields. Azo indolizines were also prepared by employing this methodology. Mild reaction conditions, tolerance of wide functionalities, operational simplicity and easy purification of the products are the notable advantages of the current protocol.

Determination of vertical ionization potential of nitroso-benzoimidazothiazole using charge transfer interaction with a series of acceptors

This is the first report of UV-Vis spectral investigations of electron donor-acceptor complexes of bio active 3-Nitroso-2-phenylbenzo[d]imidazo[2,1-b]thiazole (BIT1) with chloranils, nitrobenzenes and fullerenes in DMSO medium. Well defined charge transfer (CT) absorption bands in the visible region have been sited. Oscillator strengths, transition dipole and resonance energies of the CT complexes have been estimated. Utilizing Mullikens equation vertical ionization potential of BIT1 has been determined. A possible mechanism for the interaction between electronic subsystems of chloranils, nitrobenzenes, [60]- and [70] fullerenes with this benzoimidazothiazole compound (BIT1) have been discussed in comparing the parameters like degree of charge transfer and binding constant in polar DMSO. 1H NMR study helps to explain the mechanism well. Comparison of complexes is done with DFT/PW1PW91/6-31G* optimized gas phase geometries and FMO features of adducts.

Synthesis and characterization of host–guest inclusion complex of m -cresol with β -cyclodextrin

The host–guest inclusion complex of meta-cresol (m-cresol, liquid at room temperature, guest molecule) is synthesized with β-cyclodextrin (β-CD, host molecule). The inclusion complex is characterized by various techniques like nuclear magnetic resonance, powder X-ray diffraction, field emission scanning electron microscopy and spectroscopic (steady state as well as time-resolved) techniques. To the best of our knowledge, no literature data is available on the photophysical properties (especially fluorescence upon photoexcitation) of m-cresol in liquid media till date. Our spectroscopic studies exhibit some interesting photophysical properties of m-cresol and its inclusion complex with β-CD in different liquid media. The present work is important in view of the various potential applications of m-cresol in science, technology and medicine.