Chhanda Mukhopadhyay

Bio: Chhanda Mukhopadhyay is an academic researcher from University of Calcutta. The author has contributed to research in topics: Catalysis & Chemistry. The author has an hindex of 25, co-authored 187 publications receiving 2361 citations. Previous affiliations of Chhanda Mukhopadhyay include University of Texas MD Anderson Cancer Center & Indian National Association.

Heterogeneous ditopic ZnFe2O4 catalyzed synthesis of 4H-pyrans: further conversion to 1,4-DHPs and report of functional group interconversion from amide to ester

Abstract: Highly stable, environmentally benign ZnFe2O4 nanopowder was prepared, characterized and applied in the one-pot, three-component synthesis of 4H-pyrans in water. The ZnFe2O4 catalyst provides both acidic (Fe3+) and basic functionalities (O2−) as the reaction requires. The advantages of this method lie in its simplicity, cost effectiveness, environmental friendliness and easier scaling up for large scale synthesis. Water was exploited both as a reaction medium as well as a medium for synthesis of the catalyst. Moreover, water was the only byproduct. The present report puts forward an application of 4H-pyrans for the synthesis of 1,4-DHPs. This is the first attempt towards the synthesis of 4H-pyran-3-carboxylate from 4H-pyran-3-carboxamide. The corresponding functional group interconversion from amide to ester is rare in organic synthesis.

A facile reduction of aromatic nitro compounds to aromatic amines by samarium and iodine

Abstract: A simple method for the reduction of aromatic nitro compounds to aromatic amines was developed using samarium and catalytic amounts of iodine.

PEG-mediated catalyst-free expeditious synthesis of 2-substituted benzimidazoles and bis-benzimidazoles under solvent-less conditions

Abstract: A wide variety of 2-substituted benzimidazoles and bis-benzimidazoles were synthesized in high yields by PEG-mediated catalyst-free synthesis under solvent-less conditions. The products were directly recrystallized from hot methanol. The reaction occurred giving excellent yields with low as well as high molecular weight PEGs.

Microwave-induced bismuth nitrate-catalyzed synthesis of dihydropyrimidones via Biginelli condensation under solventless conditions

Abstract: Microwave-induced bismuth nitrate-catalyzed efficient and extremely rapid synthesis of 4-aryl-3,4-dihydropyrimidones via Biginelli condensation reaction has been developed in excellent yield.

Room temperature synthesis of tri-, tetrasubstituted imidazoles and bis-analogues by mercaptopropylsilica (MPS) in aqueous methanol: application to the synthesis of the drug trifenagrel

Abstract: The heterogeneous solid catalyst, mercaptopropylsilica (MPS), has been prepared by a modified procedure in water and its structure confirmed by solid state carbon-13 CP-MAS NMR spectrum. This catalyst has been efficiently utilized for the synthesis of a wide variety of tri-, tetrasubstituted imidazoles and their bis-analogues at room temperature. The protocol was further explored for the synthesis of the drug trifenagrel.

Protic Ionic Liquids: Evolving Structure–Property Relationships and Expanding Applications

Abstract: The thermal and physicochemical properties of protic ionic liquids (PILs) are reported. It is highly evident that there has been an extensive range of alkylammonium, imidazolium, and heterocyclic cations paired with many organic and inorganic anions that have been employed to prepare PILs. There has been strong interest in modifying the properties of PILs through the addition of water or other molecular solvents. For many applications, the presence of some water in the PILs is not detrimental, and instead leads to enhanced solvent properties such as lower viscosity, higher conductivities, and lower melting points. It remains an issue of definition though of how to refer to these resulting protic solutions. There is also an ongoing difficulty surrounding how to describe the proton activity in the PILs, analogous to pH in aqueous systems. For a broad range of applications, it has been reported that the acidity/basicity of the PIL or PIL-solvent system is crucial for their beneficial properties. It is expected that the fundamental properties of PILs will continue to be explored, along with continued interest in many existing and new applications, such as in electrochemistry, organic and inorganic synthesis, and biological applications. In particular, there has been a significant interest in a broad- range of PILs for use as electrolytes and incorporation in polymer electrolytes for fuel cells, and other energy storage devices.

Nonclassical Routes for Amide Bond Formation

Abstract: The present review offers an overview of nonclassical (e.g., with no pre- or in situ activation of a carboxylic acid partner) approaches for the construction of amide bonds. The review aims to comprehensively discuss relevant work, which was mainly done in the field in the last 20 years. Organization of the data follows a subdivision according to substrate classes: catalytic direct formation of amides from carboxylic and amines (section 2); the use of carboxylic acid surrogates (section 3); and the use of amine surrogates (section 4). The ligation strategies (NCL, Staudinger, KAHA, KATs, etc.) that could involve both carboxylic acid and amine surrogates are treated separately in section 5.

Solvent-free heterocyclic synthesis.

Abstract: 6.1. Oxadiazoles 4154 6.2. Diazaphospholes 4154 7. Six-Membered Heterocycles with One Heteroatom 4155 7.1. Pyridines 4155 7.2. Pyridinones 4155 7.3. Quinolines 4156 7.4. Quinolinones 4157 7.5. Isoquinolines 4157 7.6. Acridines 4158 7.7. Pyranones 4158 7.8. Flavones 4159 8. Six-Membered Heterocycles with Two Heteroatoms 4159 8.1. Pyridazinones 4159 8.2. Pyrimidines 4159 8.3. Pyrimidinones 4160 8.4. Quinazolines 4162 8.5. Quinazolinones 4162 8.6. Quinoxalines 4164 8.7. Quinoxalinediones 4165 8.8. Oxazines 4165 8.9. Oxazinones 4166 8.10. Thiazines 4166 9. Six-Membered Heterocycles with Three Heteroatoms 4166

Recent advances in the synthesis of pyrroles by multicomponent reactions

Abstract: Pyrrole is one of the most important one-ring heterocycles. The ready availability of suitably substituted and functionalized pyrrole derivatives is essential for the progress of many branches of science, including biology and materials science. Access to this key heterocycle by multicomponent routes is particularly attractive in terms of synthetic efficiency, and also from the environmental point of view. We update here our previous review on this topic by describing the progress made in this area in the period between mid-2009 and the end of 2013.