Recent advances in heterogeneous catalysts for the synthesis of imidazole derivatives

Among the bioactive heterocyclic frameworks, nitrogen containing multisubstituted imidazoles are versatile building blocks of many naturally occurring products. Imidazoles possess wide range of biological properties including anticancer, anti-inflammatory, antimicrobial, and antihypertensive activities with potential applications in other sectors. Multicomponent reactions in combination with heterogeneous catalysts and nanocomposites have contributed significantly to organic synthesis in general and imidazoles, in particular with high functional group tolerance. Owing to their tunable properties, lower operational cost, thermal stability, recyclability, and easily separation from products, heterogeneous catalysts and nanocomposites are integral part of numerous pharmaceutical, agrochemical, and industrial processes. There has been increased focus on the development of green and sustainable catalytic procedures for the building of novel and biologically potent imidazole conjugates. This article emphasizes the recent advances in recyclable catalysts and protocols, and their merits for the synthesis of diverse multisubstituted imidazole conjugates by one-pot reaction approach and the catalyst and reactant interactions.     

Vanadyl(IV) Acetate: An Efficient,Reusable Heterogenous Catalyst for Aza-Michael Reaction Under Solvent-Free Conditions

Vanadyl(IV) acetate [VO(OAc)₂] efficiently catalyzes the conjugate addition of aliphatic, aromatic amines to α,β-unsaturated carbonyl compounds in solvent-free media at room temperature to afford corresponding amino compounds in good to excellent yields. The catalyst can be recovered and reused for further cycles.     

Zeolite H‐Y–Supported Copper(II) Nitrate: A Simple and Effective Solid‐Supported Reagent for Nitration of Phenols and Their Derivatives

Highly regiospecific mononitration of phenols and substituted phenols is accomplished by employing copper(II) nitrate supported on a catalytic amount of zeolite H‐Y in a solid state.     

Computational basis for the design of PLK-2 inhibitors

Structural Chemistry - PLK-2 is a serine/threonine protein kinase and plays a crucial role in cell cycle regulation; due to its pivotal function, this enzyme is approved as cancer drug target. We...     

Synthesis,characterization of novel quinoline-2-carboxamide based chalcone derivatives and their molecular docking,photochemical studies

Abstract

Novel series of quinoline-2-carboxamide based chalcone derivatives (5a–g) have synthesized and characterized using ¹H-NMR, 13C-NMR, Mass, and elemental analysis. In-silico molecular docking studies exhibited that synthesized compounds 5a and 5g are good binding energy (?8.46?kcal and ?9.46?kcal) toward the essential requirements of targeted compounds for EGFR receptor-bearing quinazoline inhibitor (PDB ID: 1M17(Lapitinib)). UV-Vis and fluorescence spectroscopy measurements provided a significant effect on the absorption, emission cyclic voltammetry (CV), and highest occupied molecular orbital (HOMO). Lowest unoccupied molecular orbital (LUMO) values of compound 5g are also confirmed band along with intramolecular charge transfer character (D-π-A). The red shift maxima (510?nm) the emission spectra in various solvents with increasing solvent polarity.     

Natural abundance nitrogen-15 nuclear magnetic resonance spectral studies on selected donors

The natural abundance 15N-NMR chemical shifts of selected aliphatic amines, 2-substituted pyridine type compounds, bialicyclic tertiary amines have been measured as a function of the nature of the solvent. In the case of cyclic aliphatic amines, like piperidine, morpholine, piperazine, thiomorpholine, the nitrogen is more shielded in concentrated solution compared to that in dilute solution whereas in the hydrogen bonding and protonating solvents there is a prominent deshielding. 2-Substituted pyridines studied can be further divided into four sub groups. The site of hydrogen bonding and protonation in 2-amino, 2-hydroxy and 2-mercapto pyridines have been conclusively proved from the 15N-NMR chemical shifts and the well-known tautomeric forms of the above compounds. Similarly in the case of 2-(2-thienyl)pyridine and 2-(3-thienyl)pyridine, the site of donation has been proved as the nitrogen of the pyridine ring in both the compounds. In a similar manner, the site of hydrogen bonding and protonation in two individual compounds 2-anilinopyridine and 2-(2-pyridyl)benzimidazole have also been established. Among the bialicyclic amines, 1,2-diazabicyclo[2.2.2]octane (DABCO) behaved differently from the other two compounds. In both 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), it was possible to show that N1-nitrogen in both the compounds is the site of donation. The effect of the second donor site on the 15N-NMR chemical shift, the site of donation in the selected compounds and some typical compounds reported in literature have been presented and discussed.     

Bounded sets of KKT multipliers in vector optimization

In this article we discuss the conditions required to guarantee the non-emptiness and the boundedness of certain subsets of the set of Lagrange multipliers for an inequality and equality constrained vector minimization problem.     

Ferrocene Decorated N-doped Carbon Modified Electrode with Enhanced Electrocatalytic Activity towards Non-enzymatic Glucose Detection

The nitrogen doped carbon (NDCN) have been synthesized by flame synthetic method to prepare ferrocene decorated NDCN. The hydrolysis product (FC-SH) of ferrocene benzyne derivative (FC-SAc) was immobilized onto NDCN modified GCE and used for glucose detection with high sensitivity. Cyclic voltammetric analysis reveal that FC-S-NDCN/GCE exhibit excellent activity for glucose oxidation when compared to FC/GCE. The FC-S-NDCN/GCE with wide linear responses range from 0.001 to 0.01 mM with the regression co-efficient of 0.998. The FC-S-NDCN/GCE show low detection limit (LOD) of 0.08 μM and exhibit sensitivity of 1580 μA mM⁻¹ cm⁻². The FC-S-NDCN glucose sensor exhibit wide linear range, high sensitivity and lower detection limit on determination of glucose.