Synthesis and Pharmacological Evaluation of 4‐Aryloxyquinazoline Derivatives as Potential Cytotoxic Agents

In the present study, novel 4‐aryloxyquinazoline derivatives were synthesized and screened for in vitro cytotoxicity on human cancer cell lines at 10 μM. Some of the synthesized compounds displayed moderate to significant and selective cytotoxic activity against various leukemia, melanoma, ovarian, breast, and colon cancer cell lines. (E)‐3‐(3,4‐Dimethoxyphenyl)‐1‐(4‐(quinazolin‐4‐yloxy)phenyl)prop‐2‐en‐1‐one ( 9b ) was the most potent compound among all with an average growth inhibition of 70% against leukemia cancer cell lines. The compound also produced strong inhibition (75%) of colon cancer cell lines with 42.58% lethality of HCT‐116 cell line.     

Diversified Synthetic Strategies for Pyrroloindoles: An Overview

In current scenario, heterocyclic compounds' role in medicinal chemistry has been tremendously increased as they possess wide number of pharmacological activities. One of the common heterocycles include indole skeleton with well‐established biological significance in field of medicinal chemistry. Fusion of indole nucleus with pyrrole heterocycle constitutes pyrroloindole scaffold, which further modifies the existing properties of indole alone. Pyrroloindole is a privileged scaffold found in various types of bioactive entities including natural compounds and exhibits wide variety of pharmacological activities like muscle relaxant, antifungal, antitumor, and antibiotic. Therefore, it is considered as attractive template for drug discovery. From several years, numbers of synthetic strategies have been reported for the synthesis of pyrroloindole and its derivatives, including also natural compounds such as amauromine, yuremamine, and chimonanthines. Here, in this review, we have tried to compile various synthetic strategies of pyrroloindole and its derivatives.     

Palladium acetate and phosphine assisted synthesis of five-membered N-heterocycles

A wide variety of biological activities are possessed by oxygen, nitrogen, and sulfur heterocyclic compounds and much research has been performed for the synthesis of these heterocycles. The synthesis of heterocycles with the help of metal became highly rewarding and important method in organic synthesis. This review article concentrated on the synthesis of nitrogen containing five-membered heterocylces in the presence of palladium acetate and phosphine as a catalyst.     

Structural Engineering of Luminogens with High Emission Efficiency Both in Solution and in the Solid State

Developing molecules with high emission efficiency both in solution and the solid state is still a great challenge, since most organic luminogens are either aggregation‐caused quenching or aggregation‐induced emission molecules. This dilemma was overcome by integrating planar and distorted structures with long alkyl side chains to achieve DAπAD type emitters. A linear diphenyl–diacetylene core and the charge transfer effect ensure considerable planarity of these molecules in the excited state, allowing strong emission in dilute solution (quantum yield up to 98.2 %). On the other hand, intermolecular interactions of two distorted cyanostilbene units restrict molecular vibration and rotation, and long alkyl chains reduce the quenching effect of the π–π stacking to the excimer, eventually leading to strong emission in the solid state (quantum yield up to 60.7 %).     

Synthetic routes to seven and higher membered S-heterocycles by use of metal and nonmetal catalyzed reactions

Nitrogen, oxygen, and sulfur containing heterocycles have a wide range of biological activities. Metal and nonmetal catalysts are used in organic reactions with high activity. New strategies have been developed for the preparation of heterocycles in the last decades. The metal and nonmetal catalyzed synthesis of heterocycles is becoming an important and highly rewarding protocol in organic synthesis. In this review article, the synthesis of seven and higher-membered S-heterocycles is presented with the application of metal and nonmetal catalysts for the period from 1968 to 2018.     

Interactions of some peptides with sodium acetate and magnesium acetate in aqueous solutions at 298.15 K: A volumetric approach

The apparent molar volumes, V of diglycine, triglycine and glycyl-l-leucine have been determined in water and in aqueous sodium acetate (0.5, 1.0, 2.0, and 4.0 m_B) and magnesium acetate (0.5, 1.0, 1.5, and 2.0 m_B) solutions at 298.15 K by the measurement of densities using vibrating-tube digital densimeter. The partial molar volumes, V_2,m⁰ obtained from V have been used to calculate the partial molar volumes of transfer, Δ_trV_2,m⁰ for these peptides from water to aqueous solutions of sodium acetate (SA) and magnesium acetate (MA) solutions. The hydration numbers, n_H and volumetric interaction coefficients have also been calculated. The Δ_trV_2,m⁰ data suggest that ion-charged/or peptide group interactions of peptides are stronger with MA in comparison to SA.     

Effect of cation doping on low-temperature specific heat of LaMnO3 manganite

We have investigated the thermodynamic properties of perovskite manganite LaMnO₃, the parent compound of colossal magnetoresistive manganites, with the Ca²⁺ doping at the A-site. As strong electron-phonon interactions are present in these compounds, the lattice part of the specific heat deserves proper attention. We have described the temperature dependence of the lattice contribution to the specific heat at constant volume (C_v(lattice)) of La_1−xCa_xMnO₃ (x=0.125, 0.175, 0.25, 0.35, 0.50, 0.67, 0.75) as a function of temperature (1 K–20 K) by means of a rigid ion model (RIM).The trends of specific heat variations with temperature are almost similar at all the composition. The Debye temperatures obtained from the lattice contributions are found to be in somewhat closer agreement with the experimental data. The specific heat values revealed by using RIM are in closer agreement with the available experimental data, particularly at low temperatures for some concentrations (x) of La_1−xCa_xMnO₃. The theoretical results at higher temperatures can be improved by including the effects of the charge ordering, van der Waals attraction and anharmonicity in the framework of RIM.     

Synthesis,characterization and α‐amylase and α‐glucosidase inhibition studies of novel vanadyl chalcone complexes

A series of chalcone ligands and their corresponding vanadyl complexes of composition [VO (L^I–IV)₂(H₂O)₂]SO₄ (where L^I = 1,3‐Diphenylprop‐2‐en‐1‐one, L^II = 3‐(2‐Hydroxy‐phenyl)‐1‐phenyl‐propenone, L^III = 3‐(3‐Nitro‐phenyl)‐1‐phenyl‐propenone, L^IV = 3‐(4‐Methoxy‐phenyl)‐1‐phenyl‐propenone) have been synthesized and characterized using various spectroscopic (Fourier‐transform infrared, electrospray ionization mass, nuclear magnetic resonance, electron paramagnetic resonance, thermogravimetric analysis, vibrating sample magnetometer) and physico‐analytic techniques. Antidiabetic activities of synthesized complexes along with chalcones were evaluated by performing in vitro and in silico α‐amylase and α‐glucosidase inhibition studies. The obtained results displayed moderate to significant inhibition activity against both the enzymes by vanadyl chalcone complexes. The most potent complexes were further investigated for the enzyme kinetic studies and displayed the mixed inhibition for both the enzymes. Further, antioxidant activity of vanadyl chalcone complexes was evaluated for their efficiency to release oxidative stress using 2,2‐diphenyl‐1‐picryl‐hydrazyl‐hydrate assay, and two complexes (Complexes 2 and 4 ) have demonstrated remarkable antioxidant activity. All the complexes were found to possess promising antidiabetic and antioxidant potential.     

Singlet Fission in Carbene-Derived Diradicaloids

Herein, we present a new class of singlet fission (SF) materials based on diradicaloids of carbene scaffolds, namely cyclic (alkyl)(amino)carbenes (CAACs). Our modular approach allows the tuning of two key SF criteria: the steric factor and the diradical character. In turn, we modified the energy landscapes of excited states in a systematic manner to accommodate the needs for SF. We report the first example of intermolecular SF in solution by dimer self-assembly at cryogenic temperatures.