scholarly journals Unprecedented Coumarin-Pyronin Hybrid Dyes: Synthesis, Fluorescence Properties and Theoretical Calculations

2021 ◽  
Author(s):  
Kevin Renault ◽  
Arnaud Chevalier ◽  
Jérôme Bignon ◽  
Denis Jacquemin ◽  
Jean-Alexandre Richard ◽  
...  
Keyword(s):  
Intramolecular Charge Transfer ◽  
Knoevenagel Condensation ◽  
Theoretical Calculations ◽  
A549 Cells ◽  
Hybrid Structures ◽  
Aryl Ether ◽  
Xanthene Dyes ◽  
Wide Range ◽  
Synthetic Routes ◽  
Nucleophilic Center

A novel class of rosamine dyes bearing a 7-substituted 4-hydroxycoumarin unit as <i>meso</i>-heteroaryl ring is presented. The latent <i>C</i>-nucleophilic character of 4-hydroxycoumarin derivatives (<i>i.e.</i>, their C-3 position as nucleophilic center) has been drawn on in the designing of two unprecedented synthetic routes towards these atypical xanthene dyes. They are based on an effective formal Knoevenagel condensation with either pyronin derivatives or a mixed bis-aryl ether bearing both an aldehyde and a masked phenylogous amine, possibly applicable to a wide range of latent cyclic <i>C</i>-nucleophiles. We also report experimental and theoretical photophysical investigations of these unique coumarin-pyronin hybrid structures and particularly their form low-lying quenching states, some of dark twisted intramolecular charge transfer (TICT) nature, depending on the medium (CHCl<sub>3</sub> and water). Furthermore, two fluorophore compounds <b>9</b> and <b>11</b> have been applied for imaging in paraformaldehyde-fixed A549 cells to gain insights into their permeation and localization.

scholarly journals Unprecedented Coumarin-Pyronin Hybrid Dyes: Synthesis, Fluorescence Properties and Theoretical Calculations

2021 ◽  
Author(s):  
Kevin Renault ◽  
Arnaud Chevalier ◽  
Jérôme Bignon ◽  
Denis Jacquemin ◽  
Jean-Alexandre Richard ◽  
...  
Keyword(s):  
Intramolecular Charge Transfer ◽  
Knoevenagel Condensation ◽  
Theoretical Calculations ◽  
A549 Cells ◽  
Hybrid Structures ◽  
Aryl Ether ◽  
Xanthene Dyes ◽  
Wide Range ◽  
Synthetic Routes ◽  
Nucleophilic Center

A novel class of rosamine dyes bearing a 7-substituted 4-hydroxycoumarin unit as <i>meso</i>-heteroaryl ring is presented. The latent <i>C</i>-nucleophilic character of 4-hydroxycoumarin derivatives (<i>i.e.</i>, their C-3 position as nucleophilic center) has been drawn on in the designing of two unprecedented synthetic routes towards these atypical xanthene dyes. They are based on an effective formal Knoevenagel condensation with either pyronin derivatives or a mixed bis-aryl ether bearing both an aldehyde and a masked phenylogous amine, possibly applicable to a wide range of latent cyclic <i>C</i>-nucleophiles. We also report experimental and theoretical photophysical investigations of these unique coumarin-pyronin hybrid structures and particularly their form low-lying quenching states, some of dark twisted intramolecular charge transfer (TICT) nature, depending on the medium (CHCl<sub>3</sub> and water). Furthermore, two fluorophore compounds <b>9</b> and <b>11</b> have been applied for imaging in paraformaldehyde-fixed A549 cells to gain insights into their permeation and localization.

scholarly journals Ring-Forming Polymerization toward Perfluorocyclobutyl and Ortho-Diynylarene-Derived Materials: From Synthesis to Practical Applications

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1486
Author(s):  
Eugene B. Caldona ◽  
Ernesto I. Borrego ◽  
Ketki E. Shelar ◽  
Karl M. Mukeba ◽  
Dennis W. Smith
Keyword(s):  
Chemical Resistance ◽  
Structural Features ◽  
Review Article ◽  
Aryl Ether ◽  
Aromatic Rings ◽  
Practical Applications ◽  
Repeat Units ◽  
Wide Range ◽  
Synthetic Routes ◽  
The Cost

Many desirable characteristics of polymers arise from the method of polymerization and structural features of their repeat units, which typically are responsible for the polymer’s performance at the cost of processability. While linear alternatives are popular, polymers composed of cyclic repeat units across their backbones have generally been shown to exhibit higher optical transparency, lower water absorption, and higher glass transition temperatures. These specifically include polymers built with either substituted alicyclic structures or aromatic rings, or both. In this review article, we highlight two useful ring-forming polymer groups, perfluorocyclobutyl (PFCB) aryl ether polymers and ortho-diynylarene- (ODA) based thermosets, both demonstrating outstanding thermal stability, chemical resistance, mechanical integrity, and improved processability. Different synthetic routes (with emphasis on ring-forming polymerization) and properties for these polymers are discussed, followed by their relevant applications in a wide range of aspects.

Temperature Dependent Green Synthesis of 3-Carboxycoumarins and 3,4-unsubstituted Coumarins

2019 ◽  
Vol 16 (1) ◽  
pp. 130-135 ◽  
Author(s):  
Jack van Schijndel ◽  
Dennis Molendijk ◽  
Luiz Alberto Canalle ◽  
Erik Theodorus Rump ◽  
Jan Meuldijk
Keyword(s):  
Knoevenagel Condensation ◽  
Ammonium Bicarbonate ◽  
Solvent Free ◽  
Temperature Dependent ◽  
Step Procedure ◽  
Synthetic Routes ◽  
High Yields ◽  
Temperature Optima ◽  
Solvent Free Synthesis ◽  
Full Conversion

Aim and Objective: Because of the low abundance of 3,4-unsubstituted coumarins in plants combined with the complex purification process required, synthetic routes towards 3,4-unsubstituted coumarins are especially valuable. In the present work, we explore the possibilities of a solvent-free Green Knoevenagel condensation on various 2-hydroxybenzaldehyde derivatives and malonic acid without the use of toxic organocatalysts like pyridine and piperidine but only use ammonium bicarbonate as the catalyst. Materials and Methods: To investigate the scope of the Green Knoevenagel condensation for the synthesis of 3,4-unsubstituted coumarins, various 2-hydroxybenzaldehyde derivatives were screened as starting material in the optimized two-step procedure developed for 2-hydroxybenzaldehyde. </P><P> Results: This study shows that the intramolecular esterification and the decarboxylation are in competition, but show different temperature optima. In order to suppress premature decarboxylation and maximize the yield of coumarin, a two-step procedure was adopted. The reaction mixture containing ammonium bicarbonate is initially kept at 90ºC for 1 hour. After completion of the cyclization, the temperature of the reaction mixture is increased to 140ºC for 2 hours. Following this protocol, coumarin could be isolated with a yield of 95%. Conclusion: A two-step procedure for the solvent-free synthesis of several 3,4-unsubstituted coumarins was developed using ammonium bicarbonate, resulting in high yields of the desired products. Moreover, this procedure has a low E-factor and is, therefore an environmental friendly reaction in line with the principles of Green Chemistry. It was shown that by initially capping the temperature at 90ºC, premature decarboxylation can be suppressed. After full conversion to the intermediate 3-carboxycoumarin, the temperature can be increased to 140ºC finalizing the reaction. Ammonium bicarbonate was shown to catalyze both the Green Knoevenagel condensation and the decarboxylation step.

1,4-Diazepines: A Review on Synthesis, Reactions and Biological Significance

2019 ◽  
Vol 16 (5) ◽  
pp. 709-729 ◽  
Author(s):  
Muhammad A. Rashid ◽  
Aisha Ashraf ◽  
Sahibzada S. Rehman ◽  
Shaukat A. Shahid ◽  
Adeel Mahmood ◽  
...  
Keyword(s):  
Biological Activities ◽  
Biological Significance ◽  
Biological Evaluation ◽  
Wide Range ◽  
Pharmaceutical Industries ◽  
Biological Aspects ◽  
Synthetic Routes ◽  
Biological Attributes ◽  
Synthesis Reactions ◽  
Potential Use

Background:1,4-Diazepines are two nitrogen containing seven membered heterocyclic compounds and associated with a wide range of biological activities. Due to its medicinal importance, scientists are actively involved in the synthesis, reactions and biological evaluation of 1,4-diazepines since number of decades.Objective:The primary purpose of this review is to discuss the synthetic schemes and reactivity of 1,4- diazepines. This article also describes biological aspects of 1,4-diazepine derivatives, that can be usefully exploited for the pharmaceutical sector.Conclusion:This review summarizes the abundant literature on synthetic routes, chemical reactions and biological attributes of 1,4-diazepine derivatives. We concluded that 1,4-diazepines have significant importance due to their biological activities like antipsychotic, anxiolytic, anthelmintic, anticonvulsant, antibacterial, antifungal and anticancer. 1,4-diazepine derivatives with significant biological activities could be explored for potential use in the pharmaceutical industries.

scholarly journals Non-Nucleoside Agonists of the Adenosine Receptors: An Overview

2019 ◽  
Vol 12 (4) ◽  
pp. 150 ◽  
Author(s):  
Dal Ben ◽  
Lambertucci ◽  
Buccioni ◽  
Martí Navia ◽  
Marucci ◽  
...  
Keyword(s):  
Adenosine Receptors ◽  
Biological Activities ◽  
Great Majority ◽  
Synthetic Route ◽  
Wide Range ◽  
Pharmacological Interest ◽  
Molecular Modeling Studies ◽  
Synthetic Routes ◽  
Alternative Set ◽  
Structural Classes

Potent and selective adenosine receptor (AR) agonists are of pharmacological interest for the treatment of a wide range of diseases and conditions. Among these derivatives, nucleoside-based agonists represent the great majority of molecules developed and reported to date. However, the limited availability of compounds selective for a specific AR subtype (i.e., A2BAR) and a generally long and complex synthetic route for largely substituted nucleosides are the main drawbacks of this category of molecules. Non-nucleoside agonists represent an alternative set of compounds able to stimulate the AR function and based on simplified structures. This review provides an updated overview on the structural classes of non-nucleoside AR agonists and their biological activities, with emphasis on the main derivatives reported in the literature. A focus is also given to the synthetic routes employed to develop these derivatives and on molecular modeling studies simulating their interaction with ARs.

scholarly journals Preparation of Silver Nanoparticles and Their Industrial and Biomedical Applications: A Comprehensive Review

2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
Adnan Haider ◽  
Inn-Kyu Kang
Keyword(s):  
Silver Nanoparticles ◽  
Biomedical Applications ◽  
Consumer Products ◽  
Ag Nps ◽  
New Techniques ◽  
Governing Factor ◽  
Wide Range ◽  
Microbial Proliferation ◽  
Synthetic Routes ◽  
Biomedical Fields

Silver nanoparticles (Ag-NPs) have diverted the attention of the scientific community and industrialist itself due to their wide range of applications in industry for the preparation of consumer products and highly accepted application in biomedical fields (especially their efficacy against microbes, anti-inflammatory effects, and wound healing ability). The governing factor for their potent efficacy against microbes is considered to be the various mechanisms enabling it to prevent microbial proliferation and their infections. Furthermore a number of new techniques have been developed to synthesize Ag-NPs with controlled size and geometry. In this review, various synthetic routes adapted for the preparation of the Ag-NPs, the mechanisms involved in its antimicrobial activity, its importance/application in commercial as well as biomedical fields, and possible application in future have been discussed in detail.

First-Principles Studies of the Magnetic Properties of hcp Cr in Cr/Cu(111) and Cr/Ru(0001) Superlattices

2002 ◽  
Vol 721 ◽  
Author(s):  
G. Y. Guo
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Recent Observation ◽  
Theoretical Calculations ◽  
Ferromagnetic State ◽  
Full Potential ◽  
Generalized Gradient ◽  
Plane Wave Method ◽  
Wide Range ◽  
Linearized Augmented Plane Wave

AbstractLatest first-principles density functional theoretical calculations using the generalized gradient approximation and highly accurate all-eleectron full-potential linearized augmented plane wave method, show that bulk hcp Cr would be a paramagnet and that no ferromagnetic state could be stabilized over a wide range of volume [1]. To understand the recent observation of the weakly ferromagnetic state of Cr in hcp Cr/Ru (0001) superlattices [2], the same theoretical calculations have been carried out for the hcp Cr3/Ru7 (0001) and hcp Cr3/fcc Cu6 (111) superlattices. The Cr/Ru superlattice is found to be ferromagnetic with a small magnetic moment of ∼0.31μB/Cr while in contrast, Cr/Cu superlattice is found to be nonmagnetic.

Investigations of the Effect of Annulus Taper on Transonic Turbine Cascade Flow

1986 ◽  
Vol 108 (2) ◽  
pp. 285-292 ◽  
Author(s):  
W. Bra¨unling ◽  
F. Lehthaus
Keyword(s):  
Surface Pressure ◽  
Theoretical Calculations ◽  
Three Dimensional ◽  
Computer Code ◽  
Numerical Results ◽  
Test Facility ◽  
Turbine Cascade ◽  
Pressure Distributions ◽  
Aspect Ratios ◽  
Wide Range

In a test facility for rotating annular cascades with three conical test sections of different taper angles (0, 30, 45 deg), experiments are conducted for two geometrically different turbine cascade configurations, a hub section cascade with high deflection and a tip section cascade with low deflection. The evaluation of time-averaged data derived from conventional probe measurements upstream and downstream of the test wheel in the machine-fixed absolute system is based on the assumption of axisymmetric stream surfaces. The cascade characteristics, i.e., mass flow, deflection, and losses, for a wide range of inlet flow angles and outlet Mach numbers are provided in the blade-fixed relative system with respect to the influence of annulus taper. Some of the results are compared with simple theoretical calculations. To obtain some information about the spatial structure of the flow within the cascade passages, surface pressure distributions on the profiles of the rotating test wheels are measured at three different radial blade sections. For some examples those distributions are compared with numerical results on plane cascades of the same sweep and dihedral angles and the same aspect ratios. The computer code used is based on a three-dimensional time-marching finite-volume method solving the Euler equations. Both experimental and numerical results show a fairly good qualitative agreement in the three-dimensional blade surface pressure distributions. This work will be continued with detailed investigations on the spatial flow structure.

A Regioselective [4+2] Annulation Approach to 5-Acylindolizine-7-carbonitriles: Generation of Poly-substituted Pyridines

2021 ◽  
Author(s):  
Sunmi Kim ◽  
Jeong Hwa Lee ◽  
Seok Hyun Yoon ◽  
Ikyon Kim
Keyword(s):  
Knoevenagel Condensation ◽  
Wide Range ◽  
Aldol Cyclization ◽  
Substituted Pyridines

Reaction of β-ketonitrile and N-substituted pyrrole-2-carboxaldehyde in the presence of piperidinium acetate in CH3CN permitted regioselective access to 5-acyl-6-arylindolizine-7-carbonitrile through a domino Knoevenagel condensation-intramolecular aldol cyclization sequence. A wide range...

Novel coumarin derivatives containing a triazole moiety: A study on synthesis, cytotoxicity, membrane dysfunction, apoptosis, cell cycle, and antiangiogenic studies

2022 ◽  
Vol 22 ◽  
Author(s):  
Adem Güner ◽  
Hakan Bektaş ◽  
Emre Menteşe
Keyword(s):  
Cell Cycle ◽  
Cancer Cells ◽  
Dna Fragmentation ◽  
Human Cancer ◽  
Biological Activities ◽  
A549 Cells ◽  
Vegf Expression ◽  
Gene Expressions ◽  
M Cell ◽  
Wide Range

Background: Coumarin is a functional compound with a pronounced wide range of biological activities and has recently been shown to have anticancer effects on various human cancer cells. Cisplatin is widely used in treating many cancers, but its effectiveness is limited due to acquired resistance and dose-related side effects. Objective: This study aimed to reveal the chemosensitizing ability of novel synthesized coumarin-triazole hybrid compounds (3a-f) compared to the cisplatin in A549, MCF-7, and HeLa cancer cells. Methods: Cytotoxicity was determined by MTT assay. Lactate dehydrogenase (LDH), antioxidant/oxidant status, DNA fragmentation were determined spectrophotometrically using commercial kits. Muse™ Cell Analyzer was used to assess cell cycle progression. Pro/anti-apoptotic gene expressions were determined by Real-Time qPCR. The antiangiogenic activity was determined by VEGF expression and Hen's chorioallantoic membrane model. Results: Compounds 3c, -d, -e, and -f potentiated the cisplatin-induced cytotoxicity through the increased LDH release and DNA fragmentation, induced G2/M cell cycle arrest, overproduction of oxidative stress, and decrease of cellular antioxidant levels. These compounds combined with cisplatin caused upregulation in the pro-apoptotic Bax, Bıd, caspase-3, caspase-8, caspase-9, Fas, and p53 gene expressions while downregulating anti-apoptotic DFFA, NFkB1, and Bcl2 gene expressions. These combinations caused vascular loss and a reduction in VEGF expression. Conclusion: These results suggest that a combinational regimen of coumarin compounds with cisplatin could be enhancing the effect of cisplatin in A549 cells. Besides, considering compounds have relatively low toxicity in normal cells, they decrease the dose requirement of cisplatin in cancer treatments.

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