scholarly journals EXPERIENCING A SYNTHESIS ONE-POT OF 1,2,4-OXADIAZOLE MEDIATED BY MICROWAVE OVEN: GREEN CHEMISTRY IN FOCUS

2019 ◽  
Vol 16 (32) ◽  
pp. 820-832
Author(s):  
A. L. MOURA ◽  
J. F. SILVA ◽  
J. J. R. DE FREITAS ◽  
J. C. R. FREITAS ◽  
J. R. DE FREITAS FILHO
Keyword(s):  
Green Chemistry ◽  
Biological Activities ◽  
Hydroxylamine Hydrochloride ◽  
Microwave Oven ◽  
Chemistry Laboratory ◽  
One Pot ◽  
Sequential Procedures ◽  
Wide Range ◽  
Simple Protocol ◽  
Organic Chemistry Laboratory

1,2,4-oxadiazoles are compounds that have attracted the attention of many researchers due to their wide range of biological activities, for example, anti-inflammatory, antimicrobial, antitumor etc. The syntheses are based mostly on the use of amidoximes and acylating agents as the initial reactants. This work aims to describe a one-pot reaction for the synthesis of 1,2,4-oxadiazols, mediated by microwave irradiation, employing home-use microwave oven, in the discipline of heterocyclic Chemistry in the postgraduate. The methodology consisted of the reaction of nitriles, hydroxylamine hydrochloride, potassium carbonate and different esters to obtain 1,2,4-oxadiazole. The reactions include two sequential procedures: base-promoted intermolecular addition of hydroxylamine to nitrile to lead to amidoxime, then treatment of the amidoxime with esther to form 1,2,4-oxadiazoles in good yields. This method represents a direct and simple protocol for the synthesis of 3,5-disubstituted 1,2,4-oxadiazoles. It was initially discussed with the students the chemistry of the oxadiazoles, one-pot reactions and green chemistry through atheoretical-expository-dialogue strategy. In the course of the didactic intervention the students, through a thematic seminary, presented the results of the analysis of the spectra from the different techniques used. With the skills acquired from completing this laboratory work, the students become well-prepared to perform spectroscopic analyzes in subsequent experiments encountered in the organic chemistry laboratory.

Sulfated Tin Oxide: A Convenient Heterogeneous Catalyst for the Synthesis of 4-Arylmethylidene-3-substituted-isoxazol-5(4H)-ones

2021 ◽  
Vol 18 ◽  
Author(s):  
Nitishkumar S. Kaminwar ◽  
Sunil U. Tekale ◽  
Srinivas L. Nakkalwar ◽  
Rajendra P. Pawar
Keyword(s):  
Heterogeneous Catalyst ◽  
Tin Oxide ◽  
Heterocyclic Compounds ◽  
Biological Activities ◽  
Hydroxylamine Hydrochloride ◽  
One Pot ◽  
Easy Method ◽  
Three Component Reaction ◽  
Wide Range ◽  
The One

: Synthesis of isoxazole structural heterocyclic compounds is important due to their wide range of biological activities. In the present article, we report a convenient and easy method for the synthesis of 4-arylmethylidene-3-substituted-isoxazol-5(4H)-ones by the one-pot three-component reaction of aldehydes, β-keto ester, and hydroxylamine hydrochloride cat-alyzed by sulfated tin oxide as a heterogeneous catalyst.

scholarly journals Chalcones and Flavanones Bearing Hydroxyl and/or Methoxyl Groups: Synthesis and Biological Assessments

2019 ◽  
Vol 9 (14) ◽  
pp. 2846 ◽  
Author(s):  
Gonçalo P. Rosa ◽  
Ana M. L. Seca ◽  
Maria do Carmo Barreto ◽  
Artur M. S. Silva ◽  
Diana C. G. A. Pinto
Keyword(s):  
Aldol Condensation ◽  
Biological Activities ◽  
Sodium Hydride ◽  
Antitumor Activities ◽  
One Pot ◽  
Substitution Pattern ◽  
Control Drug ◽  
Wide Range ◽  
Biological Assessments ◽  
Isomeric Structures

Chalcones and flavanones are isomeric structures and also classes of natural products, belonging to the flavonoid family. Moreover, their wide range of biological activities makes them key scaffolds for the synthesis of new and more efficient drugs. In this work, the synthesis of hydroxy and/or methoxychalcones was studied using less common bases, such as sodium hydride (NaH) and lithium bis(trimethylsilyl)amide (LiHMDS), in the aldol condensation. The results show that the use of NaH was more effective for the synthesis of 2′-hydroxychalcone derivatives, while LiHMDS led to the synthesis of polyhydroxylated chalcones in a one-pot process. During this study, it was also possible to establish the conditions that favor their isomerization into flavanones, allowing at the same time the synthesis of hydroxy and/or methoxyflavanones. The chalcones and flavanones obtained were evaluated to disclose their antioxidant, anticholinesterasic, antibacterial and antitumor activities. 2′,4′,4-Trihydroxychalcone was the most active compound in terms of antioxidant, anti-butyrylcholinesterase (IC50 26.55 ± 0.55 μg/mL, similar to control drug donepezil, IC50 28.94 ± 1.76 μg/mL) and antimicrobial activity. 4′,7-Dihydroxyflavanone presented dual inhibition, that is, the ability to inhibit both cholinesterases. 4′-Hydroxy-5,7-dimethoxyflavanone and 2′-hydroxy-4-methoxychalcone were the compounds with the best antitumor activity. The substitution pattern and the biological assay results allowed the establishment of some structure/activity relationships.

A One-Pot Synthesis of m-Terphenyls: A Guided Exploration of Reaction Chemistry, Chromatography, and Spectroscopy. A Miniproject for the Advanced Organic Chemistry Laboratory

2002 ◽  
Vol 79 (5) ◽  
pp. 629 ◽  
Author(s):  
Kishorekumar T. Anam ◽  
Michael P. Curtis ◽  
Muhammad J. Irfan ◽  
Michael P. Johnson ◽  
Andrew P. Royer ◽  
...  
Keyword(s):  
Organic Chemistry ◽  
Chemistry Laboratory ◽  
One Pot ◽  
One Pot Synthesis ◽  
Guided Exploration ◽  
Organic Chemistry Laboratory

scholarly journals Synthesis Chalones and Their Isomerization into Flavanones and Azaflavanones

2019 ◽  
Vol 2 (3) ◽  
pp. 70 ◽  
Author(s):  
Djenisa H. A. Rocha ◽  
Patrícia A. A. M. Vaz ◽  
Diana C. G. A. Pinto ◽  
Artur M. S. Silva
Keyword(s):  
Organic Chemistry ◽  
Reaction Time ◽  
Green Chemistry ◽  
Microwave Irradiation ◽  
Aldol Condensation ◽  
Chemistry Laboratory ◽  
Efficient Catalyst ◽  
Theoretical Concepts ◽  
Catalyst Systems ◽  
Organic Chemistry Laboratory

Flavanones [2-aryl-2,3-dihydrochromen-4(1H)ones] and 2-aryl-2,3-dihydroquinolin-4(1H)-ones are valuable precursors in the synthesis of important pharmacological scaffolds, so efficient methodologies towards their synthesis are important in the medicinal chemistry context. Their synthesis also involves theoretical concepts such as aldol condensation, isomerization, and catalysis that make it useful in an undergraduate organic chemistry laboratory. The use of both microwave irradiation as a source of energy to promote reactions and efficient catalysts are considered within green chemistry principles, mostly because the reaction yields are improved and reaction time decreased. In this paper, the efficiency of microwave irradiation use in the synthesis of chalcone derivatives and efficient catalyst systems to promote their isomerization into flavanones and 2-aryl-2,3-dihydroquinolin-4(1H)-ones is demonstrated.

Green Chemistry Approaches to the Synthesis of Coumarin Derivatives

2020 ◽  
Vol 24 (1) ◽  
pp. 4-43 ◽  
Author(s):  
Maja Molnar ◽  
Melita Lončarić ◽  
Marija Kovač
Keyword(s):  
Energy Consumption ◽  
Green Chemistry ◽  
Biological Activities ◽  
Daily Basis ◽  
Biologically Active ◽  
Synthetic Methods ◽  
Specific Class ◽  
Coumarin Derivatives ◽  
Wide Range ◽  
Coumarin Synthesis

This review is a compilation of the green synthetic methods used in the synthesis of coumarin derivatives. Coumarins are a class of compounds with a pronounced wide range of biological activities, which have found their application in medicine, pharmacology, cosmetics and food industry. Their biological activity and potential application are highly dependent on their structure. Therefore, many researchers have been performing the synthesis of coumarin derivatives on a daily basis. High demands for their synthesis often result in an increased generation of different waste chemicals. In order to minimize the utilization and generation of toxic organic substances, green synthetic methods are applied in this manner. These methods are getting more attention in the last few decades. Green chemistry methods cover a wide range of methods, including the application of ultrasound and microwaves, ionic liquids and deep eutectic solvents, solvent-free synthesis, mechanosynthesis and multicomponent reactions. All typical condensation reactions for coumarin synthesis like Knoevenagel, Perkin, Kostanecki-Robinson, Pechmann and Reformansky reactions, have been successfully performed using these green synthetic methods. According to the authors mentioned in this review, not only these methods reduce the utilization and generation of toxic chemicals, but they can also enhance the reaction performance in terms of product yields, purity, energy consumption and post-synthetic procedures when compared to the conventional methods. Due to the significance of coumarins as biologically active systems and the recent demands of reducing toxic solvents, catalysts and energy consumption, this review provides a first full literature overview on the application of green synthetic methods in the coumarin synthesis. It covers a literature search over the period from 1995-2019. The importance of this work is its comprehensive literature survey on a specific class of heterocyclic compounds, and those researchers working on the coumarin synthesis can find very useful information on the green synthetic approaches to their synthesis. There are some reviews on the coumarin synthesis, but most of them cover only specific reactions on coumarin synthesis and none of them the whole range of green chemistry methods.

How the Principles of Green Chemistry Changed the Way Organic Chemistry Labs Are Taught at the University of Detroit Mercy

2017 ◽  
Vol 2 (2) ◽  
Author(s):  
Matthew J. Mio
Keyword(s):  
Organic Chemistry ◽  
Green Chemistry ◽  
Learning Outcomes ◽  
Chemistry Laboratory ◽  
Atom Economy ◽  
Laboratory Courses ◽  
Instructional Changes ◽  
Organic Chemistry Laboratory ◽  
The University ◽  
The Way

Abstract Many logistic and instructional changes followed the incorporation of the 12 principles of green chemistry into organic chemistry laboratory courses at the University of Detroit Mercy. Over the last decade, institutional limitations have been turned into green chemical strengths in many areas, including integration of atom economy metrics into learning outcomes, replacing overly toxic equipment and reagents, and modifying matters of reaction scale and type.

One-pot Synthesis of Betulin Triterpenoid Quaternized Pyridine Derivatives and their Antimicrobial Activity

2019 ◽  
Vol 17 (1) ◽  
pp. 79-84 ◽  
Author(s):  
Elvira Rifovna Shakurova ◽  
Darina Alexandrovna Pozdnyakova ◽  
Elena Valeryevna Tretyakova ◽  
Lyudmila Vyacheslavovna Parfenova
Keyword(s):  
Antifungal Activity ◽  
Biological Activities ◽  
Effective Interaction ◽  
Inhibition Zone ◽  
Pyridine Derivatives ◽  
One Pot ◽  
Biological Targets ◽  
Wide Range ◽  
Low Toxicity ◽  
Antibacterial And Antifungal

Background: A wide range of biological activity, relatively low toxicity and multiple pharmacological effects of triterpenoids are major advantages of these compounds in the prevention and treatment of various diseases. They include the lupane- type triterpenoids that proved to be a promising platform for the synthesis of analogs with a wide range of biological activities, including anti-inflammatory, antitumor, antiparasitic and antiviral properties. The main disadvantage complicating the use of all known derivatives of lupane acids in medical practice is low bioavailability associated with poor solubility in biologic fluids, limiting their effective interaction with the biological targets. Objective: The objective of this study is the synthesis of new amphiphilic betulin derivatives on the base of pyridinium salts with antifungal and antibacterial activity. Methods: In this study we have developed an effective one-pot method for the preparation of new quaternized pyridine derivatives 4-6 of the betulinic series based on the reaction of the initial triterpenes 1-3 with the Tempo+Br3 - reagent in the pyridine. The synthesized and initial compounds were tested for their antimicrobial and antifungal activity. Results: The data presented in this document indicate that all synthesized compounds 4-6 exhibited high activity against both gram-positive Staphylococcus aureus bacteria and gram-negative Pseudomonas aeruginosa strains, as well as Candida albicans and Cryptococcus neoformans fungi with the >90% coverage of the inhibition zone. The best result in a series of compounds 4-6 was found for the derivative 6 at the minimum inhibitory concentration of 1 µg/ml against S. aureus bacteria, C. albicans and C. neoformans fungi at the concentration of 8 µg/ml. Conclusion: Thus, we have demonstrated the first example of the pyridine quaternization using the betulin triterpenoids as the lipophilic substrates and Tempo+Br3 - cation. The obtained quaternized pyridine analogs of betulin triterpenes showed high antibacterial and antifungal activity in comparison with the initial compounds.

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