Substituted pyrazoles and their heteroannulated analogs—recent syntheses and biological activities

Pyrazoles are considered privileged scaffolds in medicinal chemistry. Previous reviews have discussed the importance of pyrazoles and their biological activities; however, few have dealt with the chemistry and the biology of heteroannulated derivatives. Therefore, we focused our attention on recent topics, up until 2020, for the synthesis of pyrazoles, their heteroannulated deriva-tives, and their applications as biologically active moieties. Moreover, we focused on traditional procedures used in the synthesis of pyrazoles

A RECENT UPDATE: ANTIMICROBIAL AGENTS CONTAINING PYRAZOLE NUCLEUS

Objective: In this review, we report antimicrobial candidates containing pyrazole nucleus integrated with various functionalities.Methods: research results by numerous scientists have been summarized from international journals indexed in reputed database such as Scopus and Web of Science.Results: Pyrazole derivatives are much of interest as potent bioactive molecules. They have shown large bioactivities especially antimicrobial performance against broad spectrum of bacterial strains.Conclusion: Several designed pyrazole derivates possessed good to superior antimicrobial activities

Chalcones as versatile synthons for the synthesis of 5- and 6-membered nitrogen heterocylces

Chalcones belong to the flavonoid family which constitutes one of the major classes of naturally occurring oxygen heterocyclic compounds. The alpha,beta-unsaturated carbonyl system of chalcones possesses two electrophilic reactive centers allowing them to participate in addition reactions via attack to the carbonyl group (1,2-addition) or involving the beta-carbon (1,4-conjugate addition), leading to the synthesis of promising bioactive heterocyclic compounds. The purpose of this review is to present a systematic survey of the most recent literature that uses chalcones in the synthesis of biologically active 5- and 6-membered nitrogen heterocycles such as pyrroles, indoles, isoxazoles, imidazoles, pyrazoles, indazoles, triazoles, tetrazoles, pyridines and pyrimidines. Efficiency, easy-to-handle and cheap reagents, alternative heating conditions and greener protocols will be highlighted. In this review we will cover the literature since the beginning of the 21st century in more than 400 publications.PEst-C/QUI/UI0062/2013 FCOMP-01-0124-FEDER-03729

Function of Nanocatalyst in Chemistry of Organic Compounds Revolution: An Overview

Heterocyclic motif is an important scaffold which has both industrial and pharmaceutical applications. These motifs can be prepared using wide variety of reaction conditions such as the use of expensive catalyst, toxic solvent, harsh reaction condition like the use of base, high temperature, and multistep reaction. Although various methods are involved, the chemistry arena is now shifted towards the greener way of synthesis. Nanocatalyst constitutes an important role in the green synthesis. This is because the activity of the catalyst resides in the exposed portion of the particles. By decreasing the size of the catalyst, advantages such as more surface area would be exposed to the reactant, only negligible amount would be required to give the significant result and selectivity could be achieved, thereby, eliminating the undesired products. The current review enlists the various types of nanocatalyst involved in the heterocyclic ring formation and also some other important functionalization over the ring

Recent Applications of Heteropolyacids and Related Compounds in Heterocycle Synthesis. Contributions between 2010 and 2020

Over the past two decades, polyoxometalates (POM) have received considerable attention as solid catalysts, due to their unique physicochemical characteristics, since, first, they have very strong Bronsted acidity, approaching the region of a superacid, and second, they are efficient oxidizers that exhibit rapid redox transformations under fairly mild conditions. Their structural mobility is also highlighted, since they are complex molecules that can be modified by changing their structure or the elements that compose them to model their size, charge density, redox potentials, acidity, and solubility. Finally, they can be used in substoichiometric amounts and reused without an appreciable loss of catalytic activity, all of which postulate them as versatile, economic and ecological catalysts. Therefore, in 2009, we wrote a review article highlighting the great variety of organic reactions, mainly in the area of the synthesis of bioactive heterocycles in which they can be used, and this new review completes that article with the contributions made in the same area for the period 2010 to 2020. The synthesized heterocycles to be covered include pyrimidines, pyridines, pyrroles, indoles, chromenes, xanthenes, pyrans, azlactones, azoles, diazines, azepines, flavones, and formylchromones, among others

Scope of Selective Heterocycles from Organic and Pharmaceutical Perspective

Scope of Selective Heterocycles from Organic and Pharmaceutical Perspective is a compilation of bioactive-chosen heterocyclic scaffolds intended for postgraduates, research scholars, pharmaceutical scientists, and others interested in an appreciation of the title subject. It is an edited book and is not comprehensive as well in the mentioned field. Few synthetic strategies along with bioactivity are presented, and some limitations were raised in order to arouse curiosity of the reader

Ultrasonic-accelerated rapid protocol for the green synthesis of heterocyclics and aromatic compounds.

Master of Science in Chemistry. University of KwaZulu-Natal, Durban 2015.Abstract available in PDF file

Synthetic Strategies and Biological Activities of 1,5-Disubstituted Pyrazoles and 2,5-Disubstituted Thiazoles

Pyrazoles and thiazoles belong to 5-membered aromatic heterocycles called azoles. In addition to a nitrogen, pyrazoles contain an additional nitrogen in a 1,2 linkage and thiazoles contain a sulfur atom in a 1,3 linkage. These compounds are useful pharmacophores that offer a broad range of therapeutic applications. Pyrazoles can be synthesized by (i) the condensation of 1,3 dipolar compounds and alkenes/alkynes, (b) cyclocondensation of hydrazines and dicarbonyl reagents, and (c) multi-component reactions. Access to thiazoles is typically via (a) the condensation of α-haloketones with nucleophilic thioamides containing the N-C-S fragment, (b) a reaction between α-aminonitriles and various reactants containing an X-C-S fragment, and (c) a reaction of acylaminocarbonyls and phosphorus pentasulfide. This chapter will focus on the strategies and our perspectives on the synthesis of pyrazoles and thiazoles including derivatives at the 1,5 positions and 2, 4, 5 positions respectively, reported during 2015–2022. Additionally, their therapeutic and biological evaluations will be discussed

The green chemistry of chalcones: Valuable sources of privileged core structures for drug discovery

The sustainable use of resources is essential in all production areas, including pharmaceuticals. However, the aspect of sustainability needs to be taken into consideration not only in the production phase, but during the whole medicinal chemistry drug discovery trajectory. The continuous progress in the fields of green chemistry and the use of artificial intelligence are contributing to the speed and effectiveness of a more sustainable drug discovery pipeline. In this light, here we review the most recent sustainable and green synthetic approaches used for the preparation and derivatization of chalcones, an important class of privileged structures and building blocks used for the preparation of new biologically active compounds with a broad spectrum of potential therapeutic applications. The literature here reported has been retrieved from the SciFinder database using the term "chalcone " as a keyword and filtering the results applying the concept: "green chemistry ", and from the Reaxys database using the keywords "chalcone " and "green ". For both databases the time-frame was 2017-2022. References were manually selected based on relevance