SOMOphilic Alkynylation Using Acetylenic Sulfones as Functional Reagents

Author(s):  
Danhua Ge ◽  
Xin Wang ◽  
Xue-Qiang Chu

The past decades have witnessed a boom in alkynylation mainly owing to the importance of alkynyl-containing molecules in organic synthesis, drug discovery, polymer chemistry, and materials science. Besides conventional strategies,...

2020 ◽  
Author(s):  
Abdul Aziz Ali

Among nitrogen-containing heterocyclic compounds, 1,2,3-triazoles are privileged structure motif and received a great deal of attention in academics and industry. Even though absent in nature, 1,2,3-triazoles have found broad applications in drug discovery, organic synthesis, polymer chemistry, supramolecular chemistry, bioconjugation, chemical biology, fluorescent imaging, and materials science. Therefore, the development of facile and straightforward methodology for the synthesis of 1,2,3-triazoles is of noteworthy interest. In this study, emphasis will be given to numerous synthetic approaches for the synthesis of 1,2,3-triazoles, especially the popular click chemistry approach. Furthermore, several biological activities of this promising heterocycle will also be discussed.


2020 ◽  
Vol 24 (22) ◽  
pp. 2527-2554
Author(s):  
Trimurti L. Lambat ◽  
Paavan Kavi Param Gaitry Chopra ◽  
Sami H. Mahmood

Microwave Mediated Organic Synthesis (MMOS) is typical on the proficient heat shift carried out by dielectric heating, which in turn, is primarily dependent on the capability of the reagent or solvent to take up microwave energy. The employment of microwave energy has witnessed a fast expansion in the past two decades, with novel and pioneering applications in peptide and organic synthesis, material sciences, polymer chemistry, biochemical processes and nanotechnology. This review summarizes current MW- mediated catalytic reactions in use for the synthesis of a diversity of N-heterocycles by Multi- Component Reactions (MCRs) and a variety of miscellaneous reactions. In addition, the review addresses some aspects of the use of nanoparticles for a diversity of applications in microwave chemistry.


Author(s):  
John L. Hutchison

Over the past five years or so the development of a new generation of high resolution electron microscopes operating routinely in the 300-400 kilovolt range has produced a dramatic increase in resolution, to around 1.6 Å for “structure resolution” and approaching 1.2 Å for information limits. With a large number of such instruments now in operation it is timely to assess their impact in the various areas of materials science where they are now being used. Are they falling short of the early expectations? Generally, the manufacturers’ claims regarding resolution are being met, but one unexpected factor which has emerged is the extreme sensitivity of these instruments to both floor-borne and acoustic vibrations. Successful measures to counteract these disturbances may require the use of special anti-vibration blocks, or even simple oil-filled dampers together with springs, with heavy curtaining around the microscope room to reduce noise levels. In assessing performance levels, optical diffraction analysis is becoming the accepted method, with rotational averaging useful for obtaining a good measure of information limits. It is worth noting here that microscope alignment becomes very critical for the highest resolution.In attempting an appraisal of the contributions of intermediate voltage HREMs to materials science we will outline a few of the areas where they are most widely used. These include semiconductors, oxides, and small metal particles, in addition to metals and minerals.


2019 ◽  
Vol 23 (11) ◽  
pp. 1214-1238 ◽  
Author(s):  
Navjeet Kaur ◽  
Pranshu Bhardwaj ◽  
Meenu Devi ◽  
Yamini Verma ◽  
Neha Ahlawat ◽  
...  

Due to special properties of ILs (Ionic Liquids) like their wide liquid range, good solvating ability, negligible vapour pressure, non-inflammability, environment friendly medium, high thermal stability, easy recycling and rate promoters etc. they are used in organic synthesis. The investigation for the replacement of organic solvents in organic synthesis is a growing area of interest due to increasing environmental issues. Therefore, ionic liquids have attracted the attention of chemists and act as a catalyst and reaction medium in organic reaction with high activity. There is no doubt that ionic liquids have become a major subject of study for modern chemistry. In comparison to traditional processes the use of ionic liquids resulted in improved, complimentary or alternative selectivities in organic synthesis. The present manuscript reported the synthesis of multiple nitrogen containing five-membered heterocyclic compounds using ionic liquids. This review covered interesting discoveries in the past few years.


2017 ◽  
Vol 17 (3) ◽  
pp. 305-318 ◽  
Author(s):  
Donald Sikazwe ◽  
Raghunandan Yendapally ◽  
Sushma Ramsinghani ◽  
Malik Khan

2019 ◽  
Vol 19 (1) ◽  
pp. 4-16 ◽  
Author(s):  
Qihui Wu ◽  
Hanzhong Ke ◽  
Dongli Li ◽  
Qi Wang ◽  
Jiansong Fang ◽  
...  

Over the past decades, peptide as a therapeutic candidate has received increasing attention in drug discovery, especially for antimicrobial peptides (AMPs), anticancer peptides (ACPs) and antiinflammatory peptides (AIPs). It is considered that the peptides can regulate various complex diseases which are previously untouchable. In recent years, the critical problem of antimicrobial resistance drives the pharmaceutical industry to look for new therapeutic agents. Compared to organic small drugs, peptide- based therapy exhibits high specificity and minimal toxicity. Thus, peptides are widely recruited in the design and discovery of new potent drugs. Currently, large-scale screening of peptide activity with traditional approaches is costly, time-consuming and labor-intensive. Hence, in silico methods, mainly machine learning approaches, for their accuracy and effectiveness, have been introduced to predict the peptide activity. In this review, we document the recent progress in machine learning-based prediction of peptides which will be of great benefit to the discovery of potential active AMPs, ACPs and AIPs.


2019 ◽  
Vol 16 (2) ◽  
pp. 258-275 ◽  
Author(s):  
Navjeet Kaur

Background:A wide variety of biological activities are exhibited by N, O and S containing heterocycles and recently, many reports appeared for the synthesis of these heterocycles. The synthesis of heterocycles with the help of metal and non-metal catalyst has become a highly rewarding and important method in organic synthesis. This review article concentrated on the synthesis of S-heterocylces in the presence of metal and non-metal catalyst. The synthesis of five-membered S-heterocycles is described here.Objective:There is a need for the development of rapid, efficient and versatile strategy for the synthesis of heterocyclic rings. Metal, non-metal and organocatalysis involving methods have gained prominence because traditional conditions have disadvantages such as long reaction times, harsh conditions and limited substrate scope.Conclusion:The metal-, non-metal-, and organocatalyst assisted organic synthesis is a highly dynamic research field. For ßthe chemoselective and efficient synthesis of heterocyclic molecules, this protocol has emerged as a powerful route. Various methodologies in the past few years have been pointed out to pursue more sustainable, efficient and environmentally benign procedures and products. Among these processes, the development of new protocols (catalysis), which avoided the use of toxic reagents, are the focus of intense research.


Crystals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 676
Author(s):  
Tom L. Blundell

Over the past 60 years, the use of crystals to define structures of complexes using X-ray analysis has contributed to the discovery of new medicines in a very significant way. This has been in understanding not only small-molecule inhibitors of proteins, such as enzymes, but also protein or peptide hormones or growth factors that bind to cell surface receptors. Experimental structures from crystallography have also been exploited in software to allow prediction of structures of important targets based on knowledge of homologues. Crystals and crystallography continue to contribute to drug design and provide a successful example of academia–industry collaboration.


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