scholarly journals Recent advances in the chemistry of bicyclo- and 1-azabicyclo[1.1.0]butanes

2020 ◽  
Vol 92 (5) ◽  
pp. 751-765 ◽  
Author(s):  
Alexander Fawcett
Keyword(s):  
Nitrogen Atom ◽  
Short Review ◽  
Future Research ◽  
The Past ◽  
New Methods ◽  
Recent Advances ◽  
Recent Developments ◽  
The 1950S ◽  
Highly Strained

AbstractBicyclo[1.1.0]- and 1-azabicyclo[1.1.0]butanes are structurally unique compounds that exhibit diverse chemistry. Bicyclo[1.1.0]butane is a four-membered carbocycle with a bridging C(1)-C(3) bond and 1-azabicyclo[1.1.0]butane is an analog of bicyclo[1.1.0]butane featuring a nitrogen atom at one bridgehead. These structures are highly strained, allowing them to participate in a range of strain-releasing reactions which typically cleave the central, strained bond to deliver cyclobutanes or azetidines. However, despite these molecules being discovered in the 1950s and 1960s, and possessing a myriad of alluring chemical features, the chemistry and applications of bicyclo[1.1.0]- and 1-azabicyclo[1.1.0]butanes remain underexplored. In the past 5 years, there has been a resurgent interest in their chemistry driven by the pharmaceutical industry’s increasing desire for new methods to access cyclobutanes and azetidines. This short review intends to provide a timely summary of the most recent developments in the chemistry of bicyclo[1.1.0]- and 1-azabicyclo[1.1.0]butane to highlight the diverse chemistry they can access, their value as synthetic precursors to cyclobutanes and azetidines, and to identify areas for future research.

ON "PLASTIC" WAVES IN SOLIDS

1959 ◽  
Vol 37 (9) ◽  
pp. 1017-1035 ◽  
Author(s):  
John M. Bowsher
Keyword(s):  
Theoretical Study ◽  
Short Review ◽  
Future Research ◽  
Past Work ◽  
The Past ◽  
Engineering Significance ◽  
The Subject

The study of the propagation of "plastic" waves in solids has reached a stage where it is necessary to consider which direction future research should take. In the past 90 or so years many experiments, mostly designed to elucidate certain points of engineering significance, and a few attempts at a theoretical study have cast some light on the subject and revealed it as one of formidable difficulty.Nearly all the experiments have of necessity relied on rather dubious theories for their interpretation, and part of the present paper will be devoted to a description of an apparatus which gives results capable of being interpreted with a very minimum of theory. The remainder of the paper is devoted to a short review of past work with particular emphasis on basic phenomena and to a brief discussion on the most pressing problems still remaining. The experiments described in the present paper bring to light a factor in the propagation of "plastic" waves that seems to have been overlooked in previous work.

Recent advances and new concepts for the synthesis of axially stereoenriched biaryls

2015 ◽  
Vol 44 (11) ◽  
pp. 3418-3430 ◽  
Author(s):  
J. Wencel-Delord ◽  
A. Panossian ◽  
F. R. Leroux ◽  
F. Colobert
Keyword(s):  
Chiral Compounds ◽  
The Past ◽  
Recent Advances ◽  
New Concepts ◽  
Axially Chiral ◽  
Recent Developments ◽  
Synthetic Routes

Over the past decade the field of the synthesis of axially chiral compounds has been rapidly expanding. Not only key advances have been achieved concerning the already established strategies but also new synthetic routes have been devised. This review showcases the recent developments in this domain.

scholarly journals Recent Advances in Palladium-Catalyzed Isocyanide Insertions

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 4906
Author(s):  
Jurriën W. Collet ◽  
Thomas R. Roose ◽  
Bram Weijers ◽  
Bert U. W. Maes ◽  
Eelco Ruijter ◽  
...  
Keyword(s):  
Organic Synthesis ◽  
Building Blocks ◽  
Insertion Reactions ◽  
Chemical Reagents ◽  
The Past ◽  
Recent Advances ◽  
Recent Developments ◽  
Palladium Catalyzed ◽  
Made In ◽  
Rapid Incorporation

Isocyanides have long been known as versatile chemical reagents in organic synthesis. Their ambivalent nature also allows them to function as a CO-substitute in palladium-catalyzed cross couplings. Over the past decades, isocyanides have emerged as practical and versatile C1 building blocks, whose inherent N-substitution allows for the rapid incorporation of nitrogeneous fragments in a wide variety of products. Recent developments in palladium catalyzed isocyanide insertion reactions have significantly expanded the scope and applicability of these imidoylative cross-couplings. This review highlights the advances made in this field over the past eight years.

Organic Synthesis

2017 ◽  
Author(s):  
Douglass F. Taber ◽  
Tristan Lambert
Keyword(s):  
Organic Synthesis ◽  
State Of The Art ◽  
Research Area ◽  
Organic Transformations ◽  
The Past ◽  
Catalytic Asymmetric Synthesis ◽  
New Methods ◽  
Recent Developments ◽  
Enantioselective Epoxidation ◽  
To Come

Organic synthesis is a vibrant and rapidly evolving field; chemists can now cyclize alkenes directly onto enones. Like the first five books in this series, Organic Synthesis: State of the Art 2013-2015 will lead readers quickly to the most important recent developments in a research area. This series offers chemists a way to stay abreast of what's new and exciting in organic synthesis. The cumulative reaction/transformation index of 2013-2015 outlines all significant new organic transformations over the past twelve years. Future volumes will continue to come out every two years. The 2013-2015 volume features the best new methods in subspecialties such as C-O, C-N and C-C ring construction, catalytic asymmetric synthesis, selective C-H functionalization, and enantioselective epoxidation. This text consolidates two years of Douglass Taber's popular weekly online column, "Organic Chemistry Highlights" as featured on the organic-chemistry.org website and also features cumulative indices of all six volumes in this series, going back twelve years.

Advances in Dental Imaging

2001 ◽  
Vol os8 (2) ◽  
pp. 59-62 ◽  
Author(s):  
Jackie E Brown
Keyword(s):  
Hard Tissue ◽  
Maxillofacial Region ◽  
Dental Services ◽  
Dental Imaging ◽  
The Past ◽  
New Methods ◽  
Recent Developments ◽  
Radiation Induced ◽  
Dental Radiographs ◽  
The Uk

The number of dental radiographs taken in the UK has steadily increased over the past 20 years—recently estimating around 18 million taken in the general dental services alone, and dental radiographs now account for nearly 25% of all medical radiographic exposures.1 Radiographs remain our most useful diagnostic aid. Their strength is in demonstrating hard tissue pathology, which makes radiographs particularly effective in the maxillofacial region. Although well accepted in this capacity, there remain a number of limitations and drawbacks to conventional radiographs which recent developments have begun to overcome. There have been improvements in the scope and capabilities of dental imaging equipment. There has also been a continuing effort to reduce radiation-induced harm by limiting our exposure to it. This has been possible both through the introduction of new methods and protocols for reducing individual radiation exposures and by the creation of guidelines for selecting radiographs more effectively and thereby reducing the total number of radiographs taken.

Recent Advances in the Synthesis and Chemistry of Nitronates

Synthesis ◽  
2017 ◽  
Vol 49 (15) ◽  
pp. 3255-3268 ◽  
Author(s):  
Andrey Tabolin ◽  
Alexey Sukhorukov ◽  
Sema Ioffe ◽  
Alexander Dilman
Keyword(s):  
Carbon Atom ◽  
Stereoselective Synthesis ◽  
Building Blocks ◽  
Short Review ◽  
Bioactive Molecules ◽  
Silyl Nitronates ◽  
Recent Advances ◽  
Recent Developments

Due to their availability and versatile reactivity, nitronates have become important building blocks in the stereoselective synthesis of bioactive molecules. This short review provides a summary of recent developments on the synthesis, chemistry and applications of O-alkyl and O-silyl nitronates.1 Introduction2 Approaches to the Synthesis of Nitronates2.1 Synthesis of Six-Membered Cyclic Nitronates2.1.1 Formal [4+2] Approaches2.1.2 Formal [3+3] Approaches2.1.3 Other Approaches2.2 Synthesis of Five-Membered Cyclic Nitronates2.2.1 Formal [3+2] Approaches2.2.2 Formal [4+1] Approaches2.2.3 Oxidation Approaches3 Chemistry of Nitronates3.1 Nitronates as α-C-Nucleophiles3.2 Nitronates as α-C-Electrophiles3.3 Nitronates in [3+n]-Annulation Reactions3.4 Reactions Involving the β-Carbon Atom of Nitronates3.5 Miscellaneous Transformations4 Conclusion

scholarly journals Recent advances in biochar application for water and wastewater treatment: a review

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9164
Author(s):  
Xiaoqing Wang ◽  
Zizhang Guo ◽  
Zhen Hu ◽  
Jian Zhang
Keyword(s):  
Wastewater Treatment ◽  
Future Research ◽  
Water And Wastewater Treatment ◽  
Research Directions ◽  
The Past ◽  
Recent Advances ◽  
Future Research Directions ◽  
Water And Wastewater ◽  
Contaminants Removal ◽  
Sorption Mechanisms

In the past decade, researchers have carried out a massive amount of research on the application of biochar for contaminants removal from aqueous solutions. As an emerging sorbent with great potential, biochar has shown significant advantages such as the broad sources of feedstocks, easy preparation process, and favorable surface and structural properties. This review provides an overview of recent advances in biochar application in water and wastewater treatment, including a brief discussion of the involved sorption mechanisms of contaminants removal, as well as the biochar modification methods. Furthermore, environmental concerns of biochar that need to be paid attention to and future research directions are put forward to promote the further application of biochar in practical water and wastewater treatment.

Oxford Textbook of Rheumatoid Arthritis

2020 ◽  
Keyword(s):  
Rheumatoid Arthritis ◽  
Clinical Presentation ◽  
Disease Assessment ◽  
Future Research ◽  
Clinical Aspects ◽  
Comprehensive Overview ◽  
Future Directions ◽  
The Past ◽  
Recent Advances ◽  
Drug Treatments

This new textbook provides a comprehensive overview of the scientific and clinical aspects of rheumatoid arthritis (RA). Split into eight sections—history, diagnosis, and epidemiology; pathogenesis; clinical presentation; disease assessment; impact on life; non-drug treatments; drug treatments; and management and outcomes—it collects the contemporary ideas about RA and explains the revolutionary changes that have taken place over the past two decades, and indicates areas of future research. Witten by leading clinicians and scientists in the field, each chapter gives a detailed background, key recent advances, areas of doubt, and future directions of research.

scholarly journals Epigenetics, chromatin and brain development and function

2018 ◽  
Vol 2 ◽  
pp. 239821281881201
Author(s):  
Anthony R. Isles
Keyword(s):  
Brain Development ◽  
Future Research ◽  
Biological Concept ◽  
The Past ◽  
The 1950S ◽  
And Function ◽  
Mode Of Inheritance

Research investigating epigenetics and chromatin function in brain and behaviour has mushroomed over the last two decades. And yet epigenetics as a biological concept predates the discovery in the 1950s of DNA as the principle mode of inheritance by over a decade. This review explores the past, present and future research into epigenetics as it relates to understanding brain development and function

Recent Advances in the Tandem Cyclization/Cycloaddition of Allene Intermediates from Copper-Catalyzed Cross-Coupling of Diazo Compounds with Terminal Alkynes

Synthesis ◽  
2020 ◽  
Author(s):  
Shiyong Peng ◽  
Nuan Chen ◽  
Min He ◽  
Ting Zhou ◽  
Yuqi Zhu ◽  
...  
Keyword(s):  
Cross Coupling ◽  
Short Review ◽  
Diazo Compounds ◽  
Terminal Alkynes ◽  
Recent Advances ◽  
Recent Developments ◽  
Tandem Cyclization ◽  
Cyclic Compounds

AbstractThis short review summarizes the most recent developments (since 2010) in the tandem cyclization/cycloaddition of allene intermediates­, generated from the copper-catalyzed cross-coupling of diazo compounds with terminal alkynes, to afford cyclic compounds.1 Introduction2 Cyclization2.1 Cyclization with Nucleophiles2.2 Cyclization with Electrophiles2.3 6π-Electrocyclization2.4 Other Cyclization3 Cycloaddition4 Conclusion

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