From Allenes to Spirobifluorenes: On the Way to Device-compatible Chiroptical Systems

2020 ◽  
Vol 24 (23) ◽  
pp. 2737-2754
Author(s):  
Ani Ozcelik ◽  
Raquel Pereira-Cameselle ◽  
José Lorenzo Alonso-Gómez
Keyword(s):  
Molecular Conformation ◽  
Experimental Studies ◽  
Review Article ◽  
Research Groups ◽  
Chiroptical Properties ◽  
Molecular Chirality ◽  
Axially Chiral ◽  
Molecular Cages ◽  
Cyclic Oligomers ◽  
Chiral Systems

The last decade has seen a huge growth in the construction of chiral systems to expand the scope of chiroptical applications. Dependence of chiroptical response on molecular conformation typically leads to low chiroptical intensities of chiral systems that feature several conformations in solution. In this respect, allenes were employed for the preparation of open and cyclic oligomers as well as molecular cages, presenting remarkable chiroptical responses in solution. Their molecular chirality was also transferred to metal surfaces, yet photoisomerization of allenes limited their further exploration. In search of a more robust chiral axis, theoretical and experimental studies confirmed that spirobifluorenes could give rise to stable systems with tailored optical and chiroptical properties. Additionally, incorporating a conformational lock into spirobifluorene cyclic architectures served as an efficient strategy towards the generation of distinct helical molecular orbitals. This review article outlines our results on developing device-compatible chiroptical systems through axially chiral allenes and spirobifluorenes. The contribution from other research groups is presented briefly.

scholarly journals Renoprotective Effects of DPP-4 Inhibitors

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 246
Author(s):  
Daiji Kawanami ◽  
Yuichi Takashi ◽  
Hiroyuki Takahashi ◽  
Ryoko Motonaga ◽  
Makito Tanabe
Keyword(s):  
Diabetic Kidney Disease ◽  
Experimental Studies ◽  
Review Article ◽  
Glucose Lowering ◽  
Beneficial Effects ◽  
Glucose Levels ◽  
Membrane Bound ◽  
Stage Renal Disease ◽  
End Stage

Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease (ESRD) worldwide. Dipeptidyl peptidase (DPP)-4 inhibitors are widely used in the treatment of patients with type 2 diabetes (T2D). DPP-4 inhibitors reduce glucose levels by inhibiting degradation of incretins. DPP-4 is a ubiquitous protein with exopeptidase activity that exists in cell membrane-bound and soluble forms. It has been shown that an increased renal DPP-4 activity is associated with the development of DKD. A series of clinical and experimental studies showed that DPP-4 inhibitors have beneficial effects on DKD, independent of their glucose-lowering abilities, which are mediated by anti-fibrotic, anti-inflammatory, and anti-oxidative stress properties. In this review article, we highlight the current understanding of the clinical efficacy and the mechanisms underlying renoprotection by DPP-4 inhibitors under diabetic conditions.

scholarly journals Strategies and Efforts towards the Total Synthesis of Palhinine Alkaloids

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4211
Author(s):  
Yu-Yan Liang ◽  
Shi-Chao Lu ◽  
Ya-Ling Gong ◽  
Shu Xu
Keyword(s):  
Total Synthesis ◽  
Review Article ◽  
Research Groups ◽  
Asymmetric Total Synthesis ◽  
Carbon Cage ◽  
Total Syntheses ◽  
The Past ◽  
Lycopodium Alkaloids

The palhinine family of Lycopodium alkaloids were first reported in 2010, which feature an intriguing isotwistane carbon cage and a nine-membered azonane ring. It is noteworthy that the tetracyclic 5/6/6/9 skeleton was unprecedented in Lycopodium alkaloids before their seminal discovery. Over the past decade, extensive synthetic efforts stemming from seven research groups have resulted in two racemic total syntheses to date. This review article takes the opportunity to survey these efforts and achievements so as to promote further research towards the asymmetric total synthesis of palhinine alkaloids.

Synthesis and chiroptical properties of axially chiral, binaphthol-based oligomers

1996 ◽  
Vol 37 (17) ◽  
pp. 2979-2982 ◽  
Author(s):  
Man-Kit Ng ◽  
Hak-Fun Chow ◽  
Tze-Lock Chan ◽  
Thomas C.W. Mak
Keyword(s):  
Chiroptical Properties ◽  
Axially Chiral

scholarly journals Mechanically axially chiral catenanes and noncanonical chiral rotaxanes

2021 ◽  
Author(s):  
John Maynard ◽  
Peter Gallagher ◽  
David Lozano ◽  
Patrick Butler ◽  
Steve Goldup
Keyword(s):  
Building Blocks ◽  
Biological Properties ◽  
Mirror Image ◽  
Chiral Structure ◽  
Molecular Chirality ◽  
Symmetry Properties ◽  
Axially Chiral ◽  
A Chain ◽  
Stereoselective Syntheses ◽  
Molecular Rings

Chirality, the property of objects that are distinct from their own mirror image, is important in many scientific areas but particularly chemistry, where the appearance of molecular chirality because of rigid arrangements of atoms in space famously influences a molecule’s biological properties. Less generally appreciated is that two molecular rings with chemically distinct faces combined like links in a chain results in a chiral structure even when the rings are achiral. To date, no enantiopure examples of such mechanically axially chiral catenanes has been reported. We re-examined the symmetry properties of the mechanically axially chiral motif and identified a straightforward route to such molecules from simple building blocks. We also identify that common representations of axially chiral catenanes obscure that a previously overlooked stereogenic unit arises when a ring is threaded onto a dumbbell-shaped molecule to generate a rotaxane. These insights allowed us to demonstrate the first stereoselective syntheses of an axially chiral catenane and a noncanonical axially chiral rotaxane motif. With methods to access these structures in hand, the process of exploring their properties and applications can now begin.

scholarly journals Immunity Boosting Drugs in Ayurveda – A Review

2020 ◽  
Vol 11 (SPL4) ◽  
pp. 992-996
Author(s):  
Prasad Umakant Wallalwar ◽  
Pradnya Dandekar ◽  
Shweta Dadarao Parwe
Keyword(s):  
Immune System ◽  
Medical Science ◽  
Experimental Studies ◽  
Healthy Person ◽  
Review Article ◽  
Medicinal Herbs ◽  
Immune Modulators ◽  
Diseased Condition ◽  
Immense Potential

The concept of Immunity is mentioned as ‘Vyadhikshamatwa’ in Ayurveda. In Ayurveda numbers of medicinal herbs are described under immunity-enhancing drugs category. The concept of immunity enhancer is explained under the category of Rasayan chikitsa in Ayurveda. These herbs are used in various diseases, especially by modulating the immune system. These herbs are called as Rasayan Dravyas. Ayurveda medical science comprises the herbs which are Rasayana and also which are non-Rasayana in nature. In Samhitas entirely enriched with enormous data of Rasayana medicinal herbs acting as immune modulators. The data of available Samhitas and researches show that these Rasayana herbs have immense potential as immune modulators. Advanced researches have proven that drugs like Guduchi, Haritaki, Ashwagandha, Brahmi, Jyotishmati act as a good immune enhancer. Theses herbs are mentioned in Ayurveda as Rasayana drugs. Experimental studies also have proven the role of Rasayana drugs as antioxidant, adoptogenic and having anti-stress activities. These Rasayana drugs as having immunity enhancer protect the health of a healthy person and protects them from any type of diseased condition. Charakacharya had mentioned Rasayanchikitsa adhyay as the first addhya of their chikitsasthan considering his aim as ‘Swasthasya Swasthya Rakshanam’. This means to protect the health of a healthy person as in priority by using immunity enhancer drugs as Rasayanas. This review article empowers such reviewed data on Rasayan medicinal herbs as a promising future target for immunotherapy.

scholarly journals Mechanically axially chiral catenanes and noncanonical chiral rotaxanes

2021 ◽  
Author(s):  
John Maynard ◽  
Peter Gallagher ◽  
David Lozano ◽  
Patrick Butler ◽  
Steve Goldup
Keyword(s):  
Building Blocks ◽  
Biological Properties ◽  
Mirror Image ◽  
Chiral Structure ◽  
Molecular Chirality ◽  
Symmetry Properties ◽  
Axially Chiral ◽  
A Chain ◽  
Stereoselective Syntheses ◽  
Molecular Rings

Chirality, the property of objects that are distinct from their own mirror image, is important in many scientific areas but particularly chemistry, where the appearance of molecular chirality because of rigid arrangements of atoms in space famously influences a molecule’s biological properties. Less generally appreciated is that two molecular rings with chemically distinct faces combined like links in a chain results in a chiral structure even when the rings are achiral. To date, no enantiopure examples of such mechanically axially chiral catenanes has been reported. We re-examined the symmetry properties of the mechanically axially chiral motif and identified a straightforward route to such molecules from simple building blocks. We also identify that common representations of axially chiral catenanes obscure that a previously overlooked stereogenic unit arises when a ring is threaded onto a dumbbell-shaped molecule to generate a rotaxane. These insights allowed us to demonstrate the first stereoselective syntheses of an axially chiral catenane and a noncanonical axially chiral rotaxane motif. With methods to access these structures in hand, the process of exploring their properties and applications can now begin.

scholarly journals Bioanalytical HPLC Applications of In-Tube Solid Phase Microextraction: A Two-Decade Overview

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2096 ◽  
Author(s):  
Natalia Manousi ◽  
Paraskevas D. Tzanavaras ◽  
Constantinos K. Zacharis
Keyword(s):  
Solid Phase Microextraction ◽  
Considerable Increase ◽  
Solid Phase ◽  
Time Frame ◽  
Review Article ◽  
Treatment Technique ◽  
Sample Treatment ◽  
Research Groups ◽  
The Past ◽  
Bioanalytical Applications

In-tube solid phase microextraction is a cutting-edge sample treatment technique offering significant advantages in terms of miniaturization, green character, automation, and preconcentration prior to analysis. During the past years, there has been a considerable increase in the reported publications, as well as in the research groups focusing their activities on this technique. In the present review article, HPLC bioanalytical applications of in-tube SPME are discussed, covering a wide time frame of twenty years of research reports. Instrumental aspects towards the coupling of in-tube SPME and HPLC are also discussed, and detailed information on materials/coatings and applications in biological samples are provided.

A Review of Ruthenium-catalyzed C-N Bond Formation Reactions for the Synthesis of Five-membered N-heterocycles

2019 ◽  
Vol 23 (18) ◽  
pp. 1901-1944 ◽  
Author(s):  
Navjeet Kaur ◽  
Neha Ahlawat ◽  
Yamini Verma ◽  
Pooja Grewal ◽  
Pranshu Bhardwaj
Keyword(s):  
Heterocyclic Compounds ◽  
Functional Group ◽  
Bond Formation ◽  
Review Article ◽  
Transition Metal Catalysts ◽  
Heterocyclic Chemistry ◽  
Research Groups ◽  
Reaction Conditions ◽  
Alternative Pathways ◽  
Molecular Complexity

The field of heterocyclic chemistry has been revolutionized using transition metal catalysts in recent years. Various research groups have focused on the development of general protocols to achieve better functional group compatibilities and greater levels of molecular complexity under mild reaction conditions, using easily available starting substrates. The methodologies used earlier for their synthesis were less approachable to organic chemists because of their high cost, highly specified instrumentation and inconvenient methods. For both stereoselective and regioselective synthesis of five-membered nitrogen- containing heterocycles, cyclic reactions that are Ru-catalyzed have known to be very efficient. These methods have many advantages as compared to alternative pathways involved in the synthesis of heterocyclic compounds. In this review article, we concentrated on the synthesis of nitrogen-containing five-membered heterocycles in the presence of a ruthenium catalyst. This review mostly covers the literature published during the period from 1977-2019.

Stereogenic cyclic oligonaphthalenes displaying ring size-dependent handedness of circularly polarized luminescence (CPL)

2019 ◽  
Vol 55 (19) ◽  
pp. 2749-2752 ◽  
Author(s):  
Yuki Nojima ◽  
Masashi Hasegawa ◽  
Nobuyuki Hara ◽  
Yoshitane Imai ◽  
Yasuhiro Mazaki
Keyword(s):  
Coupling Reaction ◽  
Ring Size ◽  
Chiroptical Properties ◽  
Circularly Polarized ◽  
Size Dependent ◽  
Circularly Polarized Luminescence ◽  
Polarized Luminescence ◽  
Cyclic Oligomers

A series of cyclic oligomers with Dn symmetry (n = 2–5) based on chiral (R)/(S)-binaphthyl exhibiting intensive chiroptical properties were synthesized by using a Ni(0)-catalyzed coupling reaction.

scholarly journals Anatomical, physiological and pathophysiological features of the lower urinary tract in gender and age aspects

2021 ◽  
Vol 11 (3) ◽  
pp. 241-256
Author(s):  
Igor S. Shormanov ◽  
Andrey S. Solovyov ◽  
Igor A. Tyuzikov ◽  
Sergey V. Kulikov
Keyword(s):  
Urinary Tract ◽  
Hormonal Regulation ◽  
Lower Urinary Tract ◽  
Experimental Studies ◽  
Review Article ◽  
Men And Women ◽  
Separate Section ◽  
Age Related ◽  
Gender And Age ◽  
Lower Urinary

In the review article, based on the results of modern clinical and experimental studies, gender and age-related features of the anatomy, physiology and pathophysiology of the lower urinary tract are considered. The features of the structure and functioning of the urothelium, myothelium, neurothelium and endothelium of the lower urinary tract in men and women are described in detail. A separate section of the review is devoted to the peculiarities of hormonal regulation of the lower urinary tract, depending on gender and age.

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