scholarly journals Different Strategies for Obtaining Enantiopure Hemicryptophanes

Synthesis ◽  
2019 ◽  
Vol 51 (10) ◽  
pp. 2081-2099 ◽  
Author(s):  
Cédric Colomban ◽  
Bastien Châtelet ◽  
Alexandre Martinez
Keyword(s):  
Short Review ◽  
Chiral Hplc ◽  
Synthetic Receptors ◽  
Resolution Of Enantiomers ◽  
Racemic Mixtures ◽  
Separation Of Diastereomers

Hemicryptophanes have recently emerged as an attractive class of cages due to their interesting applications as supramolecular receptors and catalysts. Over the last decade, substantial advances have been made regarding the preparation of enantiopure versions of these synthetic receptors. Enantiopure hemicryptophanes are commonly obtained through the separation of diastereomers by chromatography, or by resolution of racemic mixtures using chiral HPLC. This short review summarizes the existing methods to access to these chiral organic architectures and discusses the benefits and drawbacks of each approach.1 Introduction2 Enantiopure Hemicryptophanes Obtained by Introducing Additional Chiral Units and Separation of Diastereomers2.1 Synthesis by Means of Intramolecular Macrocyclization Reactions2.2 [1+1] Coupling of the CTV and the Southern Part3 Enantiopure Hemicryptophanes Obtained by Means of Chiral HPLC Resolution of Enantiomers3.1 Resolution of Hemicryptophane Racemates3.2 Resolution of CTV-Based Precursor Racemates4 Conclusion

Absolute structure determination as a reference for the enantiomeric resolution of racemic mixtures of cyclophosphazenes via chiral high-performance liquid chromatography

2009 ◽  
Vol 65 (3) ◽  
pp. 355-362 ◽  
Author(s):  
Simon Coles ◽  
David Davies ◽  
Michael Hursthouse ◽  
Serkan Yeşilot ◽  
Bünyemin Çoşut ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Reversed Phase ◽  
Chiral Hplc ◽  
Enantiomeric Resolution ◽  
Space Groups ◽  
X Ray Crystallography ◽  
Racemic Mixtures ◽  
The Absolute

Reversed-phase chiral high-performance liquid chromatography (HPLC) is a potentially powerful technique for the enantiomeric resolution of racemic mixtures, although the elution order of enantiomers is only relative and it is necessary to fully characterize reference systems for this method to provide absolute configurational information. The enantiomeric resolution of a series of racemic di-spiro cyclotriphosphazene derivatives, N3P3 X 2[O(CH2)3NH]2 (X = Cl, Ph, SPh, NHPh, OPh) [(1)–(5), respectively] was carried out by reversed-phase chiral HPLC on a commercially available Pirkle-type chiral stationary phase (R,R)-Whelk-01 using 85:15 (v/v) hexane–thf as the mobile phase. The absolute configurations of the resulting enantiomers of compounds (3) (X = SPh) and (5) (X = OPh) were determined unambiguously by X-ray crystallography. For both (3) and (5) it was found that the SS enantiomer eluted before the RR enantiomer, indicating a convenient method to determine the absolute configurations of enantiomers of this series of cyclophosphazene derivatives and providing the first set of enantiomeric reference compounds for cyclophosphazene derivatives. These structures demonstrate an interesting anomaly in that the pair of enantiomers of (3) crystallize in enantiomorphically paired space groups whilst, under the same conditions, the solid-state forms of the enantiomers of (5) form structures in Sohncke space groups that are not enantiomorphous.

scholarly journals Regioselective and Stereoselective Epoxidation of n-3 and n-6 Fatty Acids by Fungal Peroxygenases

Antioxidants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1888
Author(s):  
Alejandro González-Benjumea ◽  
Dolores Linde ◽  
Juan Carro ◽  
René Ullrich ◽  
Martin Hofrichter ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Double Bond ◽  
Chemical Synthesis ◽  
Polyunsaturated Fatty Acids ◽  
Chiral Hplc ◽  
Pharmacological Activities ◽  
Racemic Mixtures ◽  
Synthetic Utility ◽  
Stereoselective Epoxidation

Epoxide metabolites from n-3 and n-6 polyunsaturated fatty acids arouse interest thanks to their physiological and pharmacological activities. Their chemical synthesis has significant drawbacks, and enzymes emerge as an alternative with potentially higher selectivity and greener nature. Conversion of eleven eicosanoid, docosanoid, and other n-3/n-6 fatty acids into mono-epoxides by fungal unspecific peroxygenases (UPOs) is investigated, with emphasis on the Agrocybe aegerita (AaeUPO) and Collariella virescens (rCviUPO) enzymes. GC-MS revealed the strict regioselectivity of the n-3 and n-6 reactions with AaeUPO and rCviUPO, respectively, yielding 91%-quantitative conversion into mono-epoxides at the last double bond. Then, six of these mono-epoxides were obtained at mg-scale, purified and further structurally characterized by 1H, 13C and HMBC NMR. Moreover, chiral HPLC showed that the n-3 epoxides were also formed (by AaeUPO) with total S/R enantioselectivity (ee > 99%) while the n-6 epoxides (from rCviUPO reactions) were formed in nearly racemic mixtures. The high regio- and enantioselectivity of several of these reactions unveils the synthetic utility of fungal peroxygenases in fatty acid epoxidation.

ChemInform Abstract: Chiral HPLC for Efficient Resolution of Enantiomers

ChemInform ◽  
2009 ◽  
Vol 40 (18) ◽  
Author(s):  
Yoshio Okamoto ◽  
Tomoyuki Ikai
Keyword(s):  
Chiral Hplc ◽  
Resolution Of Enantiomers

Chiral HPLC for efficient resolution of enantiomers

2008 ◽  
Vol 37 (12) ◽  
pp. 2593 ◽  
Author(s):  
Yoshio Okamoto ◽  
Tomoyuki Ikai
Keyword(s):  
Chiral Hplc ◽  
Resolution Of Enantiomers

Pollutant Identification by Selected Area Electron Diffraction

1974 ◽  
Vol 32 ◽  
pp. 532-533
Author(s):  
R. E. Ferrell ◽  
G. G. Paulson ◽  
C. W. Walker
Keyword(s):  
Thermal Treatment ◽  
Electron Diffraction ◽  
Sample Preparation ◽  
Crystal Structures ◽  
Water Samples ◽  
Environmental Samples ◽  
Short Review ◽  
Selected Area Electron Diffraction ◽  
Multiple Component

Selected area electron diffraction (SAD) has been used successfully to determine crystal structures, identify traces of minerals in rocks, and characterize the phases formed during thermal treatment of micron-sized particles. There is an increased interest in the method because it has the potential capability of identifying micron-sized pollutants in air and water samples. This paper is a short review of the theory behind SAD and a discussion of the sample preparation employed for the analysis of multiple component environmental samples.

POPDC proteins and cardiac function

2019 ◽  
Vol 47 (5) ◽  
pp. 1393-1404 ◽  
Author(s):  
Thomas Brand
Keyword(s):  
Potential Role ◽  
Striated Muscle ◽  
Short Review ◽  
Effector Proteins ◽  
Muscle Disease ◽  
Disease Genes ◽  
Protein Protein Interaction ◽  
Interaction Partners ◽  
And Function

Abstract The Popeye domain-containing gene family encodes a novel class of cAMP effector proteins in striated muscle tissue. In this short review, we first introduce the protein family and discuss their structure and function with an emphasis on their role in cyclic AMP signalling. Another focus of this review is the recently discovered role of POPDC genes as striated muscle disease genes, which have been associated with cardiac arrhythmia and muscular dystrophy. The pathological phenotypes observed in patients will be compared with phenotypes present in null and knockin mutations in zebrafish and mouse. A number of protein–protein interaction partners have been discovered and the potential role of POPDC proteins to control the subcellular localization and function of these interacting proteins will be discussed. Finally, we outline several areas, where research is urgently needed.

4D printing technology, modern era: A short review

2020 ◽  
pp. 92-111
Author(s):  
Khodadad Mostakim ◽  
Nahid Imtiaz Masuk ◽  
Md. Rakib Hasan ◽  
Md. Shafikul Islam
Keyword(s):  
Smart Materials ◽  
Computer Aided Design ◽  
Short Review ◽  
Stimuli Responsive ◽  
4D Printing ◽  
Space Applications ◽  
Printing Technology ◽  
Practical Applications ◽  
Biomedical Technologies ◽  
Novel Material

The advancement in 3D printing has led to the rapid growth of 4D printing technology. Adding time, as the fourth dimension, this technology ushered the potential of a massive evolution in fields of biomedical technologies, space applications, deployable structures, manufacturing industries, and so forth. This technology performs ingenious design, using smart materials to create advanced forms of the 3-D printed specimen. Improvements in Computer-aided design, additive manufacturing process, and material science engineering have ultimately favored the growth of 4-D printing innovation and revealed an effective method to gather complex 3-D structures. Contrast to all these developments, novel material is still a challenging sector. However, this short review illustrates the basic of 4D printing, summarizes the stimuli responsive materials properties, which have prominent role in the field of 4D technology. In addition, the practical applications are depicted and the potential prospect of this technology is put forward.

Role of the Structural Characteristics of Dendrimers in the Manifestation of the Antiamyloid Properties

INEOS OPEN ◽  
2020 ◽  
Vol 3 ◽  
Author(s):  
S. A. Sorokina ◽  
◽  
Yu. Yu. Stroilova ◽  
V. I. Muronets ◽  
Z. B. Shifrina ◽  
...  
Keyword(s):  
Neurodegenerative Diseases ◽  
Structural Characteristics ◽  
Short Review ◽  
External Factors ◽  
Amyloid Aggregation ◽  
Amyloid Proteins ◽  
Molecular Parameters ◽  
Amyloid Aggregates ◽  
Aggregation Processes

Among the compounds able to efficiently inhibit the amyloid aggregation of proteins and decompose the amyloid aggregates that cause neurodegenerative diseases, of particular interest are dendrimers, which represent individual macromolecules with the hypercrosslinked architectures and given molecular parameters. This short review outlines the peculiarities of the antiamyloid activity of dendrimers and discusses the effect of dendrimer structures and external factors on their antiamyloid properties. The potential of application of dendrimers in further investigations on the aggregation processes of amyloid proteins as the compounds that exhibit the remarkable antiamyloid activity is evaluated.

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