scholarly journals Cover Feature: Structure‐Function Relationships in Fructose Dehydration to 5‐Hydroxymethylfurfural under Mild Conditions by Porous Ionic Crystals Constructed with Analogous Building Blocks (ChemCatChem 16/2019)

ChemCatChem ◽  
2019 ◽  
Vol 11 (16) ◽  
pp. 3553-3553
Author(s):  
Takumi Yamada ◽  
Keigo Kamata ◽  
Eri Hayashi ◽  
Michikazu Hara ◽  
Sayaka Uchida
Keyword(s):  
Structure Function ◽  
Building Blocks ◽  
Ionic Crystals ◽  
Mild Conditions ◽  
Feature Structure ◽  
Fructose Dehydration

A de novo Synthesis of Oxindoles from Cyclohexanone-Derived γ-Keto-ester Acceptors Using a Desaturative Amination–Cyclization Approach

Synthesis ◽  
2021 ◽  
Author(s):  
Henry P. Caldora ◽  
Sebastian Govaerts ◽  
Shashikant U. Dighe ◽  
Oliver J. Turner ◽  
Daniele Leonori
Keyword(s):  
Amino Acids ◽  
Primary Amine ◽  
De Novo ◽  
Building Blocks ◽  
De Novo Synthesis ◽  
Keto Ester ◽  
Mild Conditions ◽  
Blockbuster Drug

Here we report a desaturative approach for oxindole synthesis. This method uses simple γ-ester-containing cyclohexanones and primary amine building blocks as coupling partners. A dual photoredox–cobalt manifold is used to generate a secondary aniline that, upon heating, cyclizes with the pendent ester functionality. The process operates under mild conditions and was applied to the modification of several amino acids, the blockbuster drug mexiletine, as well as the formation of dihydroquinolinones.

scholarly journals Generation of Bis(ferrocenyl)silylenes from Siliranes

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5917
Author(s):  
Yang Pan ◽  
Shogo Morisako ◽  
Shinobu Aoyagi ◽  
Takahiro Sasamori
Keyword(s):  
Transition Metal ◽  
Building Block ◽  
Building Blocks ◽  
Redox Behavior ◽  
Organosilicon Compounds ◽  
Design And Synthesis ◽  
Mild Conditions ◽  
Redox Active ◽  
Electronic Perturbation ◽  
Active Transition

Divalent silicon species, the so-called silylenes, represent attractive organosilicon building blocks. Isolable stable silylenes remain scarce, and in most hitherto reported examples, the silicon center is stabilized by electron-donating substituents (e.g., heteroatoms such as nitrogen), which results in electronic perturbation. In order to avoid such electronic perturbation, we have been interested in the chemistry of reactive silylenes with carbon-based substituents such as ferrocenyl groups. Due to the presence of a divalent silicon center and the redox-active transition metal iron, ferrocenylsilylenes can be expected to exhibit interesting redox behavior. Herein, we report the design and synthesis of a bis(ferrocenyl)silirane as a precursor for a bis(ferrocenyl)silylene, which could potentially be used as a building block for redox-active organosilicon compounds. It was found that the isolated bis(ferrocenyl)siliranes could be a bottleable precursor for the bis(ferrocenyl)silylene under mild conditions.

Evolution of glycolytic enzymes

1981 ◽  
Vol 293 (1063) ◽  
pp. 191-203 ◽  
Keyword(s):  
Structure Function ◽  
Quaternary Structure ◽  
Extreme Environments ◽  
Building Blocks ◽  
Binding Domain ◽  
Glycolytic Enzymes ◽  
Nucleotide Binding Domain ◽  
Structural Adaptation ◽  
Convergence And Divergence ◽  
Complex Enzymes

The requirements for glycolysis are examined in relation to other essential metabolic processes in the most primitive organisms. The construction of more complex enzymes from primitive domain building blocks is assessed with respect to glycolytic enzymes. Special attention is given to the evolution of the NAD binding domain in dehydrogenases and the related, frequently observed nucleotide binding domain. An attempt is made to differentiate between convergence and divergence of frequently observed domains. Consideration is given to the structure-function relation of these domains and the development of quaternary structure in later stages of evolution. Some attention is also given to the evolution of structural adaptation to extreme environments as a means of differentiating between essential functions and specific modifications.

Multi-functional supramolecular building blocks with hydroxy piperidino groups: new opportunities for developing nonlinear optical ionic crystals

CrystEngComm ◽  
2016 ◽  
Vol 18 (31) ◽  
pp. 5832-5841 ◽  
Author(s):  
Kang-Hyun Lee ◽  
Seung-Heon Lee ◽  
Hoseop Yun ◽  
Mojca Jazbinsek ◽  
Jun Wan Kim ◽  
...  
Keyword(s):  
Nonlinear Optical ◽  
Building Blocks ◽  
Ionic Crystals

scholarly journals Regioselective Dehydration of Sugar Thioacetals under Mild Conditions

2020 ◽  
Author(s):  
Rachel Szpara ◽  
Alexander Goyder ◽  
Michael Porter ◽  
Helen Hailes ◽  
Tom Sheppard
Keyword(s):  
Organic Synthesis ◽  
Three Dimensional ◽  
Building Blocks ◽  
Waste Biomass ◽  
Straight Chain ◽  
Metabolic Resistance ◽  
Mild Conditions ◽  
Hexose Sugars ◽  
Dehydration Reactions ◽  
Chain Form

Pentose and hexose sugars are abundant constituents of waste biomass, making them sustainable, chiral building blocks for organic synthesis. The demand for chiral saturated heterocyclic rings from the pharmaceutical industry is increasing as they provide well-defined three-dimensional frameworks that show increased metabolic resistance. Through the formation of thioacetals, sugars may be manipulated in their straight-chain form and dehydrated selectively under basic conditions at C-2. This approach was applied to an array of sugars and extended to the production of useful chiral THFs via further selective dehydration reactions.

scholarly journals A physicochemical orthophosphate cycle via a kinetically stable thermodynamically activated intermediate enables mild prebiotic phosphorylations

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Oliver R. Maguire ◽  
Iris B. A. Smokers ◽  
Wilhelm T. S. Huck
Keyword(s):  
Aqueous Solution ◽  
Organic Compounds ◽  
Prebiotic Chemistry ◽  
Building Blocks ◽  
General Strategy ◽  
Scarce Resources ◽  
Mild Conditions ◽  
Phosphorylated Compounds ◽  
Nucleotide Triphosphates ◽  
Fundamental Challenge

AbstractThe incorporation of orthophosphate from scarce geochemical sources into the organic compounds essential for life under mild conditions is a fundamental challenge for prebiotic chemistry. Here we report a prebiotic system capable of overcoming this challenge by taking inspiration from extant life’s recycling of orthophosphate via its conversion into kinetically stable thermodynamically activated (KSTA) nucleotide triphosphates (e.g. ATP). We separate the activation of orthophosphate from its transfer to organic compounds by, crucially, first accumulating a KSTA phosphoramidate. We use cyanate to activate orthophosphate in aqueous solution under mild conditions and then react it with imidazole to accumulate the KSTA imidazole phosphate. In a paste, imidazole phosphate phosphorylates all the essential building blocks of life. Integration of this chemistry into a wet/dry cycle enables the continuous recycling of orthophosphate and the accretion of phosphorylated compounds. This system functions even at low reagent concentrations due to solutes concentrating during evaporation. Our system demonstrates a general strategy for how to maximise the usage of scarce resources based upon cycles which accumulate and then release activated intermediates.

Enantioselective C(sp3)–C(sp3) Cross-Coupling of Non-activated Alkyl Electrophiles via Nickel Hydride Catalysis

2020 ◽  
Author(s):  
Srikrishna Bera ◽  
Runze Mao ◽  
Xile Hu
Keyword(s):  
Organic Molecules ◽  
Functional Group ◽  
Cross Coupling ◽  
Building Blocks ◽  
Carbon Centers ◽  
Mild Conditions ◽  
Drug Molecules ◽  
Nickel Hydride ◽  
Alkyl Electrophiles ◽  
Attractive Candidate

Cross-coupling of two alkyl fragments is an efficient method to produce organic molecules rich in sp<sup>3</sup>-hydridized carbon centers, which are attractive candidate compounds in drug discovery. Enantioselective C(sp<sup>3</sup>)-C(sp<sup>3</sup>) coupling, especially of alkyl electrophiles without an activating group (aryl, vinyl, carbonyl) is challenging. Here we report a strategy based on nickel hydride addition to internal olefins followed by nickel-catalyzed alkyl-alkyl coupling. This strategy enables enantioselective cross-coupling of non-activated alkyl iodides with alkenyl boronates to produce chiral alkyl boronates. Employing readily available and stable olefins as pro-chiral nucleophiles, the coupling proceeds under mild conditions and exhibits broad scope and high functional group tolerance. Applications in late-stage functionalization of natural products and drug molecules, synthesis of chiral building blocks, and enantioselective formal synthesis of (<i>S</i>)-(+)-Pregabalin are demonstrated.<br>

Recent Advances in C-C/Heteroatom Bond Forming and Annulation Reactions of β-Ketodithioesters

2021 ◽  
Vol 18 ◽  
Author(s):  
Laishram Momota Devi ◽  
Thokchom Prasanta Singh ◽  
Okram Mukherjee Singh
Keyword(s):  
Heterocyclic Compounds ◽  
Multicomponent Reactions ◽  
Building Blocks ◽  
Heterocyclic Synthesis ◽  
Bond Forming ◽  
Mild Conditions ◽  
The Past ◽  
Rapid Construction ◽  
Fresh Perspective ◽  
Good Number

: β Ketodithioesters (KDEs) are versatile building blocks for the rapid construction of various heterocyclic compounds. Quite a good number of successful reactions based on KDEs have been developed in the past decade for the construction of heterocyclic skeletons under mild conditions. This review covers the new C-C/X bond formation and annulation reactions of KDEs with dielectrophilic or dinucleophilic reagents. Multicomponent reactions using KDEs to construct various heterocycles are also the major contents in this review. Objective: The aim of this review is to bring a fresh perspective on the application of KDEs in organic synthesis covering from 2013 to 2020. Conclusion: From this review, it is clear that KDEs have been the object of numerous studies on its use in heterocyclic synthesis. The presence of different functional groups on this synthon permits the incorporation of C-C/X sources into the final targets, which is the beauty of KDEs.

Fluoroazaindolines by an Uncommon Radical ipso-Substitution of a C-F Bond

2011 ◽  
Vol 64 (4) ◽  
pp. 416 ◽  
Author(s):  
Yann Laot ◽  
Laurent Petit ◽  
Ngoc Diem My Tran ◽  
Samir Z. Zard
Keyword(s):  
Fluorine Atom ◽  
Building Blocks ◽  
Mild Conditions ◽  
Ipso Substitution ◽  
Initial Procedure

Trifluoroazaindoline derivatives are prepared using the first synthetically useful radical ipso-substitution of a fluorine atom. The initial procedure has been improved to allow the gram scale synthesis of these building blocks, which can be regioselectively substituted by nucleophiles under mild conditions to rapidly access a library of new molecules. Oxidation to the corresponding fluoroazaindole core has also been accomplished.

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