scholarly journals Diversity-oriented synthesis of glycomimetics

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Michael Meanwell ◽  
Gaelen Fehr ◽  
Weiwu Ren ◽  
Bharanishashank Adluri ◽  
Victoria Rose ◽  
...  
Keyword(s):  
Electrostatic Interactions ◽  
Density Functional ◽  
Kinetic Resolution ◽  
Density Functional Theory Calculations ◽  
Building Blocks ◽  
One Pot ◽  
Functional Theory ◽  
Diversity Oriented Synthesis ◽  
Naturally Occurring ◽  
Therapeutic Leads

AbstractGlycomimetics are structural mimics of naturally occurring carbohydrates and represent important therapeutic leads in several disease treatments. However, the structural and stereochemical complexity inherent to glycomimetics often challenges medicinal chemistry efforts and is incompatible with diversity-oriented synthesis approaches. Here, we describe a one-pot proline-catalyzed aldehyde α-functionalization/aldol reaction that produces an array of stereochemically well-defined glycomimetic building blocks containing fluoro, chloro, bromo, trifluoromethylthio and azodicarboxylate functional groups. Using density functional theory calculations, we demonstrate both steric and electrostatic interactions play key diastereodiscriminating roles in the dynamic kinetic resolution. The utility of this simple process for generating large and diverse libraries of glycomimetics is demonstrated in the rapid production of iminosugars, nucleoside analogues, carbasugars and carbohydrates from common intermediates.

scholarly journals Spectroscopic identification of fragment ions of DNA/RNA building blocks: the case of pyrimidine

2020 ◽  
Vol 22 (30) ◽  
pp. 17275-17290
Author(s):  
Kuntal Chatterjee ◽  
Otto Dopfer
Keyword(s):  
Density Functional Theory ◽  
Infrared Spectroscopy ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Building Blocks ◽  
Functional Theory ◽  
Fragment Ions ◽  
Sequential Loss ◽  
Spectroscopic Identification

The structure of the predominant fragments of the fundamental pyrimidine cation arising from sequential loss of HCN are identified by infrared spectroscopy of tagged ions and dispersion-corrected density functional theory calculations.

scholarly journals Microhydration of protonated biomolecular building blocks: protonated pyrimidine

2020 ◽  
Vol 22 (23) ◽  
pp. 13092-13107
Author(s):  
Kuntal Chatterjee ◽  
Otto Dopfer
Keyword(s):  
Density Functional Theory ◽  
Infrared Spectroscopy ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Building Blocks ◽  
Protonation Site ◽  
Functional Theory

The protonation site and evolution of the hydration network in microsolvated protonated pyrimidine clusters, H+Pym–(H2O)n with n = 1–4, has been explored by infrared spectroscopy and density functional theory calculations.

scholarly journals Physicochemical Insight into Coordination Systems Obtained from Copper(II) Bromoacetate and 1,10-Phenanthroline

Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5324
Author(s):  
Ewelina Krejner ◽  
Tomasz Sierański ◽  
Marcin Świątkowski ◽  
Marta Bogdan ◽  
Rafał Kruszyński
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Building Blocks ◽  
Radiation Absorption ◽  
Ir Absorption ◽  
Bromoacetic Acid ◽  
Functional Theory ◽  
Hirshfeld Analysis ◽  
Coordination Systems

Two different coordination compounds of copper were synthesized from the same building blocks (1,10-phenanthroline, bromoacetate anions, and copper cations). The synthesis parameters were carefully designed and evaluated to allow the change of the resulting compounds molecular structure, i.e., formation of mononuclear (bromoacetato-O,O’)(bromoacetato-O)aqua(1,10-phenanthroline-N,N’)copper(II) and dinuclear (μ-bromido-1:2κ2)bis(μ-bromoacetato-1κO,2κO’)bis(1,10-phenanthroline-N,N’)dicopper(II) bromoacetate bromoacetic acid solvate. The crystal, molecular and supramolecular structures of the studied compounds were determined and evaluated in Hirshfeld analysis. The UV-Vis-IR absorption and thermal properties were studied and discussed. For the explicit determination of the influence of compounds structure on radiation absorption in UV-Vis range, density functional theory and time-dependent density functional theory calculations were performed.

scholarly journals Expedient synthesis of E-hydrazone esters and 1H-indazole scaffolds through heterogeneous single-atom platinum catalysis

2019 ◽  
Vol 5 (12) ◽  
pp. eaay1537 ◽  
Author(s):  
Cuibo Liu ◽  
Zhongxin Chen ◽  
Huan Yan ◽  
Shibo Xi ◽  
Kah Meng Yam ◽  
...  
Keyword(s):  
Density Functional ◽  
Stereoselective Synthesis ◽  
Density Functional Theory Calculations ◽  
Building Blocks ◽  
Hydrogenation Reaction ◽  
Biologically Active ◽  
Single Atom ◽  
One Pot ◽  
Platinum Catalysis ◽  
Scalable Synthesis

Unprotected E-hydrazone esters are prized building blocks for the preparation of 1H-indazoles and countless other N-containing biologically active molecules. Despite previous advances, efficient and stereoselective synthesis of these compounds remains nontrivial. Here, we show that Pt single atoms anchored on defect-rich CeO2 nanorods (Pt1/CeO2), in conjunction with the alcoholysis of ammonia borane, promotes exceptionally E-selective hydrogenation of α-diazoesters to afford a wide assortment of N-H hydrazone esters with an overall turnover frequency of up to 566 hours−1 upon reaction completion. The α-diazoester substrates could be generated in situ from readily available carboxylic esters in one-pot hydrogenation reaction. Utility is demonstrated through concise, scalable synthesis of 1H-indazole–derived pharmaceuticals and their 15N-labeled analogs. The present protocol highlights a key mechanistic nuance wherein simultaneous coordination of a Pt site with the diazo N═N and ester carbonyl motifs plays a central role in controlling stereoselectivity, which is supported by density functional theory calculations.

Activation of Cellulose with Alkaline Earth Metals

2021 ◽  
Author(s):  
Gregory Facas ◽  
Vineet Maliekkal ◽  
Matthew Neurock ◽  
Paul Dauenhauer
Keyword(s):  
Density Functional ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Density Functional Theory Calculations ◽  
Alkaline Earth Metal ◽  
Magnesium Ions ◽  
Functional Theory ◽  
Naturally Occurring ◽  
Alkaline Earth Metal Ions ◽  
And Control

Alkaline earth metal ions accelerate the breaking of cellulose bonds and control the distribution of products in the pyrolysis of lignocellulose to biofuels and chemicals. Here, the activation of cellulose via magnesium ions was measured over a range of temperatures from 370 to 430 ⁰C for 20 to 2000 milliseconds and compared with activation of cellulose via calcium, another naturally-occurring alkaline earth metal in lignocellulose materials. The experimental approach of pulse heated analysis of solid/surface reactions (PHASR) showed that magnesium significantly catalyzes cellulose activation with a second order rate dependence on the catalyst concentration. An experimental barrier of 45.6 ± 2.1 kcal mol-1 and a pre-factor of 1.18 x 1016 (mmol Mg2+ / g CD)-2 * s-1 was obtained for the activation of α-cyclodextrin (CD), a cellulose surrogate, for catalyst concentrations of 0.1 to 0.5 mmol Mg+2 per gram of CD. First principles density functional theory calculations showed that magnesium ions play a dual role in catalyzing the reaction by breaking the hydrogen bonds with hydroxymethyl groups and destabilizing the reacting cellulose chain, thus making it more active. The calculated barrier of 47 kcal mol-1 is in agreement with the experimentally measured barriers and similar to that for calcium ion catalysts (~50 kcal mol-1).

scholarly journals Structural and electronic properties of oligo- and polythiophenes modified by substituents

2012 ◽  
Vol 3 ◽  
pp. 909-919 ◽  
Author(s):  
Simon P Rittmeyer ◽  
Axel Groß
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Electronic Devices ◽  
Density Functional Theory Calculations ◽  
Building Blocks ◽  
Band Gaps ◽  
Molecular Electronic ◽  
Functional Theory ◽  
Structural And Electronic Properties ◽  
Electronic And Structural Properties

The electronic and structural properties of oligo- and polythiophenes that can be used as building blocks for molecular electronic devices have been studied by using periodic density functional theory calculations. We have in particular focused on the effect of substituents on the electronic structure of thiophenes. Whereas singly bonded substituents, such as methyl, amino or nitro groups, change the electronic properties of thiophene monomers and dimers, they hardly influence the band gap of polythiophene. In contrast, phenyl-substituted polythiophenes as well as vinyl-bridged polythiophene derivatives exhibit drastically modified band gaps. These effects cannot be explained by simple electron removal or addition, as calculations for charged polythiophenes demonstrate.

Tribological properties of a series of carbon dots modified by ionic liquids with various anion species: experimental findings and density functional theory calculations

2021 ◽  
Author(s):  
Baogang Wang ◽  
Lilong Zhang ◽  
Na Wang ◽  
Wenmeng Duan ◽  
Weiwei Tang
Keyword(s):  
Ionic Liquids ◽  
Carbon Dots ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
One Pot ◽  
Functional Theory ◽  
Exchange Processes ◽  
The One ◽  
Experimental Findings ◽  
Anion Species

A series of carbon dots modified by ionic liquids with various anion species (CDs-ILs-X) were facile synthesized by the one-pot pyrolysis method and subsequent anion exchange processes, where the X-...

Synthesis, Characterization, and Electronic Structures of Organically Templated Lead Halides with One- and Two-Dimensional Hybrid Structures, [(nbq)(PbI3)]n and {[(CH3)3NC2H4N(CH3)3]3(Pb6I18)}n

2007 ◽  
Vol 60 (8) ◽  
pp. 595 ◽  
Author(s):  
Hao-Hong Li ◽  
Zhi-Rong Chen ◽  
Liang-Qia Guo ◽  
Kai-Ning Ding ◽  
Jun-Qian Li ◽  
...  
Keyword(s):  
Quaternary Ammonium ◽  
Density Functional ◽  
Crystal Packing ◽  
Density Functional Theory Calculations ◽  
Building Blocks ◽  
Two Dimensional ◽  
Functional Theory ◽  
Structure Directing Agents ◽  
Inorganic Framework ◽  
Ammonium Compounds

Two new organically templated lead(ii) iodide complexes, [(nbq)(PbI3)]n 1 and {[(CH3)3NC2H4N(CH3)3]3(Pb6I18)}n 2, have been synthesized in the presence of aromatic and aliphatic quaternary ammonium compounds, N-(n-butyl)quinolinium (nbq+) and [(CH3)3NC2H4N(CH3)3]2+, respectively, acting as structure-directing agents. Both 1 and 2 consist of uncoordinated structure-directing agents and inorganic moieties bound to the organic structure-directing agents. In 1, an inorganic (PbI3–)n one-dimensional polyanion chain is built up by face-sharing of distorted PbI6 tetrahedra. The inorganic framework of 2 presents a two-dimensional arrangement that could be discussed in terms of [Pb3I10]4– building blocks. Static attractive interactions between organic countercations and inorganic moieties were revealed through the crystal packing. Density functional theory calculations indicate that 1 possesses semiconductor properties, tuned by the π-electrons of nbq+. In contrast, 2 is conductive in the direction of aliphatic quaternary ammonium moiety.

scholarly journals Sequentially Catalyzed Three-Component Masuda–Suzuki–Sonogashira Synthesis of Fluorescent 2-Alkynyl-4-(7-azaindol-3-yl)pyrimidines: Three Palladium-Catalyzed Processes in a One-Pot Fashion

Synlett ◽  
2020 ◽  
Author(s):  
Thomas J. J. Müller ◽  
Daniel Drießen ◽  
Lukas Biesen
Keyword(s):  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Time Dependent ◽  
Absorption Bands ◽  
One Pot ◽  
Functional Theory ◽  
Efficient Access ◽  
Three Component Reaction ◽  
Palladium Catalyzed ◽  
Wavelength Absorption

The Masuda–Suzuki–Sonogashira sequence efficiently unites, in a one-pot fashion, a borylation, an arylation, and an alkynylation in the sense of a sequentially Pd-catalyzed three-component reaction to give fluorescent 2-alkynyl-4-(7-azaindol-3-yl) pyrimidines in yields of 24–83% (14 examples). Time-dependent density-functional theory calculations supported the electronic structure of the longest wavelength absorption bands, revealing that this novel consecutive three-component synthesis opens an efficient access to alkynyl meriolins, a novel class of potential inducers of apoptosis.

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