Regioselective and Catalyst-Free Epoxidation of (E)-3-[3-(2-Hydroxyaryl)-3-oxoprop-1-en-1-yl]chromones

Synlett ◽  
2018 ◽  
Vol 29 (20) ◽  
pp. 2633-2637 ◽  
Author(s):  
Mohamed Hammadi ◽  
Oualid Talhi ◽  
Artur Silva ◽  
Rachid Ameraoui ◽  
Ridha Hassaine ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Double Bond ◽  
Single Crystal ◽  
Density Functional ◽  
2D Nmr ◽  
Theoretical Studies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Uncatalyzed Reaction ◽  
High Yields

The uncatalyzed reaction of hydrogen peroxide with (E)-3-[3-(2-hydroxyaryl)-3-oxoprop-1-en-1-yl]chromones resulted in a regio­selective epoxidation of the chromone intracyclic C(2)=C(3) double bond to afford unique isomeric (E)-7a-[3-(2-hydroxyphenyl)-3-oxoprop-1-en-1-yl]-1aH-oxireno[2,3-b]chromen-7(7aH)-ones in high yields. 2D NMR and single-crystal X-ray diffraction were used to elucidate the structures of the chromanone epoxides. Density functional theoretical studies demonstrated a high electrophilicity of the starting chromones.

Thermal-induced transformation of glutamic acid to pyroglutamic acid and self-cocrystallization: a charge–density analysis

2022 ◽  
Vol 78 (2) ◽  
Author(s):  
Sehrish Akram ◽  
Arshad Mehmood ◽  
Sajida Noureen ◽  
Maqsood Ahmed
Keyword(s):  
Hydrogen Bonds ◽  
Glutamic Acid ◽  
Single Crystal ◽  
Diffraction Data ◽  
Density Functional ◽  
Quantitative Estimation ◽  
Topological Analysis ◽  
Pyroglutamic Acid ◽  
X Ray Diffraction ◽  
X Ray

Thermal-induced transformation of glutamic acid to pyroglutamic acid is well known. However, confusion remains over the exact temperature at which this happens. Moreover, no diffraction data are available to support the transition. In this article, we make a systematic investigation involving thermal analysis, hot-stage microscopy and single-crystal X-ray diffraction to study a one-pot thermal transition of glutamic acid to pyroglutamic acid and subsequent self-cocrystallization between the product (hydrated pyroglutamic acid) and the unreacted precursor (glutamic acid). The melt upon cooling gave a robust cocrystal, namely, glutamic acid–pyroglutamic acid–water (1/1/1), C5H7NO3·C5H9NO4·H2O, whose structure has been elucidated from single-crystal X-ray diffraction data collected at room temperature. A three-dimensional network of strong hydrogen bonds has been found. A Hirshfeld surface analysis was carried out to make a quantitative estimation of the intermolecular interactions. In order to gain insight into the strength and stability of the cocrystal, the transferability principle was utilized to make a topological analysis and to study the electron-density-derived properties. The transferred model has been found to be superior to the classical independent atom model (IAM). The experimental results have been compared with results from a multipolar refinement carried out using theoretical structure factors generated from density functional theory (DFT) calculations. Very strong classical hydrogen bonds drive the cocrystallization and lend stability to the resulting cocrystal. Important conclusions have been drawn about this transition.

Quantitative Analysis of Intermolecular Interactions in 3‐Cyano‐2‐Pyridones: Evaluation through Single Crystal X‐ray Diffraction and Density Functional Theory

2018 ◽  
Vol 3 (21) ◽  
pp. 5864-5873
Author(s):  
Sunil K. Rai ◽  
Tomasz Sierański ◽  
Shaziya Khanam ◽  
Krishnan Ravi Kumar ◽  
Balasubramanian Sridhar ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Quantitative Analysis ◽  
Single Crystal ◽  
Intermolecular Interactions ◽  
Density Functional ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray

Synthesis of highly functionalized 4-amino-2-(trifluoromethyl)-1H-pyrroles

Synthesis ◽  
2021 ◽  
Author(s):  
Nilo Zanatta ◽  
Lucimara L Zachow ◽  
Mateus Mittersteiner ◽  
Estefania da Costa Aquino ◽  
Helio G Bonacorso ◽  
...  
Keyword(s):  
Single Crystal ◽  
2D Nmr ◽  
Aliphatic Amines ◽  
X Ray Diffraction ◽  
X Ray ◽  
Reaction Condition ◽  
Primary Aliphatic Amines

In this work, the reactivity of 5-bromo-1,1,1-trifluoro-4-methoxypent-3-en-2-one toward primary aliphatic amines was studied. The reaction was found to be extremely selective to synthesize a series of 1-alkyl-4-aminoalkyl-2-trifluoromethyl-1H-pyrroles (13 examples, at yields up to 90%) and a series of highly functionalized β-enaminones (6 examples, at yields up to 78%), with only the amount of amine and the reaction condition needing to be controlled. The structure of the products was unambiguously determined by single crystal X-ray diffraction and 2D NMR experiments.

scholarly journals Two Dibenzoquinones from the Fungus Acremonium cavaraeanum

2017 ◽  
Vol 12 (11) ◽  
pp. 1934578X1701201
Author(s):  
Qiao Xu ◽  
Miao-Miao Zhang ◽  
Shu-Zhen Yana ◽  
Lu-Fen Cao ◽  
Qiang Lia ◽  
...  
Keyword(s):  
Single Crystal ◽  
2D Nmr ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Time

Two symmetrical dibenzoquinone derivatives were isolated from solid cultures of the fungus Acremonium cavaraeanum. Compound 1 was new and identified as 2,7-dihydroxy-3,6,9-trimethyl-9 H-xanthene-1,4,5,8-tetraone. Compound 2 was 3,3’,6,6’-tetrahydroxy-4,4’-dimethyl-1,1’-bi- p-benzoquinone, i.e. oosporein, which was reported from A. cavaraeanum for the first time. The structure of the dibenzoquinone (1) was unambiguously elucidated using a combination of MS, IR, 1D- and 2D-NMR, and the dibenzoquinone (2) was further determined by single-crystal X-ray diffraction.

Purification, characterization, crystal structure and NO production inhibitory activity of three new sesquiterpenoids from homalomena occulta

2018 ◽  
Vol 74 (11) ◽  
pp. 1440-1446
Author(s):  
Qi Zhang ◽  
Li Ma ◽  
Zhaoxia Qu ◽  
Guige Hou ◽  
Yanan Wang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
2D Nmr ◽  
Inhibitory Effect ◽  
Raw 264.7 Cells ◽  
No Production ◽  
Raw 264.7 ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spectroscopic Analyses

Two new isodaucane-type sesquiterpenoids, namely (1R,4S,5S,6R,7S,10R)-isodauc-6,7,10-triol, C15H28O3, (1), and (1R,4S,5S,6S,7S,10R)-isodauc-6,7,10-triol, (2), and a new eudesmane-type sesquiterpenoid, 1β,4β,5α-trihydroxyeudesmane, (3), were obtained from the rhizomes of homalomena occulta with the aid of column chromatography. Their structures were elucidated based on extensive spectroscopic analyses, including 1D NMR, 2D NMR and HRESIMS. The structure of (1) was confirmed by single-crystal X-ray diffraction and the absolute configuration was assigned with respect to that of the precursor. The single-crystal structure reveals that adjacent molecules of (1) embrace through two groups of intermolecular O—H...O hydrogen bonds to generate a two-dimensional sheet with a 63-net topology. The three compounds were evaluated for their activity against lipopolysaccharide-induced production of nitrogen oxide (NO) in RAW 264.7 cells, and (1) showed an inhibitory effect on NO production, with IC50 values of 5.7±0.22 µM.

Synthetic, X-ray Diffraction, Electrochemical, and Density Functional Theoretical Studies of (Indenyl)ruthenium Complexes Containing Dithiolate Ligands

2007 ◽  
Vol 2007 (24) ◽  
pp. 3827-3840 ◽  
Author(s):  
Sin Yee Ng ◽  
Jialin Tan ◽  
Wai Yip Fan ◽  
Weng Kee Leong ◽  
Lai Yoong Goh ◽  
...  
Keyword(s):  
Density Functional ◽  
Ruthenium Complexes ◽  
Theoretical Studies ◽  
X Ray Diffraction ◽  
X Ray

Crystal structure of (Z)-Cembr-4-ene-15,19,20-triol

1977 ◽  
Vol 30 (12) ◽  
pp. 2723 ◽  
Author(s):  
EN Maslen ◽  
CL Raston ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Double Bond ◽  
Single Crystal ◽  
Least Squares ◽  
Structure Determination ◽  
Title Compound ◽  
X Ray Diffraction ◽  
Relative Configuration ◽  
Macrocyclic Ring ◽  
X Ray

The crystal structure of the title compound, CZOH3803 [compound (1) in ref.'], has been determined by single-crystal X-ray diffraction at 295(1) K and refined by least squares to a residual of 0.045 for 954 'observed' reflections. Crystals are monoclinic, P2', a 9.281(2), b 17.798(6), c 6.417(1) A, B 93.81(3)", Z 2. The structure determination establishes the relative configuration of the chiral centres within the 14-membered macrocyclic ring and shows the double bond to have the unusual (Z) configuration.

A cyanide-bridged FeIII–MnII heterobimetallic one-dimensional coordination polymer: synthesis, crystal structure, experimental and theoretical magnetism investigation

2019 ◽  
Vol 75 (11) ◽  
pp. 1475-1481 ◽  
Author(s):  
Wenlong Lan ◽  
Zhen Zhou ◽  
Jie Li ◽  
Yong Dou ◽  
Xiaoyun Hao ◽  
...  
Keyword(s):  
Coordination Polymer ◽  
Single Crystal ◽  
Density Functional ◽  
Linear Chain ◽  
Coupling Constants ◽  
Antiferromagnetic Coupling ◽  
Chain Model ◽  
X Ray Diffraction ◽  
One Dimensional ◽  
X Ray

A new cyanide-bridged FeIII–MnII heterobimetallic coordination polymer (CP), namely catena-poly[[[N,N′-(1,2-phenylene)bis(pyridine-2-carboxamidato)-κ4 N,N′,N′′,N′′′]iron(III)]-μ-cyanido-κ2 C:N-[bis(4,4′-bipyridine-κN)bis(methanol-κO)manganese(II)]-μ-cyanido-κ2 N:C], {[FeMn(C18H12N4O2)(CN)2(C10H8N2)2(CH3OH)2]ClO4} n , (1), was prepared by the self-assembly of the trans-dicyanidoiron(III)-containing building block [Fe(bpb)(CN)2]− [bpb2− = N,N′-(1,2-phenylene)bis(pyridine-2-carboxamidate)], [Mn(ClO4)2]·6H2O and 4,4′-bipyridine, and was structurally characterized by elemental analysis, IR spectroscopy, single-crystal X-ray crystallography and powder X-ray diffraction (PXRD). Single-crystal X-ray diffraction analysis shows that CP 1 possesses a cationic linear chain structure consisting of alternating cyanide-bridged Fe–Mn units, with free perchlorate as the charge-balancing anion, which can be further extended into a two-dimensional supramolecular sheet structure via inter-chain π–π interactions between the 4,4′-bipyridine ligands. Within the chain, each MnII ion is six-coordinated by an N6 unit and is involved in a slightly distorted octahedral coordination geometry. Investigation of the magnetic properties of 1 reveals an antiferromagnetic coupling between the cyanide-bridged FeIII and MnII ions. A best fit of the magnetic susceptibility based on the one-dimensional alternating chain model leads to the magnetic coupling constants J 1 = −1.35 and J 2 = −1.05 cm−1, and the antiferromagnetic coupling was further confirmed by spin Hamiltonian-based density functional theoretical (DFT) calculations.

High pressure single crystal X-ray diffraction study on α-quartz

1999 ◽  
Vol 214 (6) ◽  
Author(s):  
J. Kim-Zajonz ◽  
S. Werner ◽  
H. Schulz
Keyword(s):  
High Pressure ◽  
Single Crystal ◽  
The Other ◽  
Data Sets ◽  
Theoretical Studies ◽  
Intensity Data ◽  
X Ray Diffraction ◽  
Pressure Derivative ◽  
X Ray ◽  
Murnaghan Equation

AbstractSingle crystal X-ray diffraction experiments onVolumina of the unit cell were determined to 13.1 GPa, by combining the data with data taken from the literature; the bulk modulus and pressure derivative calculate to 38.7(3) GPa and 5.2(1) respectively according to a Birch-Murnaghan equation of state.Intensity data were collected at 10.9(1), 12.0(1), 12.1(1), 12.6(1) and 13.1(1) GPa. From the five intensity data sets, one was collected using synchrotron radiation at HASYLAB/DESY and the other four using a conventional X-ray tube. Results show that the SiOIn addition to the five intensity data sets collected, X-ray diffraction experiments were carried out up to 19.3 GPa in order to address the question of when the structure undergoes amorphization. It was observed that up to 19.3 GPa, no pressure-induced amorphization takes place. This result is in agreement with studies carried out on powder quartz and theoretical studies.

scholarly journals Ab initio and DFT study on Cu (II) complex salicylate derivative

2014 ◽  
Vol 70 (a1) ◽  
pp. C1442-C1442
Author(s):  
Karthikeyan Natarajan ◽  
Sathya Duraisamy ◽  
Sivakumar Kandasamy
Keyword(s):  
Crystal Structure ◽  
Density Functional Theory ◽  
Single Crystal ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Density Functional ◽  
Powder Diffraction Data ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray

X -ray diffraction becomes a routine process these decades for determining crystal structure of the materials. Most of the crystal structures solved nowadays is based on single crystal X-ray diffraction because it solves the crystal and molecular structures from small molecules to macro molecules without much human intervention. However it is difficult to grow single crystals of sufficient size and quality for conventional single-crystal X-ray diffraction studies. In such cases it becomes essential that structural information can be determined from powder diffraction data. With the recent developments in the direct-space approaches for structure solution, ab initio crystal structure analysis of molecular solids can be accomplished from X-ray powder diffraction data. It should be recalled that crystal structure determination from laboratory X-ray powder diffraction data is a far more difficult task than that of its single-crystal counterpart, particularly when the molecule possesses considerable flexibility or there are multiple molecules in the asymmetric unit. Salicylic acid and its derivatives used as an anti-inflammatory drug are known for its numerous medicinal applications. In our study, we synthesized mononuclear copper (II) complex of salicylate derivative. The structural characterization of the prepared compound was carried out using powder X-ray diffraction studies. Crystal structure of the compound has been solved by direct-space approach and refined by a combination of Rietveld method using TOPAS Academic V4.1. Density Functional Theory (DFT) calculations have to be carried in the solid state for the compound using GaussianW9.0 in the frame work of a generalized-gradient approximation (GGA). The geometry optimization was to be performed using B3LYP density functional theory. The atomic coordinates were taken from the final X-ray refinement cycle.

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