scholarly journals Rare Prenylated Isoflavones from Tephrosia calophylla

2014 ◽  
Vol 9 (7) ◽  
pp. 1934578X1400900 ◽  
Author(s):  
Seru Ganapaty ◽  
Vimal Nair ◽  
Devarakonda Rama Devi ◽  
Steve Thomas Pannakal ◽  
Hartmut Laatsch ◽  
...  
Keyword(s):  
Mass Spectra ◽  
Nmr Assignments ◽  
2D Nmr ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nmr Techniques ◽  
First Time

Chemical re-examination of the roots of T. calophylla led to the isolation of four isoflavones, namely 2′,4′,5-trihydroxy-6,7-(2″,2″-dimethylchromene)-8-γ,γ-dimethylallylisoflavone (1a, auriculatin), 2′,5-dihydroxy-6,7-(2″,2″-dimethylchromene)-4′-γ,γ-dimethylallyloxyisoflavone (2a, isoauriculatin), 3′,4′,5-trihy-droxy-6,7-(2″,2″-dimethylchromene)-8-γ,γ-dimethylallylisoflavone (1b, auriculasin), and 3′,5-dihydroxy-6,7-(2″,2″-dimethylchromene)-4′-γ,γ-dimethylallyl-oxyisoflavone (2b, isoauriculasin). Auriculasin and isoauriculasin are reported for the first time with full NMR assignments. All metabolites were fully characterized by 1D and 2D NMR techniques including COSY, HSQC, HMBC experiments, mass spectra and in part on the basis of X-ray diffraction. Accurate ‘invariom’ refinements with aspherical scattering factors were carried out for 1a, 1b and 2a.

scholarly journals Absolute Configuration of Cembrane Diterpenoids from Bursera multijuga

2014 ◽  
Vol 9 (9) ◽  
pp. 1934578X1400900 ◽  
Author(s):  
Juan D. Hernández-Hernández ◽  
Hugo A. García-Gutiérrez ◽  
Luisa U. Román-Marín ◽  
Yunuen I. Torres-Blanco ◽  
Carlos M. Cerda-García-Rojas ◽  
...  
Keyword(s):  
Molecular Modeling ◽  
Absolute Configuration ◽  
2D Nmr ◽  
Vibrational Circular Dichroism ◽  
Conformational Preference ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Absolute ◽  
First Time ◽  
Good Agreement

The stems of Bursera multijuga afforded (-)-(1 S,3 E,7 R,8 R,11 E)-7,8-epoxycembra-3,11-dien-1-ol (1) and its acetate 2, together with cembrene A (3), nephthenol (4), and cembrenol (5). The structures of 1 and 2 were elucidated by 1D and 2D NMR, HRESIMS, and X-ray diffraction. The conformational preference of flexible 1 was studied by molecular modeling at the DFT B3LYP/DGDZVP level of theory. Good agreement between calculated and experimental vibrational circular dichroism curves established the absolute configuration of 1. This is the first time that cembrane derivatives have been isolated from the genus Bursera.

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.

scholarly journals A Phenylpropanoid and Biflavonoids from the Needles of Cephalotaxus harringtonia var. harringtonia

2017 ◽  
Vol 12 (11) ◽  
pp. 1934578X1701201 ◽  
Author(s):  
Anju Mendiratta (Nee Chugh) ◽  
Rameshwar Dayal ◽  
John P. Bartley ◽  
Graham Smith
Keyword(s):  
Nmr Spectroscopy ◽  
Oral Dose ◽  
Spectral Data ◽  
2D Nmr ◽  
Hepatoprotective Activity ◽  
X Ray Diffraction ◽  
Soluble Extract ◽  
2D Nmr Spectroscopy ◽  
X Ray ◽  
First Time

A phenylpropanoid [2-(3-methoxy-4-hydroxyphenyl)-propane-1,3-diol] (1) together with four known biflavonoids namely 7, 4′, 7′″, 4′″-tetra- O-methyl amentoflavone (2); 7, 4′, 7″-tri- O-methyl amentoflavone (3); ginkgetin (4); sequoiaflavone (5) were isolated from the acetone soluble extract of needles of Cephalotaxus harringtonia var. harringtonia. Their structures were elucidated mainly on the basis of interpretation of 1D and 2D NMR spectroscopy and X-ray diffraction studies. The detailed spectral data of phenylpropanoid have been described for the first time. Ginkgetin (4) exhibited significant hepatoprotective activity in rat at 6 mg/kg oral dose level.

A Conformational Study of the Semisynthetic Ergot Alkaloid - Terguride

1993 ◽  
Vol 58 (12) ◽  
pp. 2944-2954 ◽  
Author(s):  
Michal Hušák ◽  
Bohumil Kratochvíl ◽  
Petr Sedmera ◽  
Josef Stuchlík ◽  
Alexandr Jegorov
Keyword(s):  
Solid State ◽  
Ergot Alkaloid ◽  
Direct Methods ◽  
2D Nmr ◽  
Free Base ◽  
Conformational Study ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
X Ray ◽  
Nmr Techniques

Conformational analysis studied by 2D NMR techniques and X-ray diffraction methods are reported for the semisynthetic ergot alkaloid - terguride, in the form of free base and as the protonated species. The structure of terguride hydrogen maleate monohydrate (C20H29N4O)+(C4H3O4)- . H2O (II) was solved by direct methods and refined anisotropically to an Rvalue of 0.068 for 1 991 unique observed reflections. The title compound crystallizes in the triclinic space group P1 with lattice parameters a = 7.061(2), b = 9.205(1), c = 12.223(4) Å, α = 96.36(2), β = 107.15(2), γ = 106.67(1)°. Studies revealed that terguride monohydrate (I) and its protonized form (terguride hydrogen maleate monohydrate) possesses the identical conformations both in solutions and in the solid state - an envelope for C and Chair for D ergoline rings.

Synthesis and characterization of a series of 4-methyl-1-[2-aryl-1-diazenyl]-1,4-diazepanes and 1,4-di-[2-aryl-1-diazenyl]-1,4-diazepanes

2004 ◽  
Vol 82 (12) ◽  
pp. 1725-1735 ◽  
Author(s):  
Shasta Lee Moser ◽  
Keith Vaughan
Keyword(s):  
Nmr Assignments ◽  
Diazonium Salt ◽  
Variable Temperature ◽  
2D Nmr ◽  
Diazonium Salts ◽  
X Ray Diffraction ◽  
X Ray ◽  
New Compounds ◽  
C Nmr

1-Methylhomopiperazine was coupled with a series of diazonium salts to afford the 4-methyl-1-[2-aryl-1-diazenyl]-1,4-diazepanes (6), a new series of triazenes. These compounds are, in the main, stable crystalline solids (some of the series are stable oils), and they have been characterized by 1H and 13C NMR spectroscopy, IR spectroscopy, and mass spectrometry. NMR assignments were determined by 2D NMR and variable-temperature NMR experiments and by comparison with model compounds. A second series of new compounds, namely, 1,4-di-[2-aryl-1-diazenyl]-1,4-diazepanes (5), were prepared by coupling unsubstituted homopiperazine (1,4-diazepane) with 2 molar equivalents of the diazonium salt and were similarly characterized. The crystal and molecular structure of the parent member of this bis-triazene series (5, X = H) has been determined by single-crystal X-ray diffraction analysis.Key words: triazene, bis-triazene, diazenyl, bis-diazenyl, diazonium salt, NMR, diazepane.

scholarly journals Cytotoxic Polyketide Metabolites from a Marine Mesophotic Zone Chalinidae Sponge-Associated Fungus Pleosporales sp. NBUF144

Marine Drugs ◽  
2021 ◽  
Vol 19 (4) ◽  
pp. 186
Author(s):  
Jing Zhou ◽  
Hairong Zhang ◽  
Jing Ye ◽  
Xingxin Wu ◽  
Weiyi Wang ◽  
...  
Keyword(s):  
Mass Spectra ◽  
Spectroscopic Analysis ◽  
2D Nmr ◽  
Leukemia Cells ◽  
Ionization Mass ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lymphatic Leukemia ◽  
Ic50 Value ◽  
Lymphatic Leukemia Cells

Two new polyketide natural products, globosuxanthone F (1), and 2′-hydroxy bisdechlorogeodin (2), were isolated from the fungus Pleosporales sp. NBUF144, which was derived from a 62 m deep Chalinidae family sponge together with four known metabolites, 3,4-dihydroglobosuxanthone A (3), 8-hydroxy-3-methylxanthone-1-carboxylate (4), crosphaeropsone C (5), and 4-megastigmen-3,9-dione (6). The structures of these compounds were elucidated on the basis of extensive spectroscopic analysis, including 1D and 2D NMR and high-resolution electrospray ionization mass spectra (HRESIMS) data. The absolute configuration of 1 was further established by single-crystal X-ray diffraction studies. Compounds 1-5 were evaluated for cytotoxicity towards CCRF-CEM human acute lymphatic leukemia cells, and it was found that 1 had an IC50 value of 0.46 µM.

Synthesis and Characterization of Hybrid Dimeric Steroid Spiroketals

Synthesis ◽  
2021 ◽  
Author(s):  
Martha C. Mayorquín-Torres ◽  
Mauricio Maldonado-Domínguez ◽  
MARCOS FLORES-ALAMOS ◽  
Martín A. Iglesias-Arteaga
Keyword(s):  
Dft Calculations ◽  
Structural Characterization ◽  
2D Nmr ◽  
Synthesis And Characterization ◽  
Sonogashira Coupling ◽  
X Ray Diffraction ◽  
X Ray ◽  
Synthetic Procedure ◽  
Nmr Techniques

The synthesis of six dimeric spiroketals bearing an estradiol half fused to the 5-or 5-epimers of androstane, cholestane and spirostane nuclei is described. The synthetic procedure comprises the Sonogashira coupling of different steroid alkynes with 2-iodoestradiol 17-monoacetate, followed by Pd-catalyzed spiroketalization. The structural characterization of the obtained hybrid dimers was performed using a combination of 1D and 2D NMR techniques, and was assisted by DFT calculations. Single crystal X-ray diffraction of one of the obtained compounds confirmed the proposed structures.

scholarly journals Quartz Crystallite Size and Moganite Content as Indicators of the Mineralogical Maturity of the Carboniferous Chert: The Case of Cherts from Eastern Asturias (Spain)

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 611
Author(s):  
Celia Marcos ◽  
María de Uribe-Zorita ◽  
Pedro Álvarez-Lloret ◽  
Alaa Adawy ◽  
Patricia Fernández ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Crystallite Size ◽  
Archaeological Sites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Infrared And Raman Spectroscopy ◽  
First Time ◽  
Geological Formations

Chert samples from different coastal and inland outcrops in the Eastern Asturias (Spain) were mineralogically investigated for the first time for archaeological purposes. X-ray diffraction, X-ray fluorescence, transmission electron microscopy, infrared and Raman spectroscopy and total organic carbon techniques were used. The low content of moganite, since its detection by X-ray diffraction is practically imperceptible, and the crystallite size (over 1000 Å) of the quartz in these cherts would be indicative of its maturity and could potentially be used for dating chert-tools recovered from archaeological sites. Also, this information can constitute essential data to differentiate the cherts and compare them with those used in archaeological tools. However, neither composition nor crystallite size would allow distinguishing between coastal and inland chert outcrops belonging to the same geological formations.

scholarly journals First Report on the Geologic Occurrence of Natural Na–A Zeolite and Associated Minerals in Cretaceous Mudstones of the Paja Formation of Vélez (Santander), Colombia

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 218
Author(s):  
Carlos Alberto Ríos-Reyes ◽  
German Alfonso Reyes-Mendoza ◽  
José Antonio Henao-Martínez ◽  
Craig Williams ◽  
Alan Dyer
Keyword(s):  
Natural Zeolite ◽  
Scanning Electron Micrographs ◽  
Total Sulfur ◽  
Zeolite A ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mineral Phases ◽  
The World ◽  
Porosity And Permeability ◽  
First Time

This study reports for the first time the geologic occurrence of natural zeolite A and associated minerals in mudstones from the Cretaceous Paja Formation in the urban area of the municipality of Vélez (Santander), Colombia. These rocks are mainly composed of quartz, muscovite, pyrophyllite, kaolinite and chlorite group minerals, framboidal and cubic pyrite, as well as marcasite, with minor feldspar, sulphates, and phosphates. Total organic carbon (TOC), total sulfur (TS), and millimeter fragments of algae are high, whereas few centimeters and not biodiverse small ammonite fossils, and other allochemical components are subordinated. Na–A zeolite and associated mineral phases as sodalite occur just beside the interparticle micropores (honeycomb from framboidal, cube molds, and amorphous cavities). It is facilitated by petrophysical properties alterations, due to processes of high diagenesis, temperatures up to 80–100 °C, with weathering contributions, which increase the porosity and permeability, as well as the transmissivity (fluid flow), allowing the geochemistry remobilization and/or recrystallization of pre-existing silica, muscovite, kaolinite minerals group, salts, carbonates, oxides and peroxides. X-ray diffraction analyses reveal the mineral composition of the mudstones and scanning electron micrographs show the typical cubic morphology of Na–A zeolite of approximately 0.45 mμ in particle size. Our data show that the sequence of the transformation of phases is: Poorly crystalline aluminosilicate → sodalite → Na–A zeolite. A literature review shows that this is an unusual example of the occurrence of natural zeolites in sedimentary marine rocks recognized around the world.

scholarly journals The Effect of Surfactant-Modified Montmorillonite on the Cross-Linking Efficiency of Polysiloxanes

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2623
Author(s):  
Monika Wójcik-Bania ◽  
Jakub Matusik
Keyword(s):  
Total Pore Volume ◽  
Cross Linking ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
The Cross ◽  
Chain Lengths ◽  
First Time ◽  
Substituent Influence ◽  
Benzyl Substituent

Polymer–clay mineral composites are an important class of materials with various applications in the industry. Despite interesting properties of polysiloxanes, such matrices were rarely used in combination with clay minerals. Thus, for the first time, a systematic study was designed to investigate the cross-linking efficiency of polysiloxane networks in the presence of 2 wt % of organo-montmorillonite. Montmorillonite (Mt) was intercalated with six quaternary ammonium salts of the cation structure [(CH3)2R’NR]+, where R = C12, C14, C16, and R’ = methyl or benzyl substituent. The intercalation efficiency was examined by X-ray diffraction, CHN elemental analysis, and Fourier transform infrared (FTIR) spectroscopy. Textural studies have shown that the application of freezing in liquid nitrogen and freeze-drying after the intercalation increases the specific surface area and the total pore volume of organo-Mt. The polymer matrix was a poly(methylhydrosiloxane) cross-linked with two linear vinylsiloxanes of different siloxane chain lengths between end functional groups. X-ray diffraction and transmission electron microscopy studies have shown that the increase in d-spacing of organo-Mt and the benzyl substituent influence the degree of nanofillers’ exfoliation in the nanocomposites. The increase in the degree of organo-Mt exfoliation reduces the efficiency of hydrosilylation reaction monitored by FTIR. This was due to physical hindrance induced by exfoliated Mt particles.

Sign in / Sign up

Export Citation Format

Share Document