scholarly journals STUDY OF CONFORMATIONAL PREFERENCES OF ERYTHRO-CAROLIGNAN E ASSESSED BY THE COUPLING BETWEEN H7'-H8' IN DIFFERENT NMR SOLVENTS

2016 ◽  
Vol 11 (1) ◽  
pp. 1
Author(s):  
Rudiyansyah Rudiyansyah ◽  
Ajuk Sapar ◽  
Masriani Masriani
Keyword(s):  
Ethanol Extract ◽  
Coupling Constant ◽  
Relative Configuration ◽  
H Nmr ◽  
Nmr Data ◽  
Conformational Preferences ◽  
Wood Bark

<p><em>Erythro</em>-carolignan E (<strong>1</strong>) has been obtained from the ethanol extract of the wood bark of <em>Durio affinis</em> Becc. This research was conducted in order to prove that conformational preferences of compound <strong>1</strong> were solvent dependent. On the basis of <sup>1</sup>H-NMR data, the relative configuration of compound <strong>1</strong> was characterized by a coupling constant (<sup>3</sup><em>J</em><sub>HH</sub>) value of 3.3 Hz at H-7' in CDCl<sub>3</sub>. The coupling constant (<sup>3</sup><em>J</em><sub>HH</sub>) values of H-7' in compound <strong>1</strong> has changed to 4.1 Hz and 5.3 Hz in pyridine-<em>d</em><sub>5</sub> and acetonitrile-<em>d</em><sub>3</sub> respectively. As a result, the conformation of compound <strong>1</strong> at C7'-C8' has changed in different NMR solvents.  In conclusion, structure of<em>erythro</em>-carolignan E that contains a dihydroxy group at C7'-C8' is able to change in different NMR solvent.</p>

STUDY OF CONFORMATIONAL PREFERENCES OF ERYTHRO-CAROLIGNAN E ASSESSED BY THE COUPLING BETWEEN H7'-H8' IN DIFFERENT NMR SOLVENTS

2015 ◽  
Vol 11 (1) ◽  
pp. 1
Author(s):  
Rudiyansyah Rudiyansyah ◽  
Ajuk Sapar ◽  
Masriani Masriani
Keyword(s):  
Ethanol Extract ◽  
Coupling Constant ◽  
Relative Configuration ◽  
H Nmr ◽  
Nmr Data ◽  
Conformational Preferences ◽  
Wood Bark

<p><em>Erythro</em>-carolignan E (<strong>1</strong>) has been obtained from the ethanol extract of the wood bark of <em>Durio affinis</em> Becc. This research was conducted in order to prove that conformational preferences of compound <strong>1</strong> were solvent dependent. On the basis of <sup>1</sup>H-NMR data, the relative configuration of compound <strong>1</strong> was characterized by a coupling constant (<sup>3</sup><em>J</em><sub>HH</sub>) value of 3.3 Hz at H-7' in CDCl<sub>3</sub>. The coupling constant (<sup>3</sup><em>J</em><sub>HH</sub>) values of H-7' in compound <strong>1</strong> has changed to 4.1 Hz and 5.3 Hz in pyridine-<em>d</em><sub>5</sub> and acetonitrile-<em>d</em><sub>3</sub> respectively. As a result, the conformation of compound <strong>1</strong> at C7'-C8' has changed in different NMR solvents.  In conclusion, structure of<em>erythro</em>-carolignan E that contains a dihydroxy group at C7'-C8' is able to change in different NMR solvent.</p>

Reaction of carbanions generated from arylmethylphosphonates with cyclic enones. Regio- and stereoselectivity of addition

1998 ◽  
Vol 76 (10) ◽  
pp. 1344-1351 ◽  
Author(s):  
Agnes M Modro ◽  
Tom A Modro ◽  
Malose J Mphahlele ◽  
Wieslawa Perlikowska ◽  
André Pienaar ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Addition Product ◽  
Coupling Constant ◽  
Vicinal Coupling Constant ◽  
Relative Configuration ◽  
H Nmr ◽  
Li Po ◽  
Cyclic Enones ◽  
C Nmr

α-Lithiated benzylphosphonate esters, XC6H4CH(Li)PO3Et2, add regioselectively to cyclohex-2-enone at the carbonyl group; higher reaction temperatures lead to the reversal to the starting materials, and not to the 1,4-addition. Relative configuration of the C(1) and Cα centers in the 1,2-adducts was determined from the 13C NMR spectra. For 2-methylcyclohex-2-enone the regioselectivity of the addition is decreased. The lithioderivative of diethyl 1-naphthylmethylphosphonate, C10H7CH(Li)PO3Et2, shows reverse regioselectivity yielding the 1,4-, but not the 1,2- addition product. The crystal and molecular structure of that 1,4-adduct has been determined and demonstrates that the conformation about the C(1)-Cα bond is close to that existing in solution, deduced from the value of the 1H NMR 3JHH vicinal coupling constant of the H(1)-C(1)-Cα-H hydrogens. The same conformation was also confirmed as the most stable by molecular modeling. Key words: α-lithiated arylmethylphosphonates, 1,2- vs. 1,4-addition to cyclic enones, steric effects of the cyclohex-2-enone, molecular structure and molecular modelling of the 1,4-adduct of 1-naphthylmethylphosphonate to cyclohex-2-enone.

The intramolecular equilibrium in 2-tert-butylphenol and some derivatives. An anomalous indicating steric distortion

1984 ◽  
Vol 62 (1) ◽  
pp. 113-116 ◽  
Author(s):  
Ted Schaefer ◽  
Rudy Sebastian ◽  
Salman R. Salman
Keyword(s):  
Carbon Tetrachloride ◽  
Equilibrium Constant ◽  
Hydroxyl Group ◽  
Coupling Constant ◽  
Spectral Parameters ◽  
H Nmr ◽  
Conformational Preferences ◽  
Out Of Plane ◽  
Alkyl Phenols ◽  
Derivatives Of

The 1H nmr spectral parameters in dilute carbon tetrachloride solution are reported for 2-tert-butylphenol, as obtained by decoupling of the sidechain protons. Long-range couplings between hydroxyl and ring protons are also reported for five derivatives of 2-tert-butylphenol. In the cis conformer of 2-tert-butylphenol an anomalous [Formula: see text] occurs, most likely as a consequence of a significant distortion of the COH geometry. Such an anomaly, which leads to an incorrect estimate of the cis–trans equilibrium constant, does not occur in other alkyl phenols, for example, in 2-tert-butyl-6-methylphenol. The coupling constant data provide no evidence for out-of-plane conformational preferences of the hydroxyl group in these compounds.

Inhibited rotation of amide group around C N bond of nicotinamide in different solvents by 1 H NMR data

2017 ◽  
Vol 231 ◽  
pp. 238-241 ◽  
Author(s):  
G.A. Gamov ◽  
V.V. Aleksandriiskii ◽  
V.A. Sharnin
Keyword(s):  
Amide Group ◽  
H Nmr ◽  
Nmr Data

scholarly journals Bioassay-guided isolation and identification of Aedes aegypti larvicidal and biting deterrent compounds from Veratrum lobelianum

2018 ◽  
Vol 16 (1) ◽  
pp. 324-332 ◽  
Author(s):  
Nurhayat Tabanca ◽  
Zulfiqar Ali ◽  
Ulrich R. Bernier ◽  
Nancy Epsky ◽  
Ayse Nalbantsoy ◽  
...  
Keyword(s):  
Larvicidal Activity ◽  
Ethanol Extract ◽  
Ethyl Linoleate ◽  
Significant Activity ◽  
Isolation And Identification ◽  
Human Carcinoma ◽  
Ethyl Palmitate ◽  
H Nmr ◽  
Bioassay Guided Fractionation ◽  
Nmr Techniques

AbstractAn ethanol extract fromVeratrum lobelianumBernh. rhizomes showed larvicidal activity with LC50values of 11.79 ppm and 89.9 ppm against 1stand 4thinstar larvae, respectively, at 24 h post-treatment. The extract also showed proportion not biting (PNB) value of 0.76 at 100 μg/cm2against females ofAe.aegypti. Systematic bioassay-guided fractionation ofV.lobelianumextract resulted in the isolation of five compounds that were identified as ethyl palmitate (1), ethyl linoleate (2), β-sitosterol (3), resveratrol (4) and oxyresveratrol (5) by GC-MS,1H-NMR, and13C-NMR techniques, comparison with literature data, and confirmation with authentic compounds. Compound2exhibited larvicidal activity with an LC50value of 24.1 (22.0-26.2) ppm whereas1was inactive. β-Sitosterol (3) displayed the highest larvicidal activity with LC50= 1.7 (1.3-12.3) ppm and LC90= 5.1 (3.4-13.8) ppm. Compounds4and5had larvicidal activity with LC50values of 18.5 (15.3-23.3) and 22.6 (19.0-26.8) ppm, respectively, and had an equivalent PNB values of 0.75 at 25 nmol/cm2. In addition,4and5were explored for their human-based repellency againstAe.aegypti, attractiveness against male medfliesCeratitis capitata, and also evaluated against series of human carcinoma cells (A549, HEK293, HeLa, SH-SY5Y); however, no significant activity was found.

scholarly journals Synthesis of Some Novel Fused Imidazo [2, 1-b] [1, 3] Thiazole and Imidazo [2, 1-b] Thiazolo [5, 4-d] Isoxazole Derivatives

2012 ◽  
Vol 9 (3) ◽  
pp. 1518-1525 ◽  
Author(s):  
Hamid Reza Jaberi ◽  
Hadi Noorizadeh
Keyword(s):  
Acetic Acid ◽  
Sodium Acetate ◽  
Carbon Disulphide ◽  
Thiazole Derivatives ◽  
H Nmr ◽  
Nmr Data ◽  
Elemental Analyses ◽  
New Compounds ◽  
Isoxazole Derivatives ◽  
C Nmr

In this work we describe the synthesis of some novel fused imidazo [2, 1-b] [1, 3] thiazole derivatives. The reaction of 1, 2-diaminoethane 1 with carbon disulphide in H2O/ETOH as solvent furnishes 4, 5-dihydro-1H-imidazol-2-thiol 2 under reflux condition. the reaction of 4,5-dihydro-1H-imidazol-2-thiol on treatment with ethylchloro acetate and aromatic aldehyde in presence of anhydrous sodium acetate and acetic acid as solvent to give (Z)-2-(arylidene)-5,6-dihydroimidazo [2,1-b] [1,3] thiazol-3(2H)-one 3a-j. Compounds 3a-j was condensed with hydroxylamine to give 3-(aryl)-2, 3, 6, 7-tetrahydroimidazo [2, 1-b] [1,3] thiazolo [5, 4-d] isoxazole 4a-j. The structures of the new compounds were established by elemental analyses, IR,1H NMR and13C NMR data.

Ein [1,3,4]Thiazaphospholidin, Darstellung und NMR-Daten / A [1,3,4]Thiazaphospholidine, Preparation and NMR Data

1987 ◽  
Vol 42 (1) ◽  
pp. 115-117 ◽  
Author(s):  
Gernot Heckmann ◽  
Ekkehard Fluck ◽  
Peter Kuhm
Keyword(s):  
Nmr Spectra ◽  
Resonance Mode ◽  
Triple Resonance ◽  
H Nmr ◽  
Nmr Data

Abstract Preparation and properties of a [1,3,4]thiazaphospholidine are described. The 31P. 13C and 1H NMR spectra in double and triple resonance mode are recorded and discussed in detail.

Preparation and characterization of some ruthenium(II) porphyrins containing tertiary phosphine axial ligands, including the crystal structure of (octaethylporphinato)bis(triphenylphosphine)ruthenium(II)

1984 ◽  
Vol 62 (4) ◽  
pp. 755-762 ◽  
Author(s):  
Sara Ariel ◽  
David Dolphin ◽  
George Domazetis ◽  
Brian R. James ◽  
Tak W. Leung ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Phosphine Ligands ◽  
Tertiary Phosphine ◽  
X Ray ◽  
Porphyrin Complex ◽  
H Nmr ◽  
Axial Ligands ◽  
Nmr Data ◽  
Phosphine Complex

The ruthenium(II) porphyrin complex Ru(OEP)(PPh3)2 (OEP = the dianion of octaethylporphyrin) has been prepared from Ru(OEP)(CO)EtOH, and the X-ray crystal structure determined; as expected, the six-coordinate ruthenium is situated in the porphyrin plane and has two axial phosphine ligands. Synthesized also from the carbonyl(ethanol) precursors were the corresponding tris(p-methoxyphenyl)phosphine complex, and the Ru(TPP)L2 (TPP = the dianion of tetraphenylporphyrin, L = PPh3, P(p-CH3OC6H4)3, P″Bu3) and Ru(TPP)(CO)PPh3 complexes. Optical and 1H nmr data are presented for the complexes in solution. In some cases dissociation of a phosphine ligand to generate five-coordinate species occurs and this has been studied quantitatively in toluene at 20 °C for the Ru(OEP)L2 and Ru(TPP)L2 systems.

Synthesis of metal-free tetraazaisobacteriochlorin and via template condensation of phthalogenes

2020 ◽  
Vol 24 (05n07) ◽  
pp. 878-886
Author(s):  
Semyon V. Dudkin ◽  
Takahiro Kawata ◽  
Svetlana A. Belova ◽  
Yusuke Okada ◽  
Nagao Kobayashi
Keyword(s):  
Mass Spectrometry ◽  
Quantum Chemical ◽  
2D Nmr ◽  
Metal Free ◽  
Tert Butyl ◽  
H Nmr ◽  
Nmr Data ◽  
Template Condensation ◽  
Td Dft ◽  
Low Symmetry

The indium(III) complexes of (4-(tert-butyl)phenyl)-substituted tetraazaisobacteriochlorin (TAiBC) and tetraazachlorin (TAC) were synthesized by direct template condensation of bis(4-(tert-butyl)phenyl)fumaronitrile and tetramethylsuccinonitrile using indium(III) ion as a matrix. The corresponding metal-free tetraazaisobacteriochlorin and tetraazachlorin were obtained by demetallation of their indium(III) complexes. These metal-free complexes were characterized using elemental analysis, mass-spectrometry, 1H and [Formula: see text]C{1H}NMR spectroscopy, UV-vis and MCD spectroscopy as well as DFT and TD-DFT calculations. Due to the low symmetry of the molecules, the NMR data were complex, but could be assigned by collecting 1D- and 2D NMR data and comparing with the results of quantum chemical calculations. From the position of the pyrrole proton signal (6.78 ppm), it was found that the diatropic current of TAiBC is much weaker than that of TAC, and plausibly the weakest among porphyrinoids so far reported. Absorption and MCD spectra were reasonably interpreted using the calculated absorption spectra.

scholarly journals Electronic Structure, Spectroscopic (IR, Raman, UV-Vis, NMR), Optoelectronic, and NLO Properties Investigations of Rubescin E (C31H36O7) Molecule in Gas Phase and Chloroform Solution Using Ab Initio and DFT Methods

2019 ◽  
Vol 2019 ◽  
pp. 1-22 ◽  
Author(s):  
Richard Arnaud Yossa Kamsi ◽  
Geh Wilson Ejuh ◽  
Fidèle Tchoffo ◽  
Pierre Mkounga ◽  
Jean-Marie Bienvenu Ndjaka
Keyword(s):  
Electronic Structure ◽  
Chloroform Solution ◽  
3D Analysis ◽  
Coupling Constant ◽  
Dft Methods ◽  
Reactivity Descriptors ◽  
H Nmr ◽  
Quantum Chemical Methods ◽  
Td Dft ◽  
Electric Susceptibility

Quantum chemical methods were used to study the electronic structure and some physicochemical properties of Rubescin E molecule. Good agreement with experiment was found for J3H-H coupling constant, IR, 1H NMR, and 13C NMR. The excitation energy and oscillator strength calculated by TD-DFT also complement with experiment. Large values were obtained for dipole moment, polarizability, first static hyperpolarizability, electric susceptibility, refractive index, and dielectric constant, meaning that Rubescin E has strong optical and phonon application and can be a good candidate as NLOs material. The 3D analysis of the title molecule leads us to the conclusion that electron can easily be transferred from furan to tetrahydrofuran ring. The global reactivity descriptors were evaluated. Mulliken, ESP, and NBO charges comparisons were carried out and described.

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