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.

Stereoselective synthesis and stereochemistry of r-2-alkoxycarbonyl-c-3-o-substituted phenyl-1,4-thiazane 1,1-dioxides

2005 ◽  
Vol 83 (3) ◽  
pp. 202-208
Author(s):  
N Bhavani ◽  
S Perumal ◽  
R Banureka
Keyword(s):  
Long Range ◽  
Trans Isomer ◽  
Stereoselective Synthesis ◽  
Nmr Assignments ◽  
Chair Conformation ◽  
Coupling Constant ◽  
Vicinal Coupling Constant ◽  
Relative Configuration ◽  
Cis Isomer ◽  
C Nmr

r-2-Alkoxycarbonyl-c-3-aryl-1,4-thiazane 1,1-dioxides were obtained as the stereoselective product, when the aldehyde used was o-substituted benzaldehyde while the p-substituted benzaldehydes gave a trans product. The relative configuration of the adjacent alkoxycarbonyl and aryl groups was assigned from the vicinal coupling constant, 3J = 10.6 Hz in the trans isomer and 3.2 Hz in the cis isomer, and from the multiplicity pattern, i.e., a doublet for the H-2 proton of the trans isomer and a triplet for the H-2 proton of the cis isomer. The unusual, large long-range coupling (4J = 2.8 Hz) because of the "W" arrangement between H-2e and H-6e across the ring type was very useful for confirming the cis configuration and chair conformation of the isomer. The various 1H and 13C NMR assignments were made with the help of 1H–1H COSY, 1H–13C COSY, HMBC, and NOESY spectral analyses.Key words: 1H and 13C NMR, 1H–1H COSY, 1H–13C COSY, HMBC, NOESY, stereoselectivity, 1,4-thiazane.

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>

Structure cristalline et moléculaire d'un composé tricyclique contenant le cycle à dix chaînons dioxo diaza diphosphécine

1992 ◽  
Vol 70 (3) ◽  
pp. 809-816 ◽  
Author(s):  
Brigitte Duthu ◽  
Karim El Abed ◽  
Douraid Houalla ◽  
Robert Wolf ◽  
Joël Jaud
Keyword(s):  
Molecular Structure ◽  
Comparative Analysis ◽  
Double Bond ◽  
Mass Spectroscopy ◽  
Crystal And Molecular Structure ◽  
Accurate Information ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nmr Parameters ◽  
C Nmr

The sulfuration of the tricyclic organophosphorous dimer 2 leads easily to the dithiotricyclic derivative 3, which has been characterized by 31P, 1H, and 13C NMR, elemental analysis, and mass spectroscopy. Its crystal and molecular structure has been established by X-ray diffraction and compared to that of 2, which was previously determined. The comparative analysis of X-ray diffraction and NMR parameters gives accurate information about the molecular structure of both compounds. A numerical value of the anistropy cone of the P=S double bond is proposed. Keywords: phosphecine, NMR, X-ray, tricycle.

Synthesis and Electrochemistry of Aluminum Porphycenes: Crystal and Molecular Structure of Methyl-σ-Bonded Aluminum Etioporphycene

1997 ◽  
Vol 01 (02) ◽  
pp. 109-119 ◽  
Author(s):  
ROGER GUILARD ◽  
VIRGINIE PICHON-PESME ◽  
HASSANE LACHEKAR ◽  
CLAUDE LECOMTE ◽  
ALLY M. AUKAULOO ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Structural Data ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Axial Ligands ◽  
Uv Visible

The synthesis and characterization of three monomeric aluminum porphycenes with anionic or σ-bonded axial ligands is reported. The investigated compounds are represented as ( EtioPc ) Al ( CH 3) and ( EtioPc ) AlX where EtioPc represents the dianion of etioporphycene and X = Cl − or OH −. Each synthesized complex was characterized by mass spectrometry. 1 H NMR, IR and UV-visible spectroscopies as well as by electrochemistry. Comparisons are made between the properties of complexes in the aluminum etioporphycene series and related chloro- or methyl σ-bonded Al ( III ) porphyrins containing octaethylporphyrin ( OEP ) or tetraphenylporphyrin ( TPP ) macrocycles. Comparisons are also made between the currently investigated compounds and a previously reported Al ( III ) μ-oxo dimer, [( EtioPc ) Al ]2 O . In addition, the crystal and molecular structure of ( EtioPc ) Al ( CH 3) was determined by X-ray diffraction. The molecular structure of this methyl-σ-bonded aluminum etioporphycene provides the first structural data for an aluminum porphycene compound. The aluminum(III) atom in ( EtioPc ) Al ( CH 3) is pentacoordinated and is located 0.54 Å from the plane of the four N -nitrogens.

Synthesis, structure, and electrochemistry of cobalt(III) complexes with bis(benzoylacetone)ethylenediimine Schiff base

2002 ◽  
Vol 80 (9) ◽  
pp. 1196-1203 ◽  
Author(s):  
Mehdi Amirnasr ◽  
Rasoul Vafazadeh ◽  
Amir H Mahmoudkhani
Keyword(s):  
Schiff Base ◽  
Reduction Potential ◽  
Crystal And Molecular Structure ◽  
Acetonitrile Solution ◽  
Potential Range ◽  
Carbon Electrode ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
C Nmr

A series of complexes of the type trans-[Co((BA)2en)(amine)2]ClO4 — where (BA)2en is the bis(benzoylacetone)ethylenediimine dianion and the amines are morpholine (mrpln) 1, aniline (aniln) 2, benzylamine (bzlan) 3, piperidine (pprdn) 4, p-toluidine (p-toldn) 5, and pyrrolidine (prldn) 6 — has been synthesized and characterized by elemental analysis, UV–vis, 1H NMR, and 13C NMR spectroscopy. The crystal and molecular structure of trans-[Co((BA)2en)(mrpln)2]ClO4 (1) has been determined by X-ray crystallography. The electrochemical reduction of these complexes at a glassy-carbon electrode, in the potential range of 0.5 to –2.0 V (vs. Ag/AgCl), in acetonitrile solution, indicates that the first reduction potential of Co(III/II) is irreversible, which is accompanied by the dissociation of the axial amine–cobalt bonds. This potential is dependent on the pKa of the axial amines. The second reduction potential of Co(II/I) shows reversible behavior and is also independent of the axial amine pKa. These results indicate the loss of the axial amines in the first redox process and the involvement of a four-coordinate species in the second redox step.Key words: Schiff base, cobalt(III), axial amine, electrochemical properties, crystal structure.

scholarly journals FeCl3-catalyzed Synthesis of Dehydrodiisoeugenol

2015 ◽  
Vol 8 (1) ◽  
pp. 1
Author(s):  
Athina Mardhatillah ◽  
Mutakin Mutakin ◽  
Jutti Levita
Keyword(s):  
Molecular Structure ◽  
Melting Point ◽  
Mobile Phase ◽  
Crystalline Form ◽  
Distilled Water ◽  
Environment Friendly ◽  
H Nmr ◽  
Abundance Peak ◽  
Layer Chromatography ◽  
C Nmr

Dehydrodiisoeugenol (DDIE) synthesis has been performed by modifying a method recommended by Leopold with a different ratio of isoeugenol and FeCl<sub>3</sub> (1.9:1). FeCl<sub>3</sub> was chosen as catalyst due to its efficiency and environment-friendly property. This modification yielded 22.93 % of product. The product, a white crystalline form, was characterized using thin layer chromatography, melting point, UV, IR, HRMS, and NMR spectroscopy, as well as HPLC, employing pure DDIE as the standard. TLC chromatogram showed Rf 0.32 using n-hexane/ethyl acetate (8:2). The crystals melted at 138-139 <sup>o</sup>C, while its UV maximum was detected at l 273 nm. IR spectrum showed a specific broad O-H stretch at 3437.15 cm<sup>-1</sup>, C-H aromatic and C-H alkene at 3163.26 and 3024.38 cm<sup>-1</sup>, C-H alkyl stretch at 2951.09 and 2927.94 cm<sup>-1</sup>. An overtone peak of aromatic was detected at 2100 to 1700 cm<sup>-1</sup>. C-O peak was detected at 1126.43 cm<sup>-1</sup>. HPLC showed that this compound was eluted at 11.886 minutes after it was injected to a C18 column 250 x 4 mm using a mixture of methanol and double distilled water (73:27) for mobile phase. HRMS spectra predicted that the molecular structure is C<sub>20</sub>H<sub>22</sub>O<sub>4</sub> as showed by abundance peak at <em>m/z </em>327.1595 of [M+H]<sup>+</sup>. <sup>1</sup>H-NMR and <sup>13</sup>C-NMR indicated that the synthesized compound contains 13 types of proton and 20 types of carbon. Herein we reported that white needle-like crystals of DDIE using FeCl<sub>3</sub> as catalyst had been synthesized, moreover the decreasing of the catalyst reduced the yield of the product.

The crystal and molecular structure of tetrabenzocyclodecan-1,6-dione

1980 ◽  
Vol 58 (8) ◽  
pp. 777-779 ◽  
Author(s):  
T. Stanley Cameron ◽  
Christine Chan ◽  
David G. Morris ◽  
Alistair G. Shepherd
Keyword(s):  
Molecular Structure ◽  
Diffraction Analysis ◽  
Title Compound ◽  
Crystal And Molecular Structure ◽  
Membered Ring ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Nmr Spectrum ◽  
X Ray ◽  
C Nmr

The crystals belong to the orthorhombic space group C222, with a = 9.226, b = 12.092, c = 16.513 Å, Z = 4. A single crystal X-ray diffraction analysis has shown that the title compound, in which all carbon atoms are sp2 hybridized, exists with the ten membered ring in a slightly twisted tub conformation. The 13C nmr spectrum is also reported.

(3E)-5-Hydroxy-3-[5-(hydroxymethyl)furan-2-ylmethylene]-1-benzofuran-2(3H)-one

2007 ◽  
Vol 63 (11) ◽  
pp. o4354-o4354
Author(s):  
Hong-Yan Ma ◽  
Ji Shi ◽  
Chang-Hong Wang ◽  
Zheng-Tao Wang
Keyword(s):  
Hydrogen Bonds ◽  
Spectroscopic Data ◽  
Furan Ring ◽  
Crystallographic Analysis ◽  
Relative Configuration ◽  
X Ray ◽  
H Nmr ◽  
Compound C ◽  
A Chain ◽  
C Nmr

The title compound, C14H10O5, was isolated from Senecio cannabifolius Less var. integrifolius aqueous extract. The structure was elucidated on the basis of spectroscopic data, including MS, 1H NMR and 13C NMR, and the relative configuration was confirmed by X-ray crystallographic analysis. The benzofuran ring is almost coplanar with the furan ring [dihedral angle = 10.47 (15)°]. A chain is formed through supramolecular R 2 2(10) synthons and three-centre hydrogen bonds.

Light Induced Properties of Chalcones Correlated with Molecular Structure and Photophysical Properties for Permanent Optical Storage Device

2014 ◽  
Vol 1033-1034 ◽  
pp. 1149-1153 ◽  
Author(s):  
S.N. Sidharth ◽  
A.R. Yuvaraj ◽  
Tay Joo Hui ◽  
B.K. Sarojini ◽  
M. Yusoff Mashitah ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Spectral Analysis ◽  
Photophysical Properties ◽  
Optical Storage ◽  
Storage Device ◽  
Storage Devices ◽  
H Nmr ◽  
Chalcone Derivative ◽  
C Nmr

The photoisomerization effect on new chalcone derivative is reported. The synthesized chalcone was characterized by different spectral analysis such as1H-NMR,13C-NMR, FTIR, LCMS and UV/Vis. It revealed the photoisomerization effect in solution, theE-Zisomerization occurred around 60sec, whereasZ-Eisomerism occurred at 0min. This chalcone derivative is more useful in fabrication of permanent optical storage devices.

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