Electrooxidation of 2-arylfurans

1981 ◽  
Vol 46 (4) ◽  
pp. 906-916 ◽  
Author(s):  
Miroslav Janda ◽  
Jan Šrogl ◽  
Hana Dvořáková ◽  
Dalimil Dvořák ◽  
Ivan Stibor
Keyword(s):  
Electronic Spectra ◽  
Nmr Spectra ◽  
Model Compounds ◽  
Methyl Group ◽  
C Nmr

Electrochemical methoxylation of 2-phenylfuran (I) and 2-(4-nitrophenyl)furan (VI) proceeded anomalously, affording 5-methoxy-2-phenylfuran (XI) and 5-methoxy-2-(4-nitrophenyl)furan (XIII), respectively. 2-Phenyl-5-methylfuran (II) and methyl-2-(2-methylphenyl)-3-furoate (VIII) behaved normally giving the respective 2,5-dimethoxy-2,5-dihydrofuran derivatives XII and XIV. The suggested ECNECB mechanism of the anomalous methoxylation was confirmed by methoxylation of compound II, in which the methyl group hinders the last CB step, and also of compound VIII in which the automaticity is suppressed by forced deviation from planarity. Forced deviation from planarity was moreover studied also on 2-(4-methylphenyl)furan (III), 5-methyl-2-(2-methylphenyl)furan (IV) and 3,5-dimethyl-2-(2-methylphenyl)furan (V) as model compounds. For all the derivatives the INDO charges were calculated and correlated with the 1H- and 13C-NMR spectra. The experimental electronic spectra were correlated with the theoretical ones (INDO-S-CI). All the results obtained confirm the suggested mechanism.

Alkylated benzimidazole and benzotriazole derivatives of 3-amino-2-propenoic acid

1989 ◽  
Vol 54 (3) ◽  
pp. 713-724 ◽  
Author(s):  
Viktor Milata ◽  
Dušan Ilavský ◽  
Igor Goljer
Keyword(s):  
Hydrogen Atom ◽  
Nmr Spectra ◽  
Model Compounds ◽  
Methyl Group ◽  
Propenoic Acid ◽  
Independent Synthesis ◽  
Amino Derivatives ◽  
Derivatives Of ◽  
Benzotriazole Derivatives ◽  
C Nmr

The alkylation of unsubstituted 3-(5-benzimidazolyl- and 5-benzotriazolyl)amino derivatives of 2-propenoic acid (I) results in the replacement of hydrogen atom at the nitrogen of YZC=CH-NH- substituent (II-IV). The model compounds with a methyl group in the azole nucleus (V-VII) have been prepared by an independent synthesis. The structure of all products has been confirmed and confronted with their IR, UV, 1H and 13C NMR spectra.

The biosynthesis of ephedrine

1989 ◽  
Vol 67 (6) ◽  
pp. 998-1009 ◽  
Author(s):  
Gunnar Grue-Sørensen ◽  
Ian D. Spenser
Keyword(s):  
Carbon Atom ◽  
Benzoic Acid ◽  
Pyruvic Acid ◽  
Nmr Spectra ◽  
Carbon Skeleton ◽  
Resonance Spectroscopy ◽  
Methyl Group ◽  
Acid Incorporation ◽  
Group A ◽  
C Nmr

It is shown by 13C nuclear magnetic resonance spectroscopy that the labelled C2 fragment of [2,3-13C2]pyruvic acid is transferred intact into the C-methyl group and the adjacent carbon atom of the Ephedra alkaloids, norephedrine, ephedrine, norpseudoephedrine, and pseudoephedrine, in growing plants of Ephedragerardiana. This finding serves to identify pyruvate as the elusive precursor of the aliphatic C2 terminus of the skeleton of the alkaloids. In earlier experiments with C-labelled substrates, label from [3-14C]pyruvic acid was incorporated mainly, but not exclusively, into the C-methyl group of ephedrine, and label from [2-14C]pyruvate was incorporated similarly into the carbon atom adjacent to the C-methyl group. A C6–C1 unit related to benzaldehyde or benzoic acid has long been known to generate the benzylic fragment of the carbon skeleton of the Ephedra alkaloids. It is likely that the carbon skeleton of ephedrine is generated from pyruvate and either benzaldehyde or benzoic acid, by a reaction analogous to the formation of acetoin or diacetyl from pyruvate and acetaldehyde or acetic acid, respectively. Keywords: biosynthesis of ephedrine, Ephedra alkaloids, 13C NMR spectra, ephedrine, biosynthesis of pyruvic acid, incorporation into ephedrine13C NMR spectra.

scholarly journals Synthetic, Infrared, 1H and 13C NMR Spectral Studies on N-(2-/3-Substituted Phenyl)-4-Substituted Benzenesulphonamides, 4-X’C6H4SO2NH(2-/3-XC6H4), where X’ = H, CH3, C2H5, F, Cl or Br, and X = CH3 or Cl

2005 ◽  
Vol 60 (1-2) ◽  
pp. 106-112 ◽  
Author(s):  
B. Thimme Gowda ◽  
Mahesha Shetty ◽  
K. L. Jayalakshmi
Keyword(s):  
Solid State ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Spectral Studies ◽  
1H And 13C Nmr ◽  
Methyl Group ◽  
Benzene Rings ◽  
Stretching Vibrations ◽  
C Nmr

Twenty three N-(2-/3-substituted phenyl)-4-substituted benzenesulphonamides of the general formula, 4-X’C6H4SO2NH(2-/3-XC6H4), where X’ = H, CH3, C2H5, F, Cl or Br and X = CH3 or Cl have been prepared and characterized, and their infrared spectra in the solid state, 1H and 13C NMR spectra in solution were studied. The N-H stretching vibrations, νN−H, absorb in the range 3285 - 3199 cm−1, while the asymmetric and symmetric SO2 vibrations vary in the ranges 1376 - 1309 cm−1 and 1177 - 1148 cm−1, respectively. The S-N and C-N stretching vibrations absorb in the ranges 945 - 893 cm−1 and 1304 - 1168 cm−1, respectively. The compounds do not exhibit particular trends in the variation of these frequencies on substitution either at ortho or meta positions with either a methyl group or Cl. The observed 1H and 13C chemical shifts of are assigned to protons and carbons of the two benzene rings. Incremental shifts of the ring protons and carbons due to -SO2NH(2-/3-XC6H4) groups in C6H5SO2NH(2-/3-XC6H4), and 4- X’C6H4SO2- and 4-X’C6H4SO2NH- groups in 4-X’C6H4SO2NH(C6H5) are computed and employed to calculate the chemical shifts of the ring protons and carbons in the substituted compounds, 4-X’C6H4SO2NH(2-/3-XC6H4). The computed values agree well with the observed chemical shifts.

Synthesis and NMR Studies of Some Steroidal Isoxazoles

1992 ◽  
Vol 47 (6) ◽  
pp. 891-897 ◽  
Author(s):  
Sergio Giacopello ◽  
Mónica E. Deluca ◽  
Alicia M. Seldes
Keyword(s):  
Nmr Spectra ◽  
Two Dimensional ◽  
Model Compounds ◽  
Nmr Studies ◽  
Reaction Conditions ◽  
Related Model ◽  
H Nmr ◽  
Short Synthesis ◽  
Nmr Methods ◽  
C Nmr

A short synthesis of 17α-pregna-2,4-dien-[2,3-d]isoxazol-17β-ol (1) is described using mild reaction conditions and with a high overall yield. The equilibrium between keto-enolic forms has been studied by 1H NMR methods. Complete assignments of all the resonances in the 1H and 13C NMR spectra of Danazol have been made using a variety of one and two-dimensional correlation methods. 13C NMR spectra of all the intermediate and related model compounds were also assigned.

ChemInform Abstract: CROSS-LINKING OF AMINO ACIDS BY FORMALDEHYDE, (13)C NMR SPECTRA OF MODEL COMPOUNDS

1975 ◽  
Vol 6 (30) ◽  
pp. no-no
Author(s):  
MICHAEL K. DEWAR ◽  
R. B. JOHNS ◽  
DAVID P. KELLY ◽  
JOHN F. YATES
Keyword(s):  
Amino Acids ◽  
Nmr Spectra ◽  
Cross Linking ◽  
Model Compounds ◽  
C Nmr

Model compounds of poly(methyl methacrylate). Conformational structure of methyl 3-methoxy-2-methylpropionate

1984 ◽  
Vol 49 (10) ◽  
pp. 2275-2284 ◽  
Author(s):  
Danica Doskočilová ◽  
Jan Štokr ◽  
Bohdan Schneider ◽  
Martin Přádný ◽  
Stanislav Ševčík
Keyword(s):  
Methyl Methacrylate ◽  
Raman Spectra ◽  
Nmr Spectra ◽  
Conformational Structure ◽  
Infrared And Raman Spectra ◽  
Model Compounds ◽  
Poly Methyl Methacrylate ◽  
C Nmr

By analysis of 1H and 13C NMR spectra, and of infrared and Raman spectra of methyl 3-methoxy-2-methylpropionate, the formation of conformers generated by rotation about the bonds CH3O-CH2, CH2-CH and C-C=O was studied. The structure of the most highly populated conformer is proposed.

Model compounds of poly(methyl methacrylate). Conformational structure of 2,2-dimethyl-1-methoxypropane and of the methyl ester of 3-methoxy-2,2-dimethylpropanoic acid

1983 ◽  
Vol 48 (11) ◽  
pp. 3050-3064 ◽  
Author(s):  
Bohdan Schneider ◽  
Danica Doskočilová ◽  
Jan Štokr ◽  
Jan Lövy ◽  
Martin Přádný ◽  
...  
Keyword(s):  
Methyl Ester ◽  
Methyl Methacrylate ◽  
Nmr Spectra ◽  
Conformational Structure ◽  
Model Compounds ◽  
Poly Methyl Methacrylate ◽  
Major Form ◽  
C Nmr

By analysis of infrared, Raman and 13C NMR spectra of 2,2-dimethyl-1-methoxypropane and of the methyl ester of 3-methoxy-2,2-dimethylpropanoic acid, the formation of conformers generated by rotation about the CH2-OCH3 and C-CH2 bonds was studied. It was found that in both molecules, only the form with trans orientation of the C-CH2-O-CH3 bonds is present. The conformational structure of the major form of the methyl ester of 3-methoxy-2,2-dimethylpropanoic acid was proposed.

Assignment of 1H and 13C NMR spectra by a combination of homo- and heteronuclear shift correlated two-dimensional NMR. Application to oligosaccharides related to arabinoxylane

1984 ◽  
Vol 49 (7) ◽  
pp. 1605-1616 ◽  
Author(s):  
Jan Schraml ◽  
Ján Hirsch ◽  
Eva Petráková ◽  
Eduard Krahé ◽  
Claus Bliefert
Keyword(s):  
Nmr Spectra ◽  
Chemical Shifts ◽  
Suitable Model ◽  
13C Nmr Spectra ◽  
Molecular Fragments ◽  
Model Compounds ◽  
1H And 13C Nmr ◽  
Complete Assignment ◽  
Other Information ◽  
C Nmr

It is shown that a combination of homo- and heteronuclear shift correlated 2 D NMR yields correct and complete assignment of 1H and 13C NMR spectra. The amount of the work necessary can be considerably reduced if some of the lines can be unambiguously assigned on the basis of other information or if suitable model compounds are available.The pattern of homonuclear cross-peaks is characteristic for molecular fragments and can be used with advantage to trace out the lines in the spectral regions with heavy overlap. The exactly assigned 13C chemical shifts of disaccharide and trisaccharide related to arabinoxylan agree satisfactorily with the shifts predicted according to the shifts found in the spectra of model mono- and disaccharides measured under the same conditions.

Synthetic and Spectroscopic Studies on N-(i,j-Disubstituted Phenyl)-4- Substituted Benzenesulphonamides, 4-X’C6H4SO2NH(i,j-X2C6H3), where X’ = H, CH3, C2H5, F, Cl or Br; i, j = 2, 3; 2, 4; 2, 5; 2, 6 or 3, 4; and X = CH3 or Cl

2005 ◽  
Vol 60 (1-2) ◽  
pp. 113-120 ◽  
Author(s):  
Mahesha Shetty ◽  
B. Thimme Gowda
Keyword(s):  
General Formula ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Spectroscopic Studies ◽  
Methyl Group ◽  
Methods Of Calculation ◽  
Benzene Rings ◽  
Stretching Vibrations ◽  
C Nmr

Fifty four N-(i,j-disubstituted phenyl)-4-substituted benzenesulphonamides of the general formula 4-X’C6H4SO2NH(i,j-X2C6H3), where X’ = H, CH3, C2H5, F, Cl or Br; i,j = 2,3; 2,4; 2,5; 2,6 or 3, 4; and X = CH3 or Cl, are prepared and characterized and their infrared, 1H and 13C NMR spectra in solution are studied. The N-H stretching vibrations νN−H absorb in the range 3305 - 3205 cm−1, while the asymmetric and symmetric SO2 vibrations vary in the ranges 1377 - 1307 cm−1 and 1184 - 1128 cm−1, respectively. The N-(i,j-disubstituted phenyl)-4-substituted benzenesulphonamides show C-S, S-N and C-N stretching vibrations in the ranges 844 - 800 cm−1, 945 - 891 cm−1 and 1309 - 1170 cm−1, respectively. The compounds do not exhibit particular trends in the variation of these frequencies on substitution either at ortho or meta positions with either a methyl group or Cl. The observed 1H and 13C chemical shifts ofare assigned to protons and carbon atoms of the two benzene rings. Incremental shifts of the ring protons and carbon atoms due to -SO2NH(i,j-X2C6H3) groups in C6H5SO2NH(i,j-X2C6H3) and 4-X’C6H4SO2NH- groups in 4-X’C6H4SO2NH(C6H*) are computed and employed to calculate the chemical shifts of the ring protons and carbon atoms in the substituted compounds 4-X’C6H4SO2NH(i,j-X2C6H3). The different methods of calculation lead to almost the same values in most cases and agree well with the observed chemical shifts, indicating the validity of the principle of additivity of the substituent effects with chemical shifts in these compounds.

scholarly journals Preparation and Spectral Properties of Mixed-Ligand Complexes of VO(IV), Ni(II), Zn(II), Pd(II), Cd(II) and Pb(II) with Dimethylglyoxime andN-acetylglycine

2010 ◽  
Vol 7 (s1) ◽  
pp. S580-S586 ◽  
Author(s):  
Shayma A. Shaker
Keyword(s):  
Metal Ions ◽  
Electronic Spectra ◽  
Nmr Spectra ◽  
Magnetic Moments ◽  
Visible Region ◽  
Mixed Ligand ◽  
Mixed Ligand Complexes ◽  
Carboxyl Oxygen Atom ◽  
Absorption Bands ◽  
C Nmr

A number of mixed-ligand complexes of the general formula [M(D)(G)] where D=dimethylglyoximato monoanion, G=N-acetylglycinato and M=VO(IV), Ni(II), Zn(II), Pd(II), Cd(II) and Pb(II) were prepared. Each complex was characterized by elemental analysis, determination of metal, infrared spectra, electronic spectra, (1H and13C) NMR spectra, conductivity and magnetic moments. All these complexes were not soluble in some of the organic solvent but highly soluble in dimethylformamide. The conductivity data showed the non-electrolytic nature of the complexes. The electronic spectra exhibited absorption bands in the visible region caused by the d-d electronic transition such as VO(IV), Ni(II) and Pd(II). The IR and (1H,13C) NMR spectra which have indicate that the dimethylglyoxime was coordinated with the metal ions through the N and O atoms of the oxime group andN-acetylglycine was coordinated with metal ions through the N atom and terminal carboxyl oxygen atom.

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