The Dinitration of Dimethylacetanilides

2003 ◽  
Vol 2003 (5) ◽  
pp. 303-304 ◽  
Author(s):  
Inmaculada C. Rodriguez Medina ◽  
James R. Hanson
Keyword(s):  
Methyl Group ◽  
H Nmr ◽  
Nmr Methods ◽  
Steric Inhibition Of Resonance

The orientation of dinitration of the dimethylacetanilides has been examined by 1H NMR methods and a possible enhancement of the hyperconjugative influence of a methyl group has been considered as an additional factor augmenting the effect of the steric inhibition of resonance on the orientation of substitution.

A 19F nuclear magnetic resonance study of the conjugate Brönsted-Lewis superacid HSO3F-SbF5. Part 1

1999 ◽  
Vol 77 (11) ◽  
pp. 1869-1886 ◽  
Author(s):  
Dingliang Zhang ◽  
Markus Heubes ◽  
Gerhard Hägele ◽  
Friedhelm Aubke
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nmr Spectra ◽  
Nuclear Magnetic Resonance Study ◽  
Magnetic Resonance Study ◽  
Formation Reaction ◽  
H Nmr ◽  
Acid Conjugate ◽  
Nmr Methods ◽  
Cis And Trans

The Brönsted-Lewis superacid HSO3F-SbF5 or "magic acid" is re-investigated by modern 19F NMR methods over a wide concentration range. The system is found to be considerably more complex than had been assumed previously. A total of 13 different anions are identified of which only five have previously been identified in magic acid. With increasing SbF5 contents the concentration of monomeric anions like [SbF6]-, [SbF5(SO3F)]-, cis- and trans-[SbF4(SO3F)2]-, and mer-[SbF3(SO3F)3]- gradually decreases. Except for [Sb2F11]-, which is present in very small concentrations only, the formation of oligomers involves exclusively μ-fluorosulfato bridges. In addition to donor (SO3F)- and acceptor (SbF5) complex formation to give [SbF5(SO3F)]- and possibly ligand redistribution, the solvolysis of SbF5 or SbF4(SO3F) in HSO3F appears to be the principal formation reaction for polyfluorosulfatofluoroantimonate(V) anions. In glass (NMR tubes) the solvolysis product HF is converted to the oxonium ion [H3O]+, which has previously been identified by 1H NMR and structurally characterized as [H3O][Sb2F11] by us.Key words: magic acid, conjugate superacid, fluorosulfuric acid, 19F NMR spectra.

Darstellung und Eigenschaften von Derivaten des 4,5-Benzo-2,3-dihydro- \ ,3-diborols/ Synthesis and Properties of Derivatives of the 4,5-Benzo-2,3-dihydro-1,3-diborole

1993 ◽  
Vol 48 (1) ◽  
pp. 68-71 ◽  
Author(s):  
Hartmut Schulz ◽  
Thomas Deforth ◽  
Walter Siebert
Keyword(s):  
Sandwich Complexes ◽  
Methyl Group ◽  
H Nmr ◽  
Derivatives Of

Reactions of 1,2-bis(trimethyIstannyl)benzene (4) with bis(dichIoroboryl)methane derivatives (Cl2B)2CHR1 (R1 = H ,Me) lead to the formation of the 4,5-benzo-1,3-dichloro-2,3-dihydro-1,3-diboroles 2a,b.Substitution of chlorine in 2a,b by a methyl group using A1Me3 yields the 4,5-benzo-1,3-dimethyl-2,3-dihydro-1,3-diboroles 2c,d, of which 2c is thermally labile. Complexation of 2c,d with [(C5H5)Co(C2H4)2] did not give the expected sandwich complexes 6c,d, but the formation of the triple-decker 7d was observed. The paramagnetic 7d and the diamagnetic 7d+, obtained by oxidation with Ag+BF4-, were studied by 1H NMR .

Das dynamische Verhalten des 1-Methyl-1-benzothiepinium-Ringsystems/The Dynamic Behaviour of the 1-Methyl-1-benzothiepinium Ring System

1981 ◽  
Vol 36 (8) ◽  
pp. 974-977 ◽  
Author(s):  
Hans Hofmann ◽  
Franz Dickert
Keyword(s):  
Nmr Spectroscopy ◽  
Room Temperature ◽  
Dynamic Behaviour ◽  
Ring System ◽  
Membered Ring ◽  
Ring Inversion ◽  
Methyl Group ◽  
H Nmr ◽  
Pyramidal Inversion ◽  
Mutual Conversion

Abstract By 1H NMR spectroscopy the stereochemistry of the 1-methyl-1-benzothiepinium ring system was investigated both in thermodynamic and kinetic respects. It was shown that in solution a rapid mutual conversion of the boat shaped seven membered ring system with exo-respectively endo-S-methyl group occurs via a ring inversion and not by a pyramidal inversion at the sulfonium ion. At room temperature predominantly the conformation with the exo-S-methyl group is present.

Proton Magnetic Resonance and Molecular Motion in Solid Methyl-Piperidines and Piperazines

1977 ◽  
Vol 32 (8) ◽  
pp. 882-885 ◽  
Author(s):  
R. Schüler ◽  
L. Brücher ◽  
W. Müller-Warmuth
Keyword(s):  
Proton Magnetic Resonance ◽  
Molecular Motion ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Methyl Group ◽  
Spin Lattice ◽  
H Nmr ◽  
Second Moments ◽  
Line Narrowing

Abstract The 1H-NMR spin-lattice relaxation time and lineshape in solid 2-, 3-, and 4-methyl-piperidine, in 2-and N-methyl-piperazine, and in NN′-diinethyl-piperazine has been measured from low temperatures to the melting point. For all cases, the experimental data can be described by classical rotation of the methyl group. Activation energies governing this motion are between 9 and 14 kJ/mole. Second moments are reduced from about 25 G2 to 17 G2. No further line-narrowing was observed.

An evaluation of high resolution nuclear magnetic resonance experiments and protocols in the structure elucidation of organic molecules. I. A relatively simple system, brucine

1985 ◽  
Vol 63 (2) ◽  
pp. 483-490 ◽  
Author(s):  
Michael A. Bernstein ◽  
Laurance D. Hall
Keyword(s):  
High Resolution ◽  
Chemical Shift ◽  
Structural Information ◽  
Nuclear Overhauser Effect ◽  
Proton Spectrum ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Overhauser Effect ◽  
Nuclear Overhauser ◽  
Nmr Methods

Using a combination of one-dimensional (1D) and two-dimensional (2D) high resolution nmr methods, the 1H nmr spectrum of brucine was fully assigned. The 2D J-resolved and homonuclear chemical shift correlated (COSY) experiments provided assignments without full structural information; this was obtained from nuclear Overhauser effect (nOe) enhancement experiments (1D and 2D). With the proton spectrum fully assigned, proton-bearing carbons in the 13C nmr spectrum were easily assigned using the 2D heteronuclear chemical shift correlation map (CSCM) experiment.

scholarly journals Intermolecular Interactions between Eosin Y and Caffeine Using 1H-NMR Spectroscopy

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Macduff O. Okuom ◽  
Mark V. Wilson ◽  
Abby Jackson ◽  
Andrea E. Holmes
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr Spectroscopy ◽  
Date Rape ◽  
Proton Exchange ◽  
Eosin Y ◽  
Club Drugs ◽  
Hydroxybutyric Acid ◽  
Color Changes ◽  
H Nmr ◽  
Nmr Methods

DETECHIP has been used in testing analytes including caffeine, cocaine, and tetrahydrocannabinol (THC) from marijuana, as well as date rape and club drugs such as flunitrazepam, gamma-hydroxybutyric acid (GHB), and methamphetamine. This study investigates the intermolecular interaction between DETECHIP sensor eosin Y (DC1) and the analyte (caffeine) that is responsible for the fluorescence and color changes observed in the actual array. Using 1H-NMR, 1H-COSY, and 1H-DOSY NMR methods, a proton exchange from C-8 of caffeine to eosin Y is proposed.

Synthesis and characterization of Pt(II) complexes containing the bidentate pyrazolylgallate ligand, [Me2Gapz2]−

1985 ◽  
Vol 63 (9) ◽  
pp. 2550-2554 ◽  
Author(s):  
Sophia Nussbaum ◽  
Alan Storr
Keyword(s):  
Variable Temperature ◽  
Synthesis And Characterization ◽  
Direct Reaction ◽  
H Nmr ◽  
Nmr Methods

The complexes [Me2Mpz2]Pt(Me)L (where L = CO, Ph3P, or PhC≡CPh for M = Ga; L = PhC≡CPh for M = B) have been synthesized by the direct reaction of the ligands Na[Me2Mpz2] with Pt(Me)Cl(COD) followed by the addition of ligand L. The complexes have been shown to be fluxional in solution by variable temperature 1H nmr methods.

Photostability of Monoazo Disperse Dyes in Different Solvents

2013 ◽  
Vol 834-836 ◽  
pp. 472-475
Author(s):  
Narumol Ittarat ◽  
Potjanart Suwanruji ◽  
Thitinun Karpkird ◽  
Jantip Setthayanond
Keyword(s):  
Melting Point ◽  
Visible Light ◽  
Elemental Analysis ◽  
Disperse Dyes ◽  
Initial Value ◽  
Methyl Group ◽  
H Nmr ◽  
Monoazo Disperse Dyes

Twelve monoazo disperse dyes were synthesized and then characterized by melting point (m.p.) measurement, elemental analysis and1H-NMR. The photostability of monoazo disperse dyes in solvents with different polarities was evaluated thereafter the dyes in each solvent were irradiated with visible light for 8 hours. The percentage of photostability of the dye decreased from the initial value in the range of 5-10%. The photostability was affected by the substituted group of the dyes regardless of the solvent used. Different R1group on the diazo component increased the photostability in order of H˃CN˃Cl. The photostability of the dye was also higher when R2group on the coupling component was a methyl group.

Synthesis and Structure of a Palladium(II) Chloride Complex with 2-(2-Methyl-3-phenyl-isoxazolidin-5-yl)-pyridine

2000 ◽  
Vol 55 (5) ◽  
pp. 373-376 ◽  
Author(s):  
Andrey B. Lysenko ◽  
Oleg V. Shishkin ◽  
Rostislav D. Lampeka
Keyword(s):  
Chelate Ring ◽  
Organic Ligand ◽  
Chloride Complex ◽  
Monoclinic Space Group ◽  
Equatorial Orientation ◽  
X Ray Diffraction ◽  
Methyl Group ◽  
X Ray ◽  
H Nmr ◽  
Square Planar

The 1:1 complex of palladium(II) chloride with 2-(2-methyl-3-phenyl-isoxazolidin-5-yl)- pyridine (L) has been prepared and studied by means of elemental analysis, 1H NMR spectroscopy and X-ray diffraction (monoclinic, space group P21/n with parameters: a = 8.141(2), b = 9.750(2),c = 20.691(6)Å ,β = 95.62(3)°,V = 1634.4(7)Å3 ,Z = 4 ;R1= 0.054 and wR2= 0.144 for 3352 unique reflections). A square-planar coordination polyhedron has been established for the palladium atom both in acetone solution and in the solid state. The organic ligand is coordinated toometal in a bidentate manner via nitrogen atoms of the pyridine substituent (Pd-N(2) 2.125(3) Å) and the isoxazolidine heterocycle (Pd-N(l) 2.102(3) Å). The other two coordination positions of palladium are occupied by chlorine atoms (Pd-Cl(l) 2.321(1) and Pd-Cl(2) 2.333(1) Å). The six-membered chelate ring formed by Pd, N(2), C(4), C(1), 0(1) and N (1) possesses a “twist-tub” conformation. The isoxazolidine cycle has an envelope conformation with an equatorial orientation of the methyl group.

5J(CH3,SH) as a negative proximate or as a positive σ−π coupling in 2-methylthiophenol derivatives

1985 ◽  
Vol 63 (8) ◽  
pp. 2217-2220 ◽  
Author(s):  
Ted Schaefer ◽  
James Peeling ◽  
Rudy Sebastian ◽  
James D. Baleja
Keyword(s):  
Nmr Spectra ◽  
Sulfhydryl Group ◽  
The Other ◽  
Coupling Mechanism ◽  
Methyl Group ◽  
Tert Butyl ◽  
H Nmr ◽  
Out Of Plane ◽  
Negative Coupling

Analyses of the 1H nmr spectra of 6-chloro-2-methylthiophenol and of 4-tert-butyl-2-methylthiophenol in CCl4 solution, together with double irradiation experiments, show that 5J(CH5,SH) in the former compound is −0.66 Hz and is +0.47 Hz in the latter. In the chloro compound, the sulfhydryl group spends relatively little time in out-of-plane conformations at 300 K. The negative coupling is a consequence of a through-space or proximate coupling mechanism. In the other compound, the sulfhydryl group samples many out-of-plane conformations but relatively few in which the S—H bond lies near the methyl group. Therefore 5J(CH3,SH) is now dominated by a σ−π electron mechanism and is positive. Probably by coincidence, 4J(H,SH) in this compound is equal in magnitude but opposite in sign to 5J(CH3,SH).

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