Configuration on the C=N double bond of monosubstituted amidines and amidoximes

1989 ◽  
Vol 54 (12) ◽  
pp. 3245-3252 ◽  
Author(s):  
Bernard Tinant ◽  
Janine Dupont-Fenfau ◽  
Jean-Paul Declercq ◽  
Jaroslav Podlaha ◽  
Otto Exner
Keyword(s):  
Double Bond ◽  
Nitrogen Atom ◽  
Steric Effects ◽  
Model Compounds ◽  
X Ray ◽  
Analogous Model

Configuration on the C=N double bond of amidines and amidoximes is controlled by steric effects on the second nitrogen atom but there is a difference in the case of N’-monosubstituted derivatives: amidines prefer E configuration (conformation around the C-N bond sp) and amidoximes Z configuration (conformation ap). This was confirmed by the X-ray structures of two analogous model compounds N,N’-dimethyl-4-nitrobenzamidine (monoclinic, P21c, a = 10.855(3), b = 11.043(3), c = 8.593(3) Å, β = 105.69(2)°, V = 991.8(5) Å3, Z = 4, Dx = 1.29 g cm-3, CuKα, λ = 1.5418 Å, μ = 7.91 cm-1, F(000) = 408, T = 291 K, R = 0.065 for 1 265 observed reflections) and N’-methyl-4-nitrobenzamidoxime (monoclinic, P21/a, a = 6.699(2), b = 24.178(9), c = 6.075(2) Å, β = 106.20(3)°, V = 944.9(6) Å3, Z = 4, Dx = 1.37 g cm-3, CuKα, λ = 1.5418 Å, μ =9.22 cm-1, F(000) = 408, T = 291 K, R = 0.079 for 1 278 observed reflections).

scholarly journals Die Kristallstruktur von PPh3Me[NbOCl4(CH3CN)] / The Crystal Structure of PPh3Me[NbOCl4(CH3CN)]

1984 ◽  
Vol 39 (1) ◽  
pp. 107-110 ◽  
Author(s):  
W. Hiller ◽  
J. Strähle ◽  
H. Prinz ◽  
K. Dehnicke
Keyword(s):  
Crystal Structure ◽  
Double Bond ◽  
Nitrogen Atom ◽  
Bond Length ◽  
Unit Cell ◽  
Trans Position ◽  
Space Group ◽  
X Ray ◽  
Oxo Ligand ◽  
Solvate Molecule

The X-ray structure of PPh3Me[NbOCl4(CH3CN)] at 210 K was solved (space group P1̄, two formula units per unit cell, a = 1173.5(5), b = 1130.1(4), c = 946.8(3) pm, α = 97.70(4), β = 93.57(3), γ = 78.62(3)°, 3688 inde­pendent reflexions, R = 0.025). The material consists of cations [P(C6H5)3CH3]⊕ and anions [NbOCl4(CH3CN)]⊖. The nitrogen atom of the acetonitrile solvate molecule is coordinated to the niobium centre in the trans-position to the oxo ligand; the NbO bond length of 169 pm corresponds to a double bond.

One-pot Synthesis of Pyrazolone Sulfones by Iodine-catalyzed Sulfenylation of Pyrazolones with Aryl Sulfonyl Hydrazides Followed by Oxidation in Water

2018 ◽  
Vol 15 (3) ◽  
pp. 380-387
Author(s):  
Xia Zhao ◽  
Xiaoyu Lu ◽  
Lipeng Zhang ◽  
Tianjiao Li ◽  
Kui Lu
Keyword(s):  
Double Bond ◽  
Efficient Method ◽  
Room Temperature ◽  
Sulfonyl Chloride ◽  
Antibacterial Activities ◽  
Oxidation Reactions ◽  
Reaction Conditions ◽  
One Pot ◽  
X Ray ◽  
Amide Form

Aim and Objective: Pyrazolone sulfones have been reported to exhibit herbicidal and antibacterial activities. In spite of their good bioactivities, only a few methods have been developed to prepare pyrazolone sulfones. However, the substrate scope of these methods is limited. Moreover, the direct sulfonylation of pyrazolone by aryl sulfonyl chloride failed to give pyrazolone sulfones. Thus, developing a more efficient method to synthesize pyrazolone sulfones is very important. Materials and Method: Pyrazolone, aryl sulphonyl hydrazide, iodine, p-toluenesulphonic acid and water were mixed in a sealed tube, which was heated to 100°C for 12 hours. The mixture was cooled to 0°C and m-CPBA was added in batches. The mixture was allowed to stir for 30 min at room temperature. The crude product was purified by silica gel column chromatography to afford sulfuryl pyrazolone. Results: In all cases, the sulfenylation products were formed smoothly under the optimized reaction conditions, and were then oxidized to the corresponding sulfones in good yields by 3-chloroperoxybenzoic acid (m-CPBA) in water. Single crystal X-ray analysis of pyrazolone sulfone 4aa showed that the major tautomer of pyrazolone sulfones was the amide form instead of the enol form observed for pyrazolone thioethers. Moreover, the C=N double bond isomerized to form an α,β-unsaturated C=C double bond. Conclusion: An efficient method to synthesize pyrazolone thioethers by iodine-catalyzed sulfenylation of pyrazolones with aryl sulfonyl hydrazides in water was developed. Moreover, this method was employed to synthesize pyrazolone sulfones in one-pot by subsequent sulfenylation and oxidation reactions.

Regiospezifische Insertion von [SCN]- und [SeCN]- in die S – C- bzw. Se– C-Bindung Übergangsmetall-koordinierter Thietane und SelenetaneRegiospecific Insertion of [SCN]- and [SeCN]- in the S–C- and Se–C-Bond of Transition-Metal-Coordinated Thietanes and Selenetanes

1993 ◽  
Vol 48 (11) ◽  
pp. 1613-1620 ◽  
Author(s):  
Helmut Fischer ◽  
Claudia Kalbas ◽  
Carsten Troll ◽  
Klaus H. Fluck
Keyword(s):  
Nitrogen Atom ◽  
Transition Metal ◽  
Structure Analysis ◽  
Trans Isomer ◽  
X Ray ◽  
Tungsten Complexes ◽  
Membered Heterocycle

Pentacarbonyl(thietane)tungsten complexes react with thiocyanate, [SCN]-, and SiO2/H2O by insertion of the CN group into a S—C bond of the four-membered heterocycle, 1,3-migration of the pentacarbonyltungsten fragment and protonation of the nitrogen atom to give tungsten-coordinated thiazinthione complexes. Analogously, the reactions of a thietane tungsten complex with [SeCN]- and SiO2/H2O affords a thiazinselone complex. A selenazinthione complex is obtained from a selenetane complex and [SCN]- (+ SiO2/H2O). The insertions are regiospecific and stereoselective. The structure of the trans-isomer of a pentacarbonyl-(thiazinthione) complex has been established by X-ray structure analysis.

The Reactions of Substituted Germyl- and Silylhydrazines with BX3 and CY2 Acceptor Species

1972 ◽  
Vol 50 (4) ◽  
pp. 562-566 ◽  
Author(s):  
L. K. Peterson ◽  
K. I. Thé
Keyword(s):  
Molecular Weight ◽  
Nitrogen Atom ◽  
Low Temperatures ◽  
Adduct Formation ◽  
Steric Effects ◽  
Reaction Products ◽  
Hydrazine Derivatives ◽  
Basic Catalysts ◽  
Series Of Experiments ◽  
Electronic And Steric Effects

Boron trimethyl reacts with each of the organometalloid-hydrazine derivatives Me2NN(R)GeMe3 (R = H, Me, SiMe3) except Me2NN(SiMe3)GeMe3, and with Me2NNHSiMe3, forming 1:1 adducts. With Me2NN(SiMe3)GeMe3 and BMe3, no adduct was formed even at low temperatures. On the basis of p.m.r. spectra, the metalloid-substituted nitrogen atom rather than the terminal nitrogen, is indicated as the basic center at which adduct formation occurs. With BF3, the Si—N and Ge—N bonds of the hydrazine derivatives were cleaved, again indicating attack at the central nitrogen atom. In a series of experiments involving CY2 (Y = O, S) and Me2NN(R)MMe3 (R = H, Me, SiMe3; M = Si, Ge), reaction occurred readily for R = H, but less readily for R = Me and for the compound Me2NN(GeMe3)2, while no reaction was observed for the compounds Me2NN(SiMe3)2 and Me2NN(SiMe3)GeMe3, even when heat or basic catalysts were employed. Reaction products, carbamate and thiocarbamate derivatives, Me2NN(R)C(Y)YMMe3, were characterized on the basis molecular weight, i.r., p.m.r., and mass spectroscopy, and m.p. data. Ease of formation is discussed in terms of electronic and steric effects.

ChemInform Abstract: Syntheses and X-Ray Structures for Model Compounds of a Pyrimidinediyl- Based Rigid-Rod Aromatic Polyamide.

ChemInform ◽  
2010 ◽  
Vol 23 (17) ◽  
pp. no-no
Author(s):  
A. G. OERTLI ◽  
W. R. MEYER ◽  
U. W. SUTER ◽  
F. B. JOHO ◽  
V. GRAMLICH ◽  
...  
Keyword(s):  
Aromatic Polyamide ◽  
Model Compounds ◽  
X Ray ◽  
Rigid Rod

W-Doped TiO2 Preparation and Photocatalytic Degradation of Guaiacol

2014 ◽  
Vol 513-517 ◽  
pp. 33-36 ◽  
Author(s):  
Zi Chang Xie ◽  
Ying Wang ◽  
Peng Wang ◽  
Lei Zhang
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Degradation Rate ◽  
Amorphous State ◽  
X Ray Diffraction ◽  
Model Compounds ◽  
Plant Fibers ◽  
X Ray ◽  
Crystallite Structure

In this paper, W-doped TiO2 (W-TiO2) powder was prepared in hydrothermal method by mixing TiO2 and ammonium metatungstate. The catalysts were characterized by X-ray diffraction and ultraviolet spectrophotometer. The results displayed that W-TiO2 showed an anatase crystallite structure with 2 % W content. W-element in W-TiO2 was amorphous state. The guaiacol was degraded with the W-TiO2 in the visible light. It was a model compounds of lignin existed in the plant fibers. The degradation rate of guaiacol was increased with the photocatalytic time, as high as 88.21 % after 360 min irradiation. It was concluded that the W-TiO2 had an obvious photocatalytic activity under visible light. It can be used in the photocatalytic degradation of lignin.

THE REACTION OF ACTIVE NITROGEN WITH PROPYLENE

1952 ◽  
Vol 30 (12) ◽  
pp. 915-921 ◽  
Author(s):  
G. S. Trick ◽  
C. A. Winkler
Keyword(s):  
Double Bond ◽  
Nitrogen Atom ◽  
Hydrogen Cyanide ◽  
Atomic Hydrogen ◽  
Atomic Nitrogen ◽  
Active Nitrogen

The reaction of nitrogen atoms with propylene has been found to produce hydrogen cyanide and ethylene as the main products, together with smaller amounts of ethane and propane and traces of acetylene and of a C4 fraction. With excess propylene, the nitrogen atoms were completely consumed and for the reaction at 242 °C., 0.77 mole of ethylene was produced for each mole of excess propylene added. For reactions at lower temperatures, less ethylene was produced. The proposed mechanism involves formation of a complex between the nitrogen atom and the double bond of propylene, followed by decomposition to ethylene, hydrogen cyanide, and atomic hydrogen. The ethylene would then react with atomic nitrogen in a similar manner.

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