Synthesis and Characterization of New Diimide Diols and Processable Poly(esterimide)s Derived Therefrom

2011 ◽  
Vol 19 (9) ◽  
pp. 763-772 ◽  
Author(s):  
P. Thiruvasagam ◽  
C. Shiva ◽  
C. Sundararaman ◽  
D. Venkatesan
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Gel Permeation Chromatography ◽  
Nitrogen Atmosphere ◽  
Solution Viscosity ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Good Thermal Stability ◽  
Phenyl Rings

New aromatic diimide-diol monomers were prepared by the aromatic nucleophilic substitution reaction of aromatic dianhydrides and 4-aminophenol/(4-aminophenyl)-2'-(4-hydroxy phenyl)propane. The monomers were characterized by IR and 1H-NMR spectroscopy. A series of poly(esterimide)s was prepared from diimide-diols and aromatic diacid chlorides by solution polycondensation reaction in N-methyl-2-pyrrolidone. The poly(esterimide)s were characterized by IR and 1H-NMR spectroscopy, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, gel-permeation chromatography, solution viscosity and solubility behaviour. The poly(esterimide)s with flexible groups, methyl groups and 1,3-disubstituted phenyl rings in the chain were expected to disturb the symmetry, and their effects on the property were studied. Most of the poly(esterimide)s exhibited good solubility in common organic solvents. The poly(esterimide)s displayed good thermal stability, and the 10% weight loss under nitrogen atmosphere ranged from 361 to 439 °C respectively.

scholarly journals CRYSTAL STRUCTURE AND TAUTOMERISM OF ALKYLAMINO-β-KETOENOLS IN SOLUTIONS

2019 ◽  
Vol 85 (8) ◽  
pp. 73-82
Author(s):  
VIKTOR CHERNII
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
1H Nmr ◽  
Trifluoroacetic Acid ◽  
1H Nmr Spectroscopy ◽  
Keto Group ◽  
Polymethine Chain ◽  
X Ray Diffraction ◽  
The Stability ◽  
Crystalline System

The structure of alkylamino-β-ketoenols obtained by opening of the pyran cycle of chalcones based on dehydracetic acid was studied by X-ray diffraction, IR, 1H NMR spectroscopy and chromatography-mass spectrometry. The infrared spectra of the compounds appear to be typical of β-ketoenols. The crystalline structure (2Z,5Z,7E,9E)-6-hydroxy-2-(methylami-no)-10-phenylethoxy-2,5,7,9-tetraene-4-one was first determined. A comparative analysis of it with 2 pre-viously published structures has been carried out. All of these compounds are crystallized in the form of yellow plates in the monoclinic crystalline system (spatial group P21/n), they have a planar arrangement of the polyene chain and β-ketoenol fragment con-jugated to the aromatic ring. It has been established that the planar configuration of the β-ketoenol fragment is stabilized by hydrogen bonds between the hydroxy and keto group and the amino and keto group in the crystalline state. The length of the polymethine chain, the nature of the substituents in the aromatic and aliphatic part of the molecule do not significantly affect the size and geometry of the alkylamino-β-ketoenolate fragment. Approximately the same lengths of bonds, the distance between atoms and the corners indicate that all these com-pounds may have similar chelating properties. Ac-cording to 1H NMR spectroscopy in various deu-terated solvents (benzene, DMSO, chloroform, ace-tone, methanol and trifluoroacetic acid), most of the main signals of the obtained compounds have sa-tellites, which indicates the existence of several isomeric forms in solutions. The analysis of integral intensities of labile protons in 1H NMR spectra does not allow to obtain accurate results regarding the ratio of tautomers in a solution, but for a series of compounds their approximate ratio in chloroform, DMSO and trifluoroacetic acid have been established (from 70:30 in CDCl3 to 90:10 in DMSO and CF3CO2D). The stability of the tautomers in the solutions is confirmed by the data of chromatogra-phy-mass spectrometry.

N-Heterocyclic Carbene-facilated Condensation of 3-Methylphenylboronic Acid to the Boroxine

2013 ◽  
Vol 68 (5-6) ◽  
pp. 453-457 ◽  
Author(s):  
Dongxiang Zhang ◽  
Jie Li ◽  
Xiao Dong ◽  
Xing Zhou ◽  
Zhi Yang ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Single Crystal ◽  
1H Nmr ◽  
Elemental Analysis ◽  
1H Nmr Spectroscopy ◽  
Phenylboronic Acid ◽  
X Ray Diffraction ◽  
X Ray

The adduct of (3-MeC6H4)3B3O3 with an N-heterocyclic carbene (NHC=1,3-diethyl-4,5- dimethylimidazol-2-ylidene) was prepared by reacting 2.5 equiv. of 3-methylphenylboronic acid with 1 equiv. of the NHC. This reaction shows a novel carbene-facilitated condensation of substituted phenylboronic acid monomers. The structure of the compound (3-MeC6H4)3B3O3(NHC) (1) has been characterized by 1H NMR spectroscopy, elemental analysis, and single-crystal X-ray diffraction studies

Isomerization of Allyl Derivatives of Bisphenol A

2020 ◽  
Vol 869 ◽  
pp. 357-361
Author(s):  
Vladimir A. Lisovenko ◽  
Pavel A. Yudaev ◽  
Evgeniy M. Chistyakov
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
Nmr Spectroscopy ◽  
Bisphenol A ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Claisen Rearrangement ◽  
Allyl Bromide ◽  
Scanning Calorimetry ◽  
Derivatives Of

4,4'-diallyloxy-2,2-diphenylpropane, based on bisphenol A and allyl bromide wassynthesized. The thermal properties of the obtained products were studied using thermogravimetricanalysis and differential scanning calorimetry. The process of thermal isomerization of allyl groupsin 4,4'-diallyloxy-2,2-diphenylpropane, which is a Claisen rearrangement, was discovered. Allcompounds were characterized by 1H NMR spectroscopy.

Asymetrical Dimer - allyl-palladiu Complexes II. Data from Infrared Spectra and Chemical Behaviour

2008 ◽  
Vol 59 (7) ◽  
Author(s):  
Maria Maganu ◽  
Filip Chiraleu ◽  
Constantin Draghici ◽  
Gheorghe Mihai
Keyword(s):  
Carbon Monoxide ◽  
Nmr Spectroscopy ◽  
1H Nmr ◽  
Infrared Spectra ◽  
Analytical Methods ◽  
1H Nmr Spectroscopy ◽  
Chemical Behaviour ◽  
The Asymmetry ◽  
Pd Complexes

The previous data obtained by 1H-NMR spectroscopy established the existence of an asymmetry of the bond between Pd and p-allylic groups, even in the p-allyl-Pd complexes dimers which are considered usually symmetric dimers. The asymmetry of the bond depends by the substitutes of the allylic group. Other analytical methods were investigated for additional proof of the obtained results. Thus, this paper discusses how this asymmetry would be reflected in the infrared spectra and in the reaction of the complexes with carbon monoxide.

Diastereoselective Reduction of Selected α-substituted β-keto Esters and the Assignment of the Relative Configuration by 1H-NMR Spectroscopy

2020 ◽  
Vol 07 ◽  
Author(s):  
Christian Trapp ◽  
Corinna Schuster ◽  
Chris Drewniok ◽  
Dieter Greif ◽  
Martin Hofrichter
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Selective Reduction ◽  
Reducing Agents ◽  
Relative Configuration ◽  
Curtius Rearrangement ◽  
Keto Esters ◽  
Hydroxy Esters ◽  
Diastereoselective Reduction

Background:: Chiral β-hydroxy esters and α-substituted β-hydroxy esters represent versatile building blocks for pheromones, β-lactam antibiotics and 1,2- or 1,3-aminoalcohols. Objective:: Synthesis of versatile α-substituted β-keto esters and their diastereoselective reduction to the corresponding syn- or anti-α-substituted β-hydroxy esters. Assignment of the relative configuration by NMR-spectroscopy after a CURTIUS rearrangement of α-substituted β-keto esters to 4-substituted 5-methyloxazolidin-2-ones. Method:: Diastereoselective reduction was achieved by using different LEWIS acids (zinc, titanium and cerium) in combination with complex borohydrides as reducing agents. Assignment of the relative configuration was verified by 1H-NMR spectroscopy after CURTIUS-rearrangement of α-substituted β-hydroxy esters to 4-substituted 5-methyloxazolidin-2-ones. Results:: For the syn-selective reduction, titanium tetrachloride (TiCl4) in combination with a pyridine-borane complex (py BH3) led to diastereoselectivities up to 99% dr. High anti-selective reduction was achieved by using cerium trichloride (CeCl3) and steric hindered reducing agents such as lithium triethylborohydride (LiEt3BH). After CURTIUS-rearrangement of each α-substituted β-hydroxy ester to the corresponding 4-substituted 5-methyloxazolidin-2-one, the relative configuration was confirmed by 1H NMR-spectroscopy. Conclusion:: We have expanded the procedure of LEWIS acid-mediated diastereoselective reduction to bulky α-substituents such as the isopropyl group and the electron withdrawing phenyl ring.

Conformational study on ribonucleoside O-phosphonylmethyl derivatives by 1H NMR spectroscopy

1985 ◽  
Vol 50 (8) ◽  
pp. 1899-1905 ◽  
Author(s):  
Milena Masojídková ◽  
Jaroslav Zajíček ◽  
Miloš Buděšínský ◽  
Ivan Rosenberg ◽  
Antonín Holý
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Conformational Study ◽  
H Nmr ◽  
Conformational Properties

Conformational properties of ribonucleoside 5'-O-phosphonylmethyl derivatives have been determined by 1H NMR spectroscopy and compared with those of natural nucleosides and 5'-nucleotides.

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