scholarly journals Synthesis and Characterization of New Heterocyclic Liquid Crystals

2009 ◽  
Vol 6 (3) ◽  
pp. 928-937 ◽  
Author(s):  
D. Srividhya ◽  
S. Manjunathan ◽  
S. Thirumaran
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Triazole Ring ◽  
Differential Scanning Calorimetric ◽  
Spectral Techniques ◽  
H Nmr ◽  
Methylene Chain ◽  
Microscopic Studies ◽  
C Nmr

This investigation enumerates the synthesis and mesomorphic properties of 1,2,3-triazole containing azobenzene liquid crystals. In these liquid crystals the methylene chain length at non polar end was varied from six to ten carbons to investigate the association properties of non polar chain on the melt. The compound was designed to have a polar ether chain at the other side of the molecule adjacent to the triazole ring and synthesized to enhance the dipolar interactions. These alterations in chemical structure produce two series of new liquid crystalline compounds with each series containing five variations in the methylene chain. The structure of the target compounds and the intermediates were confirmed by the1H NMR,13C NMR and IR spectral techniques. Polarized microscopic studies revealed that all the compounds in the series exhibited enantiotropic liquid crystalline properties. This was further confirmed using differential scanning calorimetric experiments. The energy minimized structure supports the mesogenic behavior of the structure.

Calamitische Flüssigkristalle: Beziehung zwischen Molekülstruktur und Mesogenität, trans-und cis-1,3,5,7-Tetraoxadecalin-Derivate [1,2] / Calamitic Liquid Crystals: Relationship Between Molecular Structure and Mesogenity, trans- and cis-1,3,5,7 -Tetraoxadecalin Derivatives [1, 2]

1986 ◽  
Vol 41 (6) ◽  
pp. 736-750 ◽  
Author(s):  
Bernd Kohne ◽  
Klaus Praefcke ◽  
Rashad Shabana Omar ◽  
Felix Frolow
Keyword(s):  
Liquid Crystals ◽  
Chemical Structure ◽  
Liquid Crystalline ◽  
Three Dimensional ◽  
X Ray ◽  
H Nmr ◽  
Smectic A ◽  
New Type ◽  
The Relationship ◽  
C Nmr

1,3,5,7-Tetraoxadecalin has been introduced as a novel central unit into the chemistry of calamitic liquid crystals. 2e,6e-Disubstituted derivatives 3a−h and 4b, g, i of the trans or cis fused heterobicyclus, respectively, have been synthesized. Whereas most of these tram-products (3c−h) are nematic or smectic A (new “rod-like mesogens”), the cis-products (4b, g, i) are not liquid crystalline. The configurations and conformations of all compounds have been elucidated by spectroscopic methods in particular by 1H and 13C NMR. In addition the structures of 3d, 3g and 4i as representatives of both series have been confirmed by X-ray analysis. The 1,3,5,7- tetraoxadecalin unit in the non-mesomorphic ds-products exists, as expected, in the “O-inside" conformation which has been established both by 1H NMR and X-ray studies. The relationship between the chemical structure and mesomorphic behaviour of these 1,3,5,7-tetraoxadecalin derivatives is discussed, as well as the most likely structural requirements for turning the non- mesomorphic cis-products into mesomorphic ones. The name “roof-like mesogens" is proposed for this predicted new type of liquid crystals with three-dimensional geometry.

scholarly journals Isolation and Characterization of New Ceramides from Aerial Parts of Lepidaploa cotoneaster

2012 ◽  
Vol 7 (6) ◽  
pp. 1934578X1200700 ◽  
Author(s):  
Edlene O. dos Santos ◽  
Marilena Meira ◽  
Ademir E. do Vale ◽  
Jorge M. David ◽  
Luciano P. de Queiróz ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Double Bond ◽  
Dimethyl Disulfide ◽  
Spectral Techniques ◽  
H Nmr ◽  
Aerial Parts ◽  
Isolation And Characterization ◽  
New Compounds ◽  
C Nmr

Two new ceramides were isolated from the bulbs of Lepidaploa cotoneaster (Willd. ex Spreng.) H. Rob. [ Vernonia cotoneaster (Willd. ex Spreng.) Less.)], in addition to germanicol, β-sitosterol, stigmasterol, 3-β- O-β-D-glucopyranosyl-sitosterol, lupeol, lupeoyl acetate and tiliroside. The structures of the new compounds were elucidated by spectral techniques (MS, 1H NMR, 13C NMR, HSQC, HMBC, DEPT, and TOCSY) and were compared with data reported in literature, and were established as 2 S*,2′ R*,3 S*,4 R*,11 E)- N-[2′-hydroxyhenicosanoyl]-2-amino-nonadec-11-ene-1,3,4-triol (1) and (2 S*,2′ R*,3 S*,4 R*,8 E)- N-[2′-hydroxytricosanoyl]-2-amino-nonadec-8-ene-1,3,4-triol (2). To establish the structure and to locate the double bond, the methyl ester of the fatty acid and dimethyl disulfide (DMDS) derivatives were prepared for both ceramides.

scholarly journals Structural Characterization of Amadori Rearrangement Product of Glucosylated Nα-Acetyl-Lysine by Nuclear Magnetic Resonance Spectroscopy

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Chuanjiang Li ◽  
Hui Wang ◽  
Manuel Juárez ◽  
Eric Dongliang Ruan
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Maillard Reaction ◽  
Structural Characterization ◽  
Resonance Spectroscopy ◽  
H Nmr ◽  
Amadori Rearrangement ◽  
C Nmr ◽  
Nuclear Magnetic

Maillard reaction is a nonenzymatic reaction between reducing sugars and free amino acid moieties, which is known as one of the most important modifications in food science. It is essential to characterize the structure of Amadori rearrangement products (ARPs) formed in the early stage of Maillard reaction. In the present study, the Nα-acetyl-lysine-glucose model had been successfully set up to produce ARP, Nα-acetyl-lysine-glucose. After HPLC purification, ARP had been identified by ESI-MS with intense [M+H]+ ion at 351 m/z and the purity of ARP was confirmed to be over 90% by the relative intensity of [M+H]+ ion. Further structural characterization of the ARP was accomplished by using nuclear magnetic resonance (NMR) spectroscopy, including 1D 1H NMR and 13C NMR, the distortionless enhancement by polarization transfer (DEPT-135) and 2D 1H-1H and 13C-1H correlation spectroscopy (COSY) and 2D nuclear overhauser enhancement spectroscopy (NOESY). The complexity of 1D 1H NMR and 13C NMR was observed due to the presence of isomers in glucose moiety of ARP. However, DEPT-135 and 2D NMR techniques provided more structural information to assign the 1H and 13C resonances of ARP. 2D NOESY had successfully confirmed the glycosylated site between 10-N in Nα-acetyl-lysine and 7′-C in glucose.

Synthesis and Characterization of Terthiophene-Based Rod-Like Liquid Crystals

2012 ◽  
Vol 532-533 ◽  
pp. 61-65
Author(s):  
Xiao Hui Liu ◽  
Zhong Xiao Li ◽  
Song Ya Zhang ◽  
Jia Ling Pu
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Crystal Phase ◽  
Liquid Crystal Phase ◽  
Schiff’S Base ◽  
Thermally Induced ◽  
H Nmr ◽  
Clearing Point ◽  
Temperature Ranges

With 2,2',5',2''-Terthiophene as starting material, two liquid crystalline compounds containing Schiff’s base unit were synthesized in this paper. The structure of the compounds was confirmed by FTIR and 1H NMR. The thermally induced phase transition behaviors were investigated by POM and DSC, and the temperature ranges of liquid crystal phase of the two compounds were compared. Results showed that the symmetric compound exhibited a lower clearing point temperature and broader temperature range of liquid crystal phase.

Synthesis and characterization of a new natural product analog, 132-173-bacteriochlorophyllone a

2014 ◽  
Vol 18 (03) ◽  
pp. 188-199 ◽  
Author(s):  
Áron Roxin ◽  
Thomas D. MacDonald ◽  
Gang Zheng
Keyword(s):  
Antioxidant Activity ◽  
Biological Activity ◽  
Photodynamic Therapy ◽  
Natural Product ◽  
Synthesis And Characterization ◽  
Facile Synthesis ◽  
H Nmr ◽  
F Ring ◽  
C Nmr

Here we show the facile synthesis of 132-173-bacteriochlorophyllone a (12), with a distinct seven-membered exocyclic F-ring formed by 132-173-cyclization of bacteriopheophorbide a(16). This is the latest reported bacteriochlorin with such an exocyclic F-ring since 1975 (132-173 cyclobacteriopheophorbide a-enol, 11), and is an analog of previously described natural exocyclic F-ring-containing porphyrins (1–4) and chlorins (5–10). The structure of 12 was confirmed using a combination of 1D 1 H NMR, 2D COSY 1 H NMR, Jmod 13 C NMR and HRMS analysis. The biological activity of 12 was explored, and we found that this compound does not possess strong antioxidant activity like its natural product counterparts, but is a capable photosensitizer for photodynamic therapy.

scholarly journals Synthesis and characterization of a new bis-NHC palladium complex and its catalytic activity in the Mizoroki–Heck reaction

2020 ◽  
Vol 44 (11-12) ◽  
pp. 684-688
Author(s):  
Can Feng ◽  
Cheng-xin Liu ◽  
Yu-fang Wang ◽  
Jin Cui ◽  
Ming-jie Zhang
Keyword(s):  
Palladium Complex ◽  
Coupling Reaction ◽  
Aryl Halides ◽  
Heck Coupling ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Excellent Stability ◽  
C Nmr

A new bis- N-heterocyclic carbene palladium complex, (C13H9N2F2)2PdCl2, is synthesized by a three-step reaction and characterized by 1H NMR and 13C NMR spectroscopy as well as by X-ray crystallography. This new bis- N-heterocyclic carbene palladium complex has excellent stability and is capable of efficiently catalyzing the Mizoroki–Heck coupling reaction of aryl halides with acrylates.

Synthesis and Characterization of a New Coumarin-1,2,3-Triazole Diad

2014 ◽  
Vol 618 ◽  
pp. 170-174
Author(s):  
Hong Qi Li ◽  
Xiu Juan Tian ◽  
Zhen Chen ◽  
Ding Xiao ◽  
Ning Fang ◽  
...  
Keyword(s):  
Click Chemistry ◽  
Biological Activities ◽  
Antitubercular Activity ◽  
Synthesis And Characterization ◽  
Target Compound ◽  
H Nmr ◽  
Mild Conditions ◽  
Ideal Approach ◽  
C Nmr

A new coumarin-1,2,3-triazole diad was designed and synthesized by Pechmann-Duisberg reaction and click chemistry. The three-step synthetic route to the target compound afforded an overall yield of 56%. The structures of the synthesized compounds were characterized by 1H NMR, 13C NMR, IR and mass spectrum. The click chemistry provided an ideal approach for synthesis under mild conditions of coumarin-1,2,3-triazole diads which may exhibit excellent biological activities such as antitubercular activity.

Design, preparation and characterization of a new ionic liquid, 1,3-disulfonic acid benzimidazolium chloride, as an efficient and recyclable catalyst for the synthesis of tetrahydropyridine under solvent-free conditions

RSC Advances ◽  
2015 ◽  
Vol 5 (83) ◽  
pp. 67405-67411 ◽  
Author(s):  
Mohsen Abbasi
Keyword(s):  
Ionic Liquid ◽  
Mass Spectra ◽  
Recyclable Catalyst ◽  
Solvent Free ◽  
Disulfonic Acid ◽  
H Nmr ◽  
Solvent Free Conditions ◽  
Ft Ir ◽  
C Nmr

In the present work, 1,3-disulfonic acid benzimidazolium chloride as a new ionic liquid, is synthesized, and characterized by studying its FT-IR, 1H NMR, 13C NMR as well as mass spectra.

scholarly journals Synthesis and Spectroscopic Characterization of Some New Axially Ligated Indium(III) Macrocyclic Complexes and Their Biological Activities

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Gauri D. Bajju ◽  
Altaf Ahmed ◽  
Deepmala Gupta ◽  
Ashu Kapahi ◽  
Gita Devi
Keyword(s):  
Biological Activities ◽  
Spectroscopic Characterization ◽  
Axial Ligand ◽  
Free Base ◽  
H Nmr ◽  
Pyramidal Geometry ◽  
The Stability ◽  
Square Pyramidal Geometry ◽  
C Nmr

The synthesis and spectroscopic characterization of new axially ligated indium(III) porphyrin complexes were reported. Chloroindium(III) porphyrin (TPPIn-Cl) was obtained in good yield by treating the corresponding free base with indium trichloride. The action of the different phenols on chloroderivatives (TPPIn-Cl) led to the corresponding phenolato complexes (TPPIn-X). These derivatives were characterized on the basis of mass spectrometry,1H-NMR, IR, and UV-visible data. The separation and isolation of these derivatives have been achieved through chromatography. The spectral properties of free base porphyrin and its corresponding metallated and axially ligated indium(III) porphyrin compounds were compared with each other. A detailed analysis of UV-Vis,1H-NMR, and IR suggested the transformation from free base porphyrin to indium(III) porphyrin. Besides,13C-NMR and fluorescence spectra were also reported and interpreted. The stability of these derivatives has also been studied through thermogravimetry. The complexes were also screened for anticancerous activities. Among all the complexes, 4-MePhO-InTPP shows highest anticancerous activity. The title complexe, TPPIn-X (where X = different phenolates), represents a five-coordinate indium(III) porphyrin complex in a square-pyramidal geometry with the phenolate anion as the axial ligand.

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