Liquid crystalline vinylcyclopropane derivatives bearing cholesteryl side groups: synthesis, characterization and polymerization

e-Polymers ◽  
2002 ◽  
Vol 2 (1) ◽  
Author(s):  
Valentina Alupei ◽  
Helmut Ritter
Keyword(s):  
Phase Transition ◽  
Nmr Spectroscopy ◽  
Carboxylic Acid ◽  
Ir Spectroscopy ◽  
Radical Polymerization ◽  
Liquid Crystalline ◽  
Optically Active ◽  
H Nmr

AbstractNew optically active 1,1-disubstituted 2-vinylcyclopropanes ,3a, b were synthesized by esterification of the corresponding 1-ethoxycarbonyl-2-vinylcyclopropane- 1-carboxylic acid 2a,b with cholesterol and characterized by 1H NMR and IR spectroscopy. The liquid crystalline properties of the obtained monomers are reported. The effect of the structure of the 2-vinylcyclopropane monomers on the phase transition of the mesogen was investigated. Radical polymerization of the asymmetrically substituted monomers 3a,b in solution and in bulk resulted in liquidcrystalline polymers with 1,5-opened units, as evidenced by 1H NMR spectroscopy.

scholarly journals Electron Release and Proton Acceptance Reactions of (dpp-BIAN)Mg(THF)3

2008 ◽  
Vol 63 (2) ◽  
pp. 161-168 ◽  
Author(s):  
Igor L. Fedushkin ◽  
Valentina A. Chudakova ◽  
Markus Hummert ◽  
Herbert Schumann
Keyword(s):  
Nmr Spectroscopy ◽  
Carboxylic Acid ◽  
Ir Spectroscopy ◽  
The Other ◽  
X Ray ◽  
H Nmr ◽  
Trigonal Bipyramidal ◽  
Electron Release ◽  
Coordination Spheres ◽  
Centrosymmetric Dimers

(dpp-BIAN)Mg(THF)3 (1) (dpp-BIAN = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene) and (PhCOO)2 react with splitting of the peroxide bridge and formation of the dimeric magnesium benzoate [(dpp-BIAN)MgOCOPh(THF)]2 (2). The reaction of 1 with PhCOOH yields the dimeric magnesium benzoate [(dpp-BIAN)(H)MgOCOPh(THF)]2 (3), whereas 1 and furanyl-2-carboxylic acid react with liberation of hydrogen and formation of (dpp-BIAN)Mg[OCO(2-C4H3O)]2 Mg(dpp-BIAN)(THF) (4). Compounds 2, 3, and 4 have been characterized by elemental analysis, IR spectroscopy, and X-ray structure analysis, compound 3 also by 1H NMR spectroscopy. The eightmembered metallacycles of the centrosymmetric dimers 2 and 3 are almost completely planar. The two magnesium atoms in 4 show different coordination spheres; one is surrounded by its ligands in a trigonal bipyramidal manner, the other one in a tetrahedral fashion. The Mg···Mg separations in 2, 3 and 4 are 4.236, 4.296, and 4.030 Å, respectively

Preparation of secondary alcohols of high optical purity

1986 ◽  
Vol 51 (2) ◽  
pp. 401-403 ◽  
Author(s):  
Otakar Červinka ◽  
Anna Fábryová ◽  
Irina Sablukova
Keyword(s):  
Nmr Spectroscopy ◽  
Optical Purity ◽  
Optically Active ◽  
Secondary Alcohols ◽  
Lithium Aluminium Hydride ◽  
Enantioselective Reduction ◽  
H Nmr ◽  
Lithium Aluminium ◽  
High Optical Purity ◽  
Optically Pure

Partially resolved enantiomers of optically active alcohols I-V, obtained by enantioselective reduction of the corresponding ketones with lithium aluminium hydride in the presence of (-)-quinine, were converted into crystalline 3,5-dinitrobenzoates or phenylcarbamates. The esters of the nearly optically pure enantiomers were separated by crystallization from the generally more soluble esters of the racemates. Optical purity of the hydrolytically liberated alcohols was determined by 1H NMR spectroscopy in the presence of chiral shifting agents.

Synthesis and properties of oxytocin analogues modified in the tripeptide side chain

1984 ◽  
Vol 49 (3) ◽  
pp. 642-652 ◽  
Author(s):  
Zdenko Procházka ◽  
Michal Lebl ◽  
Tomislav Barth ◽  
Jan Hlaváček ◽  
Antonín Trka ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Carboxylic Acid ◽  
Biological Activities ◽  
The Other ◽  
Side Chain ◽  
H Nmr ◽  
Fragment Condensation

Two oxytocin analogues were synthesized by fragment condensation (6 + 3) in the presence of dicyclohexylcarbodiimide and 1-hydroxybenzotriazole. In one of the analogues, proline in the position 7 and leucine in the position 8 were substituted by 2-[1-(2-oxo-3-aminopyrrolidinyl)]-4-methylpentanoic acid, in the other proline was replaced by 1-aminocyclopropane-1-carboxylic acid. Biological activities of the first analogue were strongly reduced and dissociation of the uterotonic and galoctogogic activities was observed with both the analogues. The structure of 2-(3-tert-butyloxycarbonylaminopyrrolidin-2-on-1-yl)-4-methylpentanoylglycine and its amide was confirmed by mass and 1 H NMR spectroscopy.

scholarly journals Detection of σ-alkane complexes of manganese by NMR and IR spectroscopy in solution: (η5-C5H5)Mn(CO)2(ethane) and (η5-C5H5)Mn(CO)2(isopentane)

2015 ◽  
Vol 6 (1) ◽  
pp. 418-424 ◽  
Author(s):  
Olga Torres ◽  
James A. Calladine ◽  
Simon B. Duckett ◽  
Michael W. George ◽  
Robin N. Perutz
Keyword(s):  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
H Nmr

Irradiation (355 nm) of CpMn(CO)3in liquid ethane at 133 K yields CpMn(CO)2(η2-C–H-ethane) characterised by IR and1H NMR spectroscopy with a lifetime ofca. 360 s; the corresponding isopentane complex is formed in propane/isopentane mixtures and exists in three isomeric forms.

1-Aminocyclopropanecarboxylic acid and its derivatives

1982 ◽  
Vol 47 (8) ◽  
pp. 2291-2305 ◽  
Author(s):  
Zdenko Procházka ◽  
Miloš Buděšínský ◽  
Jorga Smolíková ◽  
Petr Trška ◽  
Karel Jošt
Keyword(s):  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
H Nmr ◽  
Covalently Bonded ◽  
Acid Catalyzed ◽  
C Nmr

Action of strongly basic reagents on methyl Nα-benzyloxycarbonylamino-γ-bromobutyrate leads to 1-aminocyclopropanecarboxylic acid derivatives whose structure was determined by 1H NMR, 13C NMR and IR spectroscopy. According to IR spectroscopy, the urethane CO-NH group in crystalline methyl 1-benzyloxycarbonylaminocyclopropanecarboxylate exists in the cis(E) conformation which on dissolution is transformed into the trans(Z) form. NMR spectroscopy showed that the acid-catalyzed esterification of α-amino-γ-bromobutyric acid is accompanied by replacement of the covalently bonded bromine by chlorine.

Cycloaddition Reactions of Arylmethylenemalonaldehydes with Olefins

1992 ◽  
Vol 57 (11) ◽  
pp. 2337-2358 ◽  
Author(s):  
Dalimil Dvořák ◽  
David Šaman ◽  
Zdeněk Arnold ◽  
Ivana Císařová ◽  
Václav Petříček
Keyword(s):  
Nmr Spectroscopy ◽  
Carboxylic Acid ◽  
Vinyl Ether ◽  
Aromatic Nucleus ◽  
Ethyl Vinyl Ether ◽  
Cycloaddition Reactions ◽  
Ethyl Vinyl ◽  
X Ray ◽  
H Nmr ◽  
Conformational Equilibria

A series of 2,4-disubstituted 3,4-dihydro-2H-pyran-5-carboxaldehydes II-XIX was prepared by reaction of substituted arylmethylenemalonaldehydes I with 2-methylpropane, 1,1-diphenylethylene, styrene, ethyl vinyl ether, 1,1-dimethoxyethylene and 1,1-bis(methylthio)ethylene. In the case of the reaction with ethyl vinyl ether the dependence of the ratio of the arising cis- and trans- 2-ethoxy-4-aryl-3,4-dihydropyran-5-carboxaldehydes VII-XIV on the substitutent on the aromatic nucleus was studied. Information on the mechanism of this reaction was obtained and conformational equilibria of 2-ethoxy-4-aryl-3,4-dihydropyran-5-carboxaldehydes in solution were studied by 1H NMR spectroscopy. The structure of trans-2-ethoxy-4-(4-chlorophenyl)-3,4-dihydropyran-5-carboxaldehyde (trans-VIII) was confirmed by X-ray analysis of the corresponding carboxylic acid trans-XXII.

scholarly journals Synthesis of multivalent carbohydrate mimetics with aminopolyol end groups and their evaluation as L-selectin inhibitors

2015 ◽  
Vol 11 ◽  
pp. 638-646 ◽  
Author(s):  
Joana Salta ◽  
Jens Dernedde ◽  
Hans-Ulrich Reissig
Keyword(s):  
Nmr Spectroscopy ◽  
Carboxylic Acid ◽  
Amide Bonds ◽  
H Nmr ◽  
End Groups ◽  
Full Conversion ◽  
Purification Protocol ◽  
Micromolar Range

In this article a series of divalent and trivalent carbohydrate mimetics on the basis of an enantiopure aminopyran and of serinol is described. These aminopolyols are connected by amide bonds to carboxylic acid derived spacer units either by Schotten–Baumann acylation or by coupling employing HATU as reagent. The O-sulfation employing the SO3·DMF complex was optimized. It was crucial to follow this process by 700 MHz 1H NMR spectroscopy to ensure full conversion and to use a refined neutralization and purification protocol. Many of the compounds could not be tested as L-selectin inhibitor by SPR due to their insolubility in water, nevertheless, a divalent and a trivalent amide showed surprisingly good activities with IC50 values in the low micromolar range.

Synthesis and Characterization of Polyacrylates Side-Chain Liquid Crystalline Polymer via Atom Transfer Radical Polymerization

2012 ◽  
Vol 535-537 ◽  
pp. 1516-1519
Author(s):  
Ying Gang Jia ◽  
Peng Tian ◽  
Kun Ming Song ◽  
Bao Yan Zhang
Keyword(s):  
Atom Transfer Radical Polymerization ◽  
Radical Polymerization ◽  
Liquid Crystalline ◽  
Gel Permeation Chromatography ◽  
Crystalline Polymer ◽  
Atom Transfer ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
H Nmr

Atom transfer radical polymerization (ATRP) of methacrylate liquid crystal monomer M (4-((4-(2-(acryloyloxy)ethoxy)benzoyl)oxy)phenyl 4-propylbenzoate) was carried out using CuBr/PMDETA complex as catalyst and 2-bromo-2-methyl-propionic acid ester as initiator. The obtained monomer M and polymer P was characterized via infrared spectroscopy and1H NMR. The phase behavior and mesomorphism were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and x-ray diffraction (XRD). The molecular weight and the structure of the polymers were identified with gel permeation chromatography and nuclear magnetic resonance.

New Arylidene—Siloxane Polyesters

2003 ◽  
Vol 15 (3) ◽  
pp. 231-242 ◽  
Author(s):  
Carmen Racles ◽  
Vasile Cozan ◽  
Maria Cazacu
Keyword(s):  
Differential Scanning Calorimetry ◽  
Nmr Spectroscopy ◽  
Liquid Crystalline ◽  
Gel Permeation Chromatography ◽  
Polymer Structure ◽  
Scanning Calorimetry ◽  
Polarized Optical Microscopy ◽  
H Nmr ◽  
Gel Permeation ◽  
Thermotropic Liquid Crystalline Behavior

New siloxane-containing polyesters with arylidene mesogenic moieties were prepared by copolycondensation reactions between bis(hydroxybuthyl)siloxanes, 2,6-bis(4-hydroxybenzylidene)cyclohexanone, and diacid chlorides such as sebacoyl and terephthaloyl. The polymer structure was confirmed by IR and 1H-NMR spectroscopy. They were characterized by gel permeation chromatography and ultraviolet analyses. The thermotropic liquid crystalline behavior was investigated by differential scanning calorimetry and polarized optical microscopy.

Optisch aktive Übergangsmetall-Komplexe, LV [1]. Darstellung und Stereochemie von [C5H5Mo(CO)2 NN’]PF6 mit NN’=Ethylen-diamin und Propylendiamin / Optically Active Transition Metal Complexes, LV [1]. Preparation und Stereochemistry of [C5H5Mo(CO)2NN′]PF6 with NN′=Ethylenediamine and Propylene- diamine

1978 ◽  
Vol 33 (2) ◽  
pp. 247-248 ◽  
Author(s):  
Henri Brunner ◽  
Manfred Muschiol
Keyword(s):  
Nmr Spectroscopy ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Fractional Crystallization ◽  
Optically Active ◽  
H Nmr ◽  
Active Transition

In the reaction of C5H5Mo(CO)3Cl with ethylenediamine and propylenediamine, abbreviated with NN′, the square pyramidal cations [C5H5Mo(CO)2NN′]+ are formed. The diastereoisomeric pairs of enantiomers of the propylenediamine derivative are separated by fractional crystallization. The epimerization at the asymmetric Mo atom (τ1,2 = 30 min, 75 °C, CD3OD solution) can be followed by 1H NMR spectroscopy

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