Darstellung und Reaktionen der Oxovanadin(V)-tricarboxylate / Synthesis and Reactions of Oxovanadium(V) Tricarboxylates

1980 ◽  
Vol 35 (7) ◽  
pp. 817-823 ◽  
Author(s):  
Fritz Preuss ◽  
Willi Towae ◽  
Joachim Woitschach
Keyword(s):  
Nmr Spectroscopy ◽  
Carboxylic Acid ◽  
Complex Formation ◽  
Chemical Reactions ◽  
Acid Anhydride ◽  
Carboxylate Ligands ◽  
H Nmr ◽  
Silver Carboxylate ◽  
Carboxylic Acid Anhydride

Monomeric oxovanadium(V) tricarboxylates VO(RCOO)3 are prepared by reaction of VOCl3 with an excess of silver carboxylate in CH2Cl2 or by depolymerization of (VO2RCOO)n in carboxylic acid anhydride. Their properties are studied by IR and 1H NMR spectroscopy as well as by chemical reactions such as thermolysis, solvolysis, redistribution and complex formation. The structure of 2,2′-dipyridyl and 1,10-phenanthroline complexes [VO(RCOO)3 · B] (B = C10H8N2, C12H8N2) has been found to be octahedral with meridional arrangement of the carboxylate ligands. Syntheses of Na[VO(CH3COO)4] and Ba[VO2(CH3COO)3] · 2CH3COOH are described

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.

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.

Association between halothane and oxygenated solvents by 1H NMR spectroscopy

1995 ◽  
Vol 73 (9) ◽  
pp. 1406-1411 ◽  
Author(s):  
Marcela Tkadlecová ◽  
Jaroslav Havlíček ◽  
Vladimír Dohnal
Keyword(s):  
Nmr Spectroscopy ◽  
Complex Formation ◽  
Equilibrium Constants ◽  
Solution Model ◽  
Methyl Tert Butyl Ether ◽  
Ideal Solution ◽  
Butyl Ether ◽  
Complex Formation Equilibria ◽  
H Nmr ◽  
Halothane Concentration

Using 1H NMR spectroscopy the complex-formation equilibria between halothane (2-bromo-2-chloro-1,1,1-trifluoroethane) and methyl tert-butyl ether or tetrahydrofuran in various inert solvents (hexane, heptane, decane, cyclohexane) were measured as a function of temperature. For two different association models (ideal solution and athermal solution), assuming only the formation of a 1:1 H-bonded complex, the equilibrium constants and the standard enthalpies of the complex-formation reaction were calculated. The ideal solution model provides values of the equilibrium constant that differ for different inert solvents. The athermal solution model makes this false solvent effect much smaller. For the low halothane concentration used, its dimerization was neglected. This assumption was verified experimentally. Keywords: 1H NMR, association, complex formation, halothane.

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.

Reactions of Coinage Metal Salts with a Mixed Sulfonic/Carboxylic Acid Anhydride

2007 ◽  
Vol 633 (13-14) ◽  
pp. 2431-2434 ◽  
Author(s):  
Weifeng Shi ◽  
Le Zhang ◽  
Maryam Shafaei-Fallah ◽  
Alexander Rothenberger
Keyword(s):  
Carboxylic Acid ◽  
Acid Anhydride ◽  
Metal Salts ◽  
Coinage Metal ◽  
Carboxylic Acid Anhydride

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.

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