Vinylogues and heterocyclic analogues of benzylidenemalonaldehydes

1984 ◽  
Vol 49 (11) ◽  
pp. 2613-2619 ◽  
Author(s):  
Zdeněk Arnold ◽  
Dalimil Dvořák ◽  
Vladimír Král
Keyword(s):  
Nmr Spectroscopy ◽  
General Model ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Iminium Salt ◽  
Reaction Intermediate ◽  
Heterocyclic Aldehydes

Nine analogues of benzylidenemalonaldehyde (IV) were prepared by condensation of bis(dimethylamino)trimethinium perchlorate with two vinylogues of benzaldehyde and a series of heterocyclic aldehydes. The reaction intermediate was isolated and shown by 1H NMR spectroscopy to be the bis-iminium salt III. The conformation of 3-phenylprop-2-enylidenemalonaldehyde (IVa), determined by its 1H NMR spectrum, may serve as a more general model of arylmethylenemalonaldehydes.

Control of disaccharide conformation by π-stacking

2003 ◽  
Vol 81 (5) ◽  
pp. 364-375 ◽  
Author(s):  
Jonathan Watts ◽  
Jesús Jiménez-Barbero ◽  
Ana Poveda ◽  
T Bruce Grindley
Keyword(s):  
Nmr Spectroscopy ◽  
Molecular Modelling ◽  
Phenyl Ring ◽  
Glycosidic Linkage ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Π Stacking ◽  
Nuclear Overhauser ◽  
Derivatives Of

The conformations of a series of derivatives of the disaccharide α-L-fucopyranosyl-(1[Formula: see text]3)-2-acetamido-2-deoxy-D-glucopyranoside, part of the Lex determinant, were studied by molecular modelling using the MM3* forcefield and by 1H NMR spectroscopy. Unusually shielded O-benzyl protons were observed in the 1H NMR spectrum of phenyl 2,3,4-tri-O-benzyl-α-L-fucopyranosyl-(1[Formula: see text]3)-2-deoxy-2-phthalimido-1-thio-α-D-glucopyranoside and assigned to the 2-O-benzyl group. This observation was explained by a shift in the population of the conformational mixture present about the glycosidic linkage from the positive Ψ region in the unsubstituted disaccharide to the negative Ψ region induced by π-stacking between the phthalimide and the 2-O-benzyl phenyl ring. The experimental nuclear Overhauser enhancements confirm the accuracy of the calculations.Key words: disaccharide, conformation, π-stacking, Lex determinant, NOE measurements, MM3 calculations.

scholarly journals Design, Synthesis, and Characterization of Novel Thiol-Derivatized Ibuprofen Monolayer Protected Gold Clusters

2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
Kuan-Han Lee ◽  
Yu-Sheng Lin ◽  
Po-Jui Huang
Keyword(s):  
Nmr Spectroscopy ◽  
Gold Clusters ◽  
Hydroxyl Group ◽  
Synthesis And Characterization ◽  
Nmr Spectrum ◽  
Design Synthesis ◽  
H Nmr

A series of new thiol-derivatized ibuprofen monolayer protected gold clusters have been prepared by amidation of ibuprofen with alkyl alcohol or aminophenol affording the carboxamides, N-hydroxyalkyl amide2, and N-hydroxyphenyl amide6, which were then tosylated withp-toluenesulfonyl chloride at hydroxyl group to give3and7. Reactions of3and7with NaSH afforded the mercapto derivatives4and8. Conducting Brust’s reaction with a 3 : 1 mole ratio of thiolate ibuprofen/AuCl4-yielded polydisperse thiol-derivatized ibuprofen-MPCs5and9. All compounds have been identified by NMR, MS, UV, and IR spectroscopies. Compounds4and8and the MPCs5and9have been investigated by using the method of1H NMR spectroscopy. The broadening of the signals from 0.8 to 2.0 ppm in1H NMR spectrum of MPCs5and9confirmed the success of the conjugation of thiol-containing derivatives with nanogold cluster.

Arene–manganese and arene–rhenium compounds of formula (arene)M(CO)2(SiCl3)

1997 ◽  
Vol 75 (5) ◽  
pp. 531-535 ◽  
Author(s):  
Valerie M. Hansen ◽  
Jonathan L. Male ◽  
Roland K. Pomeroy
Keyword(s):  
Nmr Spectroscopy ◽  
Metal Atom ◽  
Good Yield ◽  
Free Rotation ◽  
Nmr Spectrum ◽  
Manganese Compound ◽  
Restricted Rotation ◽  
H Nmr ◽  
Arene Ligand ◽  
Derivatives Of

Derivatives of formula (arene)M(CO)2(SiCl3) (M = Mn, Re) have been prepared in moderate to good yield by the reaction of M(CO)5(SiCl3) and the appropriate arene (with heptane in those cases where the arene was a solid) in an evacuated sealed tube at 230–260 °C for 12–24 h, depending on the arene and the metal. Carefully purified reagents were necessary to obtain satisfactory yields. The (η6-1,4-C6H4tBu2)M(CO)2(SiCl3) complexes in solution exhibit free rotation of the arene ring about the metal atom to −120 °C as ascertained by 1H NMR spectroscopy. The manganese compound did show the onset of decoalescence of two of the signals due to the arene ligand in the 13C{1H} NMR spectrum in CD2Cl2, solution below −90 °C. This, however, is interpreted in terms of restricted rotation of the tert-butyl substituent rather than restricted rotation of the arene ring. Keywords: arene, manganese, rhenium, restricted rotation.

Application of NMR Spectroscopy to the Study of Piperidine Derivatives. Part III: Molecular Dynamics Study of N-Benzyl-4-[N-Benzyloxyacetyl)-(2-Fluorophenyl)]Amino-3-Methyl Piperidine

1993 ◽  
Vol 47 (3) ◽  
pp. 357-359 ◽  
Author(s):  
A. L. Cholli ◽  
M. L. Lau
Keyword(s):  
Molecular Dynamics ◽  
Nmr Spectroscopy ◽  
High Resolution ◽  
Detailed Analysis ◽  
Room Temperature ◽  
Variable Temperature ◽  
Proton Nmr ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Nmr Data

High-resolution 1H NMR has been used to study the molecular dynamics of the piperidine derivative. Detailed analysis of variable temperature NMR data allowed the identification of the origin of two sets of methyl resonance peaks with unequal intensities in the room-temperature proton NMR spectrum of the compound.

Hydration equilibria of 9-acridinecarboxaldehyde

1994 ◽  
Vol 72 (11) ◽  
pp. 2333-2338 ◽  
Author(s):  
Robert A. McClelland ◽  
Pratima Sukhai ◽  
Karen M. Engell ◽  
Poul E. Sorensen
Keyword(s):  
Equilibrium Constants ◽  
Acidity Constant ◽  
Separate Species ◽  
Ph Profile ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Free Aldehyde ◽  
Acidic Conditions ◽  
Acid Catalyzed ◽  
Heterocyclic Aldehydes

Hydration rate constants and equilibrium constants have been obtained for 9-acridinecarboxaldehyde in aqueous solution. Under acidic conditions where the acridine is protonated, signals for the hydrate and free aldehyde forms can be observed as separate species in the 1H NMR spectrum. Integration provides the hydration equilibrium constant[Formula: see text] Using an apparent acidity constant obtained from a spectroscopic titration curve, the rate–pH profile was fitted to provide the hydration constant for the equilibration of the neutral acridines, KH = 0.07. This analysis also provides the acidity constants for the two acridinium ions, the aldehyde with pK = 3.78 and the hydrate with pK = 5.36. A comparison with the 4-pyridinecarboxaldehdye system reveals that the [Formula: see text] ratios for the acridine and pyridine are the same within experimental error, but that the acridine and acridinium aldehydes are 20-fold less hydrated than their pyridine analogs. A comparison with benzaldehydes reveals that, in their reactivities, the two heterocyclic aldehydes behave in a similar manner. Thus, for example, plots of log kH for the acid-catalyzed dehydration and hydrations versus log Kh for the equilibrium hydration show single correlation lines including the points for the benzaldehydes and heterocyclic aldehydes (but not the aliphatic aldehydes).

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.

21,22-Disubstituted 18α,19βH-Ursane Derivatives with Oxabicyclooctane System in Ring E

1993 ◽  
Vol 58 (1) ◽  
pp. 173-190 ◽  
Author(s):  
Eva Klinotová ◽  
Jiří Klinot ◽  
Václav Křeček ◽  
Miloš Buděšínský ◽  
Bohumil Máca
Keyword(s):  
Spectral Data ◽  
Spin Systems ◽  
Coupling Constants ◽  
Complete Analysis ◽  
Nmr Spectrum ◽  
Proton Proton ◽  
H Nmr ◽  
Proton Coupling ◽  
C Nmr

Reaction of 3β-acetoxy-21,22-dioxo-18α,19βH-ursan-28,20β-olide (IIIa) and 20β,28-epoxy-21,22-dioxo-19α,19βH-ursan-3β-yl acetate (IIIb) with diazomethane afforded derivatives XII-XIV with spiroepoxide group in position 21 or 22, which were further converted into hydroxy derivatives XV and XVII. Ethylene ketals VIII-X were also prepared. In connection with the determination of position and configuration of the functional groups at C(21) and C(22), the 1H and 13C NMR spectral data of the prepared compounds are discussed. Complete analysis of two four-spin systems in the 1H NMR spectrum of bisethylenedioxy derivative Xb led to the proton-proton coupling constants from which the structure with two 1,4-dioxane rings condensed with ring E, and their conformation, was derived.

Monitoring the encapsulation of chlorin e6 derivatives into polymer carriers by NMR spectroscopy

2019 ◽  
Vol 23 (11n12) ◽  
pp. 1576-1586 ◽  
Author(s):  
Sara Pfister ◽  
Luca Sauser ◽  
Ilche Gjuroski ◽  
Julien Furrer ◽  
Martina Vermathen
Keyword(s):  
Relaxation Time ◽  
Nmr Spectroscopy ◽  
Core Region ◽  
Chlorin E6 ◽  
Polypropylene Glycol ◽  
Polymer Carriers ◽  
H Nmr ◽  
Line Shape Analysis ◽  
Dynamic Methods ◽  
Derivatives Of

The encapsulation of five derivatives of chlorin e6 with different hydrophobicity and aggregation properties into a series of five poloxamer-type triblock copolymer micelles (BCMs) with varying numbers of polyethylene and polypropylene glycol (PEG, PPG) units was monitored using 1H NMR spectroscopy. NMR chemical shift and line shape analysis, as well as dynamic methods including diffusion ordered spectroscopy (DOSY) and T1 and T2 relaxation time measurements of the chlorin and the polymer resonances, proved useful to assess the chlorin–BCM compatibility. The poloxamers had high capability to break up aggregates formed by chlorins up to intermediate hydrophobicity. Physically entrapped chlorins were always localized in the BCM core region. The loading capacity correlated with chlorin polarity for all poloxamers among which those with the lowest number of PPG units were most efficient. DOSY data revealed that relatively weakly aggregating chlorins partition between the aqueous bulk and micellar environment whereas more hydrophobic chlorins are well retained in the BCM core region, rendering these systems more stable. T1 and T2 relaxation time measurements indicated that motional freedom in the BCM core region contributes to encapsulation efficiency. The BCM corona dynamics were rather insensitive towards chlorin entrapment except for the poloxamers with short PEG chains. The presented data demonstrate that 1H NMR spectroscopy is a powerful complementary tool for probing the compatibility of porphyrinic compounds with polymeric carriers such as poloxamer BCMs, which is a prerequisite in the development of stable and highly efficient drug delivery systems suitable for medical applications like photodynamic therapy of tumors.

Different submicellar solubilization mechanisms revealed by 1H NMR and 2D diffusion ordered spectroscopy (DOSY)

2020 ◽  
Vol 22 (19) ◽  
pp. 11075-11085
Author(s):  
Mengjian Wu ◽  
Zhaoxia Wu ◽  
Shangwu Ding ◽  
Zhong Chen ◽  
Xiaohong Cui
Keyword(s):  
Nmr Spectroscopy ◽  
Sodium Dodecyl Sulfate ◽  
1H Nmr ◽  
Sodium Dodecyl ◽  
Butyl Methacrylate ◽  
H Nmr ◽  
Molecular Scale ◽  
Two Systems ◽  
Dodecyl Sulfate ◽  
Triton X

Different submicellar solubilization mechanisms of two systems, Triton X-100/tetradecane and sodium dodecyl sulfate (SDS)/butyl methacrylate, are revealed on the molecular scale by 1H NMR spectroscopy and 2D diffusion ordered spectroscopy (DOSY).

scholarly journals Structural studies of phosphorylation-dependent interactions between the V2R receptor and arrestin-2

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Qing-Tao He ◽  
Peng Xiao ◽  
Shen-Ming Huang ◽  
Ying-Li Jia ◽  
Zhong-Liang Zhu ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Conformational Changes ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Interaction Sites ◽  
Receptor Interactions ◽  
Remote Sites ◽  
Genetic Code Expansion ◽  
G Protein Coupled ◽  
Interaction Change

AbstractArrestins recognize different receptor phosphorylation patterns and convert this information to selective arrestin functions to expand the functional diversity of the G protein-coupled receptor (GPCR) superfamilies. However, the principles governing arrestin-phospho-receptor interactions, as well as the contribution of each single phospho-interaction to selective arrestin structural and functional states, are undefined. Here, we determined the crystal structures of arrestin2 in complex with four different phosphopeptides derived from the vasopressin receptor-2 (V2R) C-tail. A comparison of these four crystal structures with previously solved Arrestin2 structures demonstrated that a single phospho-interaction change results in measurable conformational changes at remote sites in the complex. This conformational bias introduced by specific phosphorylation patterns was further inspected by FRET and 1H NMR spectrum analysis facilitated via genetic code expansion. Moreover, an interdependent phospho-binding mechanism of phospho-receptor-arrestin interactions between different phospho-interaction sites was unexpectedly revealed. Taken together, our results provide evidence showing that phospho-interaction changes at different arrestin sites can elicit changes in affinity and structural states at remote sites, which correlate with selective arrestin functions.

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