The synthesis and conformational properties of the diastereoisomeric βDGal(1→4)βDGlcNAc(1→6)6-C-CH3-D-Gal trisaccharides

1982 ◽  
Vol 60 (1) ◽  
pp. 81-86 ◽  
Author(s):  
Raymond U. Lemieux ◽  
Ting C. Wong ◽  
Henning Thøgersen
Keyword(s):  
Monoclonal Antibody ◽  
Nmr Spectroscopy ◽  
Molecular Modelling ◽  
Computer Assisted ◽  
Glycosidic Linkage ◽  
H Nmr ◽  
Conformational Preferences ◽  
Conformational Properties ◽  
Derivatives Of

The trisaccharide βDGal(1 → 4)βDGlcNAc(1 → 6)DGal was known to be bound strongly by the so-called anti-I Ma monoclonal antibody. In order to help assess the conformation about the 1 → 6 glycosidic linkage that is accepted by the antibody combining site, the conformationally well-defined βDGal(1 → 4)βDGlcNAc(1 → 6) derivatives of 7-deoxy-L-glycero-D-galacto-heptopyranose and 7-deoxy-D-glycero-D-galacto-heptopyranose were synthesized. The conformational preferences for these trisaccharides were established by 1H nmr spectroscopy and rationalized by computer-assisted molecular modelling.

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.

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.

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.

Conformational analysis of the disaccharide methyl α-D-mannopyranosyl-(1→3)-2-O-acetyl-β-D-mannopyranoside monohydrate

2019 ◽  
Vol 75 (6) ◽  
pp. 610-615 ◽  
Author(s):  
Wenhui Zhang ◽  
Qingquan Wu ◽  
Allen G. Oliver ◽  
Anthony S. Serianni
Keyword(s):  
Crystal Structure ◽  
Aqueous Solution ◽  
Nmr Spectroscopy ◽  
Structural Parameters ◽  
Side Chain ◽  
Glycosidic Linkage ◽  
Torsion Angles ◽  
Conformational Properties ◽  
Statistical Program ◽  
Acetyl Group

The crystal structure of methyl α-D-mannopyranosyl-(1→3)-2-O-acetyl-β-D-mannopyranoside monohydrate, C15H26O12·H2O, (II), has been determined and the structural parameters for its constituent α-D-mannopyranosyl residue compared with those for methyl α-D-mannopyranoside. Mono-O-acetylation appears to promote the crystallization of (II), inferred from the difficulty in crystallizing methyl α-D-mannopyranosyl-(1→3)-β-D-mannopyranoside despite repeated attempts. The conformational properties of the O-acetyl side chain in (II) are similar to those observed in recent studies of peracetylated mannose-containing oligosaccharides, having a preferred geometry in which the C2—H2 bond eclipses the C=O bond of the acetyl group. The C2—O2 bond in (II) elongates by ∼0.02 Å upon O-acetylation. The phi (φ) and psi (ψ) torsion angles that dictate the conformation of the internal O-glycosidic linkage in (II) are similar to those determined recently in aqueous solution by NMR spectroscopy for unacetylated (II) using the statistical program MA′AT, with a greater disparity found for ψ (Δ = ∼16°) than for φ (Δ = ∼6°).

Imidazole Nucleosides, V. Synthesis of 3′-Fluoro-3′-deoxy-ribofuranosides of 4(5)-Amino-imidazoIe-5(4)carboxamide

1999 ◽  
Vol 54 (8) ◽  
pp. 1055-1060 ◽  
Author(s):  
Hans Guglielmi ◽  
Markus Dachtler ◽  
Klaus Albert
Keyword(s):  
Nmr Spectroscopy ◽  
Elemental Analysis ◽  
H Nmr ◽  
Anti Cancer ◽  
Derivatives Of ◽  
Fluoro Derivatives

The synthesis of the 3′-fluoro-derivatives of 5-amino-1-(β-D-ribofuranosyl)imidazole-4- carboxamide (AICA-riboside) and the isomeric 4-amino-1(β-D-ribofuranosyl)imidazole-5- carboxamide (iso-AICA-riboside) are described. Structures were confirmed by elemental analysis, UV and 1H NMR spectroscopy. The anti-viral and anti-cancer activities of these imidazole nucleosides were tested.

Enantioselective fluorescent sensors for chiral carboxylates based on BINOL — Synthesis and chiral recognition

2010 ◽  
Vol 88 (4) ◽  
pp. 367-374 ◽  
Author(s):  
Kuo-xi Xu ◽  
Yu-xia Wang ◽  
Shu-yan Jiao ◽  
Jin Zhao ◽  
Chao-jie Wang
Keyword(s):  
Nmr Spectroscopy ◽  
Chiral Recognition ◽  
Fluorescent Sensors ◽  
Enantioselective Recognition ◽  
H Nmr ◽  
Recognition Ability ◽  
Chiral Materials ◽  
Fluorescent Recognition ◽  
Derivatives Of ◽  
C Nmr

The four novel derivatives of 1,1′-bi-2-naphthol (BINOL) have been prepared, and the structures of these compounds have been characterized by IR, MS, 1H and 13C NMR spectroscopy, and elemental analysis. The enantioselective recognition of these receptors has been studied by fluorescence titration and 1H NMR spectroscopy. The receptors exhibited different chiral-recognition abilities towards some enantiomers of chiral materials and formed 1:1 complexes between host and guest. The receptors exhibit excellent enantioselective fluorescent-recognition ability towards the amino acid derivatives.

The intramolecular equilibrium in 2-tert-butylphenol and some derivatives. An anomalous indicating steric distortion

1984 ◽  
Vol 62 (1) ◽  
pp. 113-116 ◽  
Author(s):  
Ted Schaefer ◽  
Rudy Sebastian ◽  
Salman R. Salman
Keyword(s):  
Carbon Tetrachloride ◽  
Equilibrium Constant ◽  
Hydroxyl Group ◽  
Coupling Constant ◽  
Spectral Parameters ◽  
H Nmr ◽  
Conformational Preferences ◽  
Out Of Plane ◽  
Alkyl Phenols ◽  
Derivatives Of

The 1H nmr spectral parameters in dilute carbon tetrachloride solution are reported for 2-tert-butylphenol, as obtained by decoupling of the sidechain protons. Long-range couplings between hydroxyl and ring protons are also reported for five derivatives of 2-tert-butylphenol. In the cis conformer of 2-tert-butylphenol an anomalous [Formula: see text] occurs, most likely as a consequence of a significant distortion of the COH geometry. Such an anomaly, which leads to an incorrect estimate of the cis–trans equilibrium constant, does not occur in other alkyl phenols, for example, in 2-tert-butyl-6-methylphenol. The coupling constant data provide no evidence for out-of-plane conformational preferences of the hydroxyl group in these compounds.

Carbamoyl and Thiocarbamoyl Derivatives of 3-Aminopropyl-dimethyl-phosphine Oxide

2004 ◽  
Vol 59 (2) ◽  
pp. 221-227 ◽  
Author(s):  
Victoria Lachkova ◽  
Helmut Keck ◽  
Rosario Scopelliti ◽  
Wolfgang Kläui ◽  
Sabi Varbanov ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Phosphine Oxide ◽  
Elemental Analysis ◽  
Phosphine Oxides ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Derivatives Of

A series of fourteen new 3-[N-substituted carbamoyl (or thiocarbamoyl)]-aminopropyl-dimethyl-phosphine oxides have been synthesized and characterized. The compounds were prepared via reaction of the 3-aminopropyl-dimethyl-phosphine oxide with the corresponding isocyanates or isothiocyanates. The composition of the compounds was proved by elemental analysis and the structures were confirmed by IR, 1H, 31P, 31P{1H} NMR spectroscopy and by mass spectrometry. The structures of 3[(N-phenyl-thiocarbamoyl)amino]propyl-dimethyl-phosphine oxide (5), 3[(N-4- chlorophenyl-thiocarbamoyl)amino]propyl-dimethyl-phosphine oxide (6), and 3[(N-benzyl-thiocarbamoyl) amino]propyl-dimethyl-phosphine oxide (9) have been confirmed by X-ray diffraction.

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.

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