scholarly journals Microwave enhanced synthesis of halogenated derivatives of L-tyrosine labeled with deuterium in aromatic ring

2020 ◽  
Vol 326 (1) ◽  
pp. 857-860
Author(s):  
Małgorzata Pająk
Keyword(s):  
Nmr Spectroscopy ◽  
Aromatic Ring ◽  
Isotope Exchange ◽  
Spectroscopic Data ◽  
Deuterium Incorporation ◽  
H Nmr ◽  
Microwave Assisted ◽  
Acid Catalyzed ◽  
Deuterium Enrichment ◽  
Derivatives Of

Abstract Three halogenated derivatives of L-tyrosine, selectively labeled with deuterium in aromatic ring, i.e., 3′-fluoro-[5′-2H]-, 3′-chloro-[5′-2H]-, and 3′-iodo-[2′,5′-2H2]-L-tyrosine, were synthesized using microwave assisted acid-catalyzed isotope exchange between 3′-fluoro-, 3′-chloro- and 3′-iodo-L-tyrosine and heavy water. The degree of deuterium incorporation was confirmed by 1H NMR spectroscopy. The spectroscopic data indicate that isotope exchange depends on the method of heating and the power of microwaves. The deuterium enrichment of 3′-fluoro-[5′-2H]- and 3′-chloro-[5′-2H]-L-tyrosine amounted to 70% and 60%, respectively, while for 3′-iodo-[2′,5′-2H2]-L-tyrosine this value was about 50% and 95% for the 2′- and 5′-position. The isotopomers were obtained in good chemical yields of 50–70%.

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.

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 Synthesis, Spectral and Microbial Studies of Some Novel Schiff Base Derivatives of 4-Methylpyridin-2-amine

2009 ◽  
Vol 6 (4) ◽  
pp. 1205-1210 ◽  
Author(s):  
J. J. Vora ◽  
S. B. Vasava ◽  
K. C. Parmar ◽  
S. K. Chauhan ◽  
S. S. Sharma
Keyword(s):  
Schiff Base ◽  
Antimicrobial Activities ◽  
Dilution Method ◽  
Mass Spectral ◽  
H Nmr ◽  
Schiff Base Derivatives ◽  
Ft Ir ◽  
Acid Catalyzed ◽  
Derivatives Of ◽  
Broth Dilution

Schiff base derivatives ofN-{(1E)-[3-(mono or di-substituted aryl)-1-phenyl-1H-pyrazol-4-yl]methylene{-4-methylpyridin-2-amine were synthesized by the acid catalyzed condensation of 3-(mono- or di- substituted aryl)-1-phenyl-1H-pyrazole-4-carbaldehyde derivatives with 4-methylpyridin-2-amine. Schiff base derivatives were characterized by FT-IR,1H-NMR, Mass spectral analysis and elemental analysis. All the synthesized compounds have been screened for their antimicrobial activities by using broth dilution method.

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.

Synthese und Struktur von η1-2,4-Diaza-3-phosphapenta-1,4-dien-3-yl-Komplexen des Eisens und Rutheniums / Synthesis and Structure of η1-2,4-Diaza-3-phosphapenta-1,4-dien-3-yl Complexes of Iron and Ruthenium

1991 ◽  
Vol 46 (6) ◽  
pp. 714-718 ◽  
Author(s):  
Lothar Weber ◽  
Uwe Sonnenberg ◽  
H. G. Stammler ◽  
Beate Neumann
Keyword(s):  
Molecular Structure ◽  
Nmr Spectroscopy ◽  
Elemental Analysis ◽  
Spectroscopic Data ◽  
X Ray ◽  
H Nmr

The dichlorophosphido complexes (η5-C5Me5)(CO)2M–PCl2 (2a: M = Fe; 2 c: M = Ru) react with two equivalents of Ph2C=NSiMe3 to yield the first η1-2,4-diaza-3-phosphapenta-1,4-dien-3-yl complexes (4a,c). Intermediates (η5-C5Me5)(CO)2M–P(Cl)(N=CPh2) (3a,c) are detected by 31P{1H} NMR spectroscopy, the preparation of pure 3a, however, failed. The products 4a, c have been characterized by elemental analysis as well as spectroscopic data (IR, 1H, 13C, 31P NMR, MS). The molecular structure of 4a has been elucidated by single X-ray analysis.

Preparation, Crystal Structure and Spectroscopic Characterization of [Ga(OH)(SO4)(terpy)(H2O)] · H2O (terpy=2,2’:6’,2-Terpyridine): The First Characterized Gallium(III) Sulfato Complex

2004 ◽  
Vol 59 (3) ◽  
pp. 291-297 ◽  
Author(s):  
Andreas Sofetis ◽  
Giannis S. Papaefstathiou ◽  
Aris Terzis ◽  
Catherine P. Raptopoulou ◽  
Theodoros F. Zafiropoulos
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Nmr Spectroscopy ◽  
Good Yield ◽  
Spectroscopic Data ◽  
Spectroscopic Characterization ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr

The reaction of Ga2(SO4)3·18H2O and excess 2,2′:6′,2″-terpyridine (terpy) in MeOH / H2O leads to [Ga(OH)(SO4)(terpy)(H2O)]·H2O (1·H2O] in good yield. The structure of the complex has been determined by single-crystal X-ray crystallography. The GaIII atom in 1·H2O is 6-coordinate and ligation is provided by one terdentate terpy molecule, one monodentate sulfate, one terminal hydroxide and one terminal H2O molecule; the coodination polyhedron about the metal is described as a distorted octahedron. There is an extensive hydrogen-bonding network in the crystal structure which generates corrugated layers parallel to bc. The new complex was characterized by IR and 1H NMR spectroscopy. The spectroscopic data are discussed in terms of the nature of bonding

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.

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.

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.

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