An examination of sodium alginate from Sargassum by NMR spectroscopy

1997 ◽  
Vol 75 (5) ◽  
pp. 585-590 ◽  
Author(s):  
Francisco Llanes ◽  
Françoise Sauriol ◽  
Frederick G. Morin ◽  
Arthur S. Perlin
Keyword(s):  
Nmr Spectroscopy ◽  
Curve Fitting ◽  
Brown Algae ◽  
Alginic Acid ◽  
Sargasso Sea ◽  
H Nmr ◽  
Reduced Viscosity ◽  
Curve Fitting Analysis ◽  
Proton Resonances ◽  
C Nmr

Alginic acid, obtained from Sargassum brown algae that drift from the Sargasso Sea to beaches in Cuba, has been examined as an aqueous solution by 1H and 13C NMR spectroscopy, and also in the solid state by MAS 13C NMR spectroscopy. Its composition is distinctive, relative to that for alginic acid from most other brown algae, in having a lower content of β-D-mannopyranosyluronic acid residues (M) than of α-L-gulopyranosyluronic acid residues (G). That is, M/G is ~0.6, whereas ratios of >1 have been reported for many other species, including Macrocystispyrifera, which was examined here as well. In acquiring the high-resolution spectra, partial depolymerization was used to give solutions of reduced viscosity; as is well known, this procedure may cause separation into fractions and the formation of sediments, examples of which are cited. Proton resonances of the reducing end units of chain-shortened segments of the polymers exhibited unusual, marked, line broadening at elevated temperature, which may reflect thermal dehydration. MAS 13C experiments offered the advantage of information about the intact alginate samples. Although the spectra consisted of broad, heavily overlapping peaks, curve-fitting analysis afforded qualitative and quantitative data that supplement those obtained with solutions of the polymers. Keywords: Sargassum alginate, 1H NMR of fractions, M/G constituent ratios, MAS 13C NMR, curve-fitting analysis.

Synthesis, Characterization and Complexation Studies with K + and Ca2+ Cations of trans-1.2-Cyclohexanedioxydiacetamides

1988 ◽  
Vol 43 (2) ◽  
pp. 165-170 ◽  
Author(s):  
Whei Oh Lin ◽  
Maria C. B. V. de Souza ◽  
Helmut G. Alt
Keyword(s):  
Nmr Spectroscopy ◽  
Mass Spectroscopy ◽  
H Nmr ◽  
Coordination Sites ◽  
Complexation Studies ◽  
Ir And Nmr Spectroscopy ◽  
Elemental Analyses ◽  
C Nmr

The synthesis of trans-1.2-cyclohexanedioxydiacetamides starting with trans-1.2-cyclohexane-diol is described. Eleven of these compounds are characterized by IR, 1H NMR, 13C NMR and mass spectroscopy as well as elemental analyses. Most of these compounds are suitable ionophors for the cations K+ and Ca2+. The coordination sites of these ligands in the 1:2 complexes were determined by IR and NMR spectroscopy

[Zn(phen)2(CX3COO)]+, X = H orCl; Influence of X on the Coordination Mode of the Carboxylate Group (phen = 1,10-Phenanthroline)

2005 ◽  
Vol 60 (10) ◽  
pp. 1049-1053 ◽  
Author(s):  
Zeanab Talaei ◽  
Ali Morsali ◽  
Ali R. Mahjoub
Keyword(s):  
Nmr Spectroscopy ◽  
Elemental Analysis ◽  
Coordination Mode ◽  
Bidentate Ligand ◽  
Carboxylate Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Coordinate Geometry ◽  
C Nmr

Two new ZnII(phen)2 complexes with trichloroacetate and acetate anions, [Zn(phen)2(CCl3COO)- (H2O)](ClO4) and [Zn(phen)2(CH3COO)](ClO4), have been synthesized and characterized by elemental analysis, IR, 1H NMR, 13C NMR spectroscopy. The single crystal X-ray data of these compounds show the Zn atoms to have six-coordinate geometry. From IR spectra and X-ray crystallography it is established that the coordination of the COO− group is different for trichloroacetate and acetate. The former acts as a monodentate whereas the latter acts as a bidentate ligand.

scholarly journals Three-Dimensional Supramolecular Network Directed by Intermolecular Interactions in [Pb2(dmp)2(hfacac)4]

2009 ◽  
Vol 6 (4) ◽  
pp. 1085-1090
Author(s):  
Farzin Marandi ◽  
Lotfali Saghatforoush ◽  
Hossein Farzaneh
Keyword(s):  
Crystal Structure ◽  
Nmr Spectroscopy ◽  
Three Dimensional ◽  
Supramolecular Network ◽  
Stacking Interactions ◽  
H Nmr ◽  
Noncovalent Bond ◽  
Donor And Acceptor ◽  
Anionic Ligands ◽  
C Nmr

To investigate the interactions between noncovalent bond donor and acceptor giving rise to three dimensional networks, compound [Pb2(dmp)2(hfacac)2] (1) (dmp = 2,9-dimethyl-1,10-henanthroline and Hhfacac = hexafluoroacetylacetonate) has been prepared and characterized by elemental analysis, IR,1H NMR, and13C NMR spectroscopy and its crystal structures was investigated. The single crystal structure show the coordination number of Pb(II) to be eight with twoN-donor atoms from a “dmp” ligand and sixO-donors from the anionic ligands. The supramolecular structure of 1 is realized by weak directional C–H∙∙∙O–C, C–F∙∙∙F–C andπ–πstacking interactions.

Synthesis and Pharmacological Activities of Some New 2-[1-Heptyl-3-(4- methoxybenzyl)-5-oxo-1,5-dihydro-4H-1,2,4-triazol-4-yl]acetohydrazide Derivatives

2014 ◽  
Vol 69 (9-10) ◽  
pp. 969-981 ◽  
Author(s):  
Olcay Bekircan ◽  
Emre Mentese ◽  
Serdar Ulker
Keyword(s):  
Nmr Spectroscopy ◽  
Elemental Analysis ◽  
Lipase Activity ◽  
Spectral Studies ◽  
Antituberculosis Activity ◽  
Pharmacological Activities ◽  
Mass Spectral ◽  
H Nmr ◽  
Acetohydrazide Derivative ◽  
C Nmr

Abstract In the present investigation, the key intermediate acetohydrazide derivative 5 was synthesized starting from 3-(4-methoxybenzyl)-4-amino-4,5-dihydro-1,2,4-triazol-5-one (1) by a four-step reaction. Thiosemicarbazides 6a-f and arylidenehydrazide derivatives 8a-d were obtained from compound 5. The cyclization of compounds 6a-f in the presence of NaOH resulted in the formation of compounds 7a-f. The compounds were characterized by IR, 1H NMR, 13C NMR spectroscopy, elemental analysis and mass spectral studies. The compounds were tested for their anti-lipase, anti-α-glucosidase and anti-mycobacterial activities. Compounds 6b and 8c exhibited excellent anti-lipase activity, and compound 8d showed excellent anti-a-glucosidase activity. Compounds 3 and 4 exhibited good antituberculosis activity

scholarly journals Synthesis of cis, cis-1,3,5-trisubstituted cyclohexane based chelators with polyfunctional pendant arms

2005 ◽  
Vol 2005 (1) ◽  
pp. 43-45 ◽  
Author(s):  
Minati Baral ◽  
B.K. Kanungo ◽  
Peter Moore
Keyword(s):  
Schiff Base ◽  
Nmr Spectroscopy ◽  
Organic Compounds ◽  
Elemental Analysis ◽  
H Nmr ◽  
Benzenetricarboxylic Acid ◽  
New Compounds ◽  
Pendant Arms ◽  
C Nmr

Some novel organic compounds of the type: cis, cis-1,3,5-tris(X)cyclohexane, where X= –CONH(CH2)2NH2, –CONH(CH2)3NH2, –CONH(CH2)2NCH –C6H4OH, CONH(CH2)3NCHC6H4OH, which are expected to function as potential polydentate chelators have been synthesised from 1,3,5-benzenetricarboxylic acid through multi-steps reactions. 1,3,5-benzenetricarboxylic acid was reduced to cis, cis-1,3,5-tris(ethylcarboxylate)cyclohexane, which on reaction with excess of 1,2-diaminoethane and 1,2-diaminopropane afforded two new compounds. Condensation of the obtained derivatives with three equivalents of salicylaldehyde resulted the formation of two new Schiff base compounds. All the compounds were characterised by a combination of elemental analysis, mass, IR, UV-Vis, 1H NMR and 13C NMR spectroscopy.

scholarly journals Isomeric Di-C-glycosylflavones in Fig (Ficus carica L.)

1985 ◽  
Vol 40 (1-2) ◽  
pp. 8-12 ◽  
Author(s):  
Fred Siewek ◽  
Karl Herrmann ◽  
Lutz Grotjahn ◽  
Victor Wray
Keyword(s):  
Nmr Spectroscopy ◽  
Reversed Phase ◽  
Ficus Carica ◽  
Preparative Hplc ◽  
H Nmr ◽  
Gradient Hplc ◽  
C Nmr

Two isomeric C-glycosides of apigenin (apigenin-6-C-glucosyl-8-C-arabinoside (schaftoside), apigenin-6-C-arabinosyl-8-C-glucoside (isoschaftoside)) were isolated from leaves of Ficus carica with preparative HPLC. 1The glycosides were identified by UV-, 1H-NMR-, 13C-NMR-spectroscopy and FAB-MS. Their concentration in fruits and leaves were determined by gradient HPLC on reversed phase material.

Identification of (R)-Vicianin in Davallia trichomanoides Blume

1986 ◽  
Vol 41 (1-2) ◽  
pp. 5-8 ◽  
Author(s):  
Pauline A. Lizotte ◽  
Jonathan E. Poulton
Keyword(s):  
Nmr Spectroscopy ◽  
Authentic Sample ◽  
Cyanogenic Glycoside ◽  
Enzymic Hydrolysis ◽  
H Nmr ◽  
C Nmr

Abstract The cyanogenic glycoside of young fronds and fiddleheads of the fern Davallia trichomanoides Blume was identified as (R)-vicianin (the β-vicianoside of (R)-mandelonitrile) by acid and enzymic hydrolysis, 1H-NMR and 13C-NMR spectroscopy, and by comparison with an authentic sample isolated from Vicia angustifolia seeds.

Tautomeric Study of Schiff Bases Derived from o ‐Dihydroxybenzaldehyde by UV‐Vis, IR, 1 H NMR, 13 C NMR Spectroscopy and Computational Modeling.

2020 ◽  
Vol 5 (36) ◽  
pp. 11120-11126
Author(s):  
Carmen María Atzin‐Macedo ◽  
Cándida Pastor‐Ramírez ◽  
Rafael González‐Peláez ◽  
Francisco Javier Pérez‐Flores ◽  
Samuel Hernández‐Anzaldo ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Computational Modeling ◽  
Schiff Bases ◽  
H Nmr ◽  
C Nmr

Biosynthesis of the lupine alkaloids. I. Lupinine

1985 ◽  
Vol 63 (10) ◽  
pp. 2707-2718 ◽  
Author(s):  
W. Marek Golebiewski ◽  
Ian D. Spenser
Keyword(s):  
Nmr Spectroscopy ◽  
H Nmr ◽  
Dimeric Intermediate ◽  
C Nmr

The mode of incorporation into lupinine of cadaverine, intramolecularly doubly labelled with,15N and with,13C at the C-atom adjacent to 15N, i.e., 13C, 15N-"bond-labelled", was determined by,13C nmr spectroscopy; lupinine is generated from two cadaverine-derived C5-units by a route which excludes a "dimeric" intermediate with C2v symmetry. The mode of incorporation of 2H from L-(2-2H)lysine, from (R)- and (S)-(1-2H)cadaverine, and from (2-2H)-Δ1-piperideine into lupinine was determined by 2H nmr spectroscopy. The results corroborate the conclusions from the 13C,15N experiment and they establish the stereochemistry of six of the steps in the biosynthetic conversion of L-lysine into lupinine.

Darstellung von (9-β-ᴅ-Ribofuranosyl)-s-triazolo-[ 1,2a]-purin-6-on durch Cyclisierung von N-1-Aminoguanosin / Preparation of (9-β-ᴅ-Ribofuranosyl)-s-triazolo-[1,2a]-purine-6-one by Cyclization of N-1-Amino Guanosine

1978 ◽  
Vol 33 (5-6) ◽  
pp. 326-329 ◽  
Author(s):  
Eckhard Schlimme
Keyword(s):  
Nmr Spectroscopy ◽  
Nucleic Acids ◽  
Nucleoside Analogue ◽  
H Nmr ◽  
C Nmr

I report on the preparation of (9-β-ᴅ-ribofuranosyl)-s-triazolo-[1,2a]-purine-6-one (2) by cycli- zation of N-1-amino guanosine (1) with formamide. The tricyclic nucleoside analogue was charac­terized by NMR-spectroscopy (1H-NMR; 13C-NMR). The utility of 2 for the introduction of “cross­links” in double stranded nucleic acids is discussed.

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