ChemInform Abstract: NMR‐STUDIES OF THE INTERACTION OF METAL IONS WITH POLY‐(1,4‐HEXURONATES) PART 3, (1)H‐NMR‐STUDY OF THE BINDING OF LANTHANIDES TO METHYL ALPHA‐D‐GULOPYRANOSIDE IN AQUEOUS SOLUTION

Carbon-13 NMR Spectra of Sodiumd-Gluco- andd-Galactopyranuronates in the Presence of Lanthanide Ions

“…The bindings of lanthanide ions to 0-1 or 0-4 seem to be difficult because of the too long distances between the ion and these oxygen atoms both in the ex-and fJ-anomers, though a participation of 0-4 in such a binding has been suggested for sodium methyl ex-o-galactopyranosiduronate. 16 ) On the other hand, it is to be noticed that the binding sites of lanthanide ions for compounds 1 and 2 have lower x and y values and a higher z value than those for compounds 3 and 4, respectively. This is probably because the carboxyl oxygen atoms are differently disposed through a restricted rotation about the C-5/C-6 bond between the o-gluco-and Dgalactopyranuronates, as a result of avoiding the unstable pseudo-l ,3-diaxial relationship to 0-4.…”

“…3) Carbon-I 3 NMR spectra of methyl (X-and fJ-oglucopyranosiduronic acids have also been assigned except the carboxyl carbon 4 ) and applied for the spectral analysis of chondroitin sulfates A and C. 5 ) In recent years, it has been established that the lanthanide shift reagents, complexes of lanthanide metals with some fJ-diketone-type ligands, 6) can induce appreciably different patterns of the change in proton chemical shift between several peracetylated sugars in deuterated chloroform, i.e., between neutral and amino sugars,7) between the sugars of o-gluco-• and o-galactopyranose series,B) between pento-and hexopyranosides, 9) and between furanoid and pyranoid sugars. 10 ) On the other hand, some characteristic shifts induced by lanthanide cations in aqueous solution have been reported on the proton NMR spectra of methyl fJ-o-hamamelopyranoside, 11 ,12) methyl (X-o-gulopyranoside, 13,14) methyl (X-oallopyranoside,12) and sodium methyl a-Dgalactopyranosiduronate. 15 ,16) However, any lanthanide-induced shifts in carbon-13 NMR spectra of carbohydrates have not so far been measured, except for the investigation on the 1-and 6-phosphate esters of 0-mannopyranose by Gorin and Mazurek.…”

Sentinel lymph node biopsy is not accurate in predicting lymph node status for patients with cervical carcinoma

“…The chemical shifts obtained were assigned to mannuronate and guluronate in each block, with respect to previous studies,4–8 as follows (in ppm):…”

“…General methods for measuring the M/G ratio are the isolation of polymannuronate and polyguluronate by partial hydrolysis, followed by colorimetry or calculation from the 13 C‐NMR spectra 4–8. These methods are very time consuming.…”