Interactions of calcium nitrate with pyranosides in water: a 13C NMR study.
The 13C NMR spectra of methyl alpha- and beta-D-galactopyranosides, and methyl alpha- and beta-D-glucopyranosides were recorded and show that the Delta(deltaC-4) values for methyl alpha- and beta-D-galactopyranosides increase most rapidly, whereas those for methyl alpha- and beta-D-glucopyranosides vary hardly with increasing molality of calcium nitrate. It can be concluded that ax-OH-4 interacts more strongly with Ca2+ than eq-OH-4 group, namely, the Ca2+ ion interaction with ax-OH-4 leads to a stronger deshielding of the C-4 atom. Compared with other C atoms, the chemical shifts of both C-1 and C-5 atoms in these two types of glycosides decrease relatively rapidly as molality of calcium nitrate increases, indicating that the nitrate ion attractions for these glycosides cause a relatively strong enhancing shielding effect of C-1 and C-5 atoms.
Zhuo
Kelei
K
School of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007, PR China. klzhuo@263.net
Wang
Yaping
Y
Zhao
Yang
Y
Liu
Qian
Q
Wang
Jianji
J
D017610:Calcium Compounds / Q000737:chemistry*; D002236:Carbohydrate Conformation; D002244:Carbon / Q000737:chemistry; D002627:Chemistry, Physical / Q000379:methods; D005690:Galactose / Q000737:chemistry*; D006027:Glycosides / Q000737:chemistry; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008956:Models, Chemical; D009566:Nitrates / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D011134:Polysaccharides / Q000737:chemistry; D011714:Pyrans / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
D017610:Calcium Compounds; D006027:Glycosides; D009566:Nitrates; D011134:Polysaccharides; D011714:Pyrans; D014867:Water; D002244:Carbon; C059948:calcium nitrate; D010100:Oxygen; D005690:Galactose