Collect. Czech. Chem. Commun.
1985, 50, 1176-1183
https://doi.org/10.1135/cccc19851176
29Si (and 13C) NMR spectra of all pertrimethylsilylated O-acetyl and O-benzoyl 1,6-anhydro-β-D-glucopyranose derivatives. A test of empirical assignment rules
Jan Schramla, Štefan Kučárb, Jan Zelenýa and Václav Chvalovskýa
a Institute of Chemical Process Fundamentals, Czechoslovak Academy of Sciences, 165 02 Prague 6-Suchdol
b Institute of Chemistry, Slovak Academy of Sciences, 842 38 Bratislava
Abstract
All O-acetyl-1,6-anhydro-β-D-glucopyranoses and O-benzoyl-1,6-anhydro-β-D-glucopyranoses were pertrimethylsilylated. 29Si and 13C NMR spectra of the pertrimethylsilyl derivatives were measured and the 29Si chemical shifts were used to test two previously described empirical assignment rules. The rule based on the shielding order must be either restricted to the order δ(Si-2) > δ(Si-4) which holds for all the studied compounds or modified for each subclass of the studied compounds with the same O-substituents. The rule based on Hammett type dependence gives correct predictions for Si-3 chemical shifts. When both rules can be applied they yield identical assignments, in other cases they complement each other.
