Syntheses and ¹H- and ¹³C-Nuclear Magnetic Resonance Spectra of All Positional Isomers of Tetra-O-acetyl-D-glucopyranoses, and Their Monobenzyl and Monotrityl Derivatives

Abstract

All the isomers of the tetra-O-acetyl-D-glucopyranoses, and their monobenzyl and monotrityl derivatives were synthesized and systematic ¹H- and ¹³C-nuclear maghetic resonance (¹H-and ¹³C-NMR) studies were carried ont. Complete assignments of the ¹H- and ¹³C-NMR signals were achieved by ¹H[¹H]- and ¹³C[¹H]-decoupling techniques and by the use of a shift reagent and changes of solvents. Moreover, when necessary, ¹H[¹H]- and ¹³C[¹H]-shift-correlated 2D NMR spectroscopy at higher frequency (Bruker AM 400) was applied. The shifts on deacetylation, benzylation, and tritylation were estimated on the basis of the ¹H- and ¹³C-chemical shifts of these compounds, and the effects of deacetylation and benzyl- or trityl-substitution are discussed.