Collect. Czech. Chem. Commun.
1979, 44, 1965-1983
https://doi.org/10.1135/cccc19791965
1H NMR spectra and the conformation of 1,6 : 2,3- and 1,6 : 3,4-dianhydro-β-D-hexopyranoses and their derivatives
Miloš Buděšínskýa, Miloslav Černýb, Tomáš Trnkab and Soňa Vašíčkováa
a Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, 166 10 Prague 6
b Department of Organic Chemistry, Charles University, 128 40 Prague 2
Abstract
The 1H NMR spectra of 1,6 : 2,3- and 1,6 : 3,4-dianhydro-β-D-hexopyranoses and their acetyl-, trichloroacetylcarbamoyl- and 2- or 4-deoxy derivatives were measured in hexadeuteriodimethyl sulfoxide or deuteriochloroform. In these solvents dianhydro derivatives assume the half-chair conformations 5H0 or 1H0 which are not distinctly affected by the presence of substituents. The effects of substituents on the chemical shifts and the adjusted relation for the dependence of the vicinal coupling constants on the torsion angle are discussed from the point of view of conformation and the interactions of the oxirane ring with the oxygen O(5) and O(6) of the 1,6-anhydropyranose skeleton. Intramolecular hydrogen bonds in free dianhydrohexopyranoses were measured and identified in tetrachloromethane solution.
