NUCLEAR-MAGNETIC-RESONANCE SPECTROSCOPY STUDY OF A DISACCHARIDIC CROWN-ETHER

The disaccharidic anhydro derivative 6-O-(5,6-anhydro-3-deoxy-1,2-O-is opropylidene isopropylidene-3-O-n-dodecyl-alpha-D-glucofuranose (1) le d to the disaccharidic crown ether 2 in 40% yield when treated at low concentration with 2.5 eq. of KOH in toluene-Me2SO. Compound 2 structu re was proved through a detailed NMR analysis (H-1, C-13, H-1-H-1 and C-13-H-1 2D correlations). This structural elucidation indicated that compound 2 resulted from the intramolecular attack of the C-5-O- alkox ide group, generated in the basic medium, on the C-6' carbon of the 5' ,6'-anhydro group.