CONFORMATIONAL-ANALYSIS OF D-FRUCTANS .1. PROTON AND CARBON CHEMICAL-SHIFT ASSIGNMENTS FOR 1-KESTOSE, FROM 2-DIMENSIONAL NMR-SPECTRAL MEASUREMENTS

The proton chemical-shift assignment of a simple relative of inulin, namely, 1-kestose [O-β-d-fructofuranosyl-(2→1)-β-d-fructofuranosyl a-d-glucopyranoside], was determined by using two-dimensional (2D) homonuclear and heteronuclear n.m.r.-spectral methods, and corrections of, and additions to the 13C-chemical-shift assignments were made. The 1H peak of H-1 of the d-glucosyl group was determined by its chemical shift. Using H-H coupling information for this proton, the chemical shift of most of the proton signals of the β-d-glucosyl group was determined. Although the signals from the two d-fructosyl units were very similar, long-range C-H coupling allowed their complete C and H assignment. In particular, the coupling of the H-1 atom of d-glucose to C-2′ of d-fructose 1 allowed distinction between the two d-fructose units. © 1990.