New and old NMR experiments for the resonance assignment of complex oligosaccharides-application to a cyclodextrin derivative

The complete assignment of the 1H and 13C sugar resonances in mono‐3,6‐anhydro‐heptakis(2,3‐O‐methyl)‐hexakis(6‐O‐methyl)‐β‐cyclodextrin, an asymmetrically functionalized β‐cyclodextrin, was carried out by means of 2D NMR experiments. The TOCSY and the homonuclear multiple relay COSY spectra provided most of the 1H assignments. The multiplicity edited HSQC and a set of F1 selective HSQC‐TOCSY and multiple relay HSQC‐COSY spectra gave access to most of the 13C chemical shifts. The latter were fully and accurately determined by means of a pair of complementary, highly folded HSQC‐TOCSY spectra. The TOCSY‐ROESY and ROESY‐TOCSY spectra yielded the sequential assignment of the sugar units. A high resolution F1 selective F1 decoupled version of the TOCSY‐ROESY experiment was recorded. Copyright © 2011 John Wiley & Sons, Ltd. F1‐selective HSQC–Relayn–COSY, highly folded HSQC–TOCSY, F1‐selective F1‐decoupled TOCSY–ROESY are proposed as routinely usable pulse sequences for the easy analysis of complex oligosaccharides.