Detailed analysis of the 1H and 13C NMR spectra of five fructo‐oligosaccharides (1–5) isolated from Asparagus officinalis L. (Liliaceae) was carried out. Tetrasaccharides 1, 2 and 3 consist of one unit of glucose and three units of fructose, whereas trisaccharides 4 and 5 consist of one unit of glucose and two units of fructose. The 1H NMR signals of these tetrasaccharides were severely overlapped around δH 3.6–4.0 ppm and the 13C NMR signals of the corresponding signals of three fructose residues were close to each other. Therefore, it was difficult to make assignments of those signals using conventional NMR methods. Overcoming these signal‐overlapping problems required the application of some special NMR techniques. The spectral analysis was started from the anomeric proton of the glucose, since each compound had only one glucose residue and its 1H NMR spectrum showed a separate characteristic anomeric proton signal. After the 1H and 13C signals of the glucose had been assigned, the fructose residues attached to the C‐1 and/or C‐6 positions of glucose were determined from the HMBC spectrum, which also revealed further fructosyl fructose linkages. The assignments of each signal of C‐5 and C‐6 of the fructose residues overlapped in 2D spectra were achieved by the 1D INAPT method. Unresolved correlation peaks of methylene protons in HMQC could be separated by the CH2‐selected HSQC method, which gave sufficient 13C resolution to separate each CH2 signal, resulting in the determination of the chemical shift of the methylene protons. Copyright © 2000 John Wiley & Sons, Ltd.

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Two novel oligosaccharides, mono-and difructosyllactosucrose]-a-D-glucopyranoside, n = 1 and 2g were synthesized using 1 Ffructosyltransferase purified form roots of asparagus (Asparagus officinalis L.). Their 1 H and 13 C NMR spectra were assigned using several NMR techniques. The spectral analysis was started from two anomeric methines of aldose units, galactose and glucose, since they showed separate characteristic signals in their 1 H and 13 C NMR spectra. After assignments of all the 1 H and 13 C signals of two units of aldose, they were discriminated as galactose and glucose using proton-proton coupling constants. The HMBC spectrum revealed the galactose residue attached to C-4 of glucose, fructose residue attached to the C-1 of glucose, and further fructosyl fructose linkage extended from the glucosyl fructose residues.