3D NMR and Selective Techniques for the Structure Elucidation of Oligosaccharides: Structure analysis of oligosaccharides is an extremely difficult task. It requires not only the determination of tlie monosaccharide units, but also tlieir anomeric configuration, their sequence, and position of glycosidation. Since the last years, 2D NMR techniques have become very common and structure elucidation can be performed without degradation. But spectral overlap, which is a severe problem of carhohydrates, can prevent an unequivocal determination of the sequence.This problem can he alleviated by adding a third frequency dimension. From a 3D spectrum, there are three combinations possible to take 2D slices. In a 3D TOCSY-ROESY experiment, each of these slices taken at a constant frequency of an anomeric or a linkage site proton contains information about sequence and position of glycosidation. 3D NMR techniques give additional resolution and are advantageous if experiment time, storage capacity, and sensitivity are not limiting factors.The application of selective pulses to 3D NMR techniques leads to a two-dimensional method which reduces the experiment time enormously, but retains the dispersion of a third frequency axis. The full sequence information of 1 was gained in few minutes by two semisoft 2D TOCSY-ROESY experiments. These techniques were employed to the structure elucidation of the two sap onins (1 and 2) which were isolated from Flores verbasci. Cyanoglucosides from Osmaronia cerasjformis: Osmaronia cerasformis (Torr. & Gray) Greene (Rosaceae, Prunoideae) is a shrub or smali tree growing in north-west America. It has non-cyanogenic seeds but cyanogenic buds and leaves (1). We have identified two nitrile glucosides in a methanolic extract of its leaves. One of these is the known sutherlandin (1; 4-J3-n-glucopyranosyloxy-3-hydroxymethyl-Z-but-2-enenitrile) which was found recently in the leaves of Acacia sutherlandii, (Mimosaceae) (2) and of Hordeum vulgare L. (Poaceae) (3). The second is the novel 4- /3-n-glucopyranosyloxy-2 ,3-epoxy-3-methylbutyronitrilewhich we have named osmaronin (2). Osmaronin is a mixture of two epimers which can be separated by GLC. It is one of the few cyanoglucoside epoxides known today (4, 5).The methanohc extracts were purified by column chromatography on silica gel, followed by Sephadex LH-20, and MCI-Gel. Final purification was achieved by HPLC (RP-18) or MPLC (RP-18), respectively. The NMR and MS data were consistent with the published data for 1. The structure of 2 was established mainly by different NMR methods (1H, 13C, 13C-APT, and 2D-HMBC). The stereochemistry of the oxirane carbons remains as yet undetermined. It is noteworthy that both compounds are apparently derived from the aliphatic amino acid L-leucine. Usually one should expect phenylalanine-based cyanogenic glycosides in the subfamilies Maloideae and Pri.moideae whereas the Spiraeoideae contain leucine-derived cyanogenics (5).