Hydroxylamines glycosidation

Hydroxylamine glycoside linkage Walker 1994 Lecithin lipids Stouch 1991 Polybenzoxazine Kim 1998... 

Formyl C-glycosides, prepared in three steps via the thiazole-based formy-lation of sugar lactones are readily condensed with hydroxylamine to give the corresponding oximes. The latter are the precursors of glycosyl nitrile oxides via the N-bromosuccinimide method (41). 

Intermolecular reactions with O- and A-nucleophiles produce labile adducts of type 65 (equation 42). These adducts can be used for reversible generation of oxyiminium cations in situ. In contrast, reaction of hydroxylamines with S- or 8-lactols results in intramolecular additions of an oxygen nucleophilic group to intermediate oxyiminium cation, thus providing stable cyclic products. Reactions of this type have been extensively used for glycosidation of hydroxylamine derivatives such as 66 (equation 42), resulting in neoglycosides of type 67 . 

A weak response (orange-brown or brown colours) is given by streptomycin, hydroxylamine, and substituted hydrazines (e.g. phenelzine). No colour is obtained with beclomethasone, cardiac glycosides, and oestriol (two hydroxyl groups) or clindamycin (three hydroxyl groups). 

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