Efficient Synthesis of Unsymmetrical Ureido‐Linked Disaccharides

Abstract

Five nonsymmetrical urea-linked disaccharides, in which two glycopyranoside units are bound at the 1Ǟ2, 1Ǟ4, and 1Ǟ6 positions, were efficiently synthesized. A mild and safe procedure, in which glycosyl isocyanates were coupled with a glycosylamine, was employed.

Thio-click approach to the synthesis of stable glycomimetics

“…Research efforts have also been directed toward the incorporation of a novel, stable linker comprising two or three bridging atoms in place of a native O-glycosidic bond. Hence, among others, disulfide- (Szilágyi et al, 2001;Illyés et al, 2011), seleno-sulfide-, (Chakka et al, 2005), sulfonamide- (Lopez et al, 2011) or urea-bridged glycosides (Prosperi et al, 2004) have been prepared as novel carbohydrate derivatives with potential bioactive properties.…”

Synthesis of Sugar Isocyanates and Their Application to the Formation of Ureido‐Linked Disaccharides

“…triphosgene [23] or haloformates, [29] by reaction of glycosyl halides with silver cyanate, [32] through sugar phosphanimines, [33] or by oxidation of glycosyl isocyanides with pyridine N-oxide. [30,34,35] However, only one previous work addresses the preparation of a monosaccharide isocyanate at a non-anomeric position. [36] gen atoms, which in turn indicates that the plane containing the enamino group and the mean plane of the pyranose ring form a dihedral angle of approximately 90° (Figure 1).…”

Synthesis of Novel Pseudodisaccharides and Neoglycoconjugates Containing anN-Glycosyl Carbamate Backbone

“…The procedure was first applied to the case of the preparation of the urethane 1a in which a glucopyranosidic unit is connected to the primary 6-O-position of the methyl glucoside acceptor 2a through a carbamoyl bond (Scheme 2). Tetraacetyl glucopyranosyl isocyanide 3a 7 was easily oxidized in dry acetonitrile to the corresponding isocyanate with pyridine N-oxide and a catalytic amount of iodine. In these mild conditions, we observed complete disappearance of the starting material in 30 minutes.…”

“…Tetrabenzoyl The synthesis of compounds 3a-c, 2a, 2b and 2e is reported in ref. 7 For the preparation of compound 2c and 2d see ref. 10,11 mannopyranosyl isocyanide, prepared according to our previous work, 7 invariably gave a mixture of a-and b-isomers (compounds 3b and 3c) in a 7:3 ratio.…”

“…7 For the preparation of compound 2c and 2d see ref. 10,11 mannopyranosyl isocyanide, prepared according to our previous work, 7 invariably gave a mixture of a-and b-isomers (compounds 3b and 3c) in a 7:3 ratio. These two compounds were easily separated by chromatography and both used to achieve the corresponding carbamoyl linked disaccharides.…”