Dérivés diglycosyliques. Communication préliminaire

Abstract

SummaryNovel types of diglycosyl compounds, some of them bearing a resemblance to natural di-or tri-saccharides are described: a diglycosyldiyne (l), a diglycosylthiophene (2), a diglycosylaziridine (3), a diglycosyldioxolane (4), as well as six C, N-diglycosylnitrones, 9b-9f and 14. These C, N-diglycosylnitrones, on treatment with an acetylenic Grignard reagent, led to the expected acetylenic diglycosylhydroxylamine 11, whereas diglycosylisoxazolines (f. ex. 10) were obtained when these nitrones underwent 1,3-dipolar cycloaddition to acetylenic compounds.Dans la nature, de nombreux oligo-ou polysaccharides jouent des r6les biologiques importants. Ces composes sont constituks d'oses lies entre eux par des liaisons osidiques (acktaliques). L'etablissement entre des unitts d'oses de liaisons autres qu'osidiques, pour former des analogues plus ou moins proclies de disaccharides, voire de trisaccharides, classiques, prtsente un inter& biologicpe evident, d'autant plus marque que certaines des jonctions utilisees, doutes de propriktds tlectrophiles, sont eventuellernent susceptibles de rkagir avec des nuclkophiles biologiques. Nous rapportons ci-dessous la synthese de derives diglycosyliques dans lesquels deux unites d'oses sont likes par deux triples liaisons, une double liaison, une simple liaison ou encore par l'intermtdiaire d'un hetkrocycle.Nous avons anttrieurement decrit [ 11 quelques diglycosyldiynes. Le compose 1 (F. 146,4-147,0", [ u ] g ' = -30,4, c= 1,1, CHC1,) constitue un nouvel exemple de molecule de ce type. Trait& par un hydrogenosulfure alcalin ces diglycosyldiynes conduisent au diglycosylthiophene correspondant, par exemple 2 (sirop, Une communication plus dCtaillCe paraitra ulterieurement.

N–O linkage in carbohydrates and glycoconjugates

“…117) were prepared by condensation of sugar aldehyde or reducing sugar with N-hydroxyamino sugar followed by reduction of intermediate nitrone (R = H) or further reaction with carbon nucleophiles (Scheme 23c). 227,228 Another interesting approach concerns the direct oxidation of amino sugars to N-hydroxyamino sugars by a stoichiometric amount of 2,2-dimethyldioxirane (Scheme 23d). 229 The amino function on 2-, 3-or 4-positions of gluco-or allo-derivatives has been successfully oxidized into N-hydroxy amine in 70-80% yield.…”

(Z)-1,2:5,6-Di-O-isopropylidene-α-D-ribo-hexofuranos-3-uloseO-benzyloxime

“…For background to sugar-based oxime derivatives, see: Tronchet et al (1979Tronchet et al ( , 1981Tronchet et al ( , 1989; Peri et al (2004). For the synthesis, see: Plenkiewicz et al (1974); Ferná ndez-Gonzá lez & Alonso (2006).…”

“…Oxime derivatives of carbohydrates are important precursors for preparation of monosaccharide building blocks in disaccharide mimic synthesis. (Tronchet et al, 1979(Tronchet et al, , 1981(Tronchet et al, ,1989Peri et al, 2004) The title compound (I) can be easily synthesized by condensation of the corresponding keto sugar with O-benzylhydroxylamine hydrochloride in pyridine in good yield. (Plenkiewicz et al, 1974;Fernández-González & Alonso, 2006) Crystallization from pentane/ethyl acetate gave exclusively the Z diastereomer of I.…”

Spin-labeled carbohydrates

“…39 Compound 185 was obtained from earlier work. 48 The hyperfine coupling constants aH^aH«" represent the hydrogens on the carbons a to the nitroxyl group. They are very sensitive to the nature of the adjoining group.…”