Dérivés de désoxy‐hydroxylamino‐sucres et radicaux libres diglycosylnitroxydes correspondants. Communication préliminaire

Abstract

Deoxy-hydroxylamino-sugar Derivatives and Corresponding Diglycosylnitroxides Radicals SummaryA number of sugar aldonitrones, including C, N-diglycosylnitrones, and ketonitrones have been treated with Grignard reagents or cyanide anion leading to the corresponding deoxy-hydroxylamino-sugars. On oxidation (air, H,IO, or Pb02), these compounds gave the corresponding nitroxide radicals whose ESR. spectra are reported. Analogues of disaccharides, in which the interglycosidic 0-bridge is replaced by a hydroxyirnino group, have been obtained by reacting a partially blocked sugar bearing a free hemiacetal group either with a deoxy-hydroxylarninosugar or with hydroxylamine, followed by reaction with an aldehydosugar and a reducing agent (NaBH4). These reactions represents the key synthetic steps for the oligosaccharide-type synthesis of deoxy-hydroxyimino-oligosaccharides. Their oxidation yielded the corresponding nitroxide radicals whose ESR. spectra gave information on the conformation about the 'interglycosidic' bridge. This type of compounds should constitute useful spin markers for biological studies.A l'exception de deux exemples isoles que nous avons decrits dans une prtcedente communication [4], les analogues de di-ou oligosaccharides dans lesquels le pont oxygene interglycosidique habitue1 est remplacee par un pont hydroxyimino etaient inconnus. Des composes de ce type, de structure proche de celle d'oligosaccharides immunocompetents, devraient &tre appelCs a jouer un r81e important dans la comprehension des mecanismes de reconnaissance cellulaire ou tissulaire. En effet leur facile oxydation en radicaux diglycosylnitroxyde leur permet I ) 2,~~

Novel isoxazolidine analogues of homonucleosides and homonucleotides

“…The idea of incorporating the isoxazolidine ring into a nucleoside framework as a sugar replacer, first proposed by Tronchet,11 has been explored to provide several biologically active compounds (Fig. 1).…”

(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.…”

Novel Isoxazolidine and γ-Lactam Analogues of Homonucleosides

“…Incorporation of the isoxazolidine ring into a nucleoside framework as a sugar part replacer was first proposed by Tronchet and co-workers [24,25] with the intention to study antiviral [20,26,27,28,29,30,31], antibacterial [32] and antifungal [33] activities of the compounds. Other research groups then intensively explored this field further.…”