13C-NMR study of methyl- and benzyl ethers of l-arabinose and oligasaccharides having l-arabinose at the reducing end. Synthesis of 2-O-β-d-glucopyranosyl-, 2-O-α-l-rhamnopyranosyl-, 3-O-β-d-glucopyranosyl-2- O-α-l-rhamnopyranosyl- and 4-O-β-d-glucopyranosyl-2-O-α-l-rhamnopyranosyl-l-arabinose

András Lipták, Zoltán Szurmai, Pál Nánási, András Neszmélyi

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

The reaction of benzyl exo-3,4-O-benzylidene-β-l-arabinopyranoside 1 with α-acetobromo-d-glucose 3 resulted in a mixture of two disaccharides, 5 and 6, in which the configuration of the acetal ring was different. The reaction of 1 with α-acetobromo-l-rhamnose 4 gave the desired disaccharide 7 without isomerisation of the dioxolane-type benzylidene ring. The reason for the isomerisation, occuring during the Koenigs-Knorr reaction, is discussed. Similar treatment of benzyl endo-3,4-O-benzylidene-β-l-arabinopyranoside 2 with 4 yielded 8. Compounds 6, 7 and 8 were deacetylated and benzylated to obtain 9, 10 and 11. Hydrogenolysis (LiAlH4AlCl3) of all fully protected disaccharides afforded derivatives with a free OH-3 (9→13 and 11→15). Hydrogenolysis of 10 also resulted in 15, and the desired 14 with a free OH-4 was only the minor product of the reaction. Glucosylation of compounds 14 and 15 resulted in the two trisaccharide derivatives in protected form (16 and 17). Deprotection of 6, 7, 16 and 17 gave the four title compounds (22, 23, 18 and 19). The synthesized compounds were studied by 1H- and 13C-NMR spectroscopic methods. In disaccharides having (1 → 2) bonds and in trisaccharide 19 having (1 → 2) and (1 → 3) bonds the arabinose moiety is present in pyranose and furanose forms. The complex spectra of these derivatives were assigned using the methyl ethers of l-arabinose (24-29) as model compounds. The 13C-NMR spectrum of 18 was assigned with the aid of 4-O-β-d-glucopyranosyl-l-arabinopyranose. For comparisons, the spectra of all mono- and dibenzyl ethers of benzyl β-l-arabinopyranoside were also recorded and assigned.

Original languageEnglish
Pages (from-to)3489-3497
Number of pages9
JournalTetrahedron
Volume38
Issue number23
DOIs
Publication statusPublished - 1982

    Fingerprint

ASJC Scopus subject areas

  • Biochemistry
  • Drug Discovery
  • Organic Chemistry

Cite this