engleski

Synthesis and conformational analysis of the repeating units of bacterial spore peptidoglyca

The bacterial spore peptidoglycan, so called spore cortex, has a com-position different from that of the bacterial vegetative cell. In Ż-(1? 4)-linked glycan chains a substantial part of muramic acid residues lack the peptide and N-acetyl substituents and instead form an intramolecularly cy-clised ?lactam structure. We have reported synthesis and conformational analysis of several muramic ?lactams. Here we report on deprotection of the fully blocked disacharide allyl O-(2-amino-4, 6-O-benzylidene-3-O-[(R)-1- carboxyethyl]-2-deoxy-Ż-D-glucopyranosyl-1, 2-lactam)-(1 ? 4)-acetamido-3, 6- di-O-benzyl-2-deoxy-Ż-D-glucopyranoside by selective de-O-allylation and par-allel removal of the benzylidene and O-benzyl groups. The resulting Ż-muramyl lactam-(1? 4)-GlcNAc disaccharide was characterised as the per-O-acetylated derivative by 1H NMR and 13C NMR spectroscopy and X-ray structure anal-ysis. Conformational analysis about glycosidic bond is based on experimental data in solution and in solid state and molecular modelling. Relevance of the conformation adopted is related to biological functions. *Permanent address: PLIVA, Pharmaceutical Industry, Inc., Research Di-vision, Prilaz baruna Filipovi´ca 25, HR-10000 Zagreb, Croatia.

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