title: Inter vs. intraglycosidic acetal linkages control sulfation pattern in semi-synthetic chondroitin sulfate.
abstract: Microbial-sourced unsulfated chondroitin could be converted into chondroitin sulfate (CS) polysaccharide by a multi-step strategy relying upon benzylidenation and acetylation reactions as key-steps for its regioselective protection. By conducting the two reactions one- or two-pots, CSs with different sulfation patterns could be obtained at the end of the semi-synthesis. In particular, a CS polysaccharide possessing sulfate groups randomly distributed between positions 4 and 6 of N-acetyl-galactosamine (GalNAc) units could be obtained through the two-pots route, whereas the one-pot pathway allowed an additional sulfation at position 3 of some glucuronic acid (GlcA) units. This difference was ascribed to the stabilization of a labile interglycosidic benzylidene acetal involving positions O-3 and O-6 of some GlcA and GalNAc, respectively, when the benzylidene-acetylation reactions were conducted in a one-pot fashion. Isolation and characterization of a polysaccharide intermediate showing interglycosidic acetal moieties was accomplished.
authors.affiliation: Dipartimento di Scienze Chimiche, Università di Napoli "Federico II", Complesso Universitario Monte S. Angelo, via Cintia 4, I-80126 Napoli, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Laezza
authors.affiliation: Dipartimento di Scienze Chimiche, Università di Napoli "Federico II", Complesso Universitario Monte S. Angelo, via Cintia 4, I-80126 Napoli, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: De Castro
authors.affiliation: Dipartimento di Scienze Chimiche, Università di Napoli "Federico II", Complesso Universitario Monte S. Angelo, via Cintia 4, I-80126 Napoli, Italy.
authors.forename: Michelangelo
authors.initials: M
authors.lastname: Parrilli
authors.affiliation: Dipartimento di Scienze Chimiche, Università di Napoli "Federico II", Complesso Universitario Monte S. Angelo, via Cintia 4, I-80126 Napoli, Italy. Electronic address: ebedini@unina.it.
authors.forename: Emiliano
authors.initials: E
authors.lastname: Bedini
mesh_terms: D000080:Acetals / Q000737:chemistry; D001597:Benzylidene Compounds / Q000737:chemistry; D002807:Chondroitin / Q000737:chemistry; D002809:Chondroitin Sulfates / Q000138:chemical synthesis / Q000737:chemistry*; D020723:Glucuronic Acid / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy
chemical_list: D000080:Acetals; D001597:Benzylidene Compounds; D020723:Glucuronic Acid; D002807:Chondroitin; D002809:Chondroitin Sulfates
keywords: Acetal; Benzylidene; Chondroitin sulfate; Interglycosidic linkage; Regioselective sulfation; Sulfation pattern