Synthesis of a glycotripeptide and a glycosomatostatin containing the 3-O-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-l-serine residue

Three-Dimensional Arrangement of Sugar Residues along a Helical Polypeptide Backbone: Synthesis of a New Type of Periodic Glycopeptide by Polymerization of a β-O-Glycosylated Tripeptide Containing α-Aminoisobutyric Acid

“…The organic layer was evaporated to give 8 (0.49 g, 66% yield); R f ) 0. 12 Preparation of H-Ser[ -D-GlcNAc(Ac) 3 ]-Aib-OBn (9). Protected dipeptide 8 (0.23 g, 1.14 mmol) was dissolved in formic acid (10 mL) and stirred at 27°C for 8 h. Unreacted formic acid was removed by evaporation and the residue was neutralized by 5% aqueous NaHCO 3 .…”

“…The water layer was adjusted at pH 2-3 by adding 5% aqueous KHSO 4 from which 5 was extracted with ethyl acetate (1.3 g, 90% yield). The spectra data were identified with those prepared by another synthetic route reported by Lavielle et al 12 Preparation of Boc-Ser[ -D-GlcNAc(Ac) 3 ]-ONp (6). At 0°C, 5 (215 mg, 0.402 mmol), NpOH (62 mg, 0.442 mmol), and DCC (91 mg, 0.442 mmol) were dissolved in dichloromethane (0.7 mL) and stirred at 0°C for 28 h. After the reaction, acetic acid (11 µL, 0.192 mol) was added to the mixture in order to remove unreacted DCC and ethyl acetate was added to precipitate dicyclohexylurea.…”

Solid-phase synthesis of human salivary mucin-derived O-linked glycopeptides

“…Chain termination due to trifluoroacetylation and cyclization to diketopiperazine during the deprotection of the Boc group at the dipeptide stage was not encountered during SPPS of MUC7 glycopeptides. Also, repetitive use of TFA in DCM (25%, v/v) for each N-deprotection step did not affect the acid-sensitive glycosidic linkage [34]. Therefore, the use of an integrated approach as followed here seemed an effective way to make these peptides.…”

Solid-phase synthesis of oligosaccharides and glycoconjugates

“…However, implementation of solid-phase glycopeptide synthesis in an automated regime of conventional peptide synthesis required that a number of problems was solved, such as a search for supports and linkers providing both the optimum conditions for the condensation in the elongation of the peptide chain and smooth non-destructive liberation of the target glycopeptide from the support. The most common support is Merrifield's peptide resin 56 modified by incorporation of benzyl alcohol fragments (HOCH 2 C 6 H 4 OCH 2 ), 58 the role of linker is played by a compound with benzhydrylamine and phenoxyacetic acid fragment (the so-called Rink linker), 61 a variety of compounds containing b-hydroxyallylic groups (Hycron and Hycram linkers) 62,63 and nitrobenzophenone oxime. 65 In parallel with a search for linkers, the general strategy of glycopeptide synthesis required unification of procedures used for incorporation of glycosylated amino acids into the peptide chain.…”