A method for glycoconjugate synthesis

Abstract

7-Formylheptyl glycosides of 2-acetamido-2-deoxy-beta-D-glucopyranose and O-alpha-L-rhamnopyranosyl-(1-->3)-O-alpha-L-rhamnopyranose were synthesized and were coupled by reductive amination to bovine serum albumin and aminopropyl glass, respectively.

Synthetic neoglycoconjugates of cell-surface phosphoglycans of Leishmania as potential anti-parasite carbohydrate vaccines

“…one chain of a hapten per 8,300 Da of protein). Although this was around three-fold lower than that reported for oligosaccharide–BSA conjugates prepared using similar reductive amination techniques [71, 72], in the latter cases a large molar excess of oligosaccharide over BSA amino groups (about 200 : 1) was used. Since (a) the synthetic phosphoglycans are rather precious and (b) a relatively low hapten/protein ratio (like one chain of a hapten per 10 kDa of protein) may be desirable from an antigen-presentation point of view [69], the developed conditions were used for the preparation ([70] and Sizova, O. V., Nikolaev, A. V., and Ferguson, M. A. J., unpublished data) of Leishmania phosphoglycan–tetanus toxin fragment C conjugates 13-19 (Fig.…”

Purification of Subunit B of Shiga Toxin Using a Synthetic Trisaccharide-Based Affinity Matrix

“…The approach presented here is based on a chemically synthesized derivative (27) of the P 1 trisaccharide that permits its covalent attachment to a variety of linking arms. We selected an ω-aldehydoalkyl spacer (10) for covalent attachment of the P 1 trisaccharide to the insoluble matrix under the mild conditions of reductive amination. The geometry of the linking arm provided a sufficient distance of the hapten from the polymeric support that can avoid possible unfavorable steric interactions between the lectin and the supportive matrix.…”

“…Extractive workup of the residue afforded 9 as a syrup (74 g, 85%), which was sufficiently pure for the next step. Column chromatographic purification (1:1 hexane-EtOAc) afforded analytically pure 9 as a syrup: [R] D +44 o (c 1.2); NMR (CDCl 3 ) 1 H, δ 5.486 (dd, 1 H, H-2), 5.486 (s, 1 H, CHPh), 4.990 (dd, 1 H, J 2,3 ) 9.9 Hz, J 3,4 ) 3.4 Hz, H-3), 4.407 (br d, 1 H, H-4), 4.376 (d, 1 H, J 1,2 ) 9.8 Hz, H-1), 4.330 (dd, 1 H, J 5,6 ) 1.5 Hz, J 6,6* ) 12.4 Hz, H-6), 3.998 (dd, 1 H, J 5,6* ) 1.6 Hz, H-6*), 3.570 (m, 1 H, H-5), 2.239, 2.075, and 2.180 (3 s, 9 H, CH 3 CO and CH 3 S); 13 (10). To a stirred mixture of 9 (38 g, 99.4 mmol), NaCNBH 3 (30 g, 477 mmol), and 4A molecular sieves in tetrahydrofuran (500 mL) was added dropwise a saturated solution of HCl in diethyl ether (∼130 mL) at 0 °C until TLC (2:1 hexane-EtOAc) indicated complete conversion (16).…”

“…To a stirred mixture of 27 (2.05 g, 1.8 mmol), 8-(benzyloxy)octanol (10) (1.1 g, 4.7 mmol), and 4A molecular sieves (2 g) in CH 2 Cl 2 (20 mL) was added BF 3 ‚Et 2 O (100 µL, 0.8 mmol) at -30 °C. The mixture was allowed to reach 25 °C in 1 h. Removal of the solids by filtration followed by extractive workup (CHCl 3 /aqueous NaHCO 3 ) and concentration under vacuum afforded a syrup which was crystallized from EtOH-diisopropyl ether to give 28 (1.75 g, 82%): mp 143-145 °C; [R] D +49°(c 0.4); NMR (CDCl 3 ) 1 H, 5.737 (m, 1 H, J 2,3 ) 10.5 Hz, J 3,4 ) 7.7 Hz, H-3 A ), 5.573 (br d, 1 H, H-4 C ), 5.365 (dd, 1 H, J 2,3 ) 11 Hz, J 3,4 ) 3.4 Hz, H-3 C ), 5.356 (d, 1 H, J 1,2 ) 8.4 Hz, H-1 A ), 5.160 (dd, 1 H, J 1,2 ) 3.5 Hz, H-2 C ), 5…”

“…We now report a simple and efficient method for the preparative scale isolation of subunit B of Shiga toxin, using a receptor-analog affinity sorbent. Specifically, we describe the chemical synthesis of a glycosyl donor derivative of the P 1 trisaccharide antigen and the covalent attachment of the P 1 trisaccharide (3) through a chemical anchor to a solid support, using a general method reported earlier from this laboratory (10). We also demonstrate the utility of the affinity material for the rapid isolation of pure subunit B in a semiautomated fashion.…”