Polymer-supported and chemoenzymatic synthesis of the Neisseria meningitidis pentasaccharide: a methodological comparison
作者:Fengyang Yan、Warren W. Wakarchuk、Michel Gilbert、James C. Richards、Dennis M. Whitfield
DOI:10.1016/s0008-6215(00)00086-0
日期:2000.8
Neisseria meningitidis trisaccharide [GlcNAc beta(1 --> 3)Gal beta(1 --> 4)Glc-R], tetrasaccharide [Gal beta(1 --> 4)GlcNAc beta(1 --> 3)Gal beta(1 --> 4)Glc-R], and a pentasaccharide [Neu5Ac alpha(2 --> 3)Gal beta(1 --> 4)GlcNAc beta(1 --> 3)Gal beta(1 --> 4)Glc-SPh] were prepared via conventional chemical synthesis, polymer-supported synthesis, and chemoenzymatic methods, starting from D-lactose. The polymer polyethyleneglycol monomethylether (MPEG) and the linker dioxyxylene (DOX) were used with a lactose-bound acceptor to improve the purification process. Several enzymes (LgtA, GalE-LgtB fusion, and CMP-Neu5Ac synthetase/sialyltransferase fusion) were used for syntheses of these oligosaccharides. Excellent stereo- and regioselectivities as well as high yield (> 90% from Gal beta(1 --> 4)Glc-SPh) of the pentasaccharide were obtained. Both of the convenient processes are suitable for efficient preparation of target oligosaccharides. (C) 2000 Elsevier Science Ltd. All rights reserved.
Synthesis of tri-, penta-, and heptasaccharides, functionalized with orthogonally N-protected amino residues at the reducing and non-reducing ends
N-Boc-protected glycine moiety, and further connected to either a mannose (1→6) disaccharide or (1→3) lactose units (one, two or three) resulting in tri-, penta-, or heptasaccharides. All of the synthesized oligosaccharides have an N-benzyloxycarbonyl-aminoethyl residue at the reducing end. The orthogonal N-Boc/N-Cbz protection group pattern enables further conjugation/derivatization and results in a hydrophilic
A divergent approach to the synthesis of iGb3 sugar and lipid analogues via a lactosyl 2-azido-sphingosine intermediate
作者:Janice M. H. Cheng、Emma M. Dangerfield、Mattie S. M. Timmer、Bridget L. Stocker
DOI:10.1039/c4ob00241e
日期:——
Isoglobotrihexosylceramide (iGb3, 1) is an immunomodulatory glycolipid that binds to CD1d and is presented to the T-cell receptor (TCR) of invariant natural killer T (iNKT) cells.