Neue Methoden zur Glycosid- und Oligosaccharidsynthese – gibt es Alternativen zur Koenigs-Knorr-Methode?

Schmidt, Richard R.

doi:10.1002/ange.19860980305

Cited by 487 publications

(61 citation statements)

References 177 publications

(1 reference statement)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A particularly gratifying property of O-glycosyl trichloroacetimidates as glycosyl donors D [Scheme 2, -OX ϭ -OC(CCl 3 )ϭNH] is their direct reaction with Brønsted acids (HA) as glycosyl acceptors A under formation of glycosylation products P with trichloroacetamide [OϭXH ϭ Oϭ C(CCl 3 )NH 2 ] [10] as the leaving group L. This reaction was successfully employed for the synthesis of nucleoside monoand diphosphate sugars of aldoses. [3,5,11] Similar reaction behaviour can clearly be envisaged for glycosyl phosphites as glycosyl donors D [-OX ϭ OP(OR) 2 ].…”

Section: Methodsmentioning

confidence: 99%

Base- and Sugar-Modified Cytidine MonophosphateN-Acetylneuraminic Acid (CMP-Neu5Ac) Analogues - Synthesis and Studies with α(2-6)-Sialyltransferase from Rat Liver

et al. 2000

Self Cite

View full text Add to dashboard Cite

The reaction of sialyl phosphites 1, 22a‐d, 28, 39, and 45 with acyl‐protected riboside 5‐phosphorous acids 2a,b and 23 directly furnished, without addition of a catalyst, under phosphite/phosphate exchange the corresponding β‐configured sialyl riboside monophosphates 3a,b, 24a‐d, 29, 46, and 47. The synthesis of the starting materials, formation of the products, and their treatment with sodium methanolate in methanol and subsequent hydrolysis of the sialic acid ester moiety to provide the unprotected target molecules 4a,b, 25a‐d, 30, 48, and 49 is described. Investigations with α(2‐6)‐sialyltransferase from rat liver showed that base replacement in CMP‐Neu5Ac (4a,b) is not tolerated by the enzyme but that modifications of the 5‐, 8‐, or 9‐position of the neuraminic acid residue (25a‐d, 30, 48, 49) are tolerated.

show abstract

Section: Methodsmentioning

confidence: 99%

Base- and Sugar-Modified Cytidine MonophosphateN-Acetylneuraminic Acid (CMP-Neu5Ac) Analogues - Synthesis and Studies with α(2-6)-Sialyltransferase from Rat Liver

et al. 2000

Self Cite

View full text Add to dashboard Cite

show abstract

“…Anomeric oxygen-exchange reactions by thio groups (see Scheme 1, X SR) have recently attracted considerable attention for the generation of glycosyl donors [1,7]. Thioglycosides offer suf®cient temporary protection of the anomeric center, thereby enabling various ensuing chemical modi®cations of the glycosyl donor without affecting the anomeric center.…”

mentioning

confidence: 99%

“…The requirement for glycoside synthesisÐhigh chemical and stereochemical yield, applicability to large-scale preparations, with avoidance of large amounts of waste materials, by having a glycosyl transfer from the activated intermediate through a catalytic processÐwere not effectively met by any of the methods described in the foregoing for the synthesis of complex oligosaccharides and glycoconjugates. However, the general strategy for glycoside bond formation seems to be correct: valuable for the synthesis of various glycosides [1,8]. However, extension of this methodology to the synthesis of glycoconjugates is hampered by the limited generality.…”

mentioning

confidence: 99%

New aspects of glycoside bond formation

Schmidt¹,

Castro‐Palomino²,

Retz³

1999

Pure and Applied Chemistry

View full text Add to dashboard Cite

Glycoside bond formation generally requires activation of the sugar at the anomeric center. To this end, anomeric oxygen exchange reactions, resulting in the Koenigs±Knorr method and variations or, alternatively, activation through retention of the anomeric oxygen, resulting in the trichloroacetimidate method and in the phosphite method, have been proposed. The successful application of the trichloroacetimidate method to the total synthesis of GPI anchors is particularly worth mentioning. a[2-3]-Sialylation can be based on sialyl phosphites as glycosyl donors and on the nitrile effect for anomeric stereocontrol. This is exhibited for a preparative synthesis of ganglioside GM 2 which is required for tumor vaccine studies. For the generation of a[2-8]-linkage between neuraminic acid residues anchimeric assistance by a 3-thiocarbonyloxy group is introduced. The required sialyl donor can be ef®ciently prepared and a-linkage to 8-O-unprotected neuraminic acid derivatives is almost quantitative. The limitations of chemical glycopeptide synthesis encourage to employ the protein biosynthesis machinery in combination with an expanded genetic code. This is exhibited for the synthesis of glycosylated hARF-1 protein. GLYCOSIDE BOND FORMATIONÐGENERAL ASPECTSGlycoside bond formation in order to gain chemically de®ned oligosaccharides and glycoconjugates remains an important task, though generation of the anomeric linkage has seen years of dynamic progress, mainly based on highly reactive glycosyl donors, on versatile building block strategies, and on advanced protective-group design [1±3]. The endeavour was stimulated by the eminent role of carbohydrates and especially of glycoconjugates in various ®elds of modern biology [4,5]. A particularly prominent area in this regard is glycoconjugate synthesis.

show abstract

“…One reason for this discrepancy is the still limited availability of larger saccharide ligands. Although methods of synthetic carbohydrate chemistry and isolation techniques to obtain oligosaccharides from natural sources have been greatly refined during the past two decades (Schmidt, 1986;Paulsen, 1990;Thiem, 1995), it is still a difficult task in many cases to obtain substantial amounts of pentasaccharides or larger oligomers.…”

mentioning

confidence: 99%

Transferred Nuclear Overhauser Enhancement (NOE) and Rotating‐Frame NOE Experiments Reflect the Size of the Bound Segment of the Forssman Pentasaccharide in the Binding Site of Dolichos Biflorus Lectin

Casset

Pérez²,

Etzler

et al. 1997

European Journal of Biochemistry

View full text Add to dashboard Cite

A complex between the Forssman pentasaccharide a-D-GalNAc-( 1+3)-P-~-GalNAc-( 1+3)-a-~-Gal-(1+4)-P-~-Gal-( 1-4)-~-Glc and the seed lectin from Dolichos bz$hrus was studied using transfer-NOESY and transfer rotating frame NOE spectroscopy (ROESY) experiments. The evolution of transferred NOEs and ROES as a function of the pentasaccharide/lectin ratio was different for the non-reducing disaccharide moiety a-~-GalNAc-(l+3)-P-~-GalNAc compared to the rest of the molecule, which reflects distinct relaxation properties and effects of exchange broadening of the corresponding ligand resonances. Significantly, several intermolecular transferred NOEs were observed between protons of the nonreducing disaccharide moiety a-D-GalNAc-( 1 -3)-p-~-GalNAc and aliphatic as well as aromatic amino acid side chain protons in the binding pocket of the lectin. It is concluded that the non-reducing disaccharide fragment is buried in the lectin-binding pocket, whereas the reducing trisaccharide portion a-D-Gal-(1+4)-p-~-Gal-( 1-+4)-D-Glc has no immediate contacts with the protein. The experimental transfer NOE data were qualitatively compared to theoretical proton-proton distances from a model that was based on a previous homology modeling study of a complex between the disaccharide fragment a-D-GalNAc-(1+3)-p-~-GalNAc and D. bij7oru.s lectin. It was found that all intermolecular transferred NOEs matched short interatomic distances between ligand protons and aliphatic or aromatic amino acid side chain protons predicted by the theoretical model.

show abstract

Neue Methoden zur Glycosid- und Oligosaccharidsynthese – gibt es Alternativen zur Koenigs-Knorr-Methode?

Cited by 487 publications

References 177 publications

Base- and Sugar-Modified Cytidine MonophosphateN-Acetylneuraminic Acid (CMP-Neu5Ac) Analogues - Synthesis and Studies with α(2-6)-Sialyltransferase from Rat Liver

Base- and Sugar-Modified Cytidine MonophosphateN-Acetylneuraminic Acid (CMP-Neu5Ac) Analogues - Synthesis and Studies with α(2-6)-Sialyltransferase from Rat Liver

New aspects of glycoside bond formation

Transferred Nuclear Overhauser Enhancement (NOE) and Rotating‐Frame NOE Experiments Reflect the Size of the Bound Segment of the Forssman Pentasaccharide in the Binding Site of Dolichos Biflorus Lectin

Contact Info

Product

Resources

About