Zur Darstellung von Glucosiden aus Acetobromglucose

Helferich, Burckhardt; Wedemeyer, K.

doi:10.1002/jlac.19495630115

Cited by 98 publications

(40 citation statements)

References 4 publications

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“…It was converted to the 4,6-benzylidene acetal 2 using a,a-dimethoxytoluene in the presence of catalytic p-toluenesulfonic acid in acetonitrile. The subsequent stereoselective b-galactosylation to form the blocked disaccharide 4 [11] was accomplished employing the 6-O-benzyl protected galactosyl bromide 3 [14] activated with mercury(ii) cyanide under Helferich [15] conditions. Selective removal of the benzylidene acetal with aqueous acetic acid at 80 8C furnished a suitable sialyl acceptor 5.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Structural Model of an α(2,6)‐Sialyl‐T Glycosylated MUC1 Eicosapeptide under Physiological Conditions

Dziadek

Griesinger

Kunz

et al. 2006

Chemistry A European J

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To study the effect of O-glycosylation on the conformational propensities of a peptide backbone, a 20-residue peptide (GSTAPPAHGVTSAPDTRPAP) representing the full length tandem repeat sequence of the human mucin MUC1 and its analogue glycosylated with the (2,6)-sialyl-T antigen on Thr11, were prepared and investigated by NMR and molecular modeling. The peptides contain both the GVTSAP sequence, which is an effective substrate for GalNAc transferases, and the PDTRP fragment, a known epitope recognized by several anti-MUC1 monoclonal antibodies. It has been shown that glycosylation of threonine in the GVTSAP sequence is a prerequisite for subsequent glycosylation of the serine at GVTSAP. Furthermore, carbohydrates serve as additional epitopes for MUC1 antibodies. Investigation of the solution structure of the sialyl-T glycoeicosapeptide in a H(2)O/D(2)O mixture (9:1) under physiological conditions (25 degrees C and pH 6.5) revealed that the attachment of the saccharide side-chain affects the conformational equilibrium of the peptide backbone near the glycosylated Thr11 residue. For the GVTSA region, an extended, rod-like secondary structure was found by restrained molecular dynamics simulation. The APDTR region formed a turn structure which is more flexibly organized. Taken together, the joined sequence GVTSAPDTR represents the largest structural model of MUC1 derived glycopeptides analyzed so far.

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Section: Resultsmentioning

confidence: 99%

Synthesis and Structural Model of an α(2,6)‐Sialyl‐T Glycosylated MUC1 Eicosapeptide under Physiological Conditions

Dziadek

Griesinger

Kunz

et al. 2006

Chemistry A European J

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“…A slight deficit of the sym-collidine was used, as described by Garegg and Norberg (33), to ensure the rearrangement of the orthoester intermediates that normally occur. When the condensation was promoted with mercuric cyanide using toluene nitromethane as solvent (34), an about equimolar mixture of the a and p glycosides was obtained in 80% yield.…”

Section: Discussion Of Resultsmentioning

confidence: 99%

Synthesis of tri- and tetrasaccharide haptens related to the Asialo forms of the gangliosides G_M2 and G_M1

Sabesan¹,

Lemieux²

1984

Can. J. Chem.

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SUBRAMANIAM SABESAN and RAYMOND U. LEMIEUX. Can. J. Chem. 62, 644 (1984) Synthesis of PDG~INA~(I+~)PDG~~(~+~)PDG~C-O(CH~)~COOCH, (21) and PDGal(l+3)PDGalNAc(1+4)P~Gal-(~+~)PDG~C-O(CH~)~COOCH~ (33) are presented starting from PDG~I(~+~)PDG~c-O(CH~)~COOCH, (1) and ~-galactose. Improvements in the preparations of D-galactal triacetate (7) and tri-O-acetyl-2-azido-2-deoxy-a-~-galactopyranosyl bromide (11) are reported. The syntheses proceeded by way of the tri-0-acetyl-2-deoxy-2-phthalimido-P-D-galactopyranosyl and 4,6-di-0-acetyl-3-0-(tetra-O-acetyl-~~-galactopyranosyl)-2-deoxy-2-phthalimido--~-galactopyranosy bromides (18 and 30), which, in turn, were prepared from the corresponding ally1 glycosides (15 and 23). The I3C chemical shifts for the tri-and tetrasaccharide portions of 21 and 33 are assigned from the chemical shifts that were observed for the carbon atoms in the disaccharides which make up these structures. The trisaccharide (21) On rapporte des amtliorations aux prtparations du triacetate de D-galactal (7) et du bromure de tri-0-acttyl azido-2 dtoxy-2 cr-D-galactopyrannosyle. Les synthkses impliquent la prtparation des bromures de tri-0-acetyl dtoxy-2 phthalimido-2 P-D-galactopyrannosyle et de di-0-acttyl-4,6 0-(tttra-0-acttyl P-D-galactopyrannosy1)-3 dtoxy-2 phthalimido-2 P-~-galactopyrannosyle (18 et 30) qui sont eux-m&mes prtparts h partir des glycosides allyliques correspondants (15 et 23). On a attribut les dtplacements chimiques du "C des portibns tri-et tttrasaccharidiques des composts 21 et 33 en se basant sur les dtplacements chimiques observts pour les atomes de carbones des disaccharides qui composent ces structures. Le trisaccharide (21) n'inhibe que trks faiblement ]'agglutination des cellules rouges A humaines par la lectine de Dolichos biflorus. Le tttrasaccharide 33 est inactif.[Traduit par le journal]

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“…Mercuric salts such as mercuric cyanide were introduced as catalysts of oligosaccharide synthesis by Helferich and Wedemeyer in 1949. 51 This latter catalyst was applied for the first time to Scheme 19. Silver salts of hydroxyalkanoic acids and dicarboxylic acids.…”

Section: Glycosylation Using Glycosyl Bromide and Chloridementioning

confidence: 99%

The glycosylation of steroids

Pellissier

2004

Tetrahedron

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Zur Darstellung von Glucosiden aus Acetobromglucose

Cited by 98 publications

References 4 publications

Synthesis and Structural Model of an α(2,6)‐Sialyl‐T Glycosylated MUC1 Eicosapeptide under Physiological Conditions

Synthesis and Structural Model of an α(2,6)‐Sialyl‐T Glycosylated MUC1 Eicosapeptide under Physiological Conditions

Synthesis of tri- and tetrasaccharide haptens related to the Asialo forms of the gangliosides G_M2 and G_M1

The glycosylation of steroids

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Zur Darstellung von Glucosiden aus Acetobromglucose

Cited by 98 publications

References 4 publications

Synthesis and Structural Model of an α(2,6)‐Sialyl‐T Glycosylated MUC1 Eicosapeptide under Physiological Conditions

Synthesis and Structural Model of an α(2,6)‐Sialyl‐T Glycosylated MUC1 Eicosapeptide under Physiological Conditions

Synthesis of tri- and tetrasaccharide haptens related to the Asialo forms of the gangliosides GM2 and GM1

The glycosylation of steroids

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Synthesis of tri- and tetrasaccharide haptens related to the Asialo forms of the gangliosides G_M2 and G_M1