Homotrisaccharides

1 Linear Homotrisaccharides.—4-0-a-D-Glucopyranosyl-a,oi-trehalose has been made by 

1 Linear Homotrisaccharides.— Pyrolysis of sucrose at 100 C in the presence of citric acid caused the formation of the fructofuranosyl cation and thence the six non-reducing trisaccharides comprising sucrose with fructofuranose a- and - bonded to C-6, C-1 and C-6 4-0-a-D-Glucopyranosyl-c(,a-trehalose was made by use of perbenzylated glucosyl fluoride.  

0-a-L-F icp-(l- )-0-a-L-F icp- - A)-a-L-Fucpl-0Me was synthesized by use of compound (2) as the key glycosylating donor. Following condensation, deacetylation was effected and the process was repeated. The tetramer was made by a further repeat of the process.  

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Branched Homotrisaccharides - P-D-Glc-(l- 2)-(P-D-Glc-(l->3)]-a-D-Glc and the epimer P-D-Glc-(l- 2)-[P-D-Glc-(l- 3)]-a-D-Man have been prepared as a-methyl glycosides for conformational studies by NMR and Monte Carlo simulation methods. ... 

Linear Homotrisaccharides. - Maltose, cellobiose and lactose as 0-pro-tected p-thioglycosides have been tethered via their 0-2 to 0-3 of benzyl 6-0-benzyl-2-O-benzoyl-a-D-glucopyranoside. Cyclization induced by NIS gave a-linked trisaccharide products in about 60% yield. This approach has therefore given access to a-D-Glc-(l- 4)-a-D-Glc-(l- 4)-D-Glc, p-D-Glc-(l- 4)-a-D-Glc-(1—4)-d-G1c and p-D-Gal-(l- 4)-a-D-Glc-(l- 4)-D-Glc.3 ... 

Linear Homotrisaccharides.— The non-reducing, trehalose-containing trisaccharide... 

Branched Homotrisaccharides.— By use of glycosyl dimethylphosphinothioate derivatives the branched mannotriose a-D-Maiip-(l- 6)-[a-D-Manp-(l->3)]-D-Man has been prepared. ... 

Branched Homotrisaccharides.-Ogawa has published on several compounds related to 2,3-di-0-o -D-mannopyranosyl-D-mannose, ° while Paulsen and Sinay have reported preparations of 3,6-disubstituted analogues. 

Branched Homotrisaccharides.—The 0-serine glycoside of 0-p-D-Gl( -(l- 3)-0-[ 3-D-Glcp-(l- 6)]-D-Glcp has been synthesised in connection with studies on the solid phase synthesis of glycopeptides. ... 

Branched Homotrisaccharides.- The four stereoisomers of methyl 4,6-di-Q-D-glucopyranosyl- -D-glucopyranoside with the a,a a,0 0,a and anomeric configurations were prepared with the pro-S C-6 proton replaced by a deuteron and used in the conformational analysis of the compovinds. " In contrast, prop-2-y1 3,6-di-Q- [a-D-mannopyranosyl]- -D-glucopyranoside was synthesized with each of the carbohydrate carbon-bonded protons replaced by deuterons. ... 

Trisaccharides Linear Homotrisaccharides Linear Heterotrlsaccharides Branched Homotrisaccharides Branched Heterotrisaccharides... 

Linear Homotrisaccharides. - The nephritogenoside trisaccharide unit a-D-Glc-(1- 6)-P-d-G1c-(1- 6)-a-D-Glc has been prepared by application of the glycosyl sulfoxide procedure. Cellotriose can be made from cellobiose by use of a sesame seed transferase which also transfers from other disaccharide substrates. Treatment of highly concentrated aqueous solutions of D-mannose with an a-mannosidase from Aspergillus niger has resulted in the isolation of the trimers a-D-Man-(l- 2)-a-D-Man-(l->6)-D-Man and a-D-Man-(l 2)-a-D-Man-(1 ->2)-D-Man, and this latter trisaccharide has been formally synthesized by Fraser-Reid and colleagues in studies of the mannan components of phosphatidylinositol membrane anchors. In the course of the work they used the orthoesters 4 as versatile synthetic intermediates. ... 

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