A highly stereoselective construction of beta-glycosyl linkages by reductive cleavage of cyclic sugar ortho esters

Hydrogenolysis of Carboxylic Ortho Esters

It is demonstrated for the first time that carboxylic ortho esters may be reduced to acetals using hydrogen as the reducing agent. Hydrogenolysis was performed under mild conditions over commercially available hydrogenation catalysts (5% Pd/C and 5% Pt/C). The present method is especially useful for the selective transformation of carboxylic acids and lactones into acetals.

Automated Chemical Oligosaccharide Synthesis: Novel Approach to Traditional Challenges

Advances in carbohydrate chemistry have certainly made common oligosaccharides much more accessible. However, many current methods still rely heavily upon specialized knowledge of carbohydrate chemistry. The application of automated technologies to chemical and life science applications such as genomics and proteomics represents a vibrant field. These automated technologies also present opportunities for their application to organic synthesis, including that of the synthesis of oligosaccharides. However, application of automated methods to the synthesis of carbohydrates is an underdeveloped area as compared to other classes of biomolecules. The overarching goal of this review article is to present the advances that have been made at the interface of carbohydrate chemistry and automated technology.

Synthetic polyprenol-pyrophosphate linked oligosaccharides are efficient substrates for mycobacterial galactan biosynthetic enzymes

Synthetic glycosyl polyprenol phosphates are substrates for enzymes required for cell wall assembly in mycobacteria, including the organism that causes tuberculosis.

Stereocontrolled 1,2-cis glycosylation as the driving force of progress in synthetic carbohydrate chemistry

Recent developments in stereoselective 1,2-cis glycosylation that have emerged during the past decade are surveyed herein.

Recent developments in stereoselective 1,2-cis glycosylation that have emerged during the past decade are surveyed herein. For detailed coverage of the previous achievements in the field the reader is referred to our earlier reviews: A. V. Demchenko, Curr. Org. Chem. , 2003, 7 , 35–79 and Synlett , 2003, 1225–1240.

Syntheses and Biological Activities of Glycoconjugates

This review describes the oligosaccharide syntheses and biological activities of glycosphingolipids, focusing especially on those found in invertebrates like millipedes, nematoda parasites, and cestoda parasites, and model compounds related to a major antigenic epitope against antibupleurum 2IIc/PG-1-IgG from antiulcer pectic polysaccharides. A novel and simple approach for the rational design of glycoclusters and glycodendrimers by coupling with a sugar unit and a cluster unit, was developed with beta-alanine derivatives used to construct the latter compounds.

Fluorophore-Appended Steroidal Saponin (Dioscin and Polyphyllin D) Derivatives

The synthesis of three fluorophore-appended derivatives of dioscin and polyphyllin D is reported herein. Starting from trillin, dansyl derivatives A-C were prepared in overall yields of 7-12% over 7-10 steps. A study of their behavior in a variety of polar solvents suggests that dansyl derivatives A-C are capable of micellar self-assembly and can maintain cytotoxicities (IC50 = 15-18 muM) against the HeLa carcinoma cell line evaluated by standard MTT assay. [structure: see text]

Synthetic studies on glycosphingolipids from the Protostomia phyla: syntheses of arthro-series glycosphingolipids

Glycosphingolipids isolated from larvae of the green-bottle fly, Lucilia caesar, have quite unique structures containing GlcNAcbeta-(1 --> 3)-Man and GalNAcbeta-(1 --> 4)-GlcNAcbeta-(1 --> 3)-Man. We have synthesized two glycosphingolipids, beta-D-GlcNAcp-(1 --> 3)-beta-D-Manp-(1 --> 4)-beta-D-Glcp-(1 --> 1)-Cer and beta-D-GalNAcp-(1 --> 4)-beta-D-GlcNAcp-(1 --> 3)-beta-D-Manp-(1 --> 4)-beta-D-Glcp-(1 --> 1)-Cer. A key reaction in the synthetic sequence is the application of the intramolecular aglycon delivery (IAD) approach for the synthesis of the beta-mannopyranosidic linkages.

Stereocontrolled synthesis of 2,3-anhydro-beta-d-lyxofuranosyl glycosides

[reaction: see text] The stereocontrolled synthesis of 2,3-anhydro-beta-D-lyxofuranosyl glycosides from thioglycoside 2 and glycosyl sulfoxide 3 is reported.