Use of controlled pore glass in solid phase oligosaccharide synthesis. Application to the semiautomated synthesis of a glyconucleotide conjugate

Solid-phase supports for oligonucleotide synthesis

This unit attempts to provide a reasonably complete inventory of over 280 solid supports available to oligonucleotide chemists for preparation of natural and 3'-modified oligonucleotides. Emphasis is placed on non-nucleosidic solid supports. The relationship between the structural features of linkers and their behavior in oligonucleotide synthesis and deprotection is discussed wherever the relevant observations are available.

Synthesis and applications of oligonucleotide-carbohydrate conjugates

Nowadays, oligonucleotide-carbohydrate conjugates are used in antisense biotechnology and in the study of glycosylated DNA functioning in vitro. The application of mono- and disaccharide phosphoramidites, solid-phase supports with immobilized carbohydrates, glycosylated nucleoside phosphoramidites, and postsynthetic conjugation of reactive sugar derivatives with oligonucleotides for preparation of oligonucleotide-carbohydrate conjugates have been systematically studied. The advantages and disadvantages of these approaches are considered. Possible strategies for synthesis of glycoclusters with different topologies conjugated to DNA are discussed. Applications of oligonucleotide-carbohydrate conjugates are highlighted. Studies of interactions of glycosylated oligonucleotides with proteins and effective cell-specific delivery of oligonucleotide-carbohydrate conjugates are discussed.

Comparison of dansylated aminopropyl controlled pore glass solvated by molecular and ionic liquids

We compare how (i) four ionic liquids (ILs) (1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C4mim][Tf2N]), 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([C4mpy][Tf2N]), and trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide ([P(C6)3C14][Tf2N])) and (ii) two conventional molecular liquids (methanol and 1-octanol) solvate/wet luminescent organic moieties that are covalently attached to the surface of silica controlled pore glass (CPG). A series of aminopropyl CPG particles that have been covalently tagged with the solvatochromic fluorescent probe group dansyl were used in this study. The results demonstrate that ILs solvate/wet the silica surface differently in comparison to molecular liquids (MLs). Specifically, when comparing ILs and MLs that appear to solvate the free probe, dansylpropylsulfonamide (DPSA), equally in solution, we find that ILs do not solvate/wet the silica surfaces as well as the corresponding MLs. The cation component in these ILs is the significant factor in how the ILs solvate/wet silica surfaces. Solvation/wetting of surface-bound species at a silica surface depends on the cation size. Chlorosilane end-capping of the surface silanol and amine residues attenuates the cation's affects.

Solid-phase chemical tools for glycobiology

Techniques involving solid supports have played crucial roles in the development of genomics, proteomics, and in molecular biology in general. Similarly, methods for immobilization or attachment to surfaces and resins have become ubiquitous in sequencing, synthesis, analysis, and screening of oligonucleotides, peptides, and proteins. However, solid-phase tools have been employed to a much lesser extent in glycobiology and glycomics. This review provides a comprehensive overview of solid-phase chemical tools for glycobiology including methodologies and applications. We provide a broad perspective of different approaches, including some well-established ones, such as immobilization in microtiter plates and to cross-linked polymers. Emerging areas such as glycan microarrays and glycan sequencing, quantum dots, and gold nanoparticles for nanobioscience applications are also discussed. The applications reviewed here include enzymology, immunology, elucidation of biosynthesis, and systems biology, as well as first steps toward solid-supported sequencing. From these methods and applications emerge a general vision for the use of solid-phase chemical tools in glycobiology.

Solution and solid-support synthesis of a potential leishmaniasis carbohydrate vaccine

The synthesis of a potential carbohydrate vaccine for the parasitic disease leishmaniasis is described. New solution- and solid-phase synthetic strategies were explored for the assembly of a unique tetrasaccharide antigen found on the Leishmania lipophosphoglycan. An initial solution-phase synthesis relied on thioglycosides as building blocks and the establishment of the central disaccharide from lactal via an oxidation-reduction sequence. A second approach was completed both in solution and on solid support. The solid-phase synthesis relied on assembly from monosaccharide units and was used to evaluate different glycosylating agents in the efficient installation of the galactose beta-(1-->4) mannoside. Glycosyl phosphates proved most successful in this endeavor. This first solid-phase synthesis of the Leishmania cap provided rapid access to the tetrasaccharide in 18% overall yield while requiring only a single purification step. The synthetic cap tetrasaccharide was conjugated to the immunostimulator Pam3Cys to create fully synthetic carbohydrate vaccine 1 and to the carrier protein KLH to form semisynthetic vaccine 2. Currently, both constructs have entered initial immunological experiments in mice targeted at the development of a vaccine against the parasitic disease leishmaniasis.

Solid-phase oligosaccharide synthesis: preparation of complex structures using a novel linker and different glycosylating agents

[formula: see text] A beta-(1-->4)-linked trisaccharide was prepared in 53% yield on a polymer support using glycosyl phosphates and released by cross-metathesis of a novel linker to reveal the anomeric n-pentenyl glycoside. Heptasaccharide 33 was prepared in 9% yield in 14 steps.