Allyl Glycosides Research Articles

Structure of the glycopeptidolipid antigen of serovar 20 of the Mycobacterium avium serocomplex, synthesis of allyl glycosides of the outer di- and tri-saccharide units of the antigens of serovars 14 and 20, and serology of the derived neoglycoproteins

The tetrasaccharide hapten released from the glycopeptidolipid (GPL) antigen of Mycobacterium avium serovar 20 has been characterized as O-(2-O-methyl-α-d-rhamnopyranosyl)-(1 → 3)-O-(2-O-methyl-α-l-fucopyranosyl)-(1 → 3)-α-l-rhamnopyranosyl-(1 → 2)-6-deoxy-l-talose. Syntheses are reported of allyl glycosides of the outer disaccharide unit of this hapten, O-(2-O-methyl-α-d-rhamnopyranosyl)-(1 → 3)-2-O-methyl-α-l-fucopyranose, and also of the outer di- and tri-saccharide units of the GPL antigen of M. avium serovar 14, O-(N-formyl-α-l-kansosaminyl)-(1 → 3)-2-O-methyl-α-d-rhamnopyranose and O-(N-formyl-α-l-kansosaminyl)-(1 → 3)-O-(2-O-methyl-α-d-rhamnopyranosyl-(1 → 3)-2-O-methyl-α-l-fucopyranose. The key steps in the latter synthesis involve the preparation of allyl 4-azido-4,6-dideoxy-3-C-methyl-2-O-methyl-α-l-mannopyranoside as a precursor for the N-formylkansosamine unit, followed sequentially by conversion into and use of a trichloroacetimidate as glycosyl donor for di- and tri-saccharide formation, O-deacylation, reduction, and N-formylation. The allyl glycosides, representative of the haptens from both serovars, have been converted into neoglycoproteins (NGPs) and their serological activities have been compared in the light of the structural relationship between them.

ChemInform Abstract: Synthesis of Allyl 3‐Deoxy‐D‐manno‐2‐octulopyranosidic Acid 4‐ and 5‐ Phosphates.

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Preparation and characterization of N-[2-(glycosyloxy)-ethyl]chitosan derivatives

Allyl glycosides of 8 simple sugars have been prepared and characterized, including 1H- and 13C-n.m.r. assignments. Formylmethyl glycosides, obtained by reductive ozonolysis of the allyl glycosides, have been reductively N-alkylated to chitosan with typical yields of 80%. The glycosides of α- and β- d-glucopyranose, α- and β- d-galactopyranose, 2-acetamido-2-deoxy-α- and β- d-glucopyranose, β- d-glucuronic acid, and β-lactose have been incorporated by this method. The degree of substitution (d.s.) of the products was controlled by varying the molar ratio of glycoside to free amine groups of chitosan by between 0.5 and 3.0. Derivatives of degree of substitution >0.3 were typically water soluble, and compounds of higher d.s. generally gave less-viscous aqueous solutions. Assignment of 13C-n.m.r. chemical shifts verified the structure of these derivatives. The linewidths of the branch resonances (5–100 Hz) provided qualitative information about the relationship between d.s. and branch mobility. The resonances of high-d.s. products were narrower and more intense than analogous low-d.s. derivatives. The chitosan resonances of the backbone were generally broader (50–200 Hz) and less intense, and as a result were difficult to assign fully.

A Useful Method for Deprotection of the Protective Allyl Group at the Anomeric Oxygen of Carbohydrate Moieties Using Tetrakis(triphenylphosphine)palladium.

We have developed a simple method for the deprotection of allyl groups used as a protective group for the anomeric oxygen on a sugar moiety by employing tetrakis(triphenylphosphine) palladium in acetic acid. This method is applicable for not only simple but also complex allyl glycosides, such as natural lipid A intermediates and other important lipid A intermediates. Further, this method would be useful for large-scale preparation.

An efficient method for the deprotection of allyl glycosides with adjacent azides: the circumvention of unwanted dipolar cycloaddition products

A two step deallylation scheme using (bis(methyldiphenylphosphine)) 1,5-cyclooctadiene) iridium (I) hexafluorophosphate and catalytic amounts of osmium tetroxide with trimethylamine N-oxide is used to deprotect allyl glycosides in the presence of an azide group at C-2. This method avoids the formation of intramolecular 1,3-dipolar cycloaddition products which are isolated during the deprotection using other procedures.

Access to fluorescent probes via allyl glycosides: the synthesis of aBrucella trisaccharide epitope linked to a coumarin

Oligosaccharide allyl glycosides are demonstrated to provide a route to fluorescent probes and simple inhibitors. Ethyl 2-O-acetyl-4-azido-3-O-benzoyl-4,6-dideoxy-1-thio-alpha-D-mannopyranosid e (6) was used as glycosyl donor in the preparation of the trisaccharide [alpha-D-Rha p4NFo-(1----2)-]2-alpha-D-Rha p4NFo-O-allyl (16). Thioglycoside 6 was activated with N-iodosuccinimide and triflic acid or by bromine in the glycosylations and the inhibitor 16 was obtained after deprotection by transesterification, reduction of the azido groups with hydrogen sulfide, and N-formylation with ethyl formate. Ozonolysis of the allyl glycoside in 16 and reductive amination with 7-amino-4-methylcoumarin then gave the target fluorescent trisaccharide conjugate.

Convenient syntheses of 2,3,5-tri- O-benzyl-arabino- and −ribofuranoses via their allyl glycosides

Convenient syntheses of 2,3,5-tri- O-benzyl-arabino- and −ribofuranoses via their allyl glycosides

Synthesis of a tetrasaccharide of the genus-specific lipopolysaccharide epitope of Chlamydia

Allyl 2-acetamido-2-deoxy-3,4- O-(1,1,3,3,-tetraisopropyldisiloxan-1,3-diyl)-β- d-glucopyranoside was coupled with methyl (4,5,7,8-tetra- O-acetyl-3-deoxy-α- d- manno-2-octulopyranosyl bromide)onate ( 1) to give a good yield of the α-(2→6)-linked disaccharide, isolated after deacetylation and regioselective conversion into the corresponding 7′,8′- O-carbonyl or 7′,8′- O-(1,1,3,3-tetraisopropyldisiloxane-1,3-diyl) derivatives, respectively. Subsequent glycosylation with 1 gave a high yield of the α- and β-(2″→4′)-linked trisaccharide derivatives 16 and 18, whereas block synthesis using the α-(2→8)-linked Kdo-disaccharide bromide derivative 19 afforded a low yield of the corresponding α- and β-(2″→4′)-linked tetrasaccharide derivatives 20 and 22. Removal of the protecting groups furnished the disaccharide allyl O-(sodium 3-deoxy-α- d- manno-2-octulopyranosylonate)-(2→6)-2-acetamido-2-deoxy-β- d-glucopyranoside, the trisaccharide allyl O-(sodium 3-deoxy-α- d- manno-2-octulopyranosylonate)-(2→4)-(sodium 3-deoxy-α- d- manno-2-octulopyranosylonate)- (2→6)-2-acetamido-2-deoxy-β- d-glucopyranoside, and the tetrasaccharide allyl O-(sodium 3-deoxy-α- d- manno-2-octulopyranosylonate)-(2→8)-(sodium 3-deoxy-α- d- manno-2-octulopyranosylonate)- (2→4)-(sodium 3-deoxy-α- d- manno-2-octulopyranosylonate)-(2→6)-2-acetamido-2-deoxy-β- d-glucopyranoside in high yield. Copolymerization of the allyl glycosides with acrylamide gave artificial polyvalent haptens suitable for defining epitope specificities of monoclonal antibodies directed against Chlamydia lipopolysaccharides.

A stereoselective synthesis of pyruvic 4,6-acetals of d-hexopyranose residues

A stereoselective synthesis of pyruvic 4,6-acetals in their naturally occurring configurations on α- d-glucopyranose, α- d-mannopyranose, and β- d-galactopyranose residues is based on the preferential formation of 4,6-[1-(3,4-dimethoxyphenyl)ethylidene] acetals bearing equatorial methyl groups. 2,3-Di- O-acyl derivatives of these acetals are oxidized with ruthenium tetraoxide to yield the corresponding 4,6-(1-carboxyethylidene) acetals. Synthesis of allyl 4,6- O[1( S)-1-methoxycarbonylethylidene]-3- O-methyl-β- d-glucopyranoside has been achieved with protection of the allyl glycoside by epoxidation and subsequent regenerative deoxygenation with 3-methylbenzothiazole-2-selone. The allyl glycoside has been subjected in sequence to saponification, ozonolysis, and reductive amination in the presence of bovine serum albumin to furnish a neoantigen.

ChemInform Abstract: Glycosides of Monoallyl Diethylene Glycol. A New Type of Spacer Group for Synthetic Oligosaccharides.

Abstract The preparation of spacer-armed synthetic oligosaccharides, which can be coupled to either proteins or polymers for use respectively as immunogens or immunoadsorbants for affinity chromatography, is today an important field in chemistry. The methoxycarbonyloctyl glycosides developed by Lemieux and coworkers1 are frequently used and remain the most popular. Other glycosides with amide,2 thioether, 3 and ether4 type spacer groups have also been employed. Recently, an alternative to coupling to proteins appeared when copolymerization of allyl glycosides with acrylamide provided excellent immunogens.5

Oligosaccharides corresponding to biological repeating units of Shigella flexneri variant Y polysaccharide: part 3. Synthesis and 2D-nuclear magnetic resonance analysis of a heptasaccharide hapten

The block synthesis of a heptasaccharide portion of the biological repeating unit, [2)-α-L-Rhap-(1→2)-α-L-Rhap-(1→3)-α-L-Rhap-(1→3)-β-D-GlcpNAc-(1], of the Shigella flexneri variant Y polysaccharide is described. The synthetic strategy relies on the use of the key trisaccharide intermediate α-L-Rhap-(1→2)-α-L-Rhap-(1→3)-α-L-Rhap, both as a glycosyl acceptor and as a donor. Thus, the trisaccharide bromide in conjunction with the β-D-GlcpNPhth-(1→2)-α-L-Rhap-(1→2)-α-L-Rhap-(1→3)-α-L-Rhap unit under Helferich conditions yielded the blocked heptasaccharide in 86% yield. The latter unit was obtained, in turn, from the key trisaccharide intermediate functioning as an acceptor molecule. Attempts at coupling the tetrasaccharide donor, α-L-Rhap-(1→2)-α-L-Rhap-(1→3)-α-L-Rhap-(1→3)-β-D-GlcpNPhth, with the trisaccharide acceptor α-L-Rhap-(1→2)-α-L-Rhap-(1→3)-α-L-Rhap, to give the heptasaccharide under a variety of conditions were unsuccessful. The blocked derivatives were synthesized as their allyl glycosides. Removal of the blocking groups, hydrogenation of the allyl group, and N-acetylation yielded the heptasaccharide hapten, α-L-Rhap-(1→2)-α-L-Rhap-(1→3)-α-L-Rhap-(1→3)-β-D-GlcpNAc-(1→2)-α-L-Rhap-(1→2)-α-L-Rhap-(1→3)-α-L-Rhap, as its propyl glycoside, for use in inhibition studies with complementary monoclonal antibodies, and in NMR and X-ray studies. The detailed NMR analysis of the protected and deprotected heptasaccharides by use of two-dimensional NMR techniques is also described.

Synthesis of poly(acrylamide) copolymers containing 3,5-dideoxy- d- arabino-2-octulopyranosylonic acid (5-deoxy-Kdo) residues

The monosaccharides, sodium (allyl 3,5-dideoxy-α- and -β- d- arabino-2-octulopyranosid)onate, and the disaccharide, O-[sodium (3-deoxy-α- d- manno-2-octulopyranosyl)onate]-(2→4)-sodium (allyl 3,5-dideoxy-α- d- arabino-2-octulopyranosid)onate, corresponding to the 5-deoxy derivatives of Kdo-mono- and -di-saccharides, were synthesized via mercury(II) cyanide-promoted glycosylation of allyl alcohol or methyl (allyl 7,8- O-carbonyl-3,5-dideoxy-α- d- arabino-2-octulopyranosid)onate with Kdo or 5-deoxy-Kdo bromide derivatives, respectively. Removal of the protecting groups and subsequent copolymerization of the allyl glycosides with acrylamide gave artificial antigens suitable for the determination of epitope specificities displayed by monoclonal antibodies directed against the Kdo-region of enterobacterial lipopolysaccharides.

Determination of the epitope specificity of monoclonal antibodies against the inner core region of bacterial lipopolysaccharides by use of 3-deoxy- d- manno-octulosonate-containing synthetic antigens

Partial structures of enterobacterial lipopolysaccharides (LPS) of the Rechemotype, consisting of lipid A and 3-deoxy- d- manno-2-octulosonic acid (Kdo), as well as oligosaccharides and derivatives of Kdo were synthesized and used to characterize the epitope specificity of monoclonal antibodies against Re-mutant LPS. High-molecular-weight antigens, obtained after copolymerization of the respective allyl glycosides with acrylamide, and the haptenic oligosaccharides were used in immunoprecipitation, immune hemolysis, and in inhibition assays. A monoclonal antibody (clone 20, IgM) recognizing a terminal Kdo p group was shown to require for its binding the α-anomeric configuration and OH-4 and OH-5 groups, whereas the C-7C-8 chain was of minor importance. Another monoclonal antibody (clone 25, IgG 3), which recognizes a (2→4)-linked Kdo disaccharide, was shown to require for its binding the α-anomeric configuration of both residues. The isomer having a reducing β-Kdo residue was significantly less active, and that with a terminal β-Kdo group was completely inactive. The OH-5 group of the reducing residue was shown to be not important for the specificity of this antibody, since it could be replaced by a hydrogen atom without loss of serological reactivity. The α-(2→8)-linked Kdo disaccharide was strongly cross-reactive with its (2→4)-linked isomer. The antibody recognized also parts of the 2-amino-2-deoxy- d-glucose backbone of lipid A.

Synthesis of trisaccharides containing 3-deoxy- d- manno-2-octulosonic acid residues related to the KDO-region of enterobacterial lipopolysaccharides

Glycosylation of methyl (allyl 7,8- O-carbonyl-3-deoxy-α- d- manno-2-octulopyranosid)onate with an α-(2→4) linked per- O-acetylated KDO-disaccharide bromide derivative under Helferich conditions afforded a 2:1 mixture of the α- and β-linked trisaccharide derivatives in 50% yield. Removal of the protecting groups gave sodium O-[sodium (3-deoxy-α- d- manno-2-octulopyranosyl)onate]-(2→4)- O-[sodium (3-deoxy-α- and -β- d- manno-2-octulopyranosyl)onate]-(2→4)-sodium (allyl 3-deoxy-α- d- manno-2-octulopyranosid)onate. Radical copolymerization of the allyl glycosides afforded artificial antigens, suitable for defining antibody specificities directed against the KDO-region of enterobacterial lipopolysaccharides.

Glycosides of Monoallyl Diethylene Glycol. A New Type of Spacer Group for Synthetic Oligosaccharides

Abstract The preparation of spacer-armed synthetic oligosaccharides, which can be coupled to either proteins or polymers for use respectively as immunogens or immunoadsorbants for affinity chromatography, is today an important field in chemistry. The methoxycarbonyloctyl glycosides developed by Lemieux and coworkers1 are frequently used and remain the most popular. Other glycosides with amide,2 thioether, 3 and ether4 type spacer groups have also been employed. Recently, an alternative to coupling to proteins appeared when copolymerization of allyl glycosides with acrylamide provided excellent immunogens.5

Synthesis of a trisaccharide of 3-deoxy- d- manno-2-octulopyranosylonic acid (KDO) residues related to the genus-specific lipopolysaccharide epitope of chlamydia

The disaccharides, O-(sodium 3-deoxy-α- and -β- d- manno-2-octulopyranosylonate)-(2→8)-sodium (allyl 3-deoxy-α- d- manno-2-octulopyranosid)onate, were prepared via glycosylation of methyl (allyl 4,5,7-tri- O-acetyl-3-deoxy-α- d- manno-2- octulopyranosid)onate with methyl (4,5,7,8-tetra- O-acetyl-3-deoxy- d- manno-2- octulopyranosyl bromide)onate under Helferich and Koenigs-Knorr conditions, respectively. Based on g.l.c.-m.s. data of the α- and β-(2→8)-linked disaccharide derivatives, obtained after carbonyl- and carboxyl-group reduction, followed by methylation, the α-anomeric configuration was assigned to the terminal KDO-residue in the KDO-region of Chlamydial lipopolysaccharide. The trisaccharide O-(sodium 3-deoxy-α- d- manno-2-octulopyranosylonate)-(2→8)-(sodium 3-deoxy- α- d- manno-2-octulopyranosylonate)-(2→4)-sodium (allyl 3-deoxy-α- d- manno-2- octulopyranosid)onate was obtained via block synthesis using an α-(2→8)-linked disaccharide bromide derivative as the glycosyl donor. Copolymerization of the allyl glycosides with acrylamide gave water-soluble macromolecular antigens, suitable for defining epitope specificities of monoclonal antibodies directed against Chlamydial LPS.

A Novel Approach to the Synthesis of C-Glycosyl Compounds: The Wittig Rearrangement

Abstract Partially protected benzyl α-and β-pyranosides undergo Wittig rearrangement reactions on treatment with strong bases in tetrahydrofuran to give hydroxymethylphenyl C-glycosyl derivatives. Two products were generally obtained and all Wittig rearrangement products retained the configuration at the migrating anomeric center. In benzene, benzyl 4,6-O-isopropylidene-β-D-glucopyranoside reacted with n-butyl lithium to give addition to the anomeric center accompanied by ring opening with loss of the aglycone. Allyl glycosides do not give Wittig rearrangement products.

Synthesis of polyacrylamide copolymers containing α-(2→4)-β-, β-(2→4)-β-, and β-(2→4)-α-linked O-(3-deoxy- d- manno-2-octulopyranosylonate)-(3-deoxy- d- manno-2-octulo-pyranosylono) (KDO) residues

Glycosylation of methyl (allyl 7,8-di- O- tert-butyldimethylsilyl-3-deoxy-β- d- manno-2-octulopyranosid)onate with methyl (4,5,7,8-tetra- O-acetyl-3-deoxy-α- d- manno-2-octulopyranosyl bromide)onate under Helferich conditions gave a 3:1 mixture of the corresponding α- and β-(2→4)-linked disaccharide derivatives in 58% yield. Separation and subsequent deprotection of the isomers afforded sodium O-[sodium (3-deoxy-α- and -β- d- manno-2-octulopyranosyl)onate]-(2→4)-(allyl 3-deoxy-β- d- manno-2-octulopyranosid)onate. Similarly, the glycoside sodium O-[sodium (3-deoxy-β- d- manno-2-octulopyranosyl)onate]-(2→4)-(allyl 3-deoxy-α- d- manno-2-octulopyranosid)onate was obtained by glycosylation of methyl (allyl 7,8- O-carbonyl-3-deoxy-α- d- manno-2-octulopyranosid)onate, followed by removal of the protecting groups. Radical copolymerization of the allyl glycosides with acrylamide afforded linear macromolecular antigens suitable for the determination of epitope-specificities of monoclonal antibodies directed against the KDO-region of enterobacterial lipopolysaccharides.

Synthesis of oligosaccharides corresponding to the antigenic determinants of the β-haemolytic Streptococci Group A. Part 1. Overall strategy and synthesis of a linear trisaccharide

The overall strategy for the synthesis of higher-order oligosaccharides corresponding to the repeating unit of the cell-wall polysaccharide of the β-haemolytic Streptococci Group A is described. The trisaccharide, β-D-GlcpNAc-(1→3)-α-L-Rhap-(1→3)-α-L-Rhap has been synthesized by a series of Königs-Knorr reactions. The selectively protected rhamnose derivative, allyl 2-O-benzoyl-4-O-benzyl-α-L-rhamnopyranoside, reacted with 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-β-D-glucopyranosyl bromide to give the blocked disaccharide. Deallylation, followed by treatment with N,N-dimethyl(chloromethylene)ammonium chloride then gave the corresponding disaccharide chloride. In conjunction with the same rhamnose monosaccharide unit or 8-methoxycarbonyloctyl 2,4-di-O-benzoyl-α-L-rhamnopyranoside, the synthesis of the blocked trisaccharide, as its allyl glycoside or its 8-methoxycarbonyloctyl glycoside, respectively, was accomplished. Transesterification, followed by hydrazinolysis, selective N-acetylation, and hydrogenolysis afforded the pure trisaccharide, as its propyl glycoside or 8-methoxycarbonyloctyl glycoside, for use as a hapten in binding studies and n.m.r. studies or for use in the preparation of glycoconjugates, respectively. Similar treatment of the blocked disaccharide afforded the hapten, β-D-GlcpNAc-(1→3)-α-LRhap, as its propyl glycoside.

An Easy Preparation of 2-Deoxy-2-Phthalimido-β-D-Glucoand β-L-Rhamnopyranosides

Abstract Benzyl and allyl glycosides are prepared directly from 1,3,4,6-tetra-O-acetyl-2-deoxy-2-phthalimido-α,β-d-glucppyranose and 1,2,3,4-tetra-O-acetyl-β-l-rhamnopyranose using stannic chloride as catalyst with solutions of the respective alcohols in methylene chloride.