Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Chemical synthesis of the pentasaccharide repeating unit of the O-specific polysaccharide from Escherichia coli O132 in the form of its 2-aminoethyl glycoside.

ABSTRACT: The total chemical synthesis of the pentasaccharide repeating unit of the O-polysaccharide from E. coli O132 is accomplished in the form of its 2-aminoethyl glycoside. The 2-aminoethyl glycoside is particularly important as it allows further glycoconjugate formation utilizing the terminal amine without affecting the stereochemistry of the reducing end. The target was achieved through a [3 + 2] strategy where the required monosaccharide building blocks are prepared from commercially available sugars through rational protecting group manipulation. The NIS-mediated activation of thioglycosides was used extensively for the glycosylation reactions throughout.

SUBMITTER: Pal D

PROVIDER: S-EPMC6839562 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Chemical synthesis of the pentasaccharide repeating unit of the O-specific polysaccharide from Escherichia coli O132 in the form of its 2-aminoethyl glycoside.

Pal Debasish D Mukhopadhyay Balaram B

Beilstein journal of organic chemistry 20191028

The total chemical synthesis of the pentasaccharide repeating unit of the O-polysaccharide from E. coli O132 is accomplished in the form of its 2-aminoethyl glycoside. The 2-aminoethyl glycoside is particularly important as it allows further glycoconjugate formation utilizing the terminal amine without affecting the stereochemistry of the reducing end. The target was achieved through a [3 + 2] strategy where the required monosaccharide building blocks are prepared from commercially ...[more]

PMID: 31728170

Similar Datasets

Expedient Synthesis of the Pentasaccharide Repeating Unit of the Polysaccharide O-Antigen of Escherichia coli O11.

Project description:A convergent [3+2] block synthetic strategy was developed for the synthesis of the pentasaccharide repeating unit of the cell wall O-antigen of Escherichia coli O11 strain in excellent yield in a minimum number of steps. Several suitably functionalized thioglycoside derivatives were used as glycosyl donors during the synthesis of the target compound. A thioglycoside was the glycosyl donor used to couple with another thioglycoside derivative in a highly stereoselective manner exploiting the difference of their reactivity profile. A combination of Niodosuccinimide (NIS) and perchloric acid supported over silica gel (HClO4-SiO2) was used as a thiophilic glycosylation activator system in all stereoselective glycosylation reactions. HClO4-SiO2 acted as a user-friendly solid acid catalyst. Yields were very good in all glycosylation steps with a high stereoselective outcome. The synthetic pentasaccharide could be coupled to an appropriate protein to furnish a glycoconjugate derivative for its use in immunochemical studies.

| S-EPMC4906483 | biostudies-other

Synthesis of the Heptasaccharide Repeating Unit of the Cell Wall O-Polysaccharide of Enterotoxigenic Escherichia coli O139.

Project description:Enterotoxigenic Escherichia coli (ETEC) like the O139 strain are mostly responsible for traveler's diarrhea and causes diseases in pigs, cattle, and poultry. A convenient synthetic strategy was developed for the synthesis of the heptasaccharide repeating unit of the cell wall lipopolysaccharide of the E. coli O139 strain. The p-methoxybenzyl (PMB) group was used as a temporary protecting group which was removed in situ under the glycosylation conditions by changing the reaction temperature during the synthesis of the target compound. All glycosylation steps gave high yields with good stereoselectivity. A (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO)-mediated selective oxidation of the primary hydroxyl group was carried out using a biphasic reaction condition at the late stage of the synthesis. Such synthetic oligosaccharides could later be effectively conjugated with proteins to prepare glycoconjugate derivatives as vaccine candidates.

| S-EPMC4906484 | biostudies-literature

Synthesis of the pentasaccharide repeating unit of the O-antigen of E. coli O117:K98:H4.

Project description:The pentasaccharide repeating unit of the O-antigen of E. coli O117:K98:H4 strain has been synthesized using a combination of sequential glycosylations and [3 + 2] block synthetic strategy from the suitably protected monosaccharide intermediates. Thioglycosides and glycosyl trichloroacetimidate derivatives have been used as glycosyl donors in the glycosylations.

| S-EPMC4273275 | biostudies-literature

Convenient synthesis of the pentasaccharide repeating unit corresponding to the cell wall O-antigen of Escherichia albertii O4.

Project description:A straightforward sequential synthetic strategy has been developed for the synthesis of a pentasaccharide repeating unit corresponding to the cell wall O-antigen of the Escherichia albertii O4 strain in very good yield with the desired configuration at the glycosidic linkages using thioglycosides and trichloroacetimidate derivatives as glycosyl donors and perchloric acid supported over silica (HClO4/SiO2) as a solid supported protic acid glycosyl activator. The expected configuration at the glycosidic linkages was achieved using a reasonable selection of protecting groups in the manosaccharide intermediates.

| S-EPMC7006483 | biostudies-literature

Chemical synthesis of the repeating unit of type Ia group B Streptococcus capsular polysaccharide.

Project description:The structure of the capsular polysaccharide (CPS) of serotype Ia group B Streptococcus (GBS) has been characterized for years, but its repeating unit, which is a challenging pentasaccharide with a branch and a difficult α-sialic acid linkage, has not been synthesized yet. In this report, an effective synthesis was developed for the serotype Ia GBS CPS repeating unit, which had a reactive functionality linked to its main-chain reducing end to enable further elaboration, such as coupling with carrier proteins. The target molecule was accomplished by a convergent [2 + 3] glycosylation strategy employing a sialo-disaccharide as donor and a branched trisaccharide as acceptor. The strategy was designed to suit the synthesis of oligomers of the repeating unit.

| S-EPMC4664191 | biostudies-literature

Chemical Synthesis of the Repeating Unit of Type V Group B Streptococcus Capsular Polysaccharide.

Project description:The first chemical synthesis of the heptasaccharide repeating unit of type V group B Streptococcus capsular polysaccharide (CPS) by a preactivation-based one-pot [2 + 1 + 4] glycosylation strategy is described. The synthetic efficiency was further improved by using diol glycosyl acceptors for regio-/stereoselective glycosylation reactions. The synthetic target contains a free amino group at the reducing end, facilitating additional regioselective elaboration. The results should be useful for synthetic and biological studies of related CPSs.

| S-EPMC5645073 | biostudies-literature

Convergent synthesis of the pentasaccharide repeating unit of the biofilms produced by Klebsiella pneumoniae.

Project description:A pentasaccharide repeating unit containing α-linked D-glucuronic acid, β-linked D-mannose, corresponding to the repeating unit of biofilms produced by Klebsiella pneumoniae, has been synthesized using a stereoselective [2 + 3] convergent glycosylation strategy. The β-D-mannosidic moiety has been synthesized using a D-mannose-derived thioglycoside by a two-step activation process. Late stage TEMPO-mediated oxidation of the pentasaccharide derivative using phase-transfer reaction conditions furnished the target compound in satisfactory yield.

| S-EPMC6404407 | biostudies-literature

Synthesis of the Staphylococcus aureus Strain M Capsular Polysaccharide Repeating Unit.

Project description:The synthesis of the Staphylococcus aureus strain M capsular polysaccharide repeating unit is reported. A postglycosylation oxidation strategy was utilized for the construction of the α-galactosaminuronic acid linkages, relying on a stereoselective 2-azido-4,6-O-di-tert-butylsilylidene galactopyranoside donor, for which the selectivity was assessed by model glycosylations. The α-fucosamine linkage was installed stereoselectively, using a reactive 2-azidofucosyl donor. An unexpected glycosidic bond cleavage during the TEMPO/PhI(OAc)2-mediated oxidation of a disaccharide intermediate was circumvented by a TEMPO/PhI(OAc)2-Pinnick oxidation protocol.

| S-EPMC5442609 | biostudies-literature

Straightforward synthesis of a tetrasaccharide repeating unit corresponding to the O-antigen of Escherichia coli O16.

Project description:A straightforward synthesis of the tetrasaccharide repeating unit of the O-antigen of Escherichia coli O16 has been achieved following a sequential glycosylation strategy. A minimum number of steps was used for the synthesis of the target compound involving a one-pot glycosylation and a protecting group manipulation. All intermediate reactions afford their products in high yield, and the glycosylation steps are stereoselective.

| S-EPMC3778367 | biostudies-literature

Convergent synthesis of the tetrasaccharide repeating unit of the cell wall lipopolysaccharide of Escherichia coli O40.

Project description:A tetrasaccharide repeating unit corresponding to the cell-wall lipopolysaccharide of E. coli O40 was synthesized by using a convergent block glycosylation strategy. A disaccharide donor was coupled to a disaccharide acceptor by a stereoselective glycosylation. A 2-aminoethyl linker was chosen as the anomeric protecting group at the reducing end of the tetrasaccharide. All glycosylation steps are significantly high yielding and stereoselective.

| S-EPMC3511039 | biostudies-literature