1
|
Ghotekar BK, Kulkarni SS. Total Synthesis of the Conjugation-Ready Tetrasaccharide Repeating Unit of Shewanella japonica Type Strain KMM 3299 T. Org Lett 2024; 26:4346-4350. [PMID: 38722236 DOI: 10.1021/acs.orglett.4c01354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
Here we report the first total synthesis of the conjugation-ready tetrasaccharide repeating unit of Shewanella japonica type strain KMM 3299T. The presence of rare deoxyamino sugars and installation of three consecutive 1,2-cis glycosidic linkages makes the synthesis formidable. The challenging late-stage oxidation was overcome by using a galacturonate donor. The total synthesis was completed via a longest linear sequence of 22 steps in an overall yield of 3.5% starting from d-mannose.
Collapse
Affiliation(s)
- Balasaheb K Ghotekar
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Suvarn S Kulkarni
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| |
Collapse
|
2
|
Pradhan K, Paul A, Rai D, Mishra AK, Balhara P, Kulkarni SS. Total Synthesis of Vibrio Cholerae O43 Tetrasaccharide Repeating Unit. J Org Chem 2024; 89:4019-4030. [PMID: 38403962 DOI: 10.1021/acs.joc.3c02886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Vibrio cholerae is a pathogen responsible for the deadly pandemic - cholera. The glycans present on the surface of various strains of V. cholerae are considered as potential vaccine candidates. The tetrasaccharide repeating unit (RU) of V. cholerae O43 is decorated with less-explored rare deoxy amino sugars like d-quinosamine and d-viosamine, along with a rare amino acid, N-acetyl-l-allothreonine. Herein, we report a detailed account of the total synthesis of V. cholerae O43 tetrasaccharide RU. In our earlier attempt, while a one-pot assembly of trisaccharide was successful, the final coupling with a fully functionalized d-viosamine donor was low yielding. The successful route involved employing the Fmoc-protected d-viosamine building block as a donor and a late-stage amide bond formation of the tetrasaccharide.
Collapse
Affiliation(s)
- Kabita Pradhan
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Ankita Paul
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Diksha Rai
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Amar Kumar Mishra
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Preeti Balhara
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Suvarn S Kulkarni
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| |
Collapse
|
3
|
Maji S, Ghotekar BK, Kulkarni SS. Total Synthesis of a Conjugation-Ready Tetrasaccharide Repeating Unit of Vibrio cholerae O:3 O-antigen Polysaccharide. Org Lett 2024; 26:745-750. [PMID: 38198674 DOI: 10.1021/acs.orglett.3c04225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Herein, we report the first total synthesis of the tetrasaccharide repeating unit of Vibrio cholerae O:3 O-antigen polysaccharide. The highly complex tetrasaccharide contains rare amino sugars such as d-bacillosamine and l-fucosamine, highly labile sugar ascarylose, and higher carbon sugar d-d-heptose. Stereoselective glycosylation of the notoriously reactive ascarylose with d-d-heptose, poor nucleophilicity of the axial C4-OH of l-fucosamine, and amide coupling are the key challenges encountered in the total synthesis, which was completed via a longest linear sequence of 23 steps in 4.2% overall yield.
Collapse
Affiliation(s)
- Soumyakanta Maji
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Balasaheb K Ghotekar
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Suvarn S Kulkarni
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| |
Collapse
|
4
|
Rai D, Kulkarni SS. Total Synthesis of Conjugation-Ready Tetrasaccharide Repeating Units of a Multidrug-Resistant Pathogen Acinetobacter baumannii Strain 34 and O5. Org Lett 2023; 25:8332-8337. [PMID: 37955403 DOI: 10.1021/acs.orglett.3c03417] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2023]
Abstract
Herein, we report the first total synthesis of conjugation-ready tetrasaccharide repeating units of Acinetobacter baumannii strain 34 and O5 comprising a common disaccharide motif [α-l-FucpNAc-(1→4)-α-d-GalpNAcA]. The installation of 1,2-cis linkages employing a disarmed 2-azido-d-galacturonic acid derivative as the donor is addressed here. The synthesis of the tetrasaccharide repeating units of A. baumannii strain 34 and O5 is accomplished via the longest linear sequences of 19 steps in 9.8% and 21 steps in 8.4% overall yields, respectively.
Collapse
Affiliation(s)
- Diksha Rai
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Suvarn S Kulkarni
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| |
Collapse
|
5
|
Dorst KM, Widmalm G. NMR chemical shift prediction and structural elucidation of linker-containing oligo- and polysaccharides using the computer program CASPER. Carbohydr Res 2023; 533:108937. [PMID: 37734222 DOI: 10.1016/j.carres.2023.108937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 09/01/2023] [Accepted: 09/01/2023] [Indexed: 09/23/2023]
Abstract
Carbohydrate structures containing alkyl groups as aglycones are useful for investigating enzyme activity and glycan-protein interactions. Moreover, linker-containing oligosaccharides with a spacer group are commonly used to print glycan microarrays or to prepare protein-conjugates as vaccine candidates. The structural accuracy of these synthesized glycans are essential for interpretation of results from biological experiments in which the compounds have been used and NMR spectroscopy can unravel and confirm their structures. An approach for efficient 1H and 13C NMR chemical shift assignments employed a parallel NOAH-10 measurement followed by NMR spin-simulation to refine the 1H NMR chemical shifts, as exemplified for a disaccharide with an azidoethyl group as an aglycone, the NMR chemical shifts of which have been used to enhance the quality of CASPER (http://www.casper.organ.su.se/casper/). The CASPER program has been further developed to aid characterization of linker-containing oligo- and polysaccharides, either by chemical shift prediction for comparison to experimental NMR data or as structural investigation of synthesized glycans based on acquired unassigned NMR data. The ability of CASPER to elucidate structures of linker-containing oligosaccharides is demonstrated and comparisons to assigned or unassigned NMR data show the utility of CASPER in supporting a proposed oligosaccharide structure. Prediction of NMR chemical shifts of an oligosaccharide, corresponding to the repeating unit of an O-antigen polysaccharide, having a linker as an aglycone and a non-natural substituent derivative thereof are presented to exemplify the diversity of structures handled. Furthermore, NMR chemical shift predictions of synthesized polysaccharides, corresponding to bacterial polysaccharides, containing a linker are described showing that in addition to oligosaccharide structures also polysaccharide structures having an aglycone spacer group can be analyzed by CASPER.
Collapse
Affiliation(s)
- Kevin M Dorst
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden
| | - Göran Widmalm
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden.
| |
Collapse
|
6
|
Ghosh A, Kulkarni SS. Total Synthesis of a Linear Tetrasaccharide Repeating Unit of Vibrio vulnificus MO6-24. Org Lett 2023; 25:7242-7246. [PMID: 37756139 DOI: 10.1021/acs.orglett.3c02872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/29/2023]
Abstract
Herein, we report the total synthesis of a linear, conjugation-ready, tetrasaccharide repeating unit of Vibrio vulnificus MO6-24, which is composed of rare amino sugars such as l-quinovosamine and d-galactosamine uronic acid. The key challenges addressed here are the synthesis of rare deoxy amino sugars, installation of consecutive 1,2-cis glycosidic linkages, and late-stage oxidation. Total synthesis of the target molecule was completed via a longest linear sequence of 29 steps in an overall yield of 0.7% starting from l-rhamnose.
Collapse
Affiliation(s)
- Antara Ghosh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Suvarn S Kulkarni
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| |
Collapse
|
7
|
Paul A, Rai D, Pradhan K, Balhara P, Mishra AK, Kulkarni SS. Total Synthesis of a Structurally Complex Tetrasaccharide Repeating Unit of Vibrio cholerae O43. Org Lett 2023; 25:6413-6418. [PMID: 37603587 DOI: 10.1021/acs.orglett.3c02430] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
Herein we report the first total synthesis of a densely functionalized tetrasaccharide repeating unit of Vibrio cholerae O43, which contains rare deoxy amino sugars d-quinovosamine and d-viosamine attached with the rare amino acid N-acetyl-l-allothreonine. Synthesis of orthogonally protected rare sugars and unnatural amino acid building blocks, stereoselective construction of three consecutive 1,2-cis glycosidic linkages, amide coupling, and the presence of five nitrogen atoms dispersed over four sugar units as well as the carboxylic acid functionality make the total synthesis a formidable task.
Collapse
Affiliation(s)
- Ankita Paul
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Diksha Rai
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Kabita Pradhan
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Preeti Balhara
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Amar Kumar Mishra
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Suvarn S Kulkarni
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| |
Collapse
|
8
|
Streety X, Obike JC, Townsend SD. A Hitchhiker's Guide to Problem Selection in Carbohydrate Synthesis. ACS CENTRAL SCIENCE 2023; 9:1285-1296. [PMID: 37521800 PMCID: PMC10375882 DOI: 10.1021/acscentsci.3c00507] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Indexed: 08/01/2023]
Abstract
Oligosaccharides are ubiquitous in molecular biology and are used for functions ranging from governing protein folding to intercellular communication. Perhaps paradoxically, the exact role of the glycan in most of these settings is not well understood. One reason for this contradiction concerns the fact that carbohydrates often appear in heterogeneous form in nature. These mixtures complicate the isolation of pure material and characterization of structure-activity relationships. As a result, a major bottleneck in glycoscience research is the synthesis and modification of pure materials. While synthetic and chemoenzymatic methods have enabled access to homogeneous tool compounds, a central problem, particularly for newer synthetic chemists, is the matter of problem selection. This outlook aims to provide an entry level overview of fundamental principles in carbohydrate chemistry with an eye toward enabling solutions to frontier challenges.
Collapse
|
9
|
Shirsat AA, Rai D, Ghotekar BK, Kulkarni SS. Total Synthesis of Trisaccharide Repeating Unit of Staphylococcus aureus Strain M. Org Lett 2023; 25:2913-2917. [PMID: 37052906 DOI: 10.1021/acs.orglett.3c00997] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
An efficient total synthesis of a conjugation-ready trisaccharide repeating unit of Staphylococcus aureus strain M is reported here. The main challenges involved in this synthesis are the procurement of rare sugars (d-FucNAc and d-GalNAcA) and installation of consecutive 1,2-cis-glycosidic linkages between them. Stereoselective 1,2-cis glycosylation with the linker acceptor was achieved with easily accessible benzylidene protected d-galactosamine thioglycoside by employing a DMF modulated preactivation glycosylation method. The consecutive 1,2-cis linkages were installed with the help of solvent participation. The carboxylic acid functionality was introduced via postglycosylation oxidation on the disaccharide moiety. The total synthesis of trisaccharide repeating unit was accomplished with the longest linear sequence of 24 steps in 4.5% overall yield.
Collapse
Affiliation(s)
- Archana A Shirsat
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Diksha Rai
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Balasaheb K Ghotekar
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Suvarn S Kulkarni
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| |
Collapse
|