Chemoenzymatic Total Synthesis of <i>Haemophilus ducreyi</i> Lipooligosaccharide Core Octasaccharides Containing Natural and Unnatural Sialic Acids

Luo, Sanzhong; Liu, Yating; Hao, Tianhui; Ma, Wenjing; Luo, Yawen; Wang, Shasha; Xu, Zhou; Hu, Chaoyu; Wen, Liuqing; Li, Tiehai

doi:10.1021/acs.orglett.3c00657

Cited by 4 publications

(2 citation statements)

References 53 publications

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“…It should be mentioned that the IBX oxidation could also be achieved by the Swern oxidation. [38] In contrast to previous Grignard-based homologation strategies, [26,28,36] the optimized Wittig olefination are tolerable of the benzoyl (Bz) protecting group. Subsequent sequential L-Pro catalyzed aminooxylation of 16 followed by NaBH 4 reduction and cleavage of the NÀ O bond with nitrosobenzene (PhNO) produced the L,D-Hep diol 17.…”

Section: Resultsmentioning

confidence: 99%

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Orthogonal Glycosylation with Phosphate Acceptors for Expeditious Synthesis of Bacterial Inner Core Oligosaccharides

Cheng

Wang

et al. 2023

Chemistry An Asian Journal

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We report a practical one-pot glycosylation strategy for synthesis of bacterial inner core oligosaccharides that composed of unavailable L-glycero-D-manno and D-glycero-Dmanno-heptopyranose components. The glycosylation method features a new orthogonal glycosylation procedure; whereby a phosphate acceptor is coupled with a thioglycosyl donor producing a disaccharide phosphate, which can be engaged in another orthogonal glycosylation procedure to couple with a thioglycosyl acceptor. The phosphate acceptors used in above one-pot procedure are directly prepared from thioglycosyl acceptors via the in-situ phosphorylation. Such phosphate acceptor preparation protocol eliminates the traditional protection and deprotection procedures. Based on the new one-pot glycosylation strategy, two partial inner core structures of Yersinia pestis lipopolysaccharide and Haemophilus ducreyi lipooligosaccharide were acquired.

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Section: Resultsmentioning

confidence: 99%

“…[33,34] Due to the biological relevance and unique structures, synthesis of the inner core oligosaccharides and related glycoconjugates for biological studies is of interest to synthetic chemists and microbiologists. [21,24,35,36]…”

Section: Introductionmentioning

confidence: 99%

Orthogonal Glycosylation with Phosphate Acceptors for Expeditious Synthesis of Bacterial Inner Core Oligosaccharides

Cheng

Wang

et al. 2023

Chemistry An Asian Journal

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Recent chemical synthesis and immunological evaluation of glycans related to bacterial lipopolysaccharides

Qin,

Tian,

et al. 2024

Current Opinion in Chemical Biology

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Total Synthesis of a Conjugation-Ready Tetrasaccharide Repeating Unit of Vibrio cholerae O:3 O-antigen Polysaccharide

Maji,

Ghotekar,

Kulkarni

2024

Org. Lett.

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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 Lfucosamine, 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.Vibrio cholerae is a Gram-negative, facultative anaerobic, and comma-shaped bacteria, commonly found in contaminated water and food. According to the WHO fact sheet, Vibrio cholerae is a highly contagious pathogen, causing over 1 million cases of diarrhea and a significant number of deaths globally every year. 1 The world has faced seven massive cholerae pandemics, epidemics, endemics, and seasonal or sporadic outbreaks. V. cholerae can survive in adverse aquatic environments for prolonged periods, which makes the bacteria highly virulent. 2 This high-risk bacterium can cause watery diarrhea associated with dehydration, vomiting, unconsciousness, and death within a few hours if left untreated. Furthermore, epidemiological study proves that V. cholerae shows antimicrobial resistance toward first-and second-line antibiotics. 3 The prophylaxis strategies are therefore required to curb the disease. There are a few oral cholera vaccines (OCVs) approved by WHO. However, degradation of the antigen exposed to acidic pH in the stomach and short-lived immune protection leaves room for further development for a multicomponent glycoconjugate vaccine against all O-antigen serogroups of V. cholerae. 4 There are more than 200 serogroups based on O-antigen of the lipopolysaccharide present on the bacterial cell surface. 2 Recently, strain O:3 was detected in the archived clinical isolates obtained from cholera outbreaks that took place in southern Ghana during 2012− 2015. 3 Surface exposed carbohydrates are antigenic materials and are key components of a glycoconjugate vaccine. 5 Also, they are known to be safe and create a long-lasting T-cell-dependent memory, upon protein conjugation. 6 The bacterial cell surface carries glycoconjugates and oligosaccharides containing rare deoxy amino sugars that are absent in human cells. 7 This critical difference can be exploited to develop carbohydrate-

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Chemoenzymatic Total Synthesis of Haemophilus ducreyi Lipooligosaccharide Core Octasaccharides Containing Natural and Unnatural Sialic Acids

Cited by 4 publications

References 53 publications

Orthogonal Glycosylation with Phosphate Acceptors for Expeditious Synthesis of Bacterial Inner Core Oligosaccharides

Orthogonal Glycosylation with Phosphate Acceptors for Expeditious Synthesis of Bacterial Inner Core Oligosaccharides

Recent chemical synthesis and immunological evaluation of glycans related to bacterial lipopolysaccharides

Total Synthesis of a Conjugation-Ready Tetrasaccharide Repeating Unit of Vibrio cholerae O:3 O-antigen Polysaccharide

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