The effect of neighbouring group participation and possible long range remote group participation in O-glycosylation

• Rituparna Das and
• Balaram Mukhopadhyay

Beilstein J. Org. Chem. 2025, 21, 369–406, doi:10.3762/bjoc.21.27

Introduction of a human- and keyboard-friendly N-glycan nomenclature

• Friedrich Altmann,
• Johannes Helm,
• Martin Pabst and
• Johannes Stadlmann

Beilstein J. Org. Chem. 2024, 20, 607–620, doi:10.3762/bjoc.20.53

• pentasaccharide. No further definitions are required as the residues preceding the GlcNAcs are unambiguously determined by the biosynthetic pathway of N-glycans. Action of hexosaminidases would generate two isomers with just one GlcNAc and a terminal mannose residue. By defining the reading direction, we can

Synthesis of protected precursors of chitin oligosaccharides by electrochemical polyglycosylation of thioglycosides

• Md Azadur Rahman,
• Kana Kuroda,
• Hirofumi Endo,
• Norihiko Sasaki,
• Tomoaki Hamada,
• Hiraku Sakai and
• Toshiki Nokami

Beilstein J. Org. Chem. 2022, 18, 1133–1139, doi:10.3762/bjoc.18.117

• V vs SCE) gave oligosaccharides up to hexasaccharide 6a, although the yield of pentasaccharide 5a (3%) and hexasaccharide 6a (1%) was very low. For thioglycoside 1b (Ar = 4-ClC6H4, Eox = 1.68 V vs SCE), the highest conversion (79%) and the highest yield of tetrasaccharide 4b (14%) were observed

• , also showed low conversion (63%). However, it gave pentasaccharide 5d in the highest yield (6%) among these four thioglycosides. Based on these results, we optimized the reaction using thioglycoside 1a, which afforded oligosaccharides 2a–6a and recovered monosaccharide 1a in the highest total yield (88

Total synthesis of the O-antigen repeating unit of Providencia stuartii O49 serotype through linear and one-pot assemblies

• Tanmoy Halder and
• Somnath Yadav

Beilstein J. Org. Chem. 2021, 17, 2915–2921, doi:10.3762/bjoc.17.199

• synthesis of the O-antigens, that of Providencia rustigianii O34 was reported by Mukhopadhyay et al. in 2013 [34]. Chheda and co-worker, in 2015, reported the total synthesis of the pentasaccharide repeating unit of the O-specific polysaccharide of Providencia alcalifaciens O28 [35]. In 2017, Kulkarni and

Progress and challenges in the synthesis of sequence controlled polysaccharides

• Giulio Fittolani,
• Theodore Tyrikos-Ergas,
• Denisa Vargová,
• Manishkumar A. Chaube and
• Martina Delbianco

Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129

Synthesis of Streptococcus pneumoniae serotype 9V oligosaccharide antigens

• Sharavathi G. Parameswarappa,
• Claney L. Pereira and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2020, 16, 1693–1699, doi:10.3762/bjoc.16.140

• . Here, we demonstrate a convergent [2 + 3] synthetic strategy to prepare the pentasaccharide repeating unit of 9V with and without an acetate group at the C-6 position of mannosamine. Keywords: antigen; carbohydrate chemistry; oligosaccharide; Streptococcus pneumoniae; vaccines; Introduction

• degree of acetylation of the same pentasaccharide RU. The positions and degree of RU acetylation has been revised several times since the initial structure 1 was proposed in 1981 (2 and 3 in Figure 1) [20][21][22]. Antibodies raised against the natural 9V polysaccharide recognize the natural and the de-O

• natural pentasaccharide repeating unit as the methyl ester with no acetylation. Since our previous studies involving ST3 [12] and ST8 [13] indicated glucuronic acid to be an important epitope for immunogenicity, we embarked on the syntheses of 9A/9V but using a frameshift sequence of the natural

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

• Tapasi Manna,
• Arin Gucchait and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2020, 16, 106–110, doi:10.3762/bjoc.16.12

• Tapasi Manna Arin Gucchait Anup Kumar Misra Bose Institute, Division of Molecular Medicine, P-1/12, C.I.T. Scheme VII M, Kolkata 700054, India 10.3762/bjoc.16.12 Abstract A straightforward sequential synthetic strategy has been developed for the synthesis of a pentasaccharide repeating unit

• protic acid glycosyl activator. The expected configuration at the glycosidic linkages was achieved using a reasonable selection of protecting groups in the manosaccharide intermediates. Keywords: Escherichia albertii O4; glycosylation; HClO4/SiO2; O-antigen; pentasaccharide; Introduction Diarrheal

• . albertii O4 strain [11], which is a pentasaccharide comprising of α-linked ᴅ-galactosamine, β-linked ᴅ-glucosamine, β-linked ᴅ-galactose, α-linked ʟ-fucose and α-linked ʟ-rhamnose moieties. In the recent past, several vaccine candidates have been developed to control bacterial infections by conjugating

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

• Debasish Pal and
• Balaram Mukhopadhyay

Beilstein J. Org. Chem. 2019, 15, 2563–2568, doi:10.3762/bjoc.15.249

• Debasish Pal Balaram Mukhopadhyay Sweet Lab, Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, Nadia 741246, India 10.3762/bjoc.15.249 Abstract The total chemical synthesis of the pentasaccharide repeating unit of the O-polysaccharide

• the causative agent for septicemia in chicken [3], diarrhea in children under three years of age [4], diarrhea in calves and rabbits [5][6]. Recently, Knirel et al. [7] reported the structure of the O-polysaccharide of E. coli O132 as a pentasaccharide repeating unit consisting of GlcNAcp, Glcp, Rhap

• and Galf. In this communication we report on the total synthesis of this pentasaccharide repeating unit of the O-specific polysaccharide in the form of its 2-aminoethyl glycoside (Figure 1) through a [3 + 2] converging strategy. The building blocks were prepared by suitable protecting group

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

• Arin Gucchait,
• Angana Ghosh and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2019, 15, 431–436, doi:10.3762/bjoc.15.37

• Arin Gucchait Angana Ghosh Anup Kumar Misra Bose Institute, Division of Molecular Medicine, P-1/12, C.I.T. Scheme VII M, Kolkata 700054, India 10.3762/bjoc.15.37 Abstract A pentasaccharide repeating unit containing α-linked D-glucuronic acid, β-linked D-mannose, corresponding to the repeating

• pentasaccharide derivative using phase-transfer reaction conditions furnished the target compound in satisfactory yield. Keywords: beta-D-mannoside; biofilms; D-glucuronic acid; glycosylation; Klebsiella pneumoniae; pentasaccharide; polysaccharide; Introduction Klebsiella pneumoniae (K. pneumoniae) is a Gram

• contrast to the natural version. The synthesized molecules can be linked with appropriate functionalities for their conjugation with a protein for the preparation of glycoconjugates. Recently, Cescutti et al. [11] reported the structure of a pentasaccharide composed of D-glucose, D-mannose and D-glucuronic

Synthesis of α-D-GalpN₃-(1-3)-D-GalpN₃: α- and 3-O-selectivity using 3,4-diol acceptors

• Emil Glibstrup and
• Christian Marcus Pedersen

Beilstein J. Org. Chem. 2018, 14, 2805–2811, doi:10.3762/bjoc.14.258

• ] has triggered the interest of carbohydrate chemists since the early days of complex oligosaccharides synthesis. The structure of the pentasaccharide part of the Forssman antigen was resolved in the seventies [3][4] and soon thereafter Paulsen and Bünsch finished the chemical synthesis of the

• pentasaccharide chain [5][6]. The pioneering work by Paulsen was later followed up by a total synthesis by the Ogawa group [7] and an oligosaccharide synthesis by the Magnusson group [8]. With the increasing understanding of glycobiology, the Forssman antigen has remained an interesting target for vaccine

Carbohydrate inhibitors of cholera toxin

• Vajinder Kumar and
• W. Bruce Turnbull

Beilstein J. Org. Chem. 2018, 14, 484–498, doi:10.3762/bjoc.14.34

• branched pentasaccharide [Galβ1-3GalNAcβ1-4(NeuAcα2-3)Galβ1-Glcβ1-1-ceramide] bearing a ceramide moiety at the anomeric center of the Glc moiety (Figure 2). The terminal galactose residue of GM1 is buried most deeply inside the cavity of CTB [12][14], while the sialic acid branch sits in a wider shallow

Synthetic and semi-synthetic approaches to unprotected N-glycan oxazolines

• Antony J. Fairbanks

Beilstein J. Org. Chem. 2018, 14, 416–429, doi:10.3762/bjoc.14.30

• was used by Wang for the more extended synthesis of a dodecasaccharide oxazoline (Scheme 6) [78]. In this case selective removal of the PMB protecting group at OH-3 was followed by glycosylation with a pentasaccharide glycosyl fluoride donor, comprising one galactose, one glucose, and three mannose

• residues. Acid catalysed hydrolysis of the 4,6-benzylidene was followed by regioselective glycosylation of the primary 6-OH with a different pentasaccharide, this time comprised of five mannoses. Conversion of the azide to acetamide and removal of all benzyl groups by hydrogenolysis produced a completely

Preactivation-based chemoselective glycosylations: A powerful strategy for oligosaccharide assembly

• Weizhun Yang,
• Bo Yang,
• Sherif Ramadan and
• Xuefei Huang

Beilstein J. Org. Chem. 2017, 13, 2094–2114, doi:10.3762/bjoc.13.207

• their strategy to the synthesis of heparin (HP) and heparan sulfate (HS), which are more complex members of the glycosaminoglycan family [40]. A pentasaccharide 48 was chosen as the synthetic target (Figure 2). A major challenge of HP and HS synthesis lies in the coupling of an azido glucoside with a

• 59 paved the way for the synthesis of protected heparin pentasaccharide 48 (Scheme 11d). Preactivation-based chemoselective glycosylation of thioglycosides Thioglycosides are one of the most commonly utilized building blocks due to their high stabilities under a wide range of synthetic

• glycolipid family including LewisX pentasaccharide 117, dimeric LewisX 118 [63], tristearoyl lipomannan 119 [64], gangliosides GM1 120 [65] and GM2 121 (Figure 5) [66], microbial glycans such as the heptasaccharide repeating unit of type V group B Streptococcus capsular polysaccharide 122 [67], β-glucan

Glycoscience@Synchrotron: Synchrotron radiation applied to structural glycoscience

• Serge Pérez and
• Daniele de Sanctis

Beilstein J. Org. Chem. 2017, 13, 1145–1167, doi:10.3762/bjoc.13.114

• pentasaccharide from heparin, illustrates the potential of this technique. From the experimentally recorded X-ray powder diffractogram (Figure 5), the unit cell dimensions and the space group were determined. The process was continued with a computational building of the pentasaccharide and a simulated annealing

Total synthesis of a Streptococcus pneumoniae serotype 12F CPS repeating unit hexasaccharide

• Peter H. Seeberger,
• Claney L. Pereira and
• Subramanian Govindan

Beilstein J. Org. Chem. 2017, 13, 164–173, doi:10.3762/bjoc.13.19

• basic conditions using methyl iodide in 32% yield over three steps [41]. Next, TMSOTf activation of fucosyl trichloroacetimidate 8 (Scheme 1) catalyzed the glycosylation of methyl uronate 48 to afford pentasaccharide 49 exclusively as the α-isomer by virtue of remote participation of the 3-O-acetate

• group. In anticipation of the final glycosylation, the fucosazide moiety of 49 was converted into acceptor 50. The desired hexasaccharide 51 was obtained as the α-anomer in 54% yield by coupling galactose building block 9 (Scheme 1) to pentasaccharide 50 using NIS/TfOH in a mixture of toluene/dioxane

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

• Pintu Kumar Mandal

Beilstein J. Org. Chem. 2014, 10, 2724–2728, doi:10.3762/bjoc.10.287

• Pintu Kumar Mandal Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, BS-10/1, Sector 10, Jankipuram extension, Sitapur Road, Lucknow, 226 031, India 10.3762/bjoc.10.287 Abstract The pentasaccharide repeating unit of the O-antigen of E. coli O117:K98:H4 strain has

• coli; glycosylation; lipopolysaccharide; O-antigen; pentasaccharide; Introduction Escherichia coli becomes an important human pathogen in recent years owing to the emergence of new pathogenic strains [1]. Several diseases, such as meningitis and sepsis [2], diarrhoeal outbreaks [3] and urinary tract

• kidneys [10][11]. The O-specific polysaccharide of E. coli O117:K98:H4 is a linear pentasaccharide repeating unit consisting of D-galactosamine, D-glucose, D-galactose, and L-rhamnose (Figure 1) [12]. Vaccination is the recent thrust in the drug discovery program to prevent bacterial infections. Several

Galactan synthesis in a single step via oligomerization of monosaccharides

• Marius Dräger and
• Amit Basu

Beilstein J. Org. Chem. 2014, 10, 2658–2663, doi:10.3762/bjoc.10.279

• , Table 2, entry 5), followed by derivatization of the products as the TBS ethers, isolable quantities of the pentasaccharide 155c were generated. Secondary alcohols such as cyclohexanol or the sterically more hindered menthol successfully underwent glycosylation to provide mono- and disaccharides, but

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

• Manas Jana and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2013, 9, 1757–1762, doi:10.3762/bjoc.9.203

• ), 55.0 (OCH3), 54.9 (C-2A), 21.8 (COCH3), 16.5 (CCH3); ESI–MS: 804.2 [M + Na]+; Anal. calcd for C31H47N3O20: C, 47.63; H, 6.06%; found: C, 47.46; H, 6.22%. Structure of the tetrasaccharide repeating unit of the O-antigen of Escherichia coli O16. Structure of the synthesized pentasaccharide and its

Synthesis of a derivative of α-D-Glcp(1->2)-D-Galf suitable for further glycosylation and of α-D-Glcp(1->2)-D-Gal, a disaccharide fragment obtained from varianose

• Carla Marino,
• Carlos Lima,
• Karina Mariño and
• Rosa M. de Lederkremer

Beilstein J. Org. Chem. 2012, 8, 2142–2148, doi:10.3762/bjoc.8.241

• a good model for studies on the GlfTα. The constitutive oligosaccharides could be used as substrates or as standards for the identification of the products. A pentasaccharide fragment containing both, α and β-galactofuranosyl residues was synthesized by Bay and Lowary [18]. The two possible

Synthesis of 4” manipulated Lewis X trisaccharide analogues

• Christopher J. Moore and
• France-Isabelle Auzanneau

Beilstein J. Org. Chem. 2012, 8, 1134–1143, doi:10.3762/bjoc.8.126

• preparation of Lex analogues [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55], including one recent report of the synthesis of a Lex pentasaccharide 4-deoxy at the nonreducing end galactosyl residue [30]. These syntheses follow one of three strategies

Triterpenoid saponins from the roots of Acanthophyllum gypsophiloides Regel

• Elena A. Khatuntseva,
• Vladimir M. Men’shov,
• Alexander S. Shashkov,
• Yury E. Tsvetkov,
• Rodion N. Stepanenko,
• Raymonda Ya. Vlasenko,
• Elvira E. Shults,
• Genrikh A. Tolstikov,
• Tatjana G. Tolstikova,
• Dimitri S. Baev,
• Vasiliy A. Kaledin,
• Nelli A. Popova,
• Valeriy P. Nikolin,
• Pavel P. Laktionov,
• Anna V. Cherepanova,
• Tatiana V. Kulakovskaya,
• Ekaterina V. Kulakovskaya and
• Nikolay E. Nifantiev

Beilstein J. Org. Chem. 2012, 8, 763–775, doi:10.3762/bjoc.8.87

• similar sets of two oligosaccharide chains, which are 3-O-linked to the triterpenoid part trisaccharide α-L-Arap-(1→3)-[α-D-Galp-(1→2)]-β-D-GlcpA and pentasaccharide β-D-Xylp-(1→3)-β-D-Xylp-(1→3)-α-L-Rhap-(1→2)-[β-D-Quip-(1→4)]-β-D-Fucp connected through an ester linkage to C-28. The structures of the

• bidesmosidic nature of the genin, which is glycosydated at C-3 and esterified to an oligosaccharide. The structures of both the trisaccharide and pentasaccharide fragments of compound 2 are similar to those established for compound 1. Thus the structure of 2 was elucidated as gypsogenin 28-O-β-D-xylopyranosyl

Chemo-enzymatic modification of poly-N-acetyllactosamine (LacNAc) oligomers and N,N-diacetyllactosamine (LacDiNAc) based on galactose oxidase treatment

• Christiane E. Kupper,
• Ruben R. Rosencrantz,
• Birgit Henßen,
• Helena Pelantová,
• Stephan Thönes,
• Anna Drozdová,
• Vladimir Křen and
• Lothar Elling

Beilstein J. Org. Chem. 2012, 8, 712–725, doi:10.3762/bjoc.8.80

• biotinylated LacNAc 13a shown in A, or pentasaccharide (16b), respectively. Chemical conjugation of oxidised poly-LacNAc oligomers with heptasaccharide–linker–NH2 (17) by reductive amination. Beside the main products (18 and 19) several byproducts are formed. Conversion of poly-LacNAc oligomers 1a–d with

Synthesis of 6-PEtN-α-D-GalpNAc-(1–>6)-β-D-Galp-(1–>4)-β-D-GlcpNAc-(1–>3)-β-D-Galp-(1–>4)-β-D-Glcp, a Haemophilus influenzae lipopolysacharide structure, and biotin and protein conjugates thereof

• Andreas Sundgren,
• Martina Lahmann and
• Stefan Oscarson

Beilstein J. Org. Chem. 2010, 6, 704–708, doi:10.3762/bjoc.6.80

• carbohydrate surface antigens in glycoconjugate vaccines can be considered and investigated. One such suggested structure from Haemophilus influenzae LPS is the phosphorylated pentasaccharide 6-PEtN-α-D-GalpNAc-(1→6)-β-D-Galp-(1→4)-β-D-GlcpNAc-(1→3)-β-D-Galp-(1→4)-β-D-Glcp. Results: Starting from a spacer

• primary position of the non-reducing end residue afforded an acceptor to which the terminal α-galactosamine moiety was introduced using a 2-azido bromo sugar and halide assisted coupling conditions. Global deprotection afforded the non-phosphorylated target pentasaccharide, whereas removal of a silyl

• group from the primary position of the non-reducing end residue produced a free hydroxy group which was phosphorylated using H-phosphonate chemistry to yield the phosphoethanolamine-containing protected pentasaccharide. Partial deprotection afforded the phosphorylated target pentasaccharide with a free

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32

• cyclodextrin type structures in chiral discrimination is well documented [170][171][172][173]. In a recent example (Figure 21), Shizuma and Sawada demonstrated a high degree of chiral discrimination between amino acid ester salts with a permethylated fructooligosaccharide (pentasaccharide) by an induced

• -ring structure surrounding the ammonium ion was formed by the acyclic methylated pentasaccharide in the complexation. The chiral discrimination was ascribed to the steric effect of the fructofuranose rings of the pentasaccharide and the substituent of a given amino acid ester salt (complexation-induced

Chemical synthesis using enzymatically generated building units for construction of the human milk pentasaccharides sialyllacto-N-tetraose and sialyllacto-N-neotetraose epimer

• Dirk Schmidt and
• Joachim Thiem

Beilstein J. Org. Chem. 2010, 6, No. 18, doi:10.3762/bjoc.6.18

• by 6 catalyzed by N-iodosuccinimide and trifluoromethane sulfonic acid (as introduced by van Boom et al. [11]) gave the β,1-3-linked pentasaccharide 7 in 61% yield. About 5% of the corresponding α,1-3-linked compound and ca. 7% of the bis (β,1-3- and β,1-4-) linked octasaccharide were observed as

• give the β,1-4-linked pentasaccharide derivative 13 in 53% yield. In addition, the corresponding α,1-4-linked pentasaccharide was obtained in 8% yield. Finally, the azido group was reduced by the nickel boride method with sodium borohydride, nickel chloride and boric acid [12][13]. During this step

• partial cleavage of the tert-butyldiphenylsilyl groups was also observed. Complete removal was achieved with trifluoroacetic acid in dichloromethane. For characterization purposes, peracetylation was carried out to give the completely protected pentasaccharide 14 in 67% yield (Scheme 2). As evident from a