Shift of the reaction equilibrium at high pressure in the continuous synthesis of neuraminic acid

• Jannis A. Reich,
• Miriam Aßmann,
• Kristin Hölting,
• Paul Bubenheim,
• Jürgen Kuballa and
• Andreas Liese

Beilstein J. Org. Chem. 2022, 18, 567–579, doi:10.3762/bjoc.18.59

• for the aldolase from 108 to 42 mM and 91 to 37 mM, respectively. Keywords: aldolase; continuous fixed-bed reactor; enzyme; epimerase; GlcNAc; high pressure; immobilization; ManNAc; Neu5Ac; pyruvate; Introduction In times of a pandemic, the importance of substances to enhance the human immune system

• N-acetyl-ᴅ-mannosamine The quantification of ManNAc for the epimerase activity was realized with an enzymatic quantification assay as described in Klermund et al. using N-acylmannosamine 1-dehydrogenase (ManDH, EC. 1.1.1.233) [36]. The assay was performed in 100 mM Tris-HCl pH 8 containing up to 0.2

• mM ManNAc, 2 mM NAD, and 0.05 mL ManDH solution with 3 kU/mL. After starting the reaction, the mixture was incubated at room temperature for 30 minutes. The resulting NADH concentration was measured with an Eppendorf spectrophotometer at 340 nm. High-pressure set-up An HPLC pump (Nexera X2 LC-30AD

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

•  1). The final frame shift 9A and 9V pentasaccharides were compared to the natural reported repeating unit of the CPS. The C6 acetylation of ManNAc was confirmed by comparison of the NMR spectra between the acetylated (9V, compound 5) and deacetylated (9A compound 4) synthetic single RU. This data

• was further confirmed by the work of Moon Nahm et. al that showed the NMR of natural 9V matching with respect to ManNAc C6 acetylation (the observed chemical shift for the methylene H6 were 4.47 and 4.28 ppm, respectively, and for methyl at 2.17 ppm). The 1H NMR and HSQC spectra of 5 show the presence

Cyclopropene derivatives of aminosugars for metabolic glycoengineering

• Jessica Hassenrück and
• Valentin Wittmann

Beilstein J. Org. Chem. 2019, 15, 584–601, doi:10.3762/bjoc.15.54

• of the staining intensity on the cell surface. Are Ac4GlcNCyoc and Ac4GlcNCp converted into sialic acids during MGE? It is well established that carbohydrate derivatives can be interconverted into each other by epimerases. For example, both GlcNAc and UDP-GlcNAc can be converted to ManNAc [37][38

Synthesis and in vitro cytotoxicity of acetylated 3-fluoro, 4-fluoro and 3,4-difluoro analogs of D-glucosamine and D-galactosamine

• Štěpán Horník,
• Lucie Červenková Šťastná,
• Petra Cuřínová,
• Jan Sýkora,
• Kateřina Káňová,
• Roman Hrstka,
• Ivana Císařová,
• Martin Dračínský and
• Jindřich Karban

Beilstein J. Org. Chem. 2016, 12, 750–759, doi:10.3762/bjoc.12.75

• obtained in only 40% yield after chromatography and recrystallization. Cytotoxicity Some acetylated fluorinated hexosamines (HexN), including peracetates of the α-methyl glycoside of 3-fluoro-D-ManNAc [18], 3-fluoro-D-GlcNAc 5 [18], 4-fluoro-D-GlcNAc 1 [19], 4-fluoro-D-GalNAc 4 [19], 4,4-difluoro-D-xylo

Expanding the scope of cyclopropene reporters for the detection of metabolically engineered glycoproteins by Diels–Alder reactions

• Anne-Katrin Späte,
• Verena F. Schart,
• Julia Häfner,
• Andrea Niederwieser,
• Thomas U. Mayer and
• Valentin Wittmann

Beilstein J. Org. Chem. 2014, 10, 2235–2242, doi:10.3762/bjoc.10.232

• are small enough to be accepted by cellular enzymes during MOE [22][23][24]. Also, they are stable in aqueous solution in the presence of biological nucleophiles [22][28]. Consequently, cyclopropene tags were attached by an amide linkage to sialic acid [22] and ManNAc derivatives including Ac4ManNCyc

• metabolically engineered cell-surface sialic acids [24]. The application of 3 was prompted by the previous observation that carbamate-modified ManNAc derivatives are also accepted in the biosynthetic pathway [19][29]. Derivative 3 in combination with a sulfo-Cy3-tetrazine conjugate enabled dual sugar labeling

Facile synthesis of nitrophenyl 2-acetamido-2-deoxy-α-D-mannopyranosides from ManNAc-oxazoline

• Karel Křenek,
• Petr Šimon,
• Lenka Weignerová,
• Barbora Fliedrová,
• Marek Kuzma and
• Vladimír Křen

Beilstein J. Org. Chem. 2012, 8, 428–432, doi:10.3762/bjoc.8.48

• , Czech Republic 10.3762/bjoc.8.48 Abstract The synthetic procedures for a large-scale preparation of o- and p-nitrophenyl 2-acetamido-2-deoxy-α-D-mannopyranoside are described. The synthetic pathway employs the glycosylation of phenol with ManNAc oxazoline, followed by nitration of the aromatic moiety

• yielding a separable mixture of the o- and p-nitrophenyl derivative in a 2:3 ratio. Keywords: α-ManNAc; glycosidase; glycosylation; nitrophenyl; oxazoline; Introduction Hexosamines are fundamental structural elements and precursors of the peptidoglycan and membrane lipopolysaccharide layer as well as of

• capsular polysaccharides in Gram-negative bacteria. N-Acetyl-D-mannosamine (ManNAc) has been found to be, presumably, the strongest monosaccharidic ligand for the natural killer cells (NK-cells) activating protein NKR-P1 [1], and some ManNAc-containing oligosaccharides (e.g., GlcpNAc-β-(1→4)ManpNAc) have

Bioorthogonal metabolic glycoengineering of human larynx carcinoma (HEp-2) cells targeting sialic acid

• Arne Homann,
• Riaz-ul Qamar,
• Sevnur Serim,
• Petra Dersch and
• Jürgen Seibel

Beilstein J. Org. Chem. 2010, 6, No. 24, doi:10.3762/bjoc.6.24

• effects is known [11]. Recently, the regulation of UDP-GlcNAc 2-epimerase/ManNAc kinase expression on the transcriptional level by DNA methylation was demonstrated [12] and a genetic feedback regulation for this process was proposed (Scheme 3) [13]. Ac4GlcNAz 16 or Neu5Hex 3, respectively, were incubated