N-Glycosides of indigo, indirubin, and isoindigo: blue, red, and yellow sugars and their cancerostatic activity

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2840–2869, doi:10.3762/bjoc.20.240

• material in Europe (Scheme 1). It is obtained by extraction and isolation of the colorless indole-O-glycoside indicane which is then hydrolyzed to give indoxyl. The latter undergoes oxidative dimerization to provide indigo. In the 19th century, syntheses of indigo were developed which made the pigment

Photoswitchable glycoligands targeting Pseudomonas aeruginosa LecA

• Yu Fan,
• Ahmed El Rhaz,
• Stéphane Maisonneuve,
• Emilie Gillon,
• Maha Fatthalla,
• Franck Le Bideau,
• Guillaume Laurent,
• Samir Messaoudi,
• Anne Imberty and
• Juan Xie

Beilstein J. Org. Chem. 2024, 20, 1486–1496, doi:10.3762/bjoc.20.132

• -isomer is twice better than for its Z-counterpart for the S-linked compound 3 and three times better for the O-glycoside 1. Even though the other compounds do not exhibit significant variations of affinities between E- and Z-isomers, a closer look at the thermodynamic values indicates that the mechanisms

Electron-deficient pyridinium salts/thiourea cooperative catalyzed O-glycosylation via activation of O-glycosyl trichloroacetimidate donors

• Mukta Shaw,
• Yogesh Kumar,
• Rima Thakur and
• Amit Kumar

Beilstein J. Org. Chem. 2017, 13, 2385–2395, doi:10.3762/bjoc.13.236

• , the optimized method is also utilized for the regioselective O-glycosylation by using a partially protected acceptor. Keywords: cooperative catalysis; electron-deficient pyridinium salts; O-glycoside; regioselectivity; thiourea; Introduction The glycosidic linkage is the principal bond present in a

• with phosphorus acids) for stereoselective O-glycoside bond formation [30]. Similarly, Galan et al. reported a method for the preparation of 2-deoxyglycosides from glycals under the influence of cooperative catalysis (chiral phosphoric acids/thiourea derivatives) [31]. Encouraged by these reports and

• acceptor 2a in 1:1.1 molar ratio with 10 mol % of 3a in dry DCM at room temperature, the desired O-glycoside 5a was isolated in 56% yield and with poor selectivity (Table 1, entry 2). The use of 25 mol % of 3a was required to drive the reaction to completion with 86% yield (Table 1, entry 3). This result

O-Alkylated heavy atom carbohydrate probes for protein X-ray crystallography: Studies towards the synthesis of methyl 2-O-methyl-L-selenofucopyranoside

• Roman Sommer,
• Dirk Hauck,
• Annabelle Varrot,
• Anne Imberty,
• Markus Künzler and
• Alexander Titz

Beilstein J. Org. Chem. 2016, 12, 2828–2833, doi:10.3762/bjoc.12.282

• ) and ≈2 ppm (13C NMR). To prevent acidic degradation, 6 was treated with palladium on charcoal under a hydrogen atmosphere (Table 1, entries 3–5). In MeOH as the solvent, transglycosylation of the seleno glycoside 6 to its methyl O-glycoside was observed (Table 1, entry 3). Changing the solvent to the

Natural phenolic metabolites with anti-angiogenic properties – a review from the chemical point of view

• Qiu Sun,
• Jörg Heilmann and
• Burkhard König

Beilstein J. Org. Chem. 2015, 11, 249–264, doi:10.3762/bjoc.11.28

• xanthohumol intake [77]. To date, xanthohumol in vivo metabolites have not been investigated regarding their anti-angiogenic activity. Genistein Genistein (60) is an isoflavone extracted from soybeans (Glycine max (L.) MERR, Fabaceae). It is present as the 7-O-glycoside genistein in the plant; however, during

Synthesis and structure of tricarbonyl(η⁶-arene)chromium complexes of phenyl and benzyl D-glycopyranosides

• Thomas Ziegler and
• Ulrich Heber

Beilstein J. Org. Chem. 2012, 8, 1059–1070, doi:10.3762/bjoc.8.118

• reacting acetobromoglucose with 6-tert-butyl-2-hydroxypyridine [20] under Helferich conditions (Hg(CN)2). Only the corresponding O-glycoside 1l was obtained, and no N-glycoside was formed in this Helferich glycosylation (Scheme 1). Sterically hindered 6-tert-butyl-2-hydroxypyridine was chosen as the