Ethyl 2-O-benzoyl-3,6-di-O-methyl-4-O-(9-fluorenylmethoxycarbonyl)-1-thio- β-D glucopyranoside

Ethyl 2-O-benzoyl-3,6-di-O-methyl-4-O-(9-fluorenylmethoxycarbonyl)-1-thio-β-D-glucopyranoside Ethyl 2-O-benzoyl-3,6-di-O-methyl-4-O-(9-fluorenylmethoxycarbonyl)-1-thio-β-D-glucopyranoside is a strategically protected thioglycoside designed for controlled glycosylation in carbohydrate synthesis. Its architecture integrates orthogonal protecting groups to enable sequential deprotection and stereoselective coupling. Structural Features Core Scaffold : β-D-glucopyranoside with an ethylthio (–SEt) group at the anomeric (C1) position, acting as a thioglycosyl donor activated by thiophilic promoters (e.g., NIS/AgOTf). Protecting Groups : C2 : Benzoyl ester (–OBez) Participates via neighboring group participation (NGP) to enforce β-selectivity during glycosylation. Removable under basic (e.g., NaOMe/MeOH) or acidic conditions. C3/C6 : Methyl ethers (–OMe) Non-participating, electron-donating groups that stabilize the glycosyl intermediate and resist common deprotection conditions (e.g., acid/base). C4 : 9-Fluorenylmethoxycarbonyl (Fmoc) Base-labile (e.g., piperidine/DMF), enabling selective removal in solid-phase synthesis workflows. Synthetic Utility Orthogonal Deprotection : Step 1 : Fmoc cleavage (base) → exposes C4-OH for glycosylation. Step 2 : Benzoyl removal (base/acid) → unmask C2-OH for further coupling. Step 3 : Methyl groups remain intact until final global deprotection (e.g., strong acid). Reactivity Control : Benzoyl at C2 ensures β-selectivity via NGP, while methyl ethers simplify regiochemical control by limiting undesired side reactions. Characterization NMR : 1H^1 ext{H} 1H NMR shows distinct signals for Fmoc aromatic protons (7.1–7.8 ppm) and benzoyl carbonyl (~167 ppm in 13C^13 ext{C} 13C NMR). Methyl groups appear as singlets (~3.3–3.5 ppm). MS : ESI-MS confirms molecular weight (expected [M+Na]⁺ ~650–700 Da). Applications Oligosaccharide Synthesis : Ideal for constructing linear or branched glycans requiring sequential glycosylation steps. Solid-Phase Platforms : Fmoc compatibility supports automated glycan assembly for therapeutic glycoconjugates Stability : Methyl ethers enhance stability during prolonged synthetic sequences compared to acid-labile groups. This compound exemplifies the synergy of orthogonal protection (Fmoc, benzoyl, methyl) and stereochemical control, making it a versatile tool in synthetic carbohydrate chemistry. Citations: https://patents.google.com/patent/WO2000042057A1/en https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2023.1332837/full https://pubmed.ncbi.nlm.nih.gov/31895493/ https://pmc.ncbi.nlm.nih.gov/articles/PMC10808579/ https://europepmc.org/article/pmc/6531329 https://pubs.rsc.org/en/content/getauthorversionpdf/c9ob00573k https://pmc.ncbi.nlm.nih.gov/articles/PMC6259426/ https://pmc.ncbi.nlm.nih.gov/articles/PMC2952681/