3-Mercaptopropanol as a Traceless Linker for Chemical and Enzymatic Synthesis of Oligosaccharides

Abstract

The reducing end of protected carbohydrates can be equipped with a series of aglycones via the photochemical installation of a 3-mercaptoethanol linker. This linker is stable during chemical and enzymatic glycosylation reactions but can be activated readily and efficiently to couple oligosaccharides with different nucleophiles. This approach provides straightforward access to a range of molecules that serve as probes for carbohydrate modifying enzymes. [reaction: see text].

Design of α-S-Neoglycopeptides Derived from MUC1 with a Flexible and Solvent-Exposed Sugar Moiety

“…In this way, building blocks 10-Ser / Cys / Thr were obtained in a 53%, 30%, and 62%, respectively (Scheme ). It is well known that this type of reaction involving O - or S -allyl derivatives works with moderate to low yields . We also tested a recent method with 9-Ser / Cys / Thr , involving the use of BEt 3 as an initiator and catechol as a coreagent .…”

Redox Mediators in Visible Light Photocatalysis: Photocatalytic Radical Thiol–Ene Additions

“…To a 1.5 dram vial was added 171.2 mg (0.602 mmol) allyl biotin, 35 76.6 mg glutathione (0.250 mmol), 0.4 mg (0.462 μ mol) Ru(bpz) 3 (PF 6 ) 2 , 13.4 mg (0.125 mmol) p -toluidine and 1.25 mL Millipore water. The vial was sealed with a Teflon cap and irradiated with blue LEDs for 2 h. Over the course of the reaction a white solid crashed out of solution.…”

“…4,138.3,136.4,128.8,128.5,127.3,127.0,122.2,122.0,119.49,118.7,112.9,111.2,63.3,41.1,36.2,28.7,27.6,25.7;HRMS (ESI) ((3-((4-((4S)-2-oxohexahydro-1H-thieno[3,4-d]imidazol-4-yl)butanoyl)oxy)propyl)thio)propan-2-yl)amino)-5-oxopentanoic Acid (Table 4, Entry 4). To a 1.5 dram vial were added 171.2 mg (0.602 mmol) allyl biotin, 35 76.6 mg glutathione (0.250 mmol), 0.4 mg (0.462 μmol) Ru(bpz) 3 (PF 6 ) 2 , 13.4 mg (0.125 mmol) p-toluidine, and 1.25 mL Millipore water. The vial was sealed with a Teflon cap and irradiated with blue LEDs for 2 h. Over the course of the reaction a white solid crashed out of solution.…”

Continuous Flow Photochemistry

“…Thiol‐ene coupling (TEC) is a well‐established method of intra‐ and intermolecular coupling that proceeds via anti‐Markovnikov addition of a thiyl radical generated either thermally or photolytically. Building on our previous work in batch, we turned to this mode of coupling as an orthogonal method of both adorning preformed precision polymers as well as prefunctionalized monomer building blocks (Figure ). As TEC proceeds more rapidly at 254 nm than 366 nm, and standard fluorinated ethylene polymer (FEP) tubing decomposes at high UV, we envisioned a Birr/Booker‐Milburn design using Teflon AF‐2400 tubing surrounding a water‐jacketed In/Hg lamp.…”