page_title: Glucan
section_title: Structure
hierarchical_section_title: Glucan / Structure
caption_attribution_description: English: chemical structure unprotected poly(2,3)glucose
context_page_description: A glucan is a polysaccharide derived from D-glucose, linked by glycosidic bonds. Many beta-glucans are medically important. They represent a drug target for antifungal medications of the echinocandin class.
context_section_description: Glucans are polysaccharides derived from glucose monomers.  The monomers are linked by glycosidic bonds. Four types of glucose-based polysaccharides are possible: 1,6- (starch), 1,4- (cellulose), 1,3- (laminarin), and 1,2-bonded glucans.
  The first representatives of main chain unhydrolysable linear polymers made up of levoglucosan units were synthesized in 1985 by anionic polymerization of 2,3-epoxy derivatives of levoglucosan (1,6;2,3-dianhydro-4-O-alkyl-β-D-mannopyranoses).
  A wide range of unique monomers with different radical R can be synthesized. There were synthesized polymers with R= -CH₃, -CH₂CHCH₂, and -CH₂C₆H₅. Investigation of the polymerization kinetics of those derivatives, molecular weight and  molecular-weight distribution showed that the polymerization has the features of a living polymerization system. The process takes place without termination and transfer of the polymer chain with a degree of polymerization equal to the mole ratio of the monomer to the initiator. Accordingly, the upper value molecular weight polymer determines only degree of purification system what determine the presence in the system uncontrollable amount of terminators of polymer chains.
  Poly(2-3)-D-glucose was synthesized proceeds by transformation of benzyl (R= -CH₂C₆H₅) functionalized polymer.
  Polymerization of 3,4-epoxy levoglucosan (1,6;3,4-dianhydro-2-O-alkyl-β-D-galactopyranose)  results in formation 3,4-bounded levoglucosan polymer.
  The presence of 1,6-anhydro structure in every unit of polymer chains allows researchers to apply all spectra of well developed methods of carbohydrate chemistry with formation of highly intriguing biological application polymers.
  The polymers are the only known regular polyethers built up of carbohydrate units in main polymer chain.
caption: Polyglucose
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