Glycosan Type

Systematic name Alternative name M.p.. °C. E ]d Rotation solvent Refer- ences 

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VI. Anhydro Sugars of the Glycosan Type 1. Preparative Methods for 1,6-Anhydro Hexoses... 

An outline of the evidence on which the constitution of levoglucosan is based has been given in Section I. Hudson and coworkers have more recently employed the powerful weapon of attack elaborated by them, namely oxidation with per-iodic acid, to establish on the firmest basis the type of ring structures present in the glycosans.7 71> 8 64... 

Anhydro derivatives may be considered to be of two general types (1) glycosans (inner glycosides, IV) for which water is split out between an anomeric hydroxyl group and a primary or secondary alcohol group, (2) anhydrides (ethers, XI), treated under Ethers in a subsequent chapter, which may be considered to be derived by the removal of water between hydroxyl groups, neither of which is on the reducing carbon. 

Besides the 1,2-anhydro-sugars of the internal glycoside type, 1,6-anhydrides known as glycosans (CCXV, CCXVI) are formed on alkaline hydrolysis of phenyl / -glycosides (CCXIV) or by heating polysaccharides... 

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