BCHS 3304 Lecture Notes - Lecture 22: Anomer, Deoxy Sugar, Furanose
17 Nov 2016
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Beta d glucose is most important sugar. Monosaccharides are aldehyde or ketone derivatives of straight chain polyhydroxyl alcohols with at least 3 c: basic formula is (ch2o)n. The n should be at least 3. Up to n=6 (hexose: aldose= carbonyl c is an aldehyde. To find the number of stereoisomers do 2n-2. Number of chiral centers= c-2: ketose= carbonyl c is a ketone. Ketohexose: epimers= sugar molecules that differ stereochemically at one carbon atom. D glucose, d mannose are epimers because they differ at carbon number 2. D glucose, d galactose are epimers about carbon number 4: d- sugars have same stereochemical configuration at asymmetric center farthest from carbonyl. Look at the chiral center furthest from the carbonyl carbon: to find the number of stereoisomers do 2n-2, number of chiral centers= c-2. Alcohols react with aldehydes and ketones hemiacetal and hemiketal: can occur intramolecularly, makes it into a tetrahedral carbon. Cyclization: pyranose= 6 membered ring form of a sugar.
