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Cyclohexane-1,2,3,4,5,6-hexol is a family of chemical compounds with formula C 6 H 12 O 6, whose molecule consists of a ring of six carbon atoms, each bound to one hydrogen atom and one hydroxyl group (–OH). There are nine stereoisomers, that differ by the position of the hydroxyl groups relative to the mean plane of the ring.
The aldohexose that is most important in biochemistry is D-glucose, which is the main "fuel" for metabolism in many living organisms. The 2-ketohexoses psicose, fructose and tagatose occur naturally as the D-isomers, whereas sorbose occurs naturally as the L-isomer. D-Sorbose is commonly used in the commercial synthesis of ascorbic acid. [10]
Like the d-isomer, l-glucose usually occurs as one of four cyclic structural isomers—α- and β-l-glucopyranose (the most common, with a six-atom ring), and α- and β-l-glucofuranose (with a five-atom ring). In water solution, these isomers interconvert in matters of hours, with the open-chain form as an intermediate stage.
For example, there are 16 distinct aldohexose stereoisomers, but the name "glucose" means a specific pair of mirror-image aldohexoses. In the Fischer projection, one of the two glucose isomers has the hydroxyl at left on C3, and at right on C4 and C5; while the other isomer has the reversed pattern.
Two isomers whose molecules are mirror-images of each other are identified by prefixes ' D-' or ' L-', according to the handedness of the chiral carbon atom that is farthest from the carbonyl. In the Fischer projection, that is the second carbon from the bottom; the prefix is ' D -' or ' L -' according to whether the hydroxyl on that carbon ...
Glucose is a sugar with the molecular formula C 6 H 12 O 6, which is often abbreviated as Glu.It is overall the most abundant monosaccharide, [4] a subcategory of carbohydrates.It is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using energy from sunlight.
It is highly soluble in water, slightly soluble in glacial acetic acid, ethanol, glycol, and glycerin, but insoluble in chloroform and ether. [3] In its most stable conformation, the myo-inositol isomer assumes the chair conformation, which moves the maximum number of hydroxyls to the equatorial position, where they are farthest apart from each ...
For example, in α-D-glucopyranose the reference atom is C-5. If in the cyclic Fischer projection [3] the exocyclic oxygen atom at the anomeric centre is cis (on the same side) to the exocyclic oxygen attached to the anomeric reference atom (in the OH group) the anomer is α. If the two oxygens are trans (on different sides) the anomer is β.