[mehdi71000]

hi every body
i wanted to know whats the diffrese between anhydro-ß-d-glucopyranose and ß-d-glucopyranose ? do you have a picture of there molucule structures?

is there a way to change anhydro-ß-d-glucopyranose to ß-d-glucopyranose ?
or is there a place to uptain ß-d-glucopyranose?
thanks

[Yggdrasil]

anhydro-ß-d-glucopyranose and anhydro-ß-d-glucopyranose ?

I fail to see any difference in the names at all.

[mehdi71000]

sorry i'll edit

[Yggdrasil]

Many solids absorb moisture from the air and form complexes with water.  Often times, the occurs with salts, since the cations will from stable complexes with water and because solvation of the ions is thermodynamically favorable.  This also occurs in other compounds, such as sugars.  Since glucose has so many OH groups, it will also interact favorably with water and can pull moisture out of the air (the clumps you see in your sugar bowl are a result of this process, since the water can help stick sucrose crystals together).  So, when stored in a regular environment, solid glucose will be associated with some amount of water.  However, if this solid glucose is specially prepared (e.g. baked to remove the water) and stored in a moisture-free environment, then the glucose will not be associated with any water and can be called anhydrous glucose.  Chemically, the glucose in hydrated glucose and anhydrous glucose are identical.  However, when weighing out samples of your solid, you do have to make note of whether the compound is hydrated or anhydrous since you need to account for the weight of the associated water.

[mehdi71000]

thanks that was very good
so if i add water to anhydro-ß-d-glucopyranose it will become ß-d-glucopyranose?
 

[Yggdrasil]

Yes.

[mehdi71000]

thanks
1 more thing can i remove the hydrogens in ß-d-glucopyranose with out removing the oxigens? i assume it will become unstable. if so would the oxigens wich had an origenal bond with carbons and hydrogens would bond with other e oxigens or the carbons in the next molucule?
 

[Yggdrasil]

Some hydrogens can be selectively removed by oxidation.  For example, aldoses like glucose can be oxidized to aldonic acids, removing the aldehyde hydrogen (i.e. the hydrogen on the anomeric carbon).  A common reagent used to perform this reaction is Tollens' solution.  The hydrogens on carbon six of glucose can be removed by enzyme catalyzed oxidation to form an glucuronic acid.  Presumably other hydrogens in glucose can be removed by oxidation, but I don't know these reactions off of the top of my head and there are probably problems with the selectivity of these oxidations.

For more information, most college-level organic chemistry books should have a section on carbohydrate chemistry which you can read.

[mehdi71000]

thank so much great stuff
right any sugesstions guys