What types of sugars can undergo mutarotation?
Submitted by Shruti6476109
Its like I'm having difficulty in identifying which compounds will show mutarotaion and which won't. Which compounds will show mutarotation in various solvents? Eg- Which of these show mutarotation? --> D-Glucose, L-Glucose, Sucrose, all. Eg Which of these will show mutaroation in aq. solution? --> Glycogen, Cellulose, Sucrose, Maltose
Replies
Submitted by Matt
Mutarotation is occurs when the hydroxyl group at the anomeric position (C-1) switches configuration between alpha and beta. This happens because in solution a carbohydrate can "open up" to its aldehyde form. When it reforms the closed ring (which is a hemiacetal), the anomeric hydroxyl can lose its original stereochemistry (alpha and beta get "scrambled.")
For this to happen, a carbohydrate must be a hemiacetal or hemiketal.
Glucose (hemiacetal) and fructose (hemiketal) can undergo mutarotation.
But sucrose and cellulose cannot- they are not hemiacetals (or hemiketals). They do not have an OH at the anomeric position.
