Thu December 22, 2011 By: Shubham Dixit

ketones donot respond to fehling test, but why does fructose, inspite of being a ketose respond to the reaction?

Expert Reply
Fri December 23, 2011

D-Fructose rearranges to D-glucose in alkaline medium .this rearrangement is known as Lobry de Bruyn-Van Ekenstein rearrangement.

It is probably due to this isomerisation that fructose reduces fehling's solution in alkaline medium although it does not contain a -CHO group.
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