Biomolecules Question 189
Question: In osazone formation, glucose reacts with three molecules of phenylhydrazine. Which statement is true regarding this-
Options:
A) All the three molecules react in similar fashion
B) Two molecules react in similar manner, while the third reacts in different way
C) All the three molecules react in different ways
D) None of the above is true
Show Answer
Answer:
Correct Answer: B
Solution:
[b] First molecule of phenylhydrazine unedrgoes nucleophilic addition on carbonyl ( $ -CHO $ in glucose and $ >CO $ in fructose) group.
Second molecule of the reagent oxidizes $ -CHOH- $ at position 2(in aldoses) or $ -CH_2OH $ at position 1 (in ketoses) to form $ -CHO $ or $ >C=O $ respectively.
The third molecule again undergoes nucleophilic addition on the newly developed carbonyl group to form osazone.
BETA
