Question

Write the reaction of D-Glucose with the following:
(a) HCN (b) Br$_2$ water (c) (CH$_3$CO)$_2$O

Hint:

HCN: adds to C=O; Br$_2$: oxidises; Acetic anhydride: esterifies.

Answer 1

(a) D-Glucose + HCN → Cyanohydrin formation.
CHO + HCN → CH(OH)CN (adds at aldehyde C).
(b) Br$_2$ water oxidises aldehyde group to –COOH → gluconic acid.
CHO → COOH.
(c) (CH$_3$CO)$_2$O with pyridine acetylates all OH groups → pentaacetate is formed.