Question

Write the reactions of glucose with
(a) HI
(b)\((CH_3CO_2)O\)

Hint:

Glucose can undergo reduction and acetylation reactions. Reduction with HI removes oxygen functionality, yielding \( n \)-hexane. Acetic anhydride reacts with all hydroxyl (-OH) groups, forming pentaacetate derivatives.

Answer 1

Step 1: Reaction of glucose with HI Glucose undergoes complete reduction when treated with hydroiodic acid (HI) in the presence of heat. This reaction removes all oxygen functionality from glucose, converting it into \( n \)-hexane. The reaction is as follows: \[ \text{CHO} - (\text{CHOH})_4 - \text{CH}_2\text{OH} \xrightarrow{\text{HI}, \Delta} \text{CH}_3 - \text{CH}_2 - \text{CH}_2 - \text{CH}_2 - \text{CH}_3 \] Step 2: Reaction of glucose with Acetic Anhydride When glucose is treated with acetic anhydride \((CH_3CO)_2O\), all the hydroxyl groups (-OH) get acetylated, leading to the formation of glucose pentaacetate. This reaction is shown below: