How many statements are correct? D-glucose, on treating with methanol in presence of dry HCl gives methyl glucosides according to the following reaction. (i) The glucosides do not reduce fehling'

Question

How many statements are correct?

D-glucose, on treating with methanol in presence of dry HCl gives methyl glucosides according to the following reaction.

(i) The glucosides do not reduce fehling's solution

(ii) The glucosides do not react with hydrogen cyanide or hydroxylamine

(iii) Behaviour of glucosides as stated in $S_{1}$ and $S_{2}$ indicates the absence of free- CHO group.

(iv) The two forms of glucosides are enantiomers.

TestHub · Accepted Answer

Step-1: Reaction of D-glucose with methanol in presence of dry $HC ℓ$

D-glucose reacts with methanol under acidic conditions to form methyl $α$ -D-glucoside and methyl $β$ -D- glucoside. This involves the conversion of the hemiacetal (anomeric OH ) to an acetal (glucoside), locking the configuration at $C - 1$ and removing the free aldehyde functionality.

Step-2: Analyse the statements

1. Glucosides do not reduce Fehling's solution - Correct. No free aldehyde group is present.

2. Glucosides do not react with HCN or hydroxylamine - Correct. These reagents target free -CHO groups.

3. Their behaviour indicates the absence of a free - CHO group - Correct. matches statements 1 and 2

4. The two forms of glucosides are enantiomers - Incorrect. α - and β- methyl D-glucosides are diastereomers , not mirror images.

Step-3: Count of correct statements

* (i), (ii), (iii) are correct.

* (iv) is incorrect.

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