Question

Two aldopentoses $A$ and $B$ give the same osazone derivative. $A$ is oxidised to an optically active aldoric acid by dilute nitric acid. Ruff degradation of $B$ gave a tetrose which was similarly oxidised to an optically active aldaric acid. Assign the structure of $A$ and $B$ from the following list.

• A. A = I, B = IV
• B. A = IV, B = I
• C. A = III, B = II
• D. A = II, B = III

Answer 1

Answer: (C)

$A$ and $B$ have same osazone derivative, it means configuration at $C-3$ and $C-4$ is the same.