Question

What happens when glucose is treated with Hydrogen cyanite (HCN).

Write the reaction involved when D-glucose is treated with the following reagent: 

HCN

Answer 1

Glucose reacts with hydroxylamine to form an oxime and also adds a molecule of hydrogen cyanide to give cyanohydrin. The carbonyl group is present in the open-chain structure of glucose.

\[\begin{array}{cc}
\phantom{......................}\ce{CN}\\
\phantom{.......................}|\phantom{...}\\
\phantom{....}\ce{CHO}\phantom{................}\ce{CHOH}\phantom{}\\
|\phantom{.......................}|\phantom{...}\\
\phantom{.......}\ce{(CHOH)4->[HCN](CHOH)4}\\
|\phantom{........................}|\phantom{...}\\
\phantom{..............}\ce{\underset{D-glucose}{CH2OH}}\phantom{.......}\ce{\underset{Glucose cyanohydrin}{CH2OH}}\phantom{...}
\end{array}\]