Chapter 21, Problem 21.90P

Interpretation Introduction

(a)

Interpretation: The acetal and hemiacetal carbons for maltose are to be labeled.

Concept introduction: Acetals contain two alkoxy groups on a single carbon atom, whereas Hemiacetals contains one alkoxy group and one hydroxyl group attached to same carbon atom.

Interpretation Introduction

(b)

Interpretation: The products formed when maltose reacts with [1] ${\text{H}}_{\text{3}}{\text{O}}^{+}$; [2] ${\text{CH}}_{\text{3}}\text{OH}$ and $\text{HCl}$; [3] excess $\text{NaH}$, excess ${\text{CH}}_{\text{3}}\text{I}$ is to be

Concept introduction: Glycosidic linkages are hydrolyzed in presence of acid to form cyclic hemiacetal and corresponding alcohol. Acetals in the presence of acid undergo hydrolysis to form cyclic hemiacetals.

Interpretation Introduction

(c)

Interpretation: The products formed when the compound formed in the third reaction of part (b) is treated with aqueous acid are to be drawn.

Concept introduction: