Chapter 26.8, Problem 19P

Interpretation Introduction

(a)

Interpretation: The products formed by the treatment of $\text{β}$-D-galactose with ${\text{Ag}}_{\text{2}}\text{O}$, ${\text{CH}}_3\text{I}$ are to be drawn.

Concept introduction: The $\text{OH}$ groups of monosaccharides on reaction with base and an alkyl halide convert into ether. A single product is formed during this reaction because the configuration of all substituents in the starting material is retained.

Interpretation Introduction

(b)

Interpretation: The products formed by the treatment of $\text{β}$-D-galactose with $\text{NaH}+{\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{CH}}_{\text{2}}\text{Cl}$ are to be drawn.

Concept introduction: The $\text{OH}$ groups of monosaccharides on reaction with base and an alkyl halide convert into ether. A single product is formed during this reaction because the configuration of all substituents in the starting material is retained.

Interpretation Introduction

(c)

Interpretation: The products formed by the treatment of $\text{β}$-D-galactose with $\text{NaH}+{\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{CH}}_{\text{2}}\text{Cl}$ and then ${\text{H}}_3{\text{O}}^{+}$ are to be drawn.

Concept introduction: The characteristic bond of glycoside is $-\text{O}-$. A hemiacetal converts into acetal when a monosaccharide is treated with alcohol and $\text{HCl}$. The acetal formed is known as glycoside. The hydrolysis of glycoside generates two compounds that have $\text{OH}$ group.

Interpretation Introduction

(d)

Interpretation: The products formed by the treatment of $\text{β}$-D-galactose with ${\text{Ac}}_{\text{2}}\text{O}+\text{pyridine}$ are to be drawn.

Concept introduction: The $\text{OH}$ groups of monosaccharides on reaction with anhydride and acetyl chloride convert into ether in the presence of base. A single product is formed during this reaction because the configuration of all substituents in the starting material is retained.

Interpretation Introduction

(e)

Interpretation: The products formed by the treatment of D- galactose with ${\text{C}}_6{\text{H}}_5\text{COCl}+\text{pyridine}$ are to be drawn.

Concept introduction: The $\text{OH}$ groups of monosaccharides on reaction with anhydride and acetyl chloride convert into ether in the presence of base. A single product is formed during this reaction because the configuration of all substituents in the starting material is retained.

Interpretation Introduction

(f)

Interpretation: The products formed by the treatment of $\text{β}$-D-galactose with $\text{NaH}+{\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{CH}}_{\text{2}}\text{Cl}+{\text{H}}_3{\text{O}}^{+}$ and then ${\text{C}}_6{\text{H}}_5\text{COCl}+\text{pyridine}$ are to be drawn.

Concept introduction: The $\text{OH}$ groups of monosaccharides on reaction with anhydride and acetyl chloride convert into ether in the presence of base. A single product is formed during this reaction because the configuration of all substituents in the starting material is retained.