Chapter 21, Problem 21.59P

What reagents are needed to convert each compound to benzaldehyde $\left({\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CHO}\right)$? More than one step may be required.

a. ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{CH}}_{\text{2}}\text{OH}$ e. ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{CH}}_3$

b. ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{COCl}$ f. ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CH}={\text{CH}}_2$

c. ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{COOCH}}_3$ g. ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CH}={\text{NCH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}$

d. ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{COOH}$ h. ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CH}{\left({\text{OCH}}_{\text{2}}{\text{CH}}_{\text{3}}\right)}_2$

Interpretation Introduction

(a)

Interpretation: The reagents needed to convert the given compound to benzaldehyde are to be predicted.

Concept introduction: The full form of PCC is pyridinium chlorochromate. It acts as mild oxidizing agent. It oxidizes primary alcohols into aldehyde and secondary alcohol into ketones. Benzaldehyde is an aromatic aldehyde with many commercial uses. Benzaldehyde has a characteristic almond like smell; therefore, it is used as a food additive.

Answer to Problem 21.59P

The reagent needed to convert given compound to benzaldehyde is $\text{PCC}$.

Explanation of Solution

The given compound ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{CH}}_{\text{2}}\text{OH}$ can be converted into ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CHO}$ using $\text{PCC}$. PCC is oxidises the given primary alcohol into ketone. The reaction between ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{CH}}_{\text{2}}\text{OH}$ and $\text{PCC}$ is represented as,

${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{CH}}_{\text{2}}\text{OH}\stackrel{\text{PCC}}{\to }{\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CHO}$

Conclusion

The reagents needed to convert given compound to benzaldehyde are ${\text{LiAlH}}_{\text{4}}$ an ${\text{H}}_{\text{2}}\text{O}$.

Interpretation Introduction

(b)

Interpretation: The reagents needed to convert the given compound to benzaldehyde are to be predicted.

Concept introduction: Lindler’s catalyst $\left(\text{Pd}-{\text{BaSO}}_4\right)$ is a heterogenous catalyst used for hydrogenation. Benzaldehyde is an aromatic aldehyde with many commercial uses. Benzaldehyde has a characteristic almond like smell; therefore, it is used as a food additive.

Answer to Problem 21.59P

The reagents needed to convert given compound to benzaldehyde are $\text{Pd}-{\text{BaSO}}_4$ and ${\text{H}}_{\text{2}}$.

Explanation of Solution

The given compound ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{COCl}$ can be converted into ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CHO}$ using $\text{Pd}-{\text{BaSO}}_4$ and ${\text{H}}_{\text{2}}$. The reduction reaction between ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{COCl}$, $\text{Pd}-{\text{BaSO}}_4$ and ${\text{H}}_{\text{2}}$ is represented as,

${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{COCl}\underset{{\text{H}}_{\text{2}}}{\overset{\text{Pd}-{\text{BaSO}}_4}{\to }}{\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CHO}$

Conclusion

The reagents needed to convert given compound to benzaldehyde are $\text{Pd}-{\text{BaSO}}_4$ and ${\text{H}}_{\text{2}}$.

Interpretation Introduction

(c)

Interpretation: The reagents needed to convert the given compound to benzaldehyde are to be predicted.

Concept introduction: Diisobutylaluminiumhydride (DIBAL-H) is a selective reducing agent. It readily converts nitriles to corresponding aldehydes. Benzaldehyde is an aromatic aldehyde with many commercial uses. Benzaldehyde has a characteristic almond like smell; therefore, it is used as a food additive.

Answer to Problem 21.59P

The reagents needed to convert given compound to benzaldehyde are $\text{DIBAL}-\text{H}$ and ${\text{H}}_{\text{2}}\text{O}$.

Explanation of Solution

The given compound ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{COOCH}}_3$ can be converted into ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CHO}$ using $\text{DIBAL}-\text{H}$ and ${\text{H}}_{\text{2}}\text{O}$. The reaction between ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{COOCH}}_3$, $\text{DIBAL}-\text{H}$ and ${\text{H}}_{\text{2}}\text{O}$ is represented as,

${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{COOCH}}_3\underset{\left(2\right){\text{H}}_{\text{2}}\text{O}}{\overset{\left(1\right)\text{DIBAL}-\text{H}}{\to }}{\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CHO}$

Conclusion

The reagents needed to convert given compound to benzaldehyde are $\text{DIBAL}-\text{H}$ and ${\text{H}}_{\text{2}}\text{O}$.

Interpretation Introduction

(d)

Interpretation: The reagents needed to convert given compound to benzaldehyde are to be predicted.

Concept introduction: Lithium aluminium hydride is a strong reducing agent. It is used to convert a carboxylic acid into aldehyde. Benzaldehyde is an aromatic aldehyde with many commercial uses. Benzaldehyde has a characteristic almond like smell; therefore, it is used as a food additive.

Answer to Problem 21.59P

The reagents needed to convert given compound to benzaldehyde are ${\text{LiAlH}}_{\text{4}}$ and ${\text{H}}_{\text{2}}\text{O}$.

Explanation of Solution

The given compound ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{COOH}$ can be converted into ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CHO}$ using ${\text{LiAlH}}_{\text{4}}$ and ${\text{H}}_{\text{2}}\text{O}$. The reduction reaction between ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{COOH}$, ${\text{LiAlH}}_{\text{4}}$ and ${\text{H}}_{\text{2}}\text{O}$ is represented as,

${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{COOH}\underset{{\text{H}}_{\text{2}}\text{O}}{\overset{{\text{LiAlH}}_{\text{4}}}{\to }}{\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CHO}$

Conclusion

The reagents needed to convert given compound to benzaldehyde are ${\text{LiAlH}}_{\text{4}}$ and ${\text{H}}_{\text{2}}\text{O}$.

Interpretation Introduction

(e)

Interpretation: The reagents needed to convert given compound to benzaldehyde are to be predicted.

Concept introduction: Vanadium pentoxide is a good catalyst for oxidation reaction. Benzaldehyde is an aromatic aldehyde with many commercial uses. Benzaldehyde has a characteristic almond like smell; therefore, it is used as a food additive.

Answer to Problem 21.59P

The reagents needed to convert given compound to benzaldehyde are ${\text{O}}_{\text{2}}$ and ${\text{V}}_{\text{2}}{\text{O}}_{\text{5}}$.

Explanation of Solution

The given compound ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{CH}}_3$ can be converted into ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CHO}$ using ${\text{O}}_{\text{2}}$ and ${\text{V}}_{\text{2}}{\text{O}}_{\text{5}}$. The oxidation reaction between ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{CH}}_3$, ${\text{O}}_{\text{2}}$ and ${\text{V}}_{\text{2}}{\text{O}}_{\text{5}}$ is represented as,

${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{CH}}_3\underset{{\text{V}}_{\text{2}}{\text{O}}_{\text{5}}}{\overset{{\text{O}}_{\text{2}}}{\to }}{\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CHO}$

Conclusion

The reagents needed to convert given compound to benzaldehyde are ${\text{O}}_{\text{2}}$ and ${\text{V}}_{\text{2}}{\text{O}}_{\text{5}}$.

Interpretation Introduction

(f)

Interpretation: The reagents needed to convert given compound to benzaldehyde are to be predicted.

Concept introduction: Ozonolysis reaction is a very important reaction for the conversion of any alkene into aldehyde. Benzaldehyde is an aromatic aldehyde with many commercial uses. Benzaldehyde has a characteristic almond like smell; therefore, it is used as a food additive.

Answer to Problem 21.59P

The reagents needed to convert given compound to benzaldehyde are ${\text{O}}_3$, $\text{Zn}$ and ${\text{H}}_{\text{2}}\text{O}$.

Explanation of Solution

The given compound ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CH}={\text{CH}}_2$ can be converted into ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CHO}$ using ${\text{O}}_3$, $\text{Zn}$ and ${\text{H}}_{\text{2}}\text{O}$. The ozonolysis reaction between ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CH}={\text{CH}}_2$, ${\text{O}}_3$, $\text{Zn}$ and ${\text{H}}_{\text{2}}\text{O}$ is represented as,

${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CH}={\text{CH}}_2\underset{{\text{Zn/H}}_{\text{2}}\text{O}}{\overset{{\text{O}}_{\text{3}}}{\to }}{\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CHO}$

Conclusion

The reagents needed to convert given compound to benzaldehyde are ${\text{O}}_3$, $\text{Zn}$ and ${\text{H}}_{\text{2}}\text{O}$.

Interpretation Introduction

(g)

Interpretation: The reagents needed to convert given compound to benzaldehyde are to be predicted.

Concept introduction: The acid catalyzed hydrolysis of both enamines and imines yield aldehydes and ketones. Benzaldehyde is an aromatic aldehyde with many commercial uses. Benzaldehyde has a characteristic almond like smell; therefore, it is used as a food additive.

Answer to Problem 21.59P

The reagents needed to convert given compound to benzaldehyde are ${\text{H}}^{+}$ and ${\text{H}}_{\text{2}}\text{O}$.

Explanation of Solution

The given compound ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CH}={\text{NCH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}$ can be converted into ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CHO}$ using ${\text{H}}^{+}$ and ${\text{H}}_{\text{2}}\text{O}$. The acid catalyzed hydrolysis reaction between ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CH}={\text{NCH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}$, ${\text{H}}^{+}$ and ${\text{H}}_{\text{2}}\text{O}$ is represented as,

${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CH}={\text{NCH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}\stackrel{{\text{H}}^{+}/{\text{H}}_{\text{2}}\text{O}}{\to }{\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CHO}$

Conclusion

The reagents needed to convert given compound to benzaldehyde are ${\text{H}}^{+}$ and ${\text{H}}_{\text{2}}\text{O}$.

Interpretation Introduction

(h)

Interpretation: The reagents needed to convert given compound to benzaldehyde are to be predicted.

Concept introduction: The acid catalyzed hydrolysis of diester yield aldehydes. Benzaldehyde is an aromatic aldehyde with many commercial uses. Benzaldehyde has a characteristic almond like smell; therefore, it is used as a food additive.

Answer to Problem 21.59P

The reagents needed to convert given compound to benzaldehyde are ${\text{H}}^{+}$ and ${\text{H}}_{\text{2}}\text{O}$.

Explanation of Solution

The given compound ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CH}{\left({\text{OCH}}_{\text{2}}{\text{CH}}_{\text{3}}\right)}_2$ can be converted into ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CHO}$ using ${\text{H}}^{+}$ and ${\text{H}}_{\text{2}}\text{O}$. The acid catalyzed hydrolysis reaction between ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CH}{\left({\text{OCH}}_{\text{2}}{\text{CH}}_{\text{3}}\right)}_2$, ${\text{H}}^{+}$ and ${\text{H}}_{\text{2}}\text{O}$ is represented as,

${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CH}{\left({\text{OCH}}_{\text{2}}{\text{CH}}_{\text{3}}\right)}_2\stackrel{{\text{H}}^{+}/{\text{H}}_{\text{2}}\text{O}}{\to }{\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{CHO}$

Conclusion

The reagents needed to convert given compound to benzaldehyde are ${\text{H}}^{+}$ and ${\text{H}}_{\text{2}}\text{O}$.