66 - Organic Chemistry

Question

Devise a synthesis of each compound from aniline $\left(C_6{H}_{5}N{H}_2\right)$ as starting material.

a

b

c

Step-by-Step Solution

Answer

a

b

c

Aniline

Another name for anilines is aminobenzene. Anilines undergo several reactions, and one among them is diazotization.

 

Reactions of aniline

Anilines can combine with carboxylic acids to give rise to amides. They can combine with acyl chlorides to produce acetanilide. Diazotization of aniline generates the product, benzene diazonium chloride.

Synthesis of the given compounds from aniline

a. The reaction of aniline with $NaN{O}_2$ , HCl, and NaCN leads to the formation of cyanobenzene. The cyanobenzene reacts with to form benzoic acid, which in turn reacts with $SOC{l}_2$ and $N{H}_{2}C{H}_3$ to form the compound a. 

 

The reaction can be given as:

              Formation of compound a from aniline

b. Aniline reacts with $C{H}_{3}COCl$ to form acetanilide. This compound reacts with $B{r}_2$ and  $FeB{r}_3$ to form bromo substituted ortho and para isomers.

 

The ortho isomer reacts with $C{H}_{3}Cl$ and $AlC{l}_3$ to form a product where methyl group is substituted ortho to $NHCOC{H}_3$ . The reaction of this compound with base leads to the conversion of $NHCOC{H}_3$   to $N{H}_2$ .

 

This compound reacts with  $NaN{O}_2$, HCl, and $H_{3}P{O}_2$ to form compound b. The reaction can be given as:

                Formation of compound b from aniline

c. Aniline reacts with $NaN{O}_2$, HCl, and water to form phenol. This can react with $C{H}_{3}Cl$ and $AlC{l}_3$ to form a methyl substituted ortho and para isomer. The para isomer reacts with $C_6{H}_5{N}_2^{+}C{l}^{-}$ to form compound c. The reaction can be given as:  

               Formation of compound c from aniline