Chapter 13, Problem 13.37UKC

Interpretation Introduction

Interpretation:

Nitrogen containing functional group has to be labelled in lidocaine and also they have to be classified as primary, secondary or tertiary.

Concept Introduction:

Amines are compounds that contains carbon atom bonded to nitrogen in ammonia by replacing one or more hydrogen atoms.  Primary amine is the one, which has only one carbon atom and two hydrogen atoms bonded to the nitrogen atom.  General structure of primary amine is ${\text{RNH}}_{\text{2}}$.  Secondary amine is the one, which has two carbon atoms and one hydrogen atom bonded to the nitrogen atom.  General structure of secondary amine is ${\text{R}}_{\text{2}}\text{NH}$.  Tertiary amine is the one, which has three carbon atoms bonded to the nitrogen atom.  General structure of tertiary amine is ${\text{R}}_{\text{3}}\text{N}$.

Amides contain a nitrogen atom that is bonded to carbonyl group.  The nitrogen atom that is bonded to the carbonyl group may be bonded to alkyl groups or hydrogen atoms.  Depending on the number of carbon atoms that is attached to the nitrogen atom, the amide is classified as primary, secondary, and tertiary.

Primary amide is the one that contains only one $\text{C}-\text{N}$ bond.  General structure of primary amide is ${\text{RCONH}}_{\text{2}}$.  Secondary amide is the one that contains two $\text{C}-\text{N}$ bonds.  General structure of secondary amide is $\text{RCONHR'}$.  Secondary amide is the one that contains three $\text{C}-\text{N}$ bonds.  General structure of secondary amide is ${\text{RCONR'}}_{\text{2}}$.

Explanation of Solution

Structure of lidocaine is:

Lidocaine contains two nitrogen atoms.  Among this, one nitrogen atom is bonded to a carbonyl group carbon atom and another nitrogen atom is bonded to carbon atoms.  Thus the compound contains amine and amide functional group.  This is labelled as follows.

Nitrogen atom that is present in amide is bonded to two carbon atoms.  This means there are two $\text{C}-\text{N}$ bonds.  Thus, the amide is classified as a secondary amide.  The amine nitrogen atom is bonded to three other carbon atoms.  Thus it is classified as a tertiary amine.  This is depicted as follows.