Chapter 18, Problem 74P

Interpretation Introduction

(a)

Interpretation:

The given amine needs to be labeled as 1⁰, 2⁰ or 3⁰.

Concept introduction:

Amines are derivatives which are derived from ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. They can be called as alkylamines and arylamines.

Answer to Problem 74P

A tertiary (3^o) amine.

Explanation of Solution

Amines are derivatives which are derived from ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. They can be called as alkylamines and arylamines.

Whether an amine is primary (1^o), secondary (2^o) or tertiary (3^o) depends on the number of hydrogen atoms replaced by an alkyl or aryl group in ammonia. The amine is a primary amine if one hydrogen atom is replaced, it is a secondary amine if 2 hydrogen atoms are replaced and if three hydrogen atoms are replaced it is known as a tertiary amine.

The given compound is as follows:

  

Here, only one hydrogen atom is replaced and therefore this amine called as a primary (1^o) amine.

Interpretation Introduction

(b)

Interpretation:

The molecular shape around each atom of phentermine needs to be determined.

Concept introduction:

Molecular geometry is named as molecular shape and it is the three-dimensional arrangement of atoms within a molecule of the environment. Atoms arrange in space with an exact shape to minimize the repulsion. This can be determined using VSEPR theory.

Answer to Problem 74P

Carbons of benzene molecule;trigonal planar.

Carbon of −CH₂ / -C(CH₃)₂NH₂ CH₂-/-CH₃;tetrahedral.

Nitrogen of NH₂;trigonal pyramidal.

Explanation of Solution

VSEPR or Valence Shell Electron Pair Repulsion theory is a model used to determine the geometry of molecules considering minimum electrostatic repulsion between the valence electrons of central atom in the molecule.

  

  

Carbons of benzene molecule;

Number of bonds= 3

Number of lone pairs = 0

Therefore, the shape is trigonal planar.

Carbon of −CH₂/ -C(CH₃)₂NH₂CH₂-/-CH₃;

Number of bonds= 4

Number of lone pairs = 0

Therefore, the shape is tetrahedral.

Nitrogen of NH₂;

Number of bonds= 3

Number of lone pairs = 1

Therefore, the shape is trigonal pyramidal.

Interpretation Introduction

(c)

Interpretation:

The constitutional isomer containing a primary amine needs to be determined.

Concept introduction:

Constitutional isomers are called as compounds that have the unique molecular formula and different structural connectivity. To determine whether two molecules are constitutional isomer, the number of each atom needs to be counted in both molecules and see how the atoms are arranged.

Answer to Problem 74P

  

Explanation of Solution

Whether an amine is primary (1^o), secondary (2^o) or tertiary (3^o) depends on the number of hydrogen atoms replaced by an alkyl or aryl group in ammonia. The amine is a primary amine if one hydrogen atom is replaced, it is a secondary amine if 2 hydrogen atoms are replaced and if three hydrogen atoms are replaced it is known as a tertiary amine.

  

Here all one hydrogen atom is replaced and therefore this amine called a primary amine (1^o).

Interpretation Introduction

(d)

Interpretation:

The constitutional isomer that contains a secondary amine needs to be determined.

Concept introduction:

Constitutional isomers are called as compounds that have the unique molecular formula and different structural connectivity. To determine whether two molecules are constitutional isomer, the number of each atom needs to be counted in both molecules and see how the atoms are arranged.

Answer to Problem 74P

  

Explanation of Solution

Whether an amine is primary (1^o), secondary (2^o) or tertiary (3^o) depends on the number of hydrogen atoms replaced by an alkyl or aryl group in ammonia. The amine is a primary amine if one hydrogen atom is replaced, it is a secondary amine if 2 hydrogen atoms are replaced and if three hydrogen atoms are replaced it is known as a tertiary amine.

  

Here all 3 hydrogen atoms are replaced and therefore this amine called as a secondary amine (2^o).

Interpretation Introduction

(e)

Interpretation:

The structure of phentermine hydrobromide molecule needs to be drawn.

Concept introduction:

Phentermine hydrobromide can stimulate the central nervous system and increases the blood pressure and heart rate which decreases the appetite. It is taken along with diet and exercise in order to reduce obesity.

Answer to Problem 74P

  

Explanation of Solution

Phentermine hydrobromide can stimulate the central nervous system and increases the blood pressure and heart rate which decreases the appetite. It is taken along with the diet and exercise in order to reduce the obesity.

Its molecular formula is C₁₇H₂₂BrN. It has the following structure.

  

Interpretation Introduction

(f)

Interpretation:

The products formed if phentermine is treated with benzoic acid needs to be determined.

Concept introduction:

Amines are derivatives which are derived from ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. They can be called as alkylamines and arylamines.

Answer to Problem 74P

  

Explanation of Solution

Amines are derivatives which are derived from ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. They can be called as alkylamines and arylamines.

Whether an amine is primary (1^o), secondary (2^o) or tertiary (3^o) depends on the number of hydrogen atoms replaced by an alkyl or aryl group in ammonia. The amine is a primary amine if one hydrogen atom is replaced, it is a secondary amine if 2 hydrogen atoms are replaced and if three hydrogen atoms are replaced it is known as a tertiary amine.

Benzphetamine is a tertiary ammine. It has basic properties and it accepts protons from acids. Acetic acid is donated a proton to this amine and formed below the salt.