Comprehensive Study Guide: Amides and Amines

Definition: Amines are organic derivatives of ammonia ( $NH_3$ ).
Molecular Geometry: Amines exhibit a trigonal pyramidal shape.
Chemical Nature: They function as bases.
Classification Criteria: Amines are classified based on the number of carbon groups attached to the Nitrogen atom:
- Primary ( $1^{\circ}$ ) Amines: The nitrogen atom is attached to one carbon group.
- Secondary ( $2^{\circ}$ ) Amines: The nitrogen atom is attached to two carbon groups.
- Tertiary ( $3^{\circ}$ ) Amines: The nitrogen atom is attached to three carbon groups.

Boiling Point (BP) Influences:
- Intermolecular Forces: Primary and secondary amines possess $N-H$ bonds. These bonds are polar, allowing these amines to interact via dipole-dipole interactions and Hydrogen bonding (H-bonding).
- Comparison with Alkanes: Amines have higher boiling points than alkanes due to these polar interactions.
- Primary vs. Secondary: Primary amines generally have higher boiling points than secondary amines because they are more polar.
- Amines vs. Alcohols: $N-H$ bonds are less polar than $O-H$ bonds. Consequently, alcohols have higher boiling points than amines because alcohol H-bonding is stronger.
- Tertiary Amines: These contain only $C-N$ bonds, which are not as polar as $N-H$ bonds. Therefore, tertiary amines have lower boiling points than alcohols, primary amines, and secondary amines. However, they still maintain a higher boiling point than alkanes.
Solubility:
- Small amines containing $4$ carbons or fewer are soluble in water.
- This solubility is due to their ability to interact with water molecules through H-bonding.
Boiling Point Ordering (Practice):
- Students are instructed to practice ordering compounds from lowest to highest boiling point and vice versa based on these polarity and H-bonding principles.

Primary Amines:
- Identify the longest continuous carbon chain.
- Replace the final "-e" of the alkane name with the suffix "-amine".
Secondary Amines:
- Identify the two carbon chains attached to the Nitrogen atom.
- The longest chain is designated as the parent chain.
- List all substituents.
- The remaining (shorter) carbon chain on the Nitrogen is treated as a substituent using the prefix "N-".
Tertiary Amines:
- Identify the three carbon chains attached to the Nitrogen atom.
- The longest chain is designated as the parent chain.
- List all substituents.
- The two remaining carbon chains on the Nitrogen are treated as substituents using the prefix "N-".
Nomenclature Example for Practice:
- $N\text{-ethyl-4-methoxy-}N\text{-methyl-3-heptanamine}$

Acid-Base Reactions:
- Amines act as basic groups and readily bond with protons ( $H^+$ ).
- Product: The reaction results in the formation of an ammonium salt.
- Pharmacological Significance: Many important drugs are administered as ammonium salts. Because these salts are ionic, they are more soluble in aqueous solutions (body fluids) than the neutral amine.
Neutralization Reaction:
- Occurs when an amine reacts with a strong acid.

Boiling Points: Amides have very high boiling points. Their intermolecular forces include H-bonding between the $N-H$ of one molecule and the oxygen ( $O$ ) from the carbonyl group ( $C=O$ ) of another. Their boiling points are higher than those of carboxylic acids and alcohols.
State of Matter: Amides are typically solid at room temperature.
Solubility: Smaller amides are soluble in water.

Naming Rules:
- The carbon chain attached to the carbonyl group is the parent chain.
- Any carbon groups attached to the Nitrogen atom are treated as substituents.
Common Names and Examples:
- $N\text{-Methylpropanamide}$
- $N\text{-Propylacetamide}$
- $m\text{-Nitrobenzamide}$

Preparation from Acid Chlorides:
- This reaction requires two equivalents of the amine.
- Byproduct: One equivalent of the amine forms an ammonium salt.
- Primary Amide Synthesis: Requires an acid chloride (to provide the carbonyl) and ammonia ( $NH_3$ ).
- Secondary Amide Synthesis: Requires an acid chloride and a primary ( $1^{\circ}$ ) amine.
- Tertiary Amide Synthesis: Requires an acid chloride and a secondary ( $2^{\circ}$ ) amine.
Synthesis of Acetaminophen:
- Prepared via the reaction of an acid chloride and an amine component:
- $CH_3COCl + 2 \, H_2N-C_6H_4-OH \rightarrow \text{Acetaminophen} + \text{Ammonium Salt}$
Other Synthesis Examples:
- $CH_3CH_2COCl + 2 \, (CH_3)_2NH \rightarrow \text{Product}$
- Reaction involving $NH_3$ and an acid chloride to form a primary amide.

Acidic Hydrolysis:
- Conditions: Water ( $H_2O$ ), acid ( $H^+$ ), and Heat.
- Reaction: $\text{Amide} + H_2O \xrightarrow{H^+, \text{heat}} \text{Carboxylic Acid} + \text{Ammonium Ion}$
- Product: The primary organic product is a carboxylic acid.
Basic Hydrolysis:
- Conditions: Water ( $H_2O$ ), base ( $NaOH$ ), and Heat.
- Reaction: $\text{Amide} + NaOH \xrightarrow{\text{heat}} \text{Carboxylic Acid Salt} + \text{Amine/Ammonia}$
- Product: The primary organic product is a carboxylic acid salt.

Ranking: Order substances by increasing boiling point.
Nomenclature and Drawing:
- Provide the IUPAC name or draw the structure for: $N,N\text{-Diethylpentanamine}$ .
- Provide the IUPAC name or draw the structure for: $4\text{-Chlorohexanamide}$ .
Product Prediction: Predict the outcomes of reactions involving the above amides and amines.