amine notes

AMIDES

Amines

• Definition: Amines are derivatives of ammonia (NH₃).

• IUPAC Naming for Amines:

  • The 'e' in the corresponding alkane name is replaced with 'amine'.

• Numbering:

  • When the amine has a chain of three or more carbon atoms, it is numbered to show the position of the –NH₂ group and any other substituents.

Guide to IUPAC Naming of Amines

1. Identify the Longest Carbon Chain:

   • Name the longest carbon chain bonded to the N atom by replacing the 'e' of its alkane name with 'amine'.

2. Number the Carbon Chain:

   • Number the carbon chain to show the position of the amine group and other substituents.

3. Naming Substituents:

   • Any alkyl group attached to the nitrogen atom is indicated by the prefix 'N-' followed by the alkyl name, which is placed in front of the amine name.

Classification of Amines

• Amines are classified into:

  • Primary (1°) Amine: One carbon group is bonded to the nitrogen atom.

  • Secondary (2°) Amine: Two carbon groups are bonded to the nitrogen atom.

  • Tertiary (3°) Amine: Three carbon groups are bonded to the nitrogen atom.

Naming Common Amines

• Common amines may be named as alkylamines.

  • List the names of the alkyl groups bonded to the N atom in alphabetical order in front of 'amine':

  • Examples: Ethylamine, Dimethylamine.

Skeletal Formulas of Amines

• Skeletal formulas can be drawn for amines just as they are for other organic compounds.

  • The hydrogen atom must be drawn bonded to the nitrogen atom.

Functional Groups Priority in IUPAC Names

• When naming compounds with two functional groups:

  • The functional group with higher priority is used as the compound name.

  • Oxygen-containing groups have priority over an –NH₂ group, thus the –NH₂ group is named as a substituent: Amino.

Aromatic Amines

• The amine of benzene is called Aniline.

  • May have alkyl groups attached to N that use the prefix 'N-' followed by the alkyl name.

Properties of Amines

• Polarity: Amines contain polar N—H bonds.

  • Primary and secondary amines can form hydrogen bonds with water.

• Comparison to Alcohols:

  • Nitrogen is less electronegative than oxygen, leading to weaker hydrogen bonds in amines compared to alcohols.

Solubility in Water

• Amines are water soluble if they have 1 to 6 carbon atoms.

  • Solubility Order: Generally, primary amines are more soluble than tertiary amines because the N atom in smaller amines can form hydrogen bonds with water.

Amines as Bases

• Brønsted-Lowry Base: Amines can attract a H⁺ ion from water to the N atom, acting as weak bases in water.

Amine Salts

• Formed when an amine is neutralized by an acid.

  • Named by replacing the amine part of the name with Ammonium followed by the name of the negative ion.

Properties of Amine Salts

• Amine salts are:

  • Ionic Compounds: Typically solid at room temperature.

  • Soluble in Water: They are soluble in water and body fluids, often the form used for drugs.

Heterocyclic Amines

• Definition: A heterocyclic amine is a cyclic organic compound that contains one or more nitrogen atoms in a five- or six-atom ring.

• Examples and Occurrence:

  • Found in nature such as purine and pyrimidine rings in DNA and RNA, and piperidine in black pepper.

Alkaloids

• Characteristics: Physiologically active nitrogen-containing compounds produced by plants.

  • Commonly used as stimulants, anesthetics, and antidepressants.

  • Examples: Nicotine, Caffeine (a central nervous system stimulant), Morphine, and derivatives such as codeine and heroin.

Synthesizing Drugs: Pharmacology

• Research areas include:

  • Designing drugs that retain some characteristics of alkaloids without addictive side effects.

Amides

• Definition: Amides are compounds where an amino group (–NH₂) replaces the –OH group of carboxylic acids.

• Preparation of Amides: Amides are prepared by heating a carboxylic acid with ammonia or an amine (primary or secondary), in a process known as amidation.

IUPAC Naming of Amides

• Amides are named by dropping the -ic acid or -oic acid ending of the corresponding carboxylic acid and adding the suffix amide.

  • Examples: For butanamide, replace “butanoic acid” with “butanamide”.

  • Substituents on the N atom use the prefix 'N-' before the name.

Classification of Amides

• Primary (1°) Amides: One carbon atom bonded to nitrogen.

• Secondary (2°) Amides: Two carbon atoms bonded to nitrogen.

• Tertiary (3°) Amides: Three carbon atoms bonded to nitrogen.

Properties of Amides

• Melting Points:

  • Primary and secondary amides have high melting points due to hydrogen bond formation.

  • Tertiary amides (without H on N) have lower melting points.

• Solubility:

  • Amides with 1 to 5 carbon atoms can form hydrogen bonds with water and are thus soluble.

Hydrolysis of Amides

• Definition: Hydrolysis is a chemical reaction in which water molecules are split into H⁺ and OH⁻, often involving the reaction of an amide with acid or base.

• Acid Hydrolysis: Involves an acid and water, producing a carboxylic acid and ammonium salt.

• Base Hydrolysis: Involves a base and water, resulting in the salt of the carboxylic acid and an amine or ammonia.

Neurotransmitters

• Definition: Molecules that transmit impulses from nerve cells to target cells.

• Examples of Selected Neurotransmitters:

  • Acetylcholine: Synthesized from Acetyl CoA and choline.

  • Dopamine: Involved in enjoyment and derived from tyrosine.

  • Norepinephrine and Epinephrine: Hormonal neurotransmitters synthesized from tyrosine.

  • Serotonin: Synthesized from tryptophan, associated with mood regulation, relaxation, and sleep.

  • Glutamate: The most abundant neurotransmitter, involved in learning and memory.

  • GABA: The main inhibitory neurotransmitter, known for its calming effects.

Health Implications

• Acetylcholine: Linked to Alzheimer's disease; drugs like Aricept can slow its breakdown.

• Dopamine: Blocks of reuptake can result in prolonged effects in synapses, impacting mood and energy levels.