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Chapter 14: Alcohols, Phenols, and Ethers

  • 1-octanol and 3-octanol:
      - Alcohols that contribute to the distinctive flavour of mushrooms.

Unit 17: Amines and Amides

  • Nylon (polyamide):
      - Developed by DuPont in 1935.
      - One of the most commonly utilized polymers.
      - Origin of various forms due to the need for synthetic silk during WWII.

Bonding Characteristics of Nitrogen Atoms in Organic Compounds

Section 17.1: Importance of Nitrogen

  • Key Elements:
      - The four most abundant elements in living organisms: Carbon (C), Hydrogen (H), Oxygen (O), and Nitrogen (N).
  • Macronutrients Requiring Nitrogen:
      - Nitrogen is essential for growth in many organic forms.
  • Key Scientist:
      - Ernst Haber (and Carl Bosch):
        - Credited for developing a cost-effective way to fix nitrogen from the air into fertilizer through the Haber Process.

Section 17.1: Hydrocarbon Derivatives

  • Organic Molecules containing C, H, O, and/or N:
      - Hydrocarbons (C and H): Alkanes, Alkenes, Alkynes.
      - Alcohols, phenols, ethers, aldehydes, ketones, carboxylic acids, esters contain C, H, O.
      - Amines: contain C, H, and N.
      - Amides: contain C, H, O, and N.

Section 17.1: Characteristics of Nitrogen

  • Periodic Table Position:
      - Found in Group 15 (or VA) of the periodic table.
  • Valence Electrons:
      - Nitrogen has 5 valence electrons.
  • Bonds Formed:
      - Nitrogen can form up to 3 bonds.
  • Nonbonding Electron Pairs:
      - Capable of having up to 2 nonbonding (lone) electron pairs.

Structure and Classification of Amines

Section 17.2: Classification of Amines

  • Amine Types:
      - Primary Amines (1°): Nitrogen with one R group.
      - Secondary Amines (2°): Nitrogen with two R groups.
      - Tertiary Amines (3°): Nitrogen with three R groups.
  • Definition of Amines:
      - An organic derivative of ammonia (NH₃) in which one or more alkyl, cycloalkyl, or aryl (R) groups have replaced hydrogen atoms of ammonia.
  • Key Distinction:
      - For amines, consider the number of carbons directly attached to the nitrogen atom, rather than the -OH bearing carbon as with alcohols.

Section 17.2: Cyclic Amines

  • Cyclic Amines:
      - Usually secondary or tertiary due to rings (requiring at least 2 carbons attached to nitrogen).
      - Known as heterocyclic amines due to both C and N being part of the ring.

Section 17.2: Naming Priority of Amines

  • Amine Naming:
      - Amine's priority in nomenclature is just above alkene.
      - Can treat amine group as a substituent, termed as an amino group.
  • Naming Hierachy:
      - Highest to lowest: Carboxylic acid > Ester > Amide > Aldehyde > Ketone > Alcohol (Thiol) > Amine > Alkene > Alkyne > Alkane, Ether (Alkoxy), Halogen.

Nomenclature for Amines

Section 17.3: IUPAC Naming Rules

  • Primary Amines:
      - Convert alkane name to amine (e.g., Butane to butanamine).
  • Rule 1: Select the longest carbon chain the nitrogen atom is attached to.
  • Rule 2: Rename by changing the -e of the corresponding alkane name to -amine.
  • Rule 3: Number the chain from the end nearest the nitrogen.
  • Rule 4: Indicate nitrogen attachment position by a number.
  • Rule 5: Append identity and location of any substituents to the parent name.
  • Rule 6: Use di- and tri- for multiple amines, returning to full alkane name followed by -amine.

Section 17.3: Secondary and Tertiary Amines

  • Naming:
      - Secondary and tertiary amines use N or N,N prefixes to denote attached groups.
      - Use the largest carbon group as the base amine name, listing other groups before the name.
  • Examples:
      - N-methyl-2-butanamine, N,N-dimethyl-1-propanamine.

Section 17.4: Isomerism for Amines

  • Types of Isomerism:
      - Constitutional Isomerism: arises due to different carbon arrangements.
      - Positional Isomerism: arises from different positions of the amine group.
      - Functional Group Isomers: arise from different amine classifications (e.g., primary to secondary).

Physical Properties of Amines

Section 17.5: Boiling Point and Solubility

  • Boiling Points:
      - Primary amines have boiling points (B.P.) intermediate between alkanes and alcohols due to hydrogen bonding.
      - 3° amines have lower B.P. than 1° and 2° amines.
  • Hydrogen Bonding:
      - Compare hydrogen bonding strength between H-N (weaker) and H-O (stronger).
      - Amine solubility in water due to the ability to hydrogen bond

Section 17.5: Odour and Basicity

  • Odour of Amines:
      - Diamines like putrescine and cadaverine release foul smells; methylamines resemble ammonia odour.
      - Most amines have strong, disagreeable fish-like odours.
  • Basic Properties:
      - Amines are basic, acting as proton acceptors (Bronsted-Lowry principles).
      - Form alkaline solutions when reacting with acids.

Section 17.7: Reactions of Amines with Acids

  • Formation of Amine Salts:
      - Amine + Acid → Amine Salt.
      - Amine salts are ionic compounds:
        - Example: RNH₃⁺ from amines reacting with acids (R ≠ 0, 1 or 2).
      - Amine salts are soluble in water due to their ionic nature and polarity.
  • Reversibility:
      - Reaction with a strong base: salt can revert to the parent amine by releasing protons (H⁺).

Section 17.9: Heterocyclic Amines

  • Definition:
      - Organic compounds containing nitrogen in a cyclic structure.
      - Examples include purine and pyrimidine rings in nucleosides, and biologically relevant compounds like nicotine and caffeine.

Selected Biochemically Important Amines

Section 17.10: Neurotransmitters

  • Neurotransmitters:
      - Chemical substances released at nerve endings, crossing the synaptic gap and binding to receptors to trigger impulses.
  • Dopamine:
      - Role in mood and reward-driven learning; deficiency linked to Parkinson’s disease, treatable with L-DOPA.
      - Abnormal levels associated with schizophrenia and ADHD.
      - Stimulants act on dopamine systems.
  • Serotonin:
      - Influences mood, sleep, body temperature, and lactation; target for many antidepressants.
  • Norepinephrine (Noradrenaline):
      - Functions as both neurotransmitter and stimulant, produced in adrenal glands.

Section 17.10: Stimulants

  • Epinephrine (Adrenaline):
      - Released in response to stress (fight or flight), enhances physical responses.
  • Amphetamines:
      - Increases serotonin and dopamine; used for ADHD but can be addictive with severe side effects at high doses.
  • Histamine:
      - Increases vascular permeability causing allergy symptoms; antihistamines counteract its effects.

Alkaloids

Section 17.11: General Overview

  • Alkaloids:
      - Nitrogen-containing organic compounds derived from plants.
      - Examples include nicotine, caffeine, cocaine, morphine, and codeine.

Structure and Classification of Amides

Section 17.12: Definition and Formation

  • Amides:
      - Derivatives from carboxylic acids where the –OH group is replaced with an amino (-NH₂) or substituted amino group.
      - Formation occurs through dehydration synthesis (condensation reaction).
  • Classification of Amides:
      - Primary (1°): Two H atoms on N.
      - Secondary (2°): One R group and one H on N.
      - Tertiary (3°): Two R groups on N with no H.

Section 17.12: Lactams

  • Lactam Classification:
      - Ring size indicated with a Greek letter; beta-lactams have a four-member ring, common in penicillin antibiotics.

Selected Amides and Their Uses

Section 17.14: Urea

  • Urea:
      - A naturally occurring amide, produced in the human body via the urea cycle from CO₂ and ammonia.
      - Kidney function: Removes urea from blood, excreted as urine.

Polyamides and Polyurethanes

Section 17.19: Properties and Applications

  • Nylon:
      - Polyamide formed via reaction of a diacid and diamine.
      - Properties enhanced with aromatic rings in the polymer backbone, imparting strength (e.g., Kevlar).
      - Naturally occurring polyamides include silk and wool.