Amines
Caffeine
Nitrogen Chemistry

Nitrogen will readily form 3 covalent
bonds (each atom already has 5 v.e-)
– Carbon forms 4 covalent bonds
– Oxygen forms 2 covalent bonds
Structure & Classification of
Amines

Amines are derivatives of ammonia (NH3)
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Functional group = NHx
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Aromatic amines = aniline -->
Amine Nomenclature
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IUPAC (longest chain = alkane)
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– Primary
– Primary
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Alkanamine
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– # is used to ID location of fcn’l group on
alkane chain
– Can have diamines, etc.
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
Alkylalkylalkylamine
N-alkyl-N-alkylalkanamine
– Multifunctional groups

Alkylalkylamine
– Tertiary
N-alkylalkanamine
– Tertiary

Alkylamine
– Secondary
– Secondary

Common
Amine = substituent (amino),
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Carboxylic acid
Aldehyde
Ketone
Alcohol
Amine

Isomers
– Skeletal (C atoms)
– Positional (NHx group)
Physical Properties of Amines

State: low MW = gases @ RT
– Smell like ammonia
–
high MW = liquids @ RT
– Bad odors

BP: alkanes<amines<alcohols
– Hydrogen bonding

Water solubility
– Low MW = v. soluble
– High MW = soluble
Amines are weak Bases

NH3 + HOH <==> NH4+ + OHammonium ion

CH3-NH2 + HOH <==> CH3-NH3+ + OHmethylamine
methanamine

methylammonium ion
Amine Salts
– Acid + amine --> Amine salt + water

(protonation)
HCl + CH3-NH2 --> CH3-NH3+Clmethylammonium chloride
– Amine salt + base --> amine + salt + water

(deprotonation)
CH3-NH3+Cl- + NaOH --> CH3-NH2 + NaCl + HOH
Preparation of Amines

Alkylation in the presence of a base
– Ammonia + alkyl halide --> 1˚ amine

NH3 + CH3Cl --> CH3NH3+Cl- + NaOH --> CH3NH2 + NaCl + HOH

The primary amine will continue to react unless it is removed as it is produced.
– 1˚ amine + alkyl halide --> 2˚ amine
– 2˚ amine + alkyl halide --> 3˚ amine
– 3˚ amine + alkyl halide --> quaternary ammonium salt
– Quaternary ammonium salts may be biochemically
important
 Ex.: choline (growth reg.) & acetylcholine (nerve
impulse transmission)
Heterocyclic Amines
Nitrogen atoms are part of a ring system
Hemoglobin
-pyrrole derivative
Nicotine
- pyridine derivative
Caffeine
-purine derivative
Biochemically Important Amines

Neurotransmitters
– Acetylcholine, norepinephrine
– Dopamine, serotonin

Epinephrine
– Adrenaline
– Amphetamines - structurally related to adrenalin

Histamine
– Responsible for effects of hay fever & pollen allergies
– These effects are counteracted by antihistamines
Alkaloids - plant based amines

Nicotine, caffeine, cocaine

Chocolate

Quinine, atropine

Opium
– Codeine, Morphine (heroin)
Theobromine - Greek (“theo” - god; “brosis” - food)
The alkaloid atropine
is obtained from the
belladonna plant.
Poppy
What do you need to know?
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Structural characteristics (know the functional group)
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Carboxylic Acids
Esters
Phosphate Esters
Amides
Amines
Isomers; Functional group isomers
Nomenclature (the rules for naming the molecules)

Common & IUPAC
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Physical properties (basic/simple)
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pH; BP; Solubility; Flammability
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Amides: (alkylalkylamide) N-alkylalkanamide
Amines: (alkylalkylamine) N-alkylalkanamine
Acids ~ hydrogen bonding!
Esters ~ no hydrogen bonding (a lot like ethers)
Amides: lower pH; most are solids @ RT
Amines: higher pH; most are liquids @ RT
Occurrence and uses (common)


Acids - metabolic intermediates & products; antimicrobials
Esters - flavors/fragrances; pheromones; medications
–
Phosphate esters
Amides - Urea; barbiturates; polyamides & polyurethanes
 Amines - Biochemical; Alkaloids
Preparation (what basic reactions produce the molecules)
 Acids - Oxidation of aldehydes; of alkyl benzene
 Esters - Esterification (C. acid + alcohol); condensation polymerization
 Amides - (amidification) Amine + C. Acid --> amide
 Amines - Rxn w/ alkyl halide (in base)
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Characteristic reactions of the molecules
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Acids - Neutralization; Esterification; acid salts (rxn w/ SB or SA)
Esters - Ester Hydrolysis (in acid); Saponification (in base)
Amides - Hydrolysis (acidic & basic); polymerization
Amines - Protonation<==> Deprotonation