Amines Flashcards
What is an amine?
A molecule in which nitrogen is bound to one, two or three organic groups(amines are derivatives of ammonia)
Alkaloids are….
An important group of biologically active amines
Why do plants synthesize alkaloids?
To protect them from being eaten by insects or other animals
Many drugs if addiction are classified as ….
Alkaloids
Give examples to describe the biological activity of amines
Dopamine is a neurotransmitter
Epinephrine is a bio regulator
Niacin, vitamin b6, is an amine
Alkaloids: nicotine, morphine, cocaine
Amino acids
Describe each class of amines
Primary- has one alkyl group bonded to nitrogen (RNH2)
Secondary- has two alkyl groups bonded to the nitrogen (R2NH)
Tertiary- has 3 alkyl groups bonded to the nitrogen(R3N)
Quartenary- has 4 alkyl groups bonded to the nitrogen and nitrogen bears a positive charge (R4N+)
Describe aromatic amines
The amino group is bonded to a benzene ring
What is the parent compound called of an aromatic amine?
Aniline
What are heterocyclic amines?
Compounds in which the nitrogen atom occurs as part of a ring
The Herero lyric nitrogen is always numbered as…
Position 1
Describe the structure of amines
Nitrogen is sp3 hybridized with a lone pair of electrons
The angle is less than 109.5 degrees
Compare the boiling point of amines to corresponding alcohols and ethers and give a reason for the
Nitrogen is less electronegative than oxygen so N-H is less polar than O-H.
This causes amines to have weaker hydrogen bonds than corresponding alcohol but amines have higher boiling points than those of the corresponding ether
Why do tertiary amines have a lower boiling point than primary and secondary amines?
Tertiary amines cannot hydrogen bond so they have lower boiling points than primary and secondary amines
Describe the hydrogen bonding activity in primary, secondary and tertiary amines
Primary and secondary- hydrogen bond donor or acceptor
Tertiary- hydrogen bond acceptor only
Describe the odor of amines
Most amines smell like rotting fish. Some diamonds are particularly pungent
Describe the solubility of amines
All amines, including tertiary amines form hydrogen bonds with hydroxylic solvents like water and alcohols
Branching increases solubility
Describe solubility of amines in water
Small amines, less than 6 carbons are relatively soluble in water
_________ ________ are usually stronger bases than ammonia
Alkyl amines
Why are amines also nucleophiles/lewus bases?
It’s lone pair of non bonding electrons form a bond with an electrophile
Why are amines able to act as bronsted Lowry bases?
By accepting a proton from an acid (lone pair of electrons on nitrogen can accept a proton from an acid)
What is the pKb of ammonia?
4.74
How do the presence of alkyl groups affect solvation/basicity?
Increase in alkyl groups decreases solvation of ion, so secondary and tertiary amines are like primary amines in basucity
How can ammonium salts be obtained?
Protonation of an amine give an ammonium salt
What are the 2 types of ion in ammonium salt
The protonated amine cation(an ammonium ion)
The anion derived from the acid