base strength of amines
Aliphatic Amines (non-aromatic)
- Base strength depends on “availability” of the lone pair of electrons
- Alkyl groups are “electron-donating”.
- They increase the electron-density around the N atom
- More likely to gain an electron
- 1° & 2° amines are better bases than ammonia (3° amines are too crowded)
Aromatic Amines
- Less basic than aliphatic amines
- The lone pair of electrons on the N participate in the resonance stabilization of the ring (so are not as available)
Aliphatic Amines (non-aromatic)
- Base strength depends on “availability” of the lone pair of electrons
- Alkyl groups are “electron-donating”.
- They increase the electron-density around the N atom
- More likely to gain an electron
- 1° & 2° amines are better bases than ammonia (3° amines are too crowded)
Aromatic Amines
- Less basic than aliphatic amines
- The lone pair of electrons on the N participate in the resonance stabilization of the ring (so are not as available)
base strength of amines
these are not basic, the unshared pair of electrons on the Nitrogen is delocalized
- two resonance forms are possible
- so, the electrons on the Nitrogen are not “available” to be donated
- and, amides are less reactive than other carboxylic acid derivatives (esters)
- also, the geometry of amides is (almost) planar
Amides basicity
propionamide
common name for 3 C chain amide
amine toxicity
Irritating to skin, eyes, mucous membranes
Some aromatic amines can be absorbed through the skin
common name for 5 C chain amide
valeramide
biologically active amines.
heterocyclic rings
members of the xanthine family
- Central Nervous System stimulant
- Bronchodilator (dilates bronchi)
- Vasodilator (dilates BV)
Diuretic
caffeine and theobromine (chocolate) and theophylline
1° & 2° amides have the Highest Boiling Points!
- only the smallest amide is a liquid at RT
- the rest are solids at RT
- amides can form intermolecular Hydrogen-bonds
- intermolecular H-bonding in amides is stronger than in amines
- the neighboring carbonyl is electron-withdrawing. this makes the N-H bond very polar, so more likely to form H-bonds with the electron pair on the Nitrogen of another amide (or with the Oxygen of water, etc.)
amides boiling point
common name for 1 C chain amide
formamide
Irritating to skin, eyes, mucous membranes
Some aromatic amines can be absorbed through the skin
amine toxicity
formamide
common name for 1 C chain amide
amine substituent
amino group
Lewis base
unshared electron pair on N can be donated. amines are this.
e.g. ammonia
2nd lowest. lower than alcohols and higher than alkanes/alkenes/alkynes
amine priority
held together via amide linkages
types: nylon, kevlar, polyuretane and proteins
polymers
amine priority
2nd lowest. lower than alcohols and higher than alkanes/alkenes/alkynes
aliphatic amines
non aromatic amine
type of heterocyclic ring
affects CNS
nicotine
common name for 2 C chain amide
acetamide
Amines react with acids to produce these
e.g. CH3-NH3+ Cl-
amine salts
(ammonium salts)
amide
a carboxylic acid derivative where carboxyl OH group has been replaced with an amino or substituted amino group
nicotine
type of heterocyclic ring
affects CNS
•– lower than corresponding alcohols
-amines can Hydrogen-bond with other amine molecules
® but N-H bonds are weaker than O-H bonds
amine boiling point
organic derivative of ammonia NH3 where one or more alkyl, cycloalkyl or aryl groups have replaced ammonia hydrogen atoms
sp3 trigonal pyramidal geometry
amine
common name for 3 C chain amide
propionamide
in hemoglobin
carries iron which carries oxygen in blood
heme
amine smell
many have ammonia-like odors or smell of raw fish
a carboxylic acid derivative where carboxyl OH group has been replaced with an amino or substituted amino group
amide
Amine bases in DNA and RNA
Adenine, Guanine
Thymine, Cytosine, Uracil
types of heterocyclic rings
butyramide
common name for 4 C chain amide
amides solubility
•form strong Hydrogen-bonds with water
- 1° amides can form 4 Hydrogen-bonds with water
- water-soluble
acetamide
common name for 2 C chain amide
simplest aromitic amide.
benzamide
amine boiling point
•– lower than corresponding alcohols
-amines can Hydrogen-bond with other amine molecules
® but N-H bonds are weaker than O-H bonds
aromatic amines
parent compound is aniline
non aromatic amine
aliphatic amines
caffeine and theobromine (chocolate) and thephylline
biologically active amines.
heterocyclic rings
members of the xanthine family
- Central Nervous System stimulant
- Bronchodilator (dilates bronchi)
- Vasodilator (dilates BV)
Diuretic
Amides basicity
these are not basic, the unshared pair of electrons on the Nitrogen is delocalized
- two resonance forms are possible
- so, the electrons on the Nitrogen are not “available” to be donated
- and, amides are less reactive than other carboxylic acid derivatives (esters)
- also, the geometry of amides is (almost) planar
acidic hydrolysis of amide
acidic conditions convert amide to carboxylic acid and amine salt
parent compound is aniline
aromatic amines
polymers
held together via amide linkages
types: nylon, kevlar, polyuretane and proteins
heme
in hemoglobin
carries iron which carries oxygen in blood
benzamide
simplest aromitic amide.
many have ammonia-like odors or smell of raw fish
amine smell
amides boiling point
1° & 2° amides have the Highest Boiling Points!
- only the smallest amide is a liquid at RT
- the rest are solids at RT
- amides can form intermolecular Hydrogen-bonds
- intermolecular H-bonding in amides is stronger than in amines
- the neighboring carbonyl is electron-withdrawing. this makes the N-H bond very polar, so more likely to form H-bonds with the electron pair on the Nitrogen of another amide (or with the Oxygen of water, etc.)
unshared electron pair on N can be donated. amines are this.
e.g. ammonia
Lewis base
basic conditions convert amide to carboxylic acid salt and amine
basic hydrolysis of amide
common name for 4 C chain amide
butyramide
amine salts physical properties
odorless
very high boiling point
water soluble
aqueous (dissolve in water)
amine solubility
•form Hydrogen-bonds with water
-amines of less than 6 C are water soluble
amino group
amine substituent
acidic conditions convert amide to carboxylic acid and amine salt
acidic hydrolysis of amide
quaternary amines
choline and acetylcholine
amine salt where all 4 R groups attached to N are hydrocarbon groups
•form strong Hydrogen-bonds with water
- 1° amides can form 4 Hydrogen-bonds with water
- water-soluble
amides solubility
valeramide
common name for 5 C chain amide
hydrolysis of amides
requires strong base, acid, or catalyst and heat
results in carboxylic acid and amine (or ammonia for primary amide)
amine salts
(ammonium salts)
Amines react with acids to produce these
e.g. CH3-NH3+ Cl-
requires strong base, acid, or catalyst and heat
results in carboxylic acid and amine (or ammonia for primary amide)
hydrolysis of amides
•form Hydrogen-bonds with water
-amines of less than 6 C are water soluble
amine solubility
amine
organic derivative of ammonia NH3 where one or more alkyl, cycloalkyl or aryl groups have replaced ammonia hydrogen atoms
sp3 trigonal pyramidal geometry
basic hydrolysis of amide
basic conditions convert amide to carboxylic acid salt and amine
Adenine, Guanine
Thymine, Cytosine, Uracil
types of heterocyclic rings
Amine bases in DNA and RNA
odorless
very high boiling point
water soluble
aqueous (dissolve in water)
amine salts physical properties
choline and acetylcholine
amine salt where all 4 R groups attached to N are hydrocarbon groups
quaternary amines