Transcript Chemistry of Nitrogen-containing Organic Compounds

Chemistry of
Nitrogen-containing
Organic Compounds
FSF = Full Structural Formula
Key Areas
• Functional group – name and structure
• Characteristic chemical reactions
- type
- reactants
- products
- conditions
- mechanism
Nitrogen-containing
Functional Groups





NITRILES
AMINES
AMIDES
AMINO ACIDS
POLYAMIDES
NITRILES
R
C N
• Not to be confused with cyanides (CN- )
• First member is ethanenitrile. Draw the full
structural formula.
• Name the fourth member of the family.
• C N very polar
• Will the C-atom be a nucleophile or
electrophile?
Producing nitriles
• Halagenoalkanes
- heating under reflux with NaCN
or KCN in ethanol
- draw the FSF for 1-bromobutane
and then for the nitrile produced
on reaction with KCN
- what type of reaction is this?
- what is significant about the
length of the carbon chain?
Reaction mechanism
H
+
CH3 C
H
CN-
I
-
H
CH3 C
CN
H
propanenitrile
I
-
Characteristic Reactions
• Hydrolysis
Carboxylic acids
- under acid or alkaline conditions
- occurs in two steps:
1
H3C
O
CH3C
C N + H2O
HYDRATION
NH2
AMIDE
O
2
CH3C
+ H2O
NH2
NUCLEOPHILIC
SUBSTITUTION
O
CH3C
OH
+ NH4+
CARBOXYLIC ACID
Characteristic Reactions
• Reduction
Amines
- Lithium tetrahydridoaluminate(III)
- in dry ether
H3C
C N + 4[H]
CH3-CH2-NH2
REDUCTION
AMINE
Draw the FSF for the compound produced when
butanenitrile is reduced.
AMINES
NH2
AMINO GROUP
• Relatives of NH3, where H’s have been
replaced by a hydrocarbon chain
• Naming:
CH3-NH2
METHYLAMINE
AMINOMETHANE
METHYL
AMINE
or…..
AMINES
NH2
AMINO GROUP
• Draw the full structural formula for 2propylamine and give its alternative name.
• What types of INTERMOLECULAR
FORCES exist in amines?
AMINE STRUCTURE
NH2
AMINO GROUP
• Amines can be classed as primary,
secondary or tertiary
H
H
C
N
C
H
C
N
C
SECONDARY
PRIMARY
C
N
C
TERTIARY
Producing amines 1
• Halogenoalkanes
- heat with ammonia in ethanol
1
2
Overall, what type of reaction is this?
Producing amines 2
• Nitriles (What is a nitrile?)
-C≡N
- reduction
- using LiAlH4 (in dry ether + water)
• Draw the simplified strucural formula for
the amine produced by reducing
butanenitrile.
Reactions of amines
H
H
N
H
• As bases
Primary amines, although weak bases, are stronger than ammonia
Explained by the inductive effect
Inductive Effect
H
CH3
N
H
H+
Alkyl groups are electron donating (INDUCTIVE EFFECT)
More Alkyl groups = GREATER INDUCTIVE EFFECT
MORE BASIC
Reactions of amines 2
H
H
•
N
H
As nucleophiles
- with acid chlorides (acyl chlorides)
1. Find out what an acyl chloride is and draw the
general structure.
2. Draw a reaction mechanism for an acyl
chloride with 3 carbon atoms reacting with
ethylamine.
3. What is this type of reaction called?
4. What type of organic compound is the
product?
AMIDES
O
R-C
NH2
• Are white crystalline solids at room
temperature (expect methanamide)
• Are important in polymer chemistry
• How can amides be made in the lab?
Reactions of amides
• HYDROLYSIS
O
CH3C
+
NH2
H3O+
NUCLEOPHILIC
SUBSTITUTION
O
CH3C
OH
+ NH4+
CARBOXYLIC ACID
Using acid or alkali
This is the same as the second step as when nitriles are
hydrolysed
Using the notation as above, use FSF to draw the
hydrolysis carried out under alkaline conditions
Reactions of amides 2
• DEHYDRATION
Heating an amide with phosphorus(V) oxide
dehydrates the compund.
Using FSF, construct an equation for the
dehydration of an amide with 4 carbon
atoms.
Name the amide.
What type of organic compound is
produced?
AMINO ACIDS
H
H
R
N
C
H
•
•
•
•
O
C
OH
Are the building blocks of proteins
About 20 in total
Draw the FSF for a chiral amino acid
Draw the FSF of an amino acid when it is in:
Water
Zwitterion
Acid
Alkali
Reactions of amino acids
• Amino acids join together to form peptides
• This is a condensation reaction
H
N
R
O
C
H OH
R
1
R
H
O
N
C
R1
amide
An AMIDE group
Draw the FSF of a peptide consisting of alanine, cysteine and serine
POLYAMIDES
O
O
C
HO
•
•
•
•
R
C
OH
H
H
H
N
R
N
Formed from a diamine and a diacid
Nylon is a polyamide
Kevlar is an aramid
Used to make bullet-proof vests
H