chemistry of nitrogen-containing organic compounds
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
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 Nitrogen-containing Functional GroupsFunctional Groups
NITRILESNITRILES AMINESAMINES AMIDESAMIDES AMINO ACIDSAMINO ACIDS POLYAMIDESPOLYAMIDES
NITRILES
• 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?
C NR
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
+ -CH3
H
IC
H
CN-
CH3
H
CNC
H I -
propanenitrile
Characteristic Reactions
• Hydrolysis - under acid or alkaline conditions
- occurs in two steps:
Carboxylic acids
CH3C
O
NH2
C NH3C
+ H2O1
HYDRATIONAMIDE
CH3C
O
NH2
2 + H2O CH3C
O
OH
CARBOXYLIC ACID
+ NH4+
NUCLEOPHILIC
SUBSTITUTION
• Reduction - Lithium tetrahydridoaluminate(III)
- in dry ether
Characteristic Reactions
Amines
CH3-CH2-NH2
C NH3C
+ 4[H]
REDUCTION AMINE
Draw the FSF for the compound produced when butanenitrile is reduced.
AMINES
• Relatives of NH3, where H’s have been replaced by a hydrocarbon chain
• Naming:
CH3-NH2
NH2AMINO GROUP
METHYL AMINEMETHYLAMINE
or…..AMINOMETHANE
AMINES
• Draw the full structural formula for 2-propylamine and give its alternative name.
• What types of INTERMOLECULAR FORCES exist in amines?
NH2AMINO GROUP
AMINE STRUCTURE
• Amines can be classed as primary, secondary or tertiary
NH2AMINO GROUP
C NH
H
PRIMARYC N C
C
TERTIARY
C N
H
C
SECONDARY
Producing amines 1
• Halogenoalkanes
- heat with ammonia in ethanol
Overall, what type of reaction is this?
1
2
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
• As bases
N
H
H H
Primary amines, although weak bases, are stronger than ammonia
Explained by the inductive effect
Inductive Effect
N
H
CH3 H
Alkyl groups are electron donating (INDUCTIVE EFFECT)
H+
More Alkyl groups = GREATER INDUCTIVE EFFECT
MORE BASIC
Reactions of amines 2
• 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?
N
H
H H
AMIDES
• Are white crystalline solids at room temperature (expect methanamide)
• Are important in polymer chemistry
• How can amides be made in the lab?
R-C
O
NH2
Reactions of amides• HYDROLYSIS
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
CH3C
O
NH2
+ H3O+
CH3C
O
OH
CARBOXYLIC ACID
+ NH4+
NUCLEOPHILIC
SUBSTITUTION
Reactions of amides 2
• DEHYDRATIONHeating 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
• 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 Acid Alkali
R
CC
H
O
OH
N
H
H
Zwitterion
Reactions of amino acids
• Amino acids join together to form peptides
• This is a condensation reaction
H
N
H
RC
O
OHR
1
An AMIDE group
amide
N
H
R R1
C
O
Draw the FSF of a peptide consisting of alanine, cysteine and serine
POLYAMIDES
• Formed from a diamine and a diacid
• Nylon is a polyamide
• Kevlar is an aramid
• Used to make bullet-proof vests
CO
HOR C
O
OHN
H
HR N
H
H