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• Relatives of NH3, where H’s have been replaced by a hydrocarbon chain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