Chapter 27 Flashcards
What is an amine?
It is an organic compound which is derived from ammonia and which one or more H atoms in ammonia have been replaced by carbon ring or carbon chain.
What is an aliphatic amine?
It’s when the nitrogen atom is attached to at least one straight or branched carbon chain (alkyl group).
What is an aromatic amine?
It’s when the nitrogen atom is attached to at least one aromatic ring.
What can amines be classified as?
Primary, secondary or tertiary depending on the number of alkyl or aryl groups (group derived from aromatic rings) which is attached to the N atom.
How does Serotonin act?
It acts as a neurotransmitter responsible for the control of appetite, sleep, memory and learning, temperature regulation, muscle contraction and depression.
Where is pseudoeptidine round and what does it do?
Its found in decongestion medicine ie nose drops and cold remedies. It works by shrinking the nasal membranes and inhibiting nasal secretions
How do you name a primary amine with the -NH2 at the end of the chain?
Prefix = alkyl Suffix = amine
Name CH3NH2?
Methylamine
How do you name a primary amine with the -NH2 not at the end of the chain?
Prefix = amino Suffix = longest carbon chain
How do you name an amine with more than one primary group?
Prefix = Di, tri, amino Suffix = name of the longest carbon chain
Name H2N-CH2-CH2-CH2-CH2-NH2
1,4- diaminobutane
How do you name a secondary or tertiary amine with the same alkyl group?
Prefix = di or tri alkyl Suffix = amine
Name (C6H5)3N?
Triphenylamine
Name (CH3CH2CH2)NH?
Dipropylamine
How do you name a secondary or tertiary amine with the different alkyl groups?
Give the largest chain the suffix -amine
give the shorter chain(s) as N-prefixes in alphabetical order
What do amines act as?
A base due to the lone pair of electrons on the N, which accept a proton to form a dative covalent bond.
What can amines neutralise?
Acids to become salts
Write an equation for ammonia + nitric acid
NH3 + HNO3 –> NH4+NO3-
Write the product for diethyl amine + hydrochloric acid
(CH3CH2)2NH2+Cl-
Write an equation for 1,2-diaminoethane + hydrochloric acid
H2NCH2CH2NH2 + 2HCl –> Cl-+H3NCH2CH2NH3+Cl-
Write an equation for phenyl amine + sulphuric acid
2C6H5NH2 + H2SO4 –> (C6H5NH3+)2SO42-
What does ammonia act as?
A nucleophile when replacing the halogen on a halo alkane with the NH2 group
How do you prepare a primary aliphatic amine?
- NUCLEOPHILIC SUBSTITUTION
ammonia reacts with a haloalkane to form an amine salt - Aq excess alkali is added to generate an amine from the salt
How do you prepare a secondary or tertiary aliphatic amine?
- Make a primary aliphatic amine like previously.
- React further with more haloalkane to produce secondary amine salt.
- React with NaOH to produce secondary amine
- React further with more haloalkane to produce tertiary amine salt.
- React with NaOH to produce tertiary amine
What are the essential conditions producing aliphatic amines?
- Ethanol as the solvent, NOT water
2. EXCESS ammonia ensures no haloalkane is left over to react with the primary amine product
Can nucleophilic substitution work on aromatic amides?
No ammonia can’t
How are aromatic amines prepared?
They are reduced by the nitro group
- Sn/ conc HCl reflux (red agent)
- Excess NaOH (aq)
What reaction is the preparation of amides?
Condensation
How are amides formed?
From the reaction of acyl chlorides with either ammonia, primary or secondary amines
Acyl chloride + ammonia
Primary amide + HCl (reacts with another mole of ammonia)
Acyl chloride + 2 ammonia
Primary amide + ammonium salt
Acyl chloride + 2 primary amine
secondary amide + salt of primary amide
What is an amino acid?
It is a organic compound containing both amine, NH2 and carboxylic acid, COOH functional groups. An a-amino acid is when the amine group is attached to the a-carbon (one adjacent to the carboxyl group)
How many naturally occurring amino acids are there?
20
What does the COOH act as?
An acid (proton donor) to make a salt
What does the NH2 act as?
A base (proton acceptor) to make a salt
How can carboxylic acids be esterifed?
By heating with an alcohol, with the presence of conc H2SO4
What happens under acidic conditions to the amine during esterification?
The amine will be protonated.
What are structural isomers?
Same molecular formula but different structural formula
What are stereoisomers?
Same molecular and structural formula but different arrangement in 3-D space.
What are EZ isomers?
It’s when there is no rotation around the C=C each carbon in the C=C needs to be connected to 2 different substituents
What are optical isomers?
These are non-superimposable mirror images of each other
What is a chiral carbon?
A molecule which contains four different groups attached to it this molecule will exist as an optical isomer.
What are optical isomers also known as?
Enantisomers
When can there not be a chiral carbon?
If it doesn’t contain 4 single bonds.
Double bonded carbons and benzene carbons.
What molecules contain chiral carbons?
a-amino acids apart from glycine
Describe optical isomers and the body.
Naturally occurring amino acid are always one particular optical isomer. Enzymes of protein hormones are also one particular. Any medicinal molecules must be manufactured as a single optical isomer so that it can interact with the binding side of the active site so that it fits properly. The other isomer is usually pharmacologically inactive but may cause harmful effects. Thalidomide was marketed and administered as a mixture of enantiomers in which one had a pharmacological effect and the other suppressed foetal growth.
How can enantiomers interact differently with chiral receptors?
When you smell or taste something
What is condensation polymerisation?
It is the joining of monomers via a condensation reaction i.e. the elimination of a small molecule usually water or hydrogen chloride. For this reaction to different functional groups are needed.
Name some condensation polymers?
Polyesters and polyamides
What is a polyester?
It is made from monomers which are joined by ester linkages along a chain to form a polymer.
Polyesters can be made from one monomer containing what different functional groups?
A carboxylic acid and an alcohol group
Polyesters can be made from two monomer containing what different functional groups?
- one monomer is a diol with two hydroxyl groups (or phenols)
- one monomer is a dicarboxylic acid with two carboxyl groups (or diacyl chloride )
What is hydrolysis?
It is the chemical breakdown of a compound in the presence of water or aqueous solution.
What conditions are carried out when hydrolysing and ester?
Either acidic or alkaline
Describe acid hydrolysis of an ester?
It’s heated under reflux with dilute aqueous acid, and equilibrium is set up.The acid acts as a catalyst this is the reverse of esterification.
Products: CARBOXYLIC ACID + ALCOHOL
Describe alkaline hydrolysis of an ester?
Yes there is heated under reflux with aqueous 0H ions. The reaction is irreversible and a carboxylate ion is formed.
Products: CARBOXYLATE ION + ALCOHOL
What is formed in base hydrolysis (reflux: NaOH/H2O) of a polyester?
Salt of carboxylic acid (sodium salt)
Alcohol
What is formed in acid hydrolysis (reflux: H+/H2O) of a polyester?
Carboxylic acid
Alcohol
What are polyamides?
They are condensation polymers which are formed when monomers are joined by amide linkages in a long chain to form the polymer.
Polyamides can be made from one monomer containing what different functional groups?
An amine and a carboxylic acid (or acyl chloride)
What happens when a-amino acids combine?
They form a polypeptide
Polyamides can be made from two monomer containing what different functional groups?
- one monomer is a diamine
- one monomer is a dicarboxylic acid (or diacyl chloride)
How can amides be hydrolysed?
With aqueous alkali or acid
Describe acid hydrolysis of amides?
Amide —> carboxylic acid + protonated amine
Describe alkaline hydrolysis of amides?
Amide —> carboxylate ion + amine
What is formed in base hydrolysis (reflux: NaOH/H2O) of a polyamide?
Salt of dicarboxylic acid
diamine
What is formed in acid hydrolysis (reflux: H+/H2O) of a polyamide?
Dicarboxylic acid
diamine salt
What can happen in some cases with monomers of two different functional groups if it doesn’t form a polymer?
It can form a cyclic product (reacts with itself)
Describe the characteristics of addition polymerisation
Monomer contains C=C bond.
Backbone of polymer is a continuous chain of carbon atoms.
Describe the characteristics of condensation polymerisation
Two monomers each with 2 functional groups (HOOCCH2COOH & HOCH2CH2OH)
One monomer containing 2 different functional groups
Polymer containing ester or amide linkages.
