6.2.1 & 2 -Amines, Amino acids, Amines & Chirality

Question 1

Naming when NH2 is attached to 1st C

Answer 1

• amine

e. g. hexylamine

Question 2

Naming when NH2 is attached to middle C

Answer 2

no. where -NH2 is attached
amino
Longest carbon chain
e.g. 3 amino hexane

Question 3

Naming when NH2 group is attached to 2/3 groups

Answer 3

N- side chain 1 N - side chain 2 - amine

e.g. N - ethyl, N methyl amine
alphabetical order

Question 4

Primary amines

Answer 4

N attached to one R group, 2 H’s

Question 5

Secondary amines

Answer 5

N attached to two R groups, 1 H

Question 6

Tertiary amines

Answer 6

N attached to three R groups, no H’s

Question 7

Quaternary ammonium salts

Answer 7

Not amines but ammonium salts with NO lone pair on the N

Question 8

Aromatic amines

Answer 8

Have the N joined directly to the benzene ring

Question 9

Bonding between amines

Answer 9

Some H bonding between molecules but weaker than in alcohols
No H bonding in 3’ amines
Many simple amines are liquids at rt

Question 10

What does base strength of amines depend on

Answer 10

How well the N lone pair can accept H+

Question 11

When is the basicity of an amine higher

Answer 11

When the charge density is higher

Question 12

Base strength increases from ..

Answer 12

1’ to 3’ amines due to alkyl groups pushing electron density towards the N

Question 13

Base strength of 4’ amines

Answer 13

Ammonium salts aren’t bases

Question 14

Why is basicity low in aromatic amines

Answer 14

W/ aromatic amines, NH2 is an ED group so lone pair on N is drawn into delocalised ring, reducing electron density on lone pair

Question 15

Highest to lowest basicity

Answer 15

3’ > 2’ > 1’ > NH3 > Aromatic

Question 16

Synthesis of 1’ amines

Answer 16

Nucleophilic substitution

Excess ethanolic NH3 and haloalkane –> 1’ amine and NH4X

Question 17

Synthesis of 4’ ammonium salts

Answer 17

Ethanolic NH3 and a large excess of the haloalkane

Question 18

Explaining why something is the stronger base

Answer 18

X has a greater electron density on N lone pair as it is a 3’ /2’/ 1’amine
and therefore X has a greater ability to accept H+

Question 19

Synthesis of 2’ amines

Answer 19

Excess haloalkane and 1’ amine

Neutralise w/ NaOH

Question 20

Synthesis of 3’ amines

Answer 20

Excess haloalkane and 2’ amine

Neutralise w/ NaOH

Question 21

Synthesis of aromatic amines

Answer 21

Nitrophenol + 6[H] —> phenylamine + 2 H2O
Sn - gets reduced
Conc. HCl

Question 22

Large excess of haloalkane and amine –>

Answer 22

Ammonium salt

Question 23

General formula of amino acids

Answer 23

RCH(NH2)COOH

Question 24

What makes something an alpha-amino acid

Answer 24

Has both NH2 and COOH attached to same carbon (2nd)

Question 25

beta amino acids

Answer 25

Have NH2 attached to 3rd carbon

Question 26

Amino acids and acids

Answer 26

Ammonium salt

Question 27

What allows amino acids to react w/ acids

Answer 27

NH2 is basic so can accept H+

Question 28

Amino acids and strong bases

Answer 28

Carboxylate salt and water

Question 29

Amino acids and carbonates

Answer 29

Carboxylate salt, water and CO2

Question 30

What allows amino acids to react w/ bases

Answer 30

-COOH

Question 31

Ester formation from amino acids

Answer 31

Amino acids + excess alcohol + H2SO4 ---> ester w/ protonated amine group and alcohol replaced H in -OH on -COOH

Question 32

Chiral centre

Answer 32

Tetrahedral Carbon is attached to 4 DIFFERENT groups 2 optical isomers for each chiral centre No double bonds

Question 33

Which amino acid is achiral

Answer 33

Glycine | H2NCH2COOH

Question 34

Enantiomers

Answer 34

Pair of stereoisomers which are NON-SUPERIMPOSABLE mirror images of each other

Question 35

Racemic mixture

Answer 35

A 50:50 mixture of two enantiomers

Question 36

Forming dipeptides

Answer 36

Condensation reaction | Loses OH from -COOH on one AA and H from -NH2 on the other AA

Question 37

Drawing repeat units of polypeptides

Answer 37

Extend bonds and leave out H on -NH2 and OH on -COOH

Question 38

Drawing 3D molecules

Answer 38

Wedged line - coming out of the plane Dashed line - going into the plane Tetrahedral - wedged, dashed, 2 straight

Question 39

Amide group (peptide link)

Answer 39

CONH

Question 40

Syntheisis of single optical isomers

Answer 40

Enzymes or bacteria | Chiral catalyst

Question 41

Producing 1'/2' amides from acyl chlorides

Answer 41

Acyl chloride + NH3/amine/amino acid

Question 42

Acyl chloride and water

Answer 42

-COOH and HCl