Functional group

Question 1

Why do many drug compounds
contain carbonyl groups?

Answer 1

Carbonyl groups can make
hydrogen bonding interactions (and dipole interactions) with receptor binding sites in the body helping drug molecules to bind strongly.

Question 2

Explain why carboxylic acids are stronger acids than alcohols

Answer 2

he greater acidity of carboxylic acids compared to alcohols is due to resonance stabilisation of the
carboxylate ion
In an alkoxide ion, the negative charge is localised on the oxygen making it less stable

Question 3

Explain the difference in acidity between trifluoracetic acid and acetic acid

Answer 3

Trifluoroacetic acid is more acidic than acetic acid. The CF 3
group is electron withdrawing, which stabilises the carboxylate
ion and increases acidity.

Question 4

Nucleophilic addition
1. Why do nucleophiles add to carbonyl compounds?
2. Draw a mechanism for nucleophilic addition to a carbonyl group. Take care to include all charges..

Answer 4

The carbon of the carbonyl group has a partial positive charge, which attracts nucleophiles

Question 5

Name a reagent used for the reduction of aldehydes and ketones
Draw the reaction mechanism for the reduction of an aldehyde or ketone.

Answer 5

NaBH 4

Question 6

Reactions of Carbonyl Compounds
1. Why does this reaction not occur when Y = -H, -R(CH3)?

Answer 6

The Y group acts as a leaving group. The leaving group leaves and forms an anion. This anion needs to be
stable in order for the Y group to leave. H - and R - are not stable anions so they are not good leaving groups

Question 7

Acid chlorides
1. Draw the reaction mechanism for the hydrolysis of an acid chloride…
2. What could you replace water with to make an amide?

Answer 7

An amine

Question 8

Formation of Esters
1. Draw the reaction mechanism for acid-catalysed esterification …
2. Draw the reaction mechanism for base-catalysed esterification …

Answer 8

see canvas

Question 9

What is the difference between a peptide and a protein?

Question 10

Name 3 types of protein found in our bodies.

Question 11

Draw the general structure of amino acids.
How many naturally occurring amino acids are there?
3. Name 2 non-polar, neutral amino acids and 2 charged amino acids

Question 12

The isoelectric point (pI) is reached when an amino acid exists as a zwitterion.
(a) Calculate pI for Glycine if pKa α-COOH = 2.34 and pKa α-NH3+ =
9.60
(b) Calculate pI for Lysine