Amides

Question 1

Outline the formation of an amide

Answer 1

Reaction between an amine and an acyl chloride. Reaction goes via the tetrahedral intermediate and requires 2 equivalents of the amine (one for addition, one for deprotonation. Base is also required to sequester the HCl released

Question 2

Mechanism for amide formation from an acyl chloride

Answer 2

Check notes

Question 3

Why is the hydrolysis of amides difficult

Answer 3

The lone pairs on nitrogen are very readily available, and readily delocalise into the pi system of the C=O bond. This increases the energy of the pi* orbital making it less acessible and the carbonyl less electrophilic

Question 4

Conditions for amide hydrolysis

Answer 4

They are forcing conditions. Strong acid or base (H2SO4 or NaOH) and high temperatures (100 C)

Question 5

Why is strong acidic conditions favoured over strong basic conditions for amide hydrolysis

Answer 5

After the OH group is added, the intermediate will more often than not collapse back into the starting material as supposed to progressing towards the product.

Question 6

Mechanism for amide hydrolysis under acidic and basic conditions

Answer 6

Check notes

Question 7

Conditions and mechanism for the formation of an acyl chloride

Answer 7

SOCl2, EtN3

Question 8

Why can’t you form an amide directly from a carboxylic acid

Answer 8

The basic amine used will form a salt of the carboxylic acid instead of acting as a nucleophile