ACYLATION

L.O.: What is an acylation reaction?

What is the nucleophilic addition-elimination mechanism fro acylation reactions?

R CO

The acyl group:

Acylation is the process by which the acyl group is introduced into another molecule.

Think of examples of types of compounds containing the acyl group.

R CO

Z

ester

+R C

O

O R'H O R'+R C

O

X HX X = Cl or O C

O

R'

amide

+R C

O

N R'

H

H N R'

H

+ 2 NH3R'+ X- X = Cl or O C

O

R'R C

O

Cl

water + propanoyl chloride

ammonia + ethanoyl chloride

propan-2-ol + ethanoyl chloride

ethylamine + propanoic anhydride

propylamine + butanoyl chloride

propan-1-ol + ethanoic anhydride

water + butanoic anhydride

ammonia + propanoic anhydride

Addition-elimination mechanism

- H+- Cl-

_

+R C O

Cl

O

R'

H

R C

O

Cl

H O R'

R C O

O

R'

H

+R C O

O

R'

Addition-elimination mechanism

- H+- Cl-

_

+R C N

Cl

O

R'

H

H

R C

O

Cl

H N R'

H

R C N

O

R'

H

H

+R C N

O

R'

H

Name and outline the mechanism for the reaction between propanoyl chloride and methylamine.

Advantages of using ethanoic anhydride over ethanoyl chloride as an acylating agent:

CheaperLess corrosiveIt does not react with water as readilySafer. By-product is ethanoic acid rather than

HCl.

ASPIRIN

+

O

CCH3 O C

O

CH3 O CH3C

O

COOH

OH

COOH

O

CCH3 O H+

2-hydroxybenzenecarboxylic acid aspirin