Carboxylic Acid Derivatives | Organic Chemistry 2

The carboxylic acid derivatives are studied in this chapter: their properties and relative reactivities, the chemistry of acyl halides, the chemistry of esters, the chemistry of carboxylic anhydrides, the chemistry of amides.

Properties and Relative Reactivities

 

H is acidic. The pKa depends on the electronegativity of
⇒ The lower the electronegativity, the higher the pKa.
​​​​​Acyl Halide: pKa ~ 16; Carb. Anh.: pKa ~ 20; Ester: pKa ~ 25; Amide: pKa ~ 30.

 

Chemistry of Acyl Halides

Naming:
The -oic acid ending of the corresponding carboxylic acid is replace by -oyl halide
('halide' = fluoride, chloride, bromide, iodide)

 

Formation of Carboxylic Acid, Carboxylic Anhydride, Ester and Amide:
 


- NuH = HOH ⇒ Carboxylic Acid Formation
- NuH = R'COOH ⇒ Carboxylic Anhydride Formation
- NuH = R'OH ⇒ Ester Formation
- NuH = R'HNH ⇒ Amide Formation

Mechanism: Addition-Elimination

 

Formation of Ketone:
 

Mechanism: Addition-Elimination

Formation of Aldehyde:
 

Mechanism: Addition-Elimination

 

Chemistry of Esters

Naming:
The alkyl chain R' is named as a substituent.
This is followed by the name of the parent chain (RC) where the -ane of the corresponding alkane is replaced by -oate.

 

 

Formation of Carboxylic Acid, Ester and Amide:
 


- NuH = HOH ⇒ Carboxylic Acid Formation
- NuH = R''OH ⇒ New Ester Formation (Transesterification)
- NuH = R''HNH ⇒ Amide Formation

Mechanism: Addition-Elimination

 

Formation of Alcohol:
 

Mechanism: Addition-Elimination

Mechanism: Addition-Elimination

 

 

Formation of Aldehyde:
 

 

Chemistry of Carboxylic Anhydrides

Naming:
Add the term anhydride to the carboxylic acid name.


Formation of Carboxylic Acid, Ester and Amide:
 


- NuH = HOH ⇒ Carboxylic Acid Formation
- NuH = R'OH ⇒ Ester Formation
- NuH = R'HNH ⇒ Amide Formation

Mechanism: Addition-Elimination

Chemistry of Amides

Naming:
The -ane ending of the corresponding alkane is replace by -amide.
Substituents on the nitrogen are indicated by the prefix N- or N,N- (if two similar groups).

 

Formation of Carboxylique Acid:
 

Mechanism: Addition-Elimination

 

 Formation of Amine:
 

 Formation of Aldehyde: