8. DCC

Chemistry and applications of DCC is discussed.

1. 8. Dicyclohexyl carbodiimide (DCC)
Dr. Shivendra Singh
UGC-NET-JRF, PhD- IIT Indore
Assistant Professor
[email protected]
Webpage: https://sites.google.com/view/drshivendrasingh/home
Youtube: https://bit.ly/2YM0QG0

2. 2
…Dicyclohexyl carbodiimide (DCC)
Ø N,N-Dicyclohexylcarbodiimide (DCC) is a dehydrating agent often used
to form esters, amides or anhydrides.
Ø It is commercially available as a waxy low-melting solid (34-35
o
C).

3. 3
…Dicyclohexyl carbodiimide (DCC)
ü It can also be prepared by oxidation of dicyclohexylurea with p-toluene-
sulfonyl chloride in hot pyridine or
ü by heating dicyclohexylthiourea with yellow mercuric oxide.

4. 4
Ø Some important applications in organic synthesis;
1. Synthesis of peptides
2. Synthesis of esters
3. Synthesis of ethers and thioethers
4. Synthesis of nitriles
5. Synthesis of α,β-Unsaturated Esters
6. Heterocyclization Reactions
…Dicyclohexyl carbodiimide (DCC)

5. 5
…Dicyclohexyl carbodiimide (DCC)
1. Synthesis of Peptides
ü DCC is useful for the coupling of amino acids via amide C-N bonds.
ü The amino acid monomers should be such that the ends to be available and other
reactive groups protected.
ü For example, for the synthesis of dipeptide between to two α-amino acids, the
amino group of one of the amino acids and the carboxylic group of the other must
be protected before the two amino acids are brought together in the presence of
DCC.

6. 6
…Dicyclohexyl carbodiimide (DCC)
Mechanism:
DCC reacts with the
carboxyl group of
amino protected acid to
give activated acylating
agent that undergoes
reaction with amino
group of other amino
acid to form of a new
amide bond.

7. 7
…Dicyclohexyl carbodiimide (DCC)
2. Synthesis of Esters
ü The synthesis of esters from carboxylic acids and alcohols can be
accomplished in the presence of DCC in CH
2
Cl
2
solvent at ambient
conditions.
ü This reaction is called Steglich esterification and usually for the sterically
hindered substrates.

8. 8
…Dicyclohexyl carbodiimide (DCC)
Mechanism:
The carboxylic acid proceeds reaction with DCC to afford activated acylating
agent that undergoes reaction with the alcohol.

9. 9
…Dicyclohexyl carbodiimide (DCC)
3. Synthesis of Ethers and Thioethers

10. 10
…Dicyclohexyl carbodiimide (DCC)
4. Synthesis of Nitrile
The readily accessible oximes from aldehydes and hydroxyl amine readily
undergo dehydration in the presence of DCC to nitriles in quantitative yields.

11. 11
…Dicyclohexyl carbodiimide (DCC)
5. Synthesis of α,β-Unsaturated Esters
The dehydration of β-hydroxy esters can be efficiently carried out using DCC
to give α,β-unsaturated ester.

12. 12
…Dicyclohexyl carbodiimide (DCC)
6. Heterocyclization Reactions
ü DCC is used as reactant as well as reagent in heterocyclization reactions.
ü For an example, barbituric acid and its derivatives can be prepared by the
reaction of malonic acid with DCC