Chemistry Reference
In-Depth Information
R'
H
O
R'
H
2
N
COOH
ON
N
COOH
O
R
H
The Schotten-Baumann reaction is used in many peptide syntheses. It is usually carried out in the
presence of common bases to remove the halogen acid. Another reaction that is also utilized often is
an acid azide condensation:
H
O
H
O
H
N
N
N
OH
+
H
2
N
NH
2
N
H
R
R
H
R'
H
O
H
O
R'
HNO
3
N
H
2
N
COOR"
N
OR"
N
3
N
R
R
H
O
N
N
0
-dicyclohexyl
A unique way of coupling carboxylic acids with an amine groups is by using an
,
carbodiimide method. This can be illustrated as follows:
H
O
N
COOH
NN
N
H
2
N
+
O
HO
H
O
O
N
O
C
2
H
5
N
N
+
NN
O
O
H
H
HH
In addition to the above mentioned, rather painstaking, techniques of polypeptide syntheses, a very
elegant technique was developed by Merrifield [
53
]. This
solid phase peptide synthesis
automates the
reaction sequences. The method makes use of an insoluble cross-linked polymer substrate with
pendant reactive groups for attachment of peptide chains. Chloromethylated polystyrene microgels
are often used (see Chap.
9
for more discussions on the use of chloromethylated polystyrene for
