22
Classical bioisosteres
1. Monovalent atoms or groups:
OH
SH
Br
I
NH
PH
-Pr
2
2
i
CH 3
CI
F
H
CH 2
COCH R
2
CONHR
NH
O
S
CO R
2
COSR
CH
P
N
As
2. Bivalent atoms or groups:
3. Trivalent atoms:
C
Si
N
+
P
+
4. Tetravalent atoms:
Nonclassical bioisosteres
1. Functional group replacements:
a. Halogens:
X
C F 3
CN
N(CN) 2
C(CN) 3
b. Hydroxyl group:
OH
NHCOR
CH OH
NHSO R
2
2
CH(CN)
NHCN
2
NHCONHR
c. Carbonyl group:
C
O
S
O
O
O
S
S
O
NH
C
NC
CN
N OH
C
d. Carboxylic acid group:
(Continued)