Prof.Dr. Meral Tunçbilek
ISOMERISM IN DRUG
Isomers, are molecules that are very similar to each other but are not identical due to differences in their chemical structure Isomerism: I- Structural isomerism II-Stereoisomerism i) Configurational Isomers * Geometric Isomerism * Optical Isomerism ii) Conformational Isomers
Structural isomerism (Constitutional Isomerism):
*The same molecular formula
*Different bonding patterns and atomic organization
Stereoisomerism:
Molecules have
*the same molecular formula and sequence of
bonded atoms (constitution),
*but differ in the three-dimensional orientations of
Configurational Isomerism
Configurational isomers are stereoisomers that can cannot be converted into one another by rotation around a single bond.
The two main types of configurational isomers are *geometric isomers and
Conformational Isomerism
Conformational isomerism is a form of stereoisomerism in which the isomers can be interconverted just by rotations about formally single bonds (single (σ) bonds)
While any two arrangements of atoms in a molecule that differ by rotation about single bonds can be referred to as different conformations,
conformations that correspond to local minima on the energy surface are specifically called conformational isomers or conformers
In activity differences in stereoisomers, *Drug-receptor interactions are important
