structural isomers
same molecular formula, different structural formula
stereoisomers
same structural formula, different spatial arrangement
chiral centre
carbon with 4 different groups attached
optical isomers
non- superimposable mirror images about a chiral centre
physical properties of optical isomers
identical
chemical properties of optical isomers
can be exceptionally different
2 benefits of using single stereoisomers in the synthesis of drugs
1- fewer side effects
2- increase pharmacological effectiveness
3- reduces need for separating steriorimers