applications of chirality

multiple chiral centre in a molecule

if a compound has ‘n’ chiral centers, there are 2ⁿ possible stereoisomers

1 chiral center - 2 stereoisomers i.e. R and S

2 chiral centers - 4 stereoisomers i.e. RR,SS,RS,SR

if it is chiral, it only has 3 stereoisomers

diastereomers

stereoisomers that are not mirror images of one another. different physical and chemical properties

different effects on the plane of polarized light. The specific angles of rotation will be unequal and may not differ in sign

tartartic acid

3 stereoisomers because each of its 2 asymmetric centers have the same set of four substituents

thalidomide

occupation: to induce sleep and prevent nausea during pregnancy

side effects: teratogen i.e. causes foetal abnormalities

R-isomer: sedative properties

S-isomer: responsible for birth defects afecting the eyes, ears, internal organs and limbs

applications of chirality

molecules with different shapes fit into different receptors. A receptor shaped like a right glove, for example, would interact only with a right handed glove

drug design and chirality

most drugs are chiral

usually only one enantiomer is therapeutically active

other enantiomer:

• may be totally inactive or have significantly reduced activity

• may produce unwanted side effects