medchem 3

Question 1

2 chiral centres give rise to

Answer 1

4 steriosimers ( rr,ss, rs, sr )

Question 2

Fischer projection is most useful for molecules with

Answer 2

more than 2 chiral centres

Question 3

diasteriosmers have

Answer 3

same configuration in one and opposite configuration in another. they have different physical and chemical properties ( melting, boiling, solubility). Specific angles of rotation won’t be equal and have different effects on plan of polarised light.

Question 4

tartaric acid has

Answer 4

• three sterioisomers instead of 4
• 2 asymmetric centres w/ same substituents
• has chiral centres but is achiral ( so inactive )

Question 5

Compounds that have 2 chiral centres but are achiral are called

Answer 5

meso compounds ( inactive and have the opposite configuration and have plane of symmetry )

Question 6

thalidomide

Answer 6

• used to induce sleep and prevent nausea during pregnancy
• side effects: teratogen and may cause foetal abnormalities
• r- isomer: sedative properties
• s- isomer: birth defects
• Ada approved for leprosy

Question 7

isomers with different bond pattern are called

Answer 7

consitiutional or structural

Question 8

isomers with the same bond pattern

Answer 8

stereoisomers ; different by bond rotation about single bonds.
yes: conformational
no: configurational.