Lecture 03, 4

• What type of carbon atom is involved in optical isomerism?

  Tetrahedral carbon atom
• What are stereoisomers known as when they are non-superimposable mirror images?

  Enantiomers
• What is a characteristic of optically active compounds?

  No centre of symmetry
• What defines enantiomers in terms of their properties?

  Identical except for light rotation
• What is the term for molecules that can rotate the plane of polarised light?

  Optically active
• What is the term for a carbon atom bonded to four different groups?

  Chiral centre
• What is the rotation direction for dextrorotatory isomers?

  Clockwise
• What is the rotation direction for laevorotatory isomers?

  Anticlockwise
• What does a polarimeter do?

  Measures optical rotation

  
• What factors affect the measured angle of rotation in optical activity?

  Structure, temperature, wavelength, concentration, solvent
• What is specific rotation denoted as?

  [α]
• What does the specific rotation measure?

  Rotation produced by 1g in 1ml
• What is the path length in a polarimeter tube for specific rotation?

  1.0 decimetre
• What is a racemic mixture?

  Equal parts of enantiomers
• How many forms can a chiral molecule exist in?

  Three forms
• What indicates a dextrorotatory isomer?

  (+)- sign or d
• What indicates a laevorotatory isomer?

  (−)- sign or l
• What is the Fischer projection convention for horizontal bonds?

  Project forward towards the reader
• What is the purpose of the CIP rules?

  Assign configuration at chiral centres
• What does the D/L system indicate?

  Configuration of glyceraldehyde
• What is the configuration for NH2 on the right in glyceraldehyde?

  D configuration
• What is the configuration for NH2 on the left in glyceraldehyde?

  L configuration
• What happens when the sequence from highest to lowest priority is clockwise?

  Configuration is R
• What happens when the sequence from highest to lowest priority is anticlockwise?

  Configuration is S
• What is a racemic mixture of ibuprofen indicated as?

  (±)-(R,S)-ibuprofen
• What is a racemic mixture of adrenaline indicated as?

  (±)-(R,S)-adrenaline
• What is significant in pharmaceuticals regarding molecular shape?

  3D spatial arrangement of atoms
• What do compounds with multiple chiral centres produce?

  2$^n$ stereoisomers
• What are diastereoisomers?

  Stereoisomers that are not enantiomers
• What are epimers?

  Different at one stereogenic centre
• How many stereoisomers does erythrose have?

  Four stereoisomers
• What is the relationship between erythrose and threose?

  They are diastereomeric pairs
• What is the significance of a line of symmetry in a molecule?

  It indicates the molecule is not optically active
• What is a meso form?

  Achiral due to internal compensation
• What is the effect of symmetry on stereoisomers?

  Reduces the number of stereoisomers
• What is the significance of chirality in biological systems?

  Preference for one enantiomer over another
• What is the "Three Point Interaction" in biological systems?

  Interaction with a biological target