C25. Nomenclature and Isomerism (A2) Flashcards
Describe the nomenclature of alkenes.
RCH=CH2
Suffix; -ene
Describe the nomenclature of alkynes.
RC≡CH
Suffix; -yne
Describe the nomenclature of halogenoalkanes.
R-X
prefix; halo-
Describe the nomenclature of carboxylic acids.
RCOOH
Suffix; -oic acid
Describe the nomenclature of anhydrides.
RCOOCOR’
Suffix; -anhydride
Describe the nomenclature of esters.
RCOOR’
Suffix; -oate (named from parent alcohol and acid)
Describe the nomenclature of acyl chlorides.
RCOCl
Suffix; -oyl chloride
Describe the nomenclature of amides.
RCONH2
Suffix; -amide
Describe the nomenclature of nitriles.
RC≡N
Suffix; -nitrile
Describe the nomenclature of aldehydes.
RCHO
Suffix; -al
Describe the nomenclature of ketones.
RCOR’
Suffix; -one
Describe the nomenclature of alcohols.
ROH
Suffix; -ol
Prefix; hydroxyl-
Describe the nomenclature of amines.
RNH2
Suffix; -amine
Prefix; amino-
What is a stereoisomer?
Compounds with the same structural formula but a different arrangement of bonds in space; EZ isomer; optical isomer
What is an optical isomer?
Compounds that contain an asymmetric carbon that differ in their effect on polarised light; Two non superimposable isomers that are mirror images of each other
What is a chiral centre?
Carbon atom that has 4 different atoms or groups of atoms attached
What are enantiomers?
Optical isomers that are nonsuperimposable mirror images of each other
What is the method of differentiating enantiomers?
Pass light through polaroid, polarises light; Polarised light passed through 2 solutions of same concentration, containing different enantiomers of the same substance; Measure optical rotation with polarimeter; 1 enantiomer will rotate plane of polarisation clockwise, + isomer; Other anticlockwise, - isomer
What is a racemate?
Mixture where equal amounts of enantiomers are present in the solution, optically inactive due to enantiomers cancelling each other effects
How are only the useful enantiomers formed in nature?
Naturally occurring molecules are formed from enzyme catalyst, forming only one best possible enantiomer
What are the options for selling a production 50/50 optical isomers of a drug?
Separate the two isomers, difficult and expensive; Sell the mixture as a drug, wasteful due to half being inactive; Design alternative synthesis of the drug, producing one enantiomer
Name an example of a racemate drug that is sold.
Ibuprofen
Explain the thalidomide tragedy.
Drug prescribed to relieve morning sickness; Enantiomers were hard to separate, prescribed as racemate; S enantiomer caused birth defects, R enantiomer was a safe sedative
