Naming compounds having various functional groups

The name of an organic compound specifies
 
  1.  
    the length of the longest carbon chain containing the functional group and the presence or absence of unsaturation.
     
    The stem indicates the length of the longest chain including the functional group.
    It is followed by -an- (indicating no carbon-carbon multiple bond) or -en- (indicating C=C) or -yn- (indicating C≡C).
    lengthstemlengthstem
    1meth6hex
    2eth7hept
    3prop8oct
    4but9non
    5pent10dec

    The stem may be preceded by the prefix cyclo if the carbons are in a ring.

  2. the functional group(s) present. These are indicated by the suffixes (endings) shown in the table.
    functional groupsuffix
    alkane (RH)
    alkene (R2C=CR2)
    alkyne (RC≡CR)    		ane
    ene
    yne
    amide (RCONH2)amide
    alcohol (ROH)ol
    aldehyde (RCHO)al
    ketone (RCOR)one
    acid (RCO2H)oic acid
    ester (RCO2R)oate
  3. the position of the functional group in the chain, if there is more than one possible location.
    Functional groups appearing in the middle of the chain are given the lowest number counting from the end of the chain. The number (locator) appears in the name directly before the functional group that it locates.

    By convention the amide, aldehyde and carboxylic acid functional groups take priority in numbering, and therefore the carbonyl (C=O)carbon in these groups is always numbered as C-1. For these functional groups C-1 does not have to be specified in the name.

Through the International Union of Pure and Applied Chemists, naming of organic compounds has become much more systematic In the last decade. See the Official IUPAC rules through this link.
Dr Sheila Woodgate
© The University of Auckland 2002