IUPAC Nomenclature - Rules of Writing Names

Description:

Note that while writing the name of the organic compound,

• Numbers are separated from the groups by hyphens. There is no space between the names.  For example, it is 6 − Ethyl − 2 − methylnonane and not 6 − Ethyl − 2 − methylnonane.

• If two or more identical substituent groups are present, then the numbers are separated by commas. For example, 2,2,4 − Trimethylpentane.

• While writing the name of substituents in alphabetical order, the prefixes, −iso and –neo are considered but –sec,–tert,di,tri are not considered to be part of the fundamental naming of alkyl group. For example, IUPAC name of the given compound is

5 − sec − butyl − 2,7 − dimethylnonane.

(sec − and di − are not considered while naming alphabetically).

• If there are two chains of equal length, then that one is selected which has more number of side chains.

  In the given molecule, there are two branches at C − 5. The longest chain is the one with more branching. The numbering of the main chain and the substituent is shown as given below.

IUPAC Name is −

𝟓−(2-Ethylbutyl)−3,3−dimethyldecane and NOT 5−(2,2−Dimethylbutyl)−3-ethyldecane