 | Determine of the compound is likely named with a common name (e.g. toluene). |
|
| If the compound cannot be named "commonly", then the substitutive name of an
organic compound can be derived by identifying its principal group and principal
chain. The principal group is identified by the presence of a priority group as follows
(listed from highest to lowest priority): |
Carboxylic acid
Anhydride
Ester
Acid halide
Amide
Nitrile
Aldehyde
Ketone
Alcohol/phenol
Thiol
Amine
|
| In order to derive the parent name, apply the following criteria (in order), find
the chain of carbon atoms in a molecule that contains: |
the maximum number of substituents including the priority group(s)
the maximum number of double and triple bonds
the maximum length
the maximum number of double bonds
maximum number of substituents
Use that chain to derive the parent name for the molecule according to the base name
set in Table 1.3 of your Fox and Whitesell text. If there is more than one chain of
equal length, then choose the one with the greater number of branches. If no priority
group exists, simply name as a substituted hydrocarbon. If a priority group is
present, then use an appropriate suffix (see Table 3.6 in your Fox
and Whitesell text).
|
| Number the atoms in the parent chain starting with the lowest number for the highest
priority group. If no priority groups are present then start at the end nearest the
first branch point (in order to derive the lowest number combination). If there is
branching an equal distance from both ends, then start numbering from the end nearer to
the second branch point. You want to achieve the lowest possible number combination. |
|
| Identify each substituent (branch) by name and number. If there is more than one
substituent on the same carbon, assign them all the same number. Be on the lookout for
"complex" substituents (isopropyl, sec-butyl, etc.) as noted in Table
1.4 of your Fox and Whitesell text. |
|
| Arrange and cite the branches in alphabetical order. |
|
| Use hyphens to separate different prefixes and commas to separate numbers. |
|
| If more than one identical substituent is present, use the prefixes di-, tri-, and
tetra-. |
|
| Special Rules: |
| Rules are essentially the same for cyclic hydrocarbons --- except when the ring has
significantly fewer carbons than a side chain. In this case, the side chain will get the
parent name. |
|
| For alkenes and alkynes, you want to find the longest chain containing the greatest
number of pi bonds. This chain will be used to derive the parent name. |
|
| For alkenes, use the E/Z designation to assign stereochemistry about geometric double
bonds. |
|
| For compounds containing asymmetric carbons, use the R/S designation to assign
stereochemistry. |
|
| The nomenclature for aromatic hydrocarbons is completely different and will be treated
separately. |
|
