Hi William, naming complicated organic compounds can be difficult, but in gereral, there are standard rules, the IUPAC rules (for "International Union of Pure and Applied Chemistry") for naming all organic compounds. Organic ompounds are categorized according to the functional group (or groups) in it, such as the alkene group (C=C double bond), alkyne, arene, alcohol, etc. The procedure for naming is typically:
1) Find the longest carbon chain in the molecule (it usually includes the the functional group carbon(s), such as the two alkene or alkyne carbons, if a functional group is present) and write the "parent" alkane name based on the number of carbons in this long chain.
2) Number the carbons in the main chain starting at the end that has the functional group closest to it (if it is an alkane with no functional group, start numbering from the end that has a group closest to it, such as methyl, ethyl, etc., or halogen groups such as fluoro, chloro, bromo, etc.).
3) Change the name ending to reflect the functional group present, such as "ol" for the alcohol functional group.
4) Prefix the parent name with the names of other groups attached to the main chain, in alphabetical order, with each group's position (the number of the carbon the group is attached to).
Common functional groups:
Hydrocarbons:
alkene
alkyne
arene
("alkane" is not a functional group)
Halogen-containing:
alkyl halide
Oxygen-containing:
alcohol
ether
aldehyde
ketone
carboxylic acid
ester
Nitrogen-containing:
amine
amide
nitrile
and lots more, but these are the main ones.
Example: Name the following compound -
CH3CHCH2CH2CH2CHCH2CH2OH
| |
Br CH3
1) The longest carbon chain has 8 carbons. 2) Therefore the "parent" alkane name = "octane"
The functional group (of highest priority) is the alcohol group, so we will name this compound as an alcohol.
2) Number the carbons in the main chain starting from the OH carbon.
8 7 6 5 4 3 2 1
CH3CHCH2CH2CH2CHCH2CH2OH
| |
Br CH3
3) Change the name ending to "ol" to give "octanol". Since the OH group is attached to carbon #1, we indicate this in the name: "1-octanol".
4) Adding the group names and positions gives "7-bromo-3-methyl-1-octanol" for the name of the compound.
That's the general idea! Depending on the compound, there may be some variations in the naming rules, and there are "common" names of many compounds also, such as "propanone", "dimethyl ketone", and "acetone" for CH3C(O)CH3. Of course, your organic chemistry textbook should explain in good detail. If you are not taking organic chem yet, your textbook hopefully introduces naming and drawing structures of alkanes, alkenes, and alkynes at least, which are a good place to start. There is a link under "Organic Sites" to a site about naming rules and examples, and there are probably quite a few more organic web sites out there now, although I haven't done a careful search recently.
It's a big subject! With so many possible organic compounds in existence (many millions are already named and characterized) it is important to have reliable rules for naming them. Hope this answers your question or gives you an idea of the strategy used for naming organic compounds.
Steve
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