Question

Step wise rules for naming ring compounds

Answer 1

To name cyclic compounds, you want to first count how many carbons are in the circle and simply add cyclo- as a prefix. For example, a cyclic alkane with 3 carbons is named cyclopropane, 4 carbons is cyclobutane, 5 carbons is cyclopentane, etc.

If there are any functional groups on the cyclic compound, then the carbons with the circle will be numbered so that the functional groups have the lowest numbers possible. For multiple functional groups, name the groups in alphabetical order, not in the order of the numbered carbon chains. For example, 2-bromo-1-chloro-3-methylcyclopentane. If there is only 1 functional group, the "1" can be omitted because it is assumed the functional group is on carbon 1, eg. bromohexane.

If the cyclic compound is not the longest carbon chain, simply name as above, but change the suffix to -yl to denote it as a side chain. For example, 2-cyclopentyldecane. This also applies if there are multiple cyclic compounds linked together - the smaller circle will be named as a side chain.

Other than these exceptions, the normal rules of IUPAC naming apply for double bonds, triple bonds, cis/trans stereochemistry, and other functional group suffixes such as -ol for alcohols, -al for aldehydes, -amine for amines, -one for ketones, and -oic acid for carboxylic acids.