IUPAC names of Cyclic etheres (epoxides)
If the ring contains less carbon atoms than the alkyl group attached to it, the compound is named as a derivative of alkane and the ring is treated as cycloalkyl substituent, otherwise, it is named as a derivative of cycloalkane. This is clear from the following examples.
If however, the side chain contains multiple bond or a functional group, the alicyclic ring is treated as the substituent irrespective of the size of the ring.
If some characteristic functional group alongwith other substituent group are present in the ring, it is indicated by using suitable prefixes and suffixes as in case of acyclic compounds. If the functional group, directly attached to the ring contains carbon atom, then suitable suffixes are used to indicate the presence of such groups. In such cases the carbon atoms of such groups are not counted in the word root. Suffixes for such groups are as follows.
Compounds containing —SH as the principal group directly attached to carbon are named “thiols”. In substitutive nomenclature their names are formed by adding “ -thiol” as a suffix to the name of the parent compound. When —SH is not the principal group, the prefix “ mercapto-” is placed before the name of the parent compound to denote an unsubstituted —SH group.
Disulfides, trisulfides, etc., and polysulfides are named analogously to sulfides, except that “di-”, “tri-”, or “poly-sulfide” replaces “sulfide”, and that “di-”, “tri-”, or “poly-thio-” replaces “thio-”.