Monocyclic Hydrocarbons

Monocyclic Hydrocarbons

Rule A-11. Unsubstituted Compounds and Radicals 

11.1 - The names of saturated monocyclic hydrocarbons (with no side chains) are formed by attaching the prefix "cyclo" to the name of the acyclic saturated unbranched hydrocarbon with the same number of carbon atoms. The generic name of saturated monocyclic hydrocarbons (with or without side chains) is "cycloalkane".

Examples to Rule A-11.1

11.2 - Univalent radicals derived from cycloalkanes (with no side chains) are named by replacing the ending "-ane" of the hydrocarbon name by "-yl", the carbon atom with the free valence being numbered as 1. The generic name of these radicals is "cycloalkyl".

Examples to Rule A-11.2

11.3 - The names of unsaturated monocyclic hydrocarbons (with no side chains) are formed by substituting "-ene", "-adiene", "-atriene", "-yne", "-adiyne", etc., for "-ane" in the name of the corresponding cycloalkane. The double and triple bonds are given numbers as low as possible as in Rule A-3.3.

Examples to Rule A-11.3

 

The name "benzene" is retained.11.4 - The names of univalent radicals derived from unsaturated monocyclic hydrocarbons have the endings "-enyl", "-ynyl", "-dienyl", etc., the positions of the double and triple bonds being indicated according to the principles of Rule A-3.3. The carbon atom with the free valence is numbered as 1, except as stated in the rules for terpenes (see Rules A-72 to A-75).

Examples to Rule A-11.4

The radical name "phenyl" is retained.11.5 - Names of bivalent radicals derived from saturated or unsaturated monocyclic hydrocarbons by removal of two atoms of hydrogen from the same carbon atom of the ring are obtained by replacing the endings "-ane", "-ene", "-yne", by "-ylidene", "-enylidene" and "-ynylidene", respectively. The carbon atom with the free valences is numbered as 1 except as stated in the rules for terpenes.

Examples to Rule A-11.5

11.6 - Bivalent radicals derived from saturated or unsaturated monocyclic hydrocarbons by removing a hydrogen atom from each of two different :carbon atoms of the ring are named by replacing the endings "-ane", "-ene", "-diene", "-yne", etc., of the hydrocarbon name by "-ylene", "-enylene", "-dienylene", "-ynylene", etc., the positions of the double and triple bonds and of the points of attachment being indicated. Preference n lowest numbers is given to the carbon atoms having the free valences.

Examples to Rule A-11.6

 
The following name is retained:

See Recommendations'93 R-2.3.1

Rule A-12. Substituted Aromatic Compounds 

12.1 - The following names for monocyclic substituted aromatic hydro carbons are retained:

Examples to Rule A-12.1

12.2 - Other monocyclic substituted aromatic hydrocarbons are named as derivatives of benzene or of one of the compounds listed in Part .1 of this rule. However, if the substituent introduced into such a compound is identical with one already present in that compound, then the substituted compound is named as a derivative of benzene (see Rule 61.4).12.3 - The position of substituents is indicated by numbers except that o- (ortho), m- (meta) and p- (para) may be used in place of 1,2-, 1,3-, and 1,4-, respectively, when only two substituents are present. The lowest numbers possible are given to substituents, choice between alternatives being governed by Rule A-2so far as applicable except that when names are based on those of compounds listed in Part .1 of this rule the first priority for lowest numbers is given to the substituent(s) already present in those compounds.

Examples to Rule A-12.3

  
 

12.4 - The generic name of monocyclic and polycyclic aromatic hydrocarbons is "arene".See Recommendations'93 R-9.1, Table 19(a)

Rule A-13. Substituted Aromatic Radicals 

13.1 - Univalent radicals derived from monocyclic substituted aromatic hydrocarbons and having the free valence at a ring atom are given the names listed below. Such radicals not listed below are named as substituted phenyl radicals. The carbon atom having the free valence is numbered as 1.

Examples to Rule A-13.1

13.2 - Since the name phenylene (o-, m- or p-) is retained for the radical  (exception to Rule A-11.6), bivalent radicals formed from substituted benzene derivatives and having the free valences at ring atoms are named as substituted phenylene radicals. The carbon atoms having the free valences are numbered 1,2-, 1,3- or 1,4- as appropriate.13.3-The following trivial names for radicals having a single free valence in the side chain are retained:

Examples to Rule A-13.3

13.4 - Multivalent radicals of aromatic hydrocarbons with the free valences in the side chain are named in accordance with Rule A-4.

Examples to Rule A-13.4

13.5 - The generic names of univalent and bivalent aromatic hydrocarbon radicals are "aryl" and "arylene", respectively.See Recommendations'93 R-9.1, Table 19(b)