ACD/Name

Preamble

Elision of Vowels


The terminal "e" in names of parent compounds is elided when followed by a suffix beginning with "a", "I", or "o":
Examples: Cf. Rule
4-Penten(e)-1-ol C-10.3
2-Hexan(e)amine C-11.42
Anilin(e)ium C-82.2
Butan(e)ide C-84.3
1-Chrysen(e)ol C-202.1
Hexan(e)al C-302.1
2-Butan(e)one C-312.1
Heptan(e)oic acid C-401.1
5-Pentan(e)olide C-472.2
1-Hexan(e)imine C-815.3
Hexan(e)amide C-822.1


The terminal "a" in the names of multiplying affixes is elided when followed by a suffix or ending (not a separate word) beginning with "a" or "o":
Examples: Cf. Rule
[1,1'-Binaphthalene]-3,3',4,4'-tetramine C-71.3
1,3,6,8(2H,7H)-Pyrenetetrone C-315.1
Benzenehexol


There is no elision in the following cases:
(1) in conjunctive nomenclature, Cf. Rule
e.g., Quinolineacetic acid C-51.2
,-Dimethyl-2-naphthaleneethanol C-52.1
(2) in replacement nomenclature,
e.g., Tetraoxatridecane C-61.1
(3) in multiplying parent compounds,
e.g., Ethylenediaminetetraacetic acid C-815.1
(4) with multiplying prefixes,
e.g., 1,4,6,9-Tetraoxo-2-pyrenecarboxylic acid
(5) The terminal "e" in the names of parent hydrides is elided when adding "-yl" in formation of names of radicals. For example, pyrene, pyrenyl. However, when ambiguity results the "e" is retained, e.g. pentaphene, pentapheneyl to avoid confusion with pentaphenyl (five phenyl radicals).

(6) For elision of vowels in forming names of fused polycyclic compounds see Rule A-21.4 and in Hantzsch-Widman names see Rule B-1.1.

See Recommendations'93 R-0.1.7


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This HTML reproduction of Sections A, B and C of IUPAC "Blue Book" is as close as possible to the published version [see Nomenclature of Organic Chemistry, Sections A, B, C, D, E, F, and H, Pergamon Press, Oxford, 1979. Copyright 1979 IUPAC.] If you need to cite these rules please quote this reference as their source.

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