Here is an example of two compounds

$$\ce{CH3CH2COOCH3}$$ vs $$\ce{(CH3)2CHCOO-}$$


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whose possible IUPAC names

methyl propanoate

accidentally differ only in presence/absence of a space. (Note that complete, unambiguous name of the second compound is 2-methylpropanoate)

Is there an (accidental) example of two IUPAC names for different compounds, that differ only in presence/absence of a hyphen ("-") instead?

(Question might sound hypothetical, strange and inappropriate, but is related to to this one)

UPDATE: Mentioned ‘methylpropanoate’ preferred IUPAC name is 2-methylpropanoate. There's a better example pair:

  • phenyl acetate ($\ce{CH3COOPh}$)
  • phenylacetate ($\ce{PhCH2COO^{-}}$)

Note that in some language localized official IUPAC nomenclatures, the names really differ by the hyphen instead of the space (e.g. in Czech: fenyl-acetát vs fenylacetát), but I was wondering about the English nomenclature.


1 Answer 1


The compound with the formula $\ce{CH3COOPh}$ is known as phenyl acetate, but the IUPAC name is: phenyl ethanoate.

The compound $\ce{PhCH2COO-}$ has the IUPAC name: 2-phenylethanoate.

The similarity is interesting, but the names are distinct enough, unless I'm missing something.

  • 2
    $\begingroup$ Note that a IUPAC name is not a synonym for a systematic name . preferred IUPAC names are acetic acid/acetate, while ethanoic acid/ethanoate are systematic IUPAC names. $\endgroup$
    – Poutnik
    Nov 2, 2022 at 6:21
  • $\begingroup$ What you say is almost 10 years old info, look at IUPAC 2013 Organic chemistry nomenclature (Blue book). $\endgroup$
    – mykhal
    Nov 2, 2022 at 12:41

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