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Why are ethers not considered as functional groups in IUPAC nomenclature?

Let us consider the following example:

Image source

The PIN for this compound is 2-ethoxy-1,1-dimethylcyclohexane. And we get this by first point of difference as ether is also considered as a substituent here.
But ethers do confer specific properties to the compound. They are studied as a separate functional group. Yet they aren’t given the preference in nomenclature in the absence of any other functional group too. Why is this so? Is it just a convention or is there a reason behind it?


PS: I checked this similar question on our site but it doesn’t answer my question as to why ethers aren’t functional groups when it comes to naming.

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The priority order for functional groups is as follows:

Radicals > Anions > Cations > Zwitterionic compounds > Acids (In the order -COOH, -COO(O)H, S-derivatives, Se-derivatives, Sulphonic acids, Phosphonic acids, etc)> Anhydrides > Esters > Acid halides > Amides > Hydrazides > Imides > Nitriles > Aldehydes > Ketones > Alcohols and Phenols > Amines > Imines > hydrazine > Phosphanes > Alkene > Alkynes > Alkanes> Ethers > peroxides > Halo, Nitro, Nitroso, Alkoxy > Oxiranes

Functional groups such as Ethers and Nitro-groups are way down the order and will not be the primary functional group more often than not, the reason behind them be named as substituents.

In your question, the alkane group is given priority over the ether as per the above-mentioned priority order for functional groups. Thus the name given is 2-Ethoxy-1,1-dimethylcyclohexane.

Let's say instead of the 2 methyl groups over there, you had a nitro group, then the ether would have become the principal functional group and the nitro group being the substituent. There's no rule saying that ethers are always to be named as substituents as per my knowledge.

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    $\begingroup$ @J_B892 I'm not sure if I agree with this explanation. The question still remains as it was. See: alkanes are not a functional group, whereas nitro and ether are a functional group. Yet the former is given a higher priority over the latter. So, what was the need to separate ether and nitro from the rest of the functional groups (which are above alkanes), and place them below the alkanes instead? $\endgroup$ – Gaurang Tandon Mar 30 '18 at 9:07
  • $\begingroup$ “In your question, the alkane group is given priority over the ether as per the above-mentioned priority order for functional groups.” No. The name 2-ethoxy-1,1-dimethylcyclohexane is simply based on the usual substitutive nomenclature. The seniority order is not relevant in this case since no functional group is expressed by suffix or class. Compare also the analogous compound 1,1-diethyl-2-methoxycyclohexane. $\endgroup$ – Faded Giant Jun 22 '18 at 12:41
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    $\begingroup$ “Let's say instead of the 2 methyl groups over there, you had a nitro group, then the ether would have become the principal functional group and the nitro group being the substituent.” No. That compound would still be named by usual substitutive nomenclature as 1-ethoxy-2-nitrocyclohexane. $\endgroup$ – Faded Giant Jun 22 '18 at 12:43
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Note that the genre of this post is is going to be dystopian speculative science fiction. (I'm not sure whether I should hope that in IUPAC commission, nobody reads it, or at least somebody reads it).

 

InChI=1S/C10H20O/c1-4-11-9-7-5-6-8-10(9,2)3/h9H,4-8H2,1-3H3

This compound could be named by our ancestors like e.g. amines, O-ethyl-2,2-dimethylcyclohexan-1-ol.

Or like e.g. phosphane derivatives. Note that in ancient times, they could be naming it like „(2,2-dimethylcyclohexyl)(ethyl)ether“ (beware archaic „2,2-dimethylcyclohexyl-“ or „ethyl-“), which would be silly, because by removing both substituents, you don't get ether at all! But, „(cycloalkyl)(alkyl)water“ would sound even more silly. Therefore, it could be named rather (2,2-dimethylcyclohexan-1-yl)(ethan-1-yl)oxidane (beware, „… oxane“ would be something completely different).

In the year 202X, funnily, e.g. $\ce{(C2H5)2O}$ was still being officially preferably named „ethoxyethane“ instead of oxydiethane, even though 1,1′-oxybis(2,2-dimethylcyclohexane) was already the correct name for our compound with ethyl replaced by the left-hand substituted cyclohexyl. So, one could obviously name it 1,1′-oxy(2,2-dimethylcyclohexane)(ethane).

But no, in the current century, we name it C₁₀H₂₀O/c1-4-11-9-7-5-6-8-10(9,2)3/h9H,4-8H2,1-3H3 (EIN) (some historic variants of the Enforced IUPAX Name were called InChI).

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  • $\begingroup$ .. don't get me wrong, I LOVE IUPAC, often. $\endgroup$ – mykhal Jun 12 at 17:25

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