Reference:Order of nomenclature precedence among these functional groups

The post above describes an alkyl side chain to be prior to alkoxy and halo. In that case how can we number the carbons based on alphabetical priority when there is a tie of numbers of locant carbons? For instance the given priority order demands a name 5-methoxy-4-propyloctane, whereas alphabetical order(since numbering from either side goes to a tie)prefers the name 4-methoxy-5-propyloctane?


closed as unclear what you're asking by Loong Jan 13 at 10:31

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    $\begingroup$ That chart is a very simplified and occasionally misleading representation of the IUPAC rules. To quote Loong, "...the IUPAC recommendations have more than 1500 pages. Hence, you should be careful when applying any simplified or abridged version of the nomenclature rules." $\endgroup$ – orthocresol Jan 12 at 1:08
  • $\begingroup$ In the example i mentioned above, which is the preferred name by IUPAC? $\endgroup$ – Nandakumar U K Jan 12 at 1:58
  • $\begingroup$ 4-methoxy-5-propyl. $\endgroup$ – orthocresol Jan 12 at 2:15
  • $\begingroup$ Now can I draw the conclusion that when out of alkoxy, halo, alkyl and nitro groups -any two are preset on side chain, then first observe minimum number set;if tie comes observe alphabetic priority; this is because these groups have no independent priority over one another. Right? $\endgroup$ – Nandakumar U K Jan 12 at 3:32
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    $\begingroup$ Please note that your edit has changed the topic of the question. First you asked about the priority order of the first 20 functional groups (something you would find in Rule P-41 or P-43); now you ask about the numbering of locants in case no decision can be attained by application of the lowest set of locants (something you would find in Rule P-14.4). Was this change intentional; or is the actual problem behind your question that you are not aware that these are two separate topics? $\endgroup$ – Loong Jan 13 at 10:31

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