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Naming/ IUPAC Nomenclature 2

Now that you have the basics of naming, here are some tips on prioritization rules (i.e. giving functional groups priority or the lowest position number).

  • Double bond “-enes” have priority over triple bond “-ynes”.
  • Triple bond -ynes get priority over over phenyl.
  • Halides/halogens have no special priority over alkyl groups.
  • In general, you can expect any functional group containing an oxygen will have priority over functional groups without the oxygen.
  • Alcohol has priority over alkyl, amines, halides, ethers, phenyl, and thiols.
  • Thiols -SH get priority over alkyl and halides.
  • If both thiols and alcohols are present, then alcohol gets priority.
  • Aldehyde gets priority over double bond -enes and alcohol.
  • Carboxyl group gets priority over aldehydes.
  • Ketones get priority over -enes, phenyls, and alcohols.
  • Carboxylic acids are highest priority and are terminal; there can only be a maximum of two carboxylic acids. Carboxylic acids get priority over alcohols, amines, ketones and aldehydes.
  • Non carboxylic acid carbonyls (acting as substituents) get the “oxo” name.
  • Esters have priority over carboxylic acids and the nitrile group.
  • Groups with oxygen have priority over amines.
  • Amides get priority over amines.