The IUPAC name I came up with was 1-hydroxy-4-methyl-3-pentanone because:

  • Ketone has higher priority over alcohol

  • The lowest locant set is achieved by numbering the C bonded to -OH group as 1.

But the answer given states it is 4-methyl-3-oxo-1-pentanol which violates the first rule mentioned above.

Please clarify the discrepancy between my reasoning and the textbook answer.

  • $\begingroup$ I think you book has a few nomenclature mistakes. $\endgroup$
    – ralk912
    Mar 26 '18 at 20:48

Your assessment is correct. According to the current version of Nomenclature of Organic Chemistry – IUPAC Recommendations and Preferred Names 2013 (Blue Book), the order of seniority of classes in decreasing order of seniority is as follows.

16. Ketones
17. Hydroxy compounds (includes alcohols)

However, locants are placed immediately in front of the part of the name to which they refer. Therefore, the correct name for the compound that is given in the question is 1-hydroxy-4-methylpentan-3-one.


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