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What is the mechanism of reaction of a ketone with $\ce{NaNO2/HCl}$? Can $\ce{NaNO2/HCl}$ be considered as freshly prepared $\ce{HONO}$ here? I am confused about how the reaction will proceed.

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  • $\begingroup$ Consider also production of nitrosyl chloride $\endgroup$
    – Poutnik
    Apr 23 '19 at 10:25
  • $\begingroup$ I know how Sodium nitrite reacts with amines. I was just curious about how it would react with a carbonyl group. $\endgroup$
    – Arshiya
    Apr 23 '19 at 13:30
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$\ce{NaNO2/HCl}$ is as you suggest a source of $\ce{HONO}$. This will be protonated by $\ce{HCl}$ to give the nitrosonium ion $\ce{NO+}$ (in equilibrium with nitrosyl chloride). This strongly electrophilic species will react with the enol of the ketone to nitrosate the alpha position. This nitroso compound then rearranges to give the alpha oxime.

pdfs.semanticscholar.org

Image from: Emilia Iglesias and Isabel Brandariz, A further study of acetylacetone nitrosation. Org. Biomol. Chem. 2013, 11, 1059-1064. DOI: 10.1039/C2OB26073E; available as pdf from pdfs.semanticscholar.org.

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  • 1
    $\begingroup$ Slightly weird diagram ... two methyl groups disappeared $\endgroup$
    – orthocresol
    Apr 23 '19 at 11:14
  • $\begingroup$ I noticed that, think they were meant to be hydrogens $\endgroup$
    – Waylander
    Apr 23 '19 at 11:37
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    $\begingroup$ See also: chemistry.stackexchange.com/questions/86061/… $\endgroup$
    – user55119
    Apr 23 '19 at 14:35
  • $\begingroup$ @Waylander can this same reaction take place with aldehydes too ? $\endgroup$
    – Ashish
    Apr 18 at 4:00
  • $\begingroup$ Multiple literature sources state that this reaction works for carbonyl compounds, but I can find no examples with aldehydes. $\endgroup$
    – Waylander
    Apr 18 at 7:26

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