Why does adipic acid give cyclic ketone on heating while glutaric and succinic acid give cyclic anhydride?

enter image description here

  • 2
    $\begingroup$ It's different reaction, with Ba(OH)2. I guess you should find more precise source of information. $\endgroup$
    – Mithoron
    Jan 6, 2018 at 20:32
  • 6
    $\begingroup$ Seven-rings are notoriously unstable. $\endgroup$
    – Karl
    Jan 6, 2018 at 21:20
  • 3
  • $\begingroup$ The calcium salt of adipic acid also works. Essentially a Dieckmann cyclization with decarboxylation. Been there. Done it. No metal salt needed with succinic and glutaric acid. $\endgroup$
    – user55119
    Mar 23, 2018 at 15:17
  • $\begingroup$ @RitwikDas Can you specify the source? Thanks! $\endgroup$
    – Rishi
    Jul 13, 2021 at 12:39

2 Answers 2


According to Blanc Rule for Dibasic Carboxylic acids, A cyclic Ketone is formed unless a five or six membered cyclic acid anhydride can be formed. This rule is valid for 1,4; 1,5; 1,6. dicarboxylic acids


Because cyclic anhydride formed will be a 7 Member ring compound which is less stable than 5 membered cyclic ketone

  • 4
    $\begingroup$ Can you please cite some sources? Also, note that the rings are substituted. Btw, welcome to Chem.SE! $\endgroup$ May 18, 2018 at 8:41

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.