2
$\begingroup$

A compound having formula $\ce{C9H7O2Cl}$ (O = oxygen) exists predominantly in enol form (A) and also in keto form (B). On oxidation with $\ce{KMnO4}$ it gives m-chlorobenzoic acid as one of the products. Identify (A) and (B).

(subjective question; no options were given)

I tried it and found the double bond equivalent as 6, 4 of which were utilized in benzene ring. Also, the benzylic carbon must have at least one hydrogen. Therefore I determined the following structure as (A):

enter image description here

But my book suggests (A) should be:

enter image description here

Please explain whether both are correct or only one product will exist.

Source: Joint Entrance Exam (JEE) 2003 India

$\endgroup$
-5
$\begingroup$

Both the answers are correct but the most appropriate will be B as the chelation occurs because of hydrogen bonding which makes it more stable. H-bonding is possible in your structure but the ring is less stable .Less stable chelate ring is formed than the other.

$\endgroup$
  • $\begingroup$ But there will also be H bonding i product 1 $\endgroup$ – Anirudh May 8 '18 at 13:20
  • $\begingroup$ In your case the ring will be 5 membered which is less stable than 6 membered ring $\endgroup$ – Aman Chande May 8 '18 at 13:54
  • $\begingroup$ Where is there a 5-membered ring? $\endgroup$ – pentavalentcarbon May 8 '18 at 14:14
  • $\begingroup$ What do you mean by 5 membered ring $\endgroup$ – Anirudh May 8 '18 at 14:40
  • $\begingroup$ There is no actual ring there $\endgroup$ – Anirudh May 8 '18 at 14:41

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

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