The product depends on the reaction condition such as heating, KMnO4 concentration, catalysis, ....

Nabeel Arif Tawfeeq Sir can you please elaborate? let's say KMnO4 Conc. with heat (usual organic chem 2 reaction)

https://www.masterorganicchemistry.com/reaction-guide/oxidation-of-aromatic-alkanes-with-kmno4-to-give-carboxylic-acids/

I hope this is helpful.

Ishita Virmani I actually read that, this is a bit more advanced since its cyclic and benzylic carbons are different from top and bottom.

Thanks though

That’s alright. I will try going through it and let you know !

In Organic chemistry one considers first the product/products formed in the reaction and then a mechanism is proposed to explain it.The reverse is not always true. Thus I would like to know what is the end product? Is it Phthalic acid? If so a possible explanation may be like this (Figure attached): Since like beta keto acid vinylogous beta keto acid also decarboxylates easily , the intermediate diacid (a phenylacetic acid derivative, as shown as a possible possible product) can undergo decarboxylation to form 2-isopropylbenzoic acid which then can undergo further oxidation of side chain to form phthalic acid. [It is to be noted that salicylic acid decarboxylate more easily than benzoic acid because salicylic acid can tautomerise to beta keto acid even by loss of aromaticity under harsh condition] . This is a plausible mechanism assuming that phthalic acid is the end product.

Gandhi K. Kar Thank you!! this is very helpful sir.

But How did we reach that intermediate, the upper benzylic carbon got oxidized to COOH since it does have benzylic hydrogens unlike the lower benzylic carbon, whatever happened to the lower benzylic carbon? how did it become that intermediate? Any suggestions would be greatly appreciated.

• Sharbel Damouni , I thought you got this product (I) as an intermediate as shown in the scheme. Any way, if you propose the structure (I) as an intermediate then it can tautomerize to an enol (II) and it is easily oxidized to the diacid (III) (Figure-2 attached). This type of reactions are very common in organic chemistry. The lower benzylic carbon can't be oxidised (as it is a quaternery carbon and contain no benzylic "H") unless it is converted to isopropyl group by decarboxylation. Once it is converted to isopropyl group it will bear a benzylic hydrogen. Then via free radical mechanism it will first will be converted to a 3o alcohol and subequently it will then form the -COOH by further oxidation.

Sharbel Damouni , The entire reaction may proceed like this though I dont know what was the intermediates? (Figure -3 attached). This logically explains all the steps provided it matches with the intermediates formed. If you can provide me the details of the intermediates , I can give further suggestions. Thanks.

I got my answer, just perfect! Thank you.