[xshadow]

Hi!!

According to you is it possible this reaction?


It seems that the carboxylic oxygen attacks the  amidic C=O. No  other reagent or acid catalyst,only temperature.

I don't usually see a carboxylic acid reacts with an amide.
The OH- of COOH group is a very   weak nucleophile and in addition the  carbon of C=O of amide is a weak electrophile due to the strong azote retrodonation  (And in this case also from  benzene ring)

Can this reaction occour?
Also didn't understand how the amidic oxygen  leaved the molecule?!

I'm not sure that this reaction occours...
According to you?
Thanks

[Orcio_87]

Also didn't understand how the amidic oxygen  leaved the molecule?!

Did you read about tautomery ?

https://en.wikipedia.org/wiki/Tautomer

C₆H₅-CO-NH-CH₂-COOH C₆H₅-C(OH)=N-CH₂-COOH

Amidic oxygen can't be pushed out, as (in the formation of ester) oxygen in H₂O always comes from carboxylic acid (-COOH), never from alcohol.

[Babcock_Hall]

I would think about the differences between intramolecular versus intermolecular reactions.

[rolnor]

https://en.wikipedia.org/wiki/Erlenmeyer–Plöchl_azlactone_and_amino-acid_synthesis


mod edit fixed link

[xshadow]

https://en.wikipedia.org/wiki/Erlenmeyer–Plöchl_azlactone_and_amino-acid_synthesis


mod edit fixed link

thanks

Looking at the mechanism It seems that  I also need Ac₂O as reagent.
The only heating  is not enough

(because it should happen a intramolecular reaction between the carboxylic OH and amide (and they are both very unreactive /ppor nucloephile and electrophile)
Thanks Ac2O I have an "activated" C=O and also the less reactive carboxylic oxygen can attack the electrophilic carbon

[xshadow]

Also didn't understand how the amidic oxygen  leaved the molecule?!

Did you read about tautomery ?

https://en.wikipedia.org/wiki/Tautomer

C₆H₅-CO-NH-CH₂-COOH C₆H₅-C(OH)=N-CH₂-COOH

Amidic oxygen can't be pushed out, as (in the formation of ester) oxygen in H₂O always comes from carboxylic acid (-COOH), never from alcohol.

Is the  C₆H₅-C(OH)=N-CH₂-COOH tautomer  less favorite than C₆H₅-CO-NH-CH₂-COOH (as C=O is much stable than enol in tautomerism) ?

anyway yes, I've found a mechanism where actually is the carboxylic oxygen that leaves as H₂O

[xshadow]

I would think about the differences between intramolecular versus intermolecular reactions.

thanks

[Orcio_87]

Is the  C6H5-C(OH)=N-CH2-COOH tautomer  less favorite than C6H5-CO-NH-CH2-COOH (as C=O is much stable than enol in tautomerism) ?

Yes, after all hydrolysis of RCN gives R-CO-NH2, not R-C(OH)=NH.