ISSUE:

Hello!! I would like to know the operating conditions (Temp, Concentrations, etc) and the reason for the two possible reaction paths in the case of the Retrosynthesis of Cochineal Red E-124 (Ponceau). Thank you very much for the answer!

Hello, at this address you can find the retrosynthesis of the molecule.

www.quimicaorganica.org/foro/121-pregunt...chinilla-a.html#4357

Regards

Thank you very much Germán for the retrosynthesis, if it is not too much trouble I would ask you if you could tell me because there are two possible ways to obtain the Red E-124 dye... And it would also help me a lot to know the working temperatures... Many Thank you..

As it is an azo dye, the usual reaction to obtain it is azo coupling.

The retrosynthesis was carried out by Wilbert, who may be able to provide us with an alternative. Greetings

Hello friends.

It is true that an azo dye is ultimately formed by the diazo coupling reaction, also called azo coupling. Due to the structure of Cochineal Red, it would seem that it is possible that this coupling occurs in the two ways that I allow myself to reflect in the following scheme:




the alternative (to) is correct and (b) incorrect, by the following criteria:
Preferred precursor molecules (substrates) for a diazo coupling reaction are, in decreasing order, the following:
Compounds that have hydroxyls such as phenols and naphthols, aromatic amines, molecules with an aliphatic enolizable ketone group, heterocyclic molecules such as pyrrole, indole, etc.
In relation to the azo coupling reaction, certain general rules must be taken into account or heuristic principles, namely:
a) Phenols couple more easily than amines and members of the naphthalene series more easily than those of benzene,
b) Substituents with a negative inductive effect (-I) such as halogen, nitro and sulfo, retard the coupling.
c) In the naphthalene series, when the hydroxyl or amino group is in the 2(beta) position, the reagent couples in the 1(alpha) position. If the hydroxyl or amino group is in the alpha position, the bond usually occurs at the 4 position, but if the 3 or 6 position is occupied by a sulfonic group, the bond is made at the beta position.

Finally, the position of the sulfonic groups is achieved selectively if the sulfonation is carried out at certain temperatures and this aspect can be found in the literature as "sulfonation of naphthols."

Greetings

P.S. I have problems uploading image

PS2. I changed my browser and the file attachment problem was resolved, which is why I am correcting this post.

Greetings.
Greetings

Hello, good evening, hear a question, do you happen to know about the retrosynthesis of red-p, I need your help, please. It is urgent.