Sciencemadness Discussion Board

Condensation of substituted phenols with aldehydes

497 - 6-3-2009 at 20:35

According to this patent one can obtain substituted phenyl propenes by acid catalyzed condensation of the phenol with propionaldehyde to form a "bisphenol" and then cleaving it with a basic catalyst. All in fairly high yield.

This looks like an interesting route to phenyl alkenes. I'm curious about how well the reaction will work with phenols other than guaiacol. I haven't been able to find much information on the reaction other than stuff pertaining to production of bisphenol-A, etc, and very little on the cleavage reaction.

Ebao-lu - 6-3-2009 at 22:54

I wonder if aldehyde can be changed to longer chained aldehydes like heptanal. If that will yield p-heptenylphenols, they can be good intermetiates for cannabinoids. Maybe there is a problem with distilling longer chained ankenylbenzenes, and without immediate distilling they will irreversibly polymerise.
But i think, authors of the petant are not just junkies to claim this invention only for prohionaldehyde, other substances must have been tested as well to undergo the reaction. And if they don't claim any other aldehydes, that means they failed with them(supposably).

[Edited on 6-3-2009 by Ebao-lu]


[Edited on 6-3-2009 by Ebao-lu]

Nicodem - 7-3-2009 at 06:19

Quote:
Originally posted by Ebao-lu
But i think, authors of the petant are not just junkies to claim this invention only for prohionaldehyde, other substances must have been tested as well to undergo the reaction. And if they don't claim any other aldehydes, that means they failed with them(supposably).

Isougenol is an important industrial chemical. What use would a patent claiming such a route to some 1-(4-hydroxy-3-methoxyphenyl)-hept-1-en have? Such a compound has no commercial importance of which I'm aware. I also have no idea in what way would such a reaction be useful for the synthesis of cannabinoids, for which one generally starts with 5-alkylresocinols, thus phenols with the alkyl at the meta position in regard to the hydroxy groups.

Ebao-lu - 7-3-2009 at 10:27

Maybe you're right, i just thought that if this is a general reaction for all the aldehydes, and having comperative good yields with them, the authors of the patent should claim them also, just in academical purposes. As for cannabinoids, once i came accross some active, derived from p-alkylphenols, if i am not mistaken. Or they can be found in future (possibly).