Sciencemadness Discussion Board

acetoxy-methoxy exchange from acetylsalicylic acid? [edit]

nitro-genes - 6-11-2016 at 12:41

There is no short question thread in this section and I'm to dumb to figure it out so I'll just post it here:

Would it be possible to produce an anisole from acetylsalicylic acid by boiling with 1 or 2 mole eqvts of sodium methoxide or anhydrous methylsulfuric acid in absolute (m)ethanol? Would the carboxyl interfere or does it react completely different?

Seen how stable anisoles are to hydrolysis compared to acetyl salicylic, it might be favorable

[Edited on 6-11-2016 by nitro-genes]

Crowfjord - 6-11-2016 at 13:02

Anisole can indeed be made from aspirin, but the way you propose wouldn't get you there. That might get you a little methyl salicylate.

You can get there by hydrolyzing to salicylic acid, decarboxylating that to phenol, then methylating the phenol. The first two reactions are detailed on this forum. Methylation can be done with base and any of a number of reagents like methyl bromide, methyl iodide, dimethyl sulfate, etc.

nitro-genes - 6-11-2016 at 13:49

Of course decarboxylation wouldn't occur spontaneously, I edited the title since this is indeed not direclty apprent, though I was wondering whether the acetoxy group might exchange for a methoxy group, catalyzed by an acid or base. Sort of a transetherification reaction producing 2-methoxy benzoic acid. Methylation of phenol can indeed be done by Williamson ether synthesis using methyl iodide/bromide and base, though I don't have the time, equipment and experience to make/handle these compounds. Besides, the iodides to produce the iodine are not completely OTC, so I was reasoning more from an OTC and simplicity perspective where generally available acetylsalicylic acid could possibly produce 2-methoxy benzoic acid instead with only few steps and non-toxic reactants.

[Edited on 6-11-2016 by nitro-genes]

myristicinaldehyde - 6-11-2016 at 16:42

The problem with your scheme is that anisole is an ether, not a ester! You can't exchange the entire acetoxy for a methoxy: think of the acetoxy as an ester of phenol and acetic acid (ethanoic acid).

I found some links and papers for you to enjoy:
http://www.organic-chemistry.org/synthesis/C1O/esters/transe...
http://www.sciencedirect.com/science/article/pii/S0040402001...


Attachment: Transesterification kinetics of phenyl salicylate 1.pdf (463kB)
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Attachment: Transesterification kinetics of phenyl salicylate 2.pdf (953kB)
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