BrominatedSicariidae
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Synthesis of Vetraldehyde from Vanillin: Question(s)
Hello,
Inspired by the Klute's synthesis [1] of vetraldehyde, I would like to synthesize vetraldehyde via methylation of vanillin; however, I can't seem to
find any useful examples of this that I can fully read, so I only get a brief synopsis—such as this [2] paper. Should I just assume that the reaction is just a normal SN2 substitution?
I also found this [3] paper, which is slightly more in-depth; nevertheless, the aforementioned paper uses dimethyl sulfate, and makes no mention on what type
of solvent used. It almost makes it seem like they did it in water, since solvents like dimethylformamide would react with the sodium hydroxide. I'd
like to refrain from using dimethyl sulfate or iodomethane; however, as previously stated, I don't know what type of conditions allow for some other
methylating agent—say dimethyl carbonate—to work.
Perhaps I'm just a n00b; regardless, thanks for any help.
References:
[1]http://www.sciencemadness.org/talk/viewthread.php?tid=13273
[2]http://www.dissertationtopic.net/doc/1142187
[3]http://www.bstu.unibel.by/english/proceeding_bstu/Chemistry,...
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Nicodem
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Quote: Originally posted by BrominatedSicariidae  | | Inspired by the Klute's synthesis [1] of vetraldehyde, I would like to synthesize vetraldehyde via methylation of vanillin; however, I can't seem to
find any useful examples of this that I can fully read, |
There are plenty of literature examples of this conversion, but since you want to avoid dimethyl sulfate or methyl iodide, you will have a hard time
finding something efficient using an available reagent. You can use methyl bromide, trimethylanilinium chloride, tetramethylammonium chloride, methyl tosylate, or many other (UTFSE for more), however this depends on what you have access to.
| Quote: | | Should I just assume that the reaction is just a normal SN2 substitution? |
Yes, a very normal SN2 substitution.
| Quote: | | the aforementioned paper uses dimethyl sulfate, and makes no mention on what type of solvent used. It almost makes it seem like they did it in water,
since solvents like dimethylformamide would react with the sodium hydroxide. |
O-Methylation of phenols with dimethyl sulfate is commonly performed in aqueous solutions. See the examples in Vogel's or Organikum.
| Quote: | | however, as previously stated, I don't know what type of conditions allow for some other methylating agent—say dimethyl carbonate—to work.
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See the example on syringaldehyde in Prepublication section: https://www.sciencemadness.org/whisper/viewthread.php?tid=22...
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unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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S.C. Wack
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orgsyn.org has the methyl sulfate version. Do you actually have a DMC or TMP?
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BrominatedSicariidae
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Thank you, Nicodem; I don't have particular access to any of those compounds—except for perhaps methyl tosylate, which I'd have to prepare—but the
paper on quaternary ammonium salts is especially interesting.
| Quote: |
Do you actually have a DMC or TMP?
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Yes, I actually have DMC.
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S.C. Wack
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AFAIK there's no getting around that the conditions for DMC phenol methylation are fairly severe and may involve a hot vapor phase reaction or both
being fed into hot PEG.
http://chemistry.mdma.ch/hiveboard/rhodium/pdf/dimethylcarbo...
TMP would be more interesting if you had it.
https://www.google.com/patents/US4453004
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