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I would like to know if there is an alternative to Dimethyl sulfate in when methylating Syringaldehyde to gain 3,4,5-tmba
yes, I used TFSE but didn't find anything useful :(
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I am the analog synthesis of a digital sound
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There's tons of stuff posted by me and Antoncho.
http://www.geocities.com/dritte123/PSPF.html (http://www.geocities.com/dritte123/PSPF.html)
The hardest thing to explain is the obvious
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Other alkylating agents that may work are:
Trimethyl Phosphate
Dimethyl Carbonate
https://www.thevespiary.org/rhodium/Rhodium/chemistry/me3po4.html (https://www.thevespiary.org/rhodium/Rhodium/chemistry/me3po4.html)
https://www.thevespiary.org/rhodium/Rhodium/pdf/dimethylcarbonate.phenol.methylation.pdf (https://www.thevespiary.org/rhodium/Rhodium/pdf/dimethylcarbonate.phenol.methylation.pdf)
Dimethyl Carbonate is less toxic than Trimethyl Phospate, but has a lower boiling point. The Dimethyl Carbonate reaction scheme presented in the above URL is conducted above the boiling point of Dimethyl Carbonate. This is achieved by progressive introduction of DMC through the course of the reaction.
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Dimethylsulphat is the methylester of sulfuric acid. I'm sure it's easy to make at home, but remember to doo it in a hood :-).
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Unfortunately, as the practice shows, aromatic aldehydes are significantly harder to methylate than 'simple' phenols.
Me3PO4 gives not-quite-satisfactory results on tri-OH-benzoic acid (also deactivated), as reported by Uemura.
MeI does a relatively poor job on 2-OH-5-MeO-BA (at least, in the far-from-perfect runs by moi and Vitsh). However, there are some ideas to make this much more workable - which should apply to syringaldehyde as well. I'll elaborate, if you want to.
Syringaldehyde is certainly more electron-rich than trihydroxy-benzoic acid and even hydroxysalicylaldehyde. But here we have an steric hindrance, i'm afraid - what will the wiser ones say?
Antoncho
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A PTC improves the yield considerably. Isn't Pihkal full of examples (or possibly my page)?
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PiHKAL is indeed full of such examples - however, it was my impression that PTC was employed in conjunction w/acetone/K2CO3 system - the rationale being simply to increase the phenolate's 'solubility' in acetone.
And acetone was being used beecause fragile alkyl iodides are rapidly destroyed by alkaline alcoholic medium, thus making them unfit for the more sturdily methylated aldehydes (if you notice, acetone/PTC is ALWAYS used in PiHKAL in conjunction w/aldehydes and alcoholic KOH is ALWAYS used for the unformylated phenols).
Unfortunately, getting a PTC is an unresolvable problem for the most of us HyperLabbers ::)
My idea was to first prepare phenolate from the aldehyde and alcoholic NaOH and then azeotropically remove water w/benzene (having an absolute alcohol would bee better since it dissolves both MeI and phenolate) and then react this mixture w/MeI - which will thus have nothing to react with but the phenolate.
What do you think of the idea, let me know, bees! Also - what kind of alcohol would bee the best to use, EtOH or IPA?
Antoncho
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No PTC's? Can't you get a trialkylamine, and methylate it with MeI to a quat? PEG-400?
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Can't you get a trialkylamine?
Nope. Well, not me personally, at least. Even if i could, a kilo would probably cost a zillion roubles - in Russia an average-income person like SWIM can only afford the very very basic reagents. Of course, if he still wants to have some money left to buy normal clothes and Christmas presents :)
Of course, people who live, say, in Moscow are much luckier both in terms of available reagents and income - some of us even can afford buying 'real' PTC :)
and methylate it with MeI to a quat?
Jeez, Rhodi, you must bee kidding - i struggled so much to make a few mls of this damned MeI ;D and you suggest i use it to make PTCs? ;D Beesides, do you know how much iodine compounds cost? ;D
Now, i just KNOW there is some way to extract those quats from some fabric softeners - but HOW IN THE WORLD would one go about extracting and purifying such a compd as a quaternary ammonium salt??? That's what always puzzled me (we don't have the kinds that have ONLY PTCs in them - and none of those 'dryer sheets' whatever they are :) ).
Well, the day that someone figures that out (and that day WILL come) will undoubtedly bee the day of another major victory of our small circle against our stupid, stupid laws ;)
Antoncho
P.S. Oh, yes. PEG-400, this is somewhat more realistic to get - but all examples i've seen thus far mention exclusively quat ammonium salts. Are PEGs any good and what they can bee used for (and for what they CAN'T bee used) - can you or someone else give us some info on this subject (as offtopic as it may bee - please?) :)
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Hmm... you might have bumped into these before but
Post 264275 (missing)
(halfapint: "Re: Nitrostyrene or Nitropropene electrochem reduction", Chemistry Discourse) and Post 86697 (missing)
(Cherrie Baby: "Re: OTC PTC", Chemicals & Equipment)
might be interesting. This has been one of the subjects I should've tried to find out about but other things have repeatedly captured my attention.
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Antoncho: See
https://www.thevespiary.org/rhodium/Rhodium/pdf/ptc.review.catalysis-today.pdf (https://www.thevespiary.org/rhodium/Rhodium/pdf/ptc.review.catalysis-today.pdf)
and https://www.thevespiary.org/rhodium/Rhodium/pdf/ptc.peg.pdf (https://www.thevespiary.org/rhodium/Rhodium/pdf/ptc.peg.pdf)
for example.
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... for the provided reading!
And yeah, i certainly could've UTFSE'd bee4 asking :-[
Your humble Antoncho :)
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aurelius had no idea so many (basic) reagents/catalysts were that hard to get in russia. perhaps a few optimized procedures for PTC's are in high demand.
aurelius hates to suggest this- it is a last recourse because of the number of contaminants, but look for a shampoo with few ingredients and it's bound to have some surfactants/PTCs.
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If i were to use hydroxyvanillin, would I be able to perform the methylation?
I'm trying to do this synth almost otc.
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everything posted above is completely 100% fictional.
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Yes, methylation of 5-hydroxyvanillin will produce 3,4,5-trimethoxybenzaldehyde.