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Author Topic: Methylating agent sources??  (Read 1305 times)

atara

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Re: Methylating agent sources??
« Reply #60 on: December 05, 2010, 10:06:55 PM »
Quote from: Enkidu on April 16, 2009, 08:33:06 PM
Um, I'd just buy the tosyl chloride. What substrate do you plan on methylating? Phenol? Amine? Carboxylic acid?
At that rate you might as well just buy Me3OBF4 -- safer and more effective.

I'm wondering if SAM-e, that is, S-adenosyl-methionine, might be strong enough to methylate phenolates without enzymes. R3S+ is actually a decent leaving group IIRC.

Vespula germanica

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Re: Methylating agent sources??
« Reply #61 on: December 05, 2010, 10:59:11 PM »
NO! Triethyloxonium and trimethyloxonium tetrafluoroborate may be more effective (no own experience) but are definitely not safer than tosyl chloride!
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Sedit

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Re: Methylating agent sources??
« Reply #62 on: December 06, 2010, 12:50:01 AM »
I have not found the time to test it but has anyone attempted to use AMS(Ammonium MethylSulfate) generated very very easy by refluxing Sulfamic acid in MeOH. Its ability to decompose into Methylamine Bisulfate is nothing more then a demonstration of its methylating abilitys since it decomposes to a Me* radical that attacks the NH3 Bisulfate formed yeilding Methylamine Bisulfate. This would be a very easy to source and very safe methylating reagent compaired to others.
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zzhuchila_clocker

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Re: Methylating agent sources??
« Reply #63 on: December 13, 2010, 10:35:22 AM »
electrochemical borodin-hunsdiecker reaction for MeBr
http://www.springerlink.com/content/u1326r237hj75t33/fulltext.pdf
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akcom

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Re: Methylating agent sources??
« Reply #64 on: December 16, 2010, 06:15:19 PM »
On the sciencemadness thread dealing with 2C-T-X synthesis there was a link to a easily acquirable methylating agent.

jon

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Re: Methylating agent sources??
« Reply #65 on: December 18, 2010, 05:49:42 AM »
dimethoxalate methylations courtesy of  sciencemadness
http://www.sciencemadness.org/talk/viewthread.php?tid=11580

poisoninthestain

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Re: Methylating agent sources??
« Reply #66 on: December 23, 2010, 11:09:14 PM »
dimethyloxalate isn't so bad synthesis with a dean stark is easy but never got around to it with my current situation...

methyl tosylate(beautiful leaving group) is excellent and completely otc

this can be simplified in a one pot but for purity i'll extend the workup...

first sulphonation of toluene with con. H2SO4 as per Vogel with the dean stark again to yield tosic acid. very easy.

boric acid and methanol Fischer esterification for trimethyl borate. easy.

mix and distil. just ask ullmann from sciencemadness. you'll love it.

atara

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Re: Methylating agent sources??
« Reply #67 on: January 23, 2011, 03:16:52 AM »
Can trimethylborate be used to methylate other acids? Sounds interesting in itself!

Bluebottle

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Re: Methylating agent sources??
« Reply #68 on: January 23, 2011, 06:01:25 PM »
"And now we divide both sides by zero..."

psychexplorer

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Re: Methylating agent sources??
« Reply #69 on: February 07, 2011, 08:08:22 AM »
OTC methylating agents @ The Hive; focus, references on the oxalates.

Good read for those looking to eliminate the twin problems of DMS and MI.

Can't seem to find any reasonably feasible OTC path to trimethyl phosphate.

Fortunately for many of our purposes the dimethyl oxalate will work fine. Oxalic acid is cheap, OTC, and useful to have on hand for other procedures.
« Last Edit: February 07, 2011, 08:14:14 AM by psychexplorer »

Enkidu

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Re: Methylating agent sources??
« Reply #70 on: February 10, 2011, 04:24:17 AM »
Alkylation using dimethyl oxalate (DMO) is a very special reaction. Naf1 pulled up a great paper long ago, and it states that
Quote
This reaction appears to be dependent on dimethylformamide, since the substitution of xylene or dimethyl sulfoxide as the solvent caused the reaction to fail.
Maybe all you'd need is a catalytic amount of DMF. Nicodem suggested N-methylpyrrolidone as a suitable, OTC substitution. I don't agree that it will work, but it might.


Alkylation of Amines with Alcohols and Carboxylate Esters: the Origin of N-Methylpyridinium Cations in the Synthesis of Pyridine-Molybdate(V) Complexes
Darko Dolenc and Barbara Modec
Acta Chim. Slov. 2008, 55, 752–756

Alkylation with Oxalic Esters. Scope and Mechanism.
Jan Bergman*. Per-Ola Norrby, and Peter Sand
Tetrahedron VoL 46, No. 17. pp. 6113-6124 (1990)


Anomalous Ether Formation in Attempts to Transesterify Oxalate Esters with Phenoxides
EDWARD E. SMISSMAN, * MICHAEL D. CORBETT, SAMIR EL-ANTABLY, AND KATHRYN C. KROBOTH
J. Org. Chem., Vol. 37, No. 24, pp 3944–3945 (1972)

===

Heat, instead of a N,N-dimethylamide, may also work. (Found by Naf1.)

n-Octylation of Phenols
Yoshiaki Sakakibara

http://kamome.lib.ynu.ac.jp/dspace/bitstream/10131/3334/1/KJ00004767518.pdf

Allylation of Phenols
Yoshiaki Sakakibara

http://kamome.lib.ynu.ac.jp/dspace/bitstream/10131/3336/1/KJ00004767519.pdf

N-methylation and N-ethylation of Aniline
Yoshiaki Sakakibara

http://kamome.lib.ynu.ac.jp/dspace/bitstream/10131/3338/1/KJ00004767520.pdf

Syntheses of Derivatives of 5, 8-Diethoxyquinoxaline-2,3-Dicarboxylic acid
Yoshiaki Sakakibara

http://kamome.lib.ynu.ac.jp/dspace/bitstream/10131/3332/1/KJ00004767517.pdf
« Last Edit: February 10, 2011, 04:35:07 AM by Enkidu »

Enkidu

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Re: Methylating agent sources??
« Reply #71 on: March 09, 2011, 10:01:59 AM »
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