Author Topic: Monomethylation of Amphetamines  (Read 1292 times)

letters

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Re: Monomethylation of Amphetamines
« Reply #20 on: September 08, 2011, 05:20:22 AM »
water will form during formation of imine. the overall reaction is R'NH2 + RC(O)R -> R'N=CR2 + H2O.
following your progress, id like to see success here, though im skeptical.

dingbow

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Re: Monomethylation of Amphetamines
« Reply #21 on: September 08, 2011, 07:32:43 AM »
Ah, MgSO4 could be used in the reaction to remove any water produced yes? None the less using paraformaldehyde would reduce the molar amount of water present significantly over formalin.

Im starting to become very skeptical as well, besides the erowid german patent reference, all other references with relation to producing secondary amines from primary amines generally involve the use of NaBH4, NaCNBH3 or catalytic hydrogenation...

Hmm, maybe I should investigate the other methods and not waste anymore amine on this. Would need to start procuring again though which is a pita.

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Re: Monomethylation of Amphetamines
« Reply #22 on: September 08, 2011, 08:53:37 PM »
Hmm, maybe I should investigate the other methods and not waste anymore amine on this. Would need to start procuring again though which is a pita.

I would suggest aminating acetone and working with that as your amine source so that you are not wasting any valuble amine while attempting this. Once the kinks are worked out then you could try other alternatives.
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dingbow

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Re: Monomethylation of Amphetamines
« Reply #23 on: September 14, 2011, 01:56:32 PM »
Interesting, aminating acetone provides isopropylamine yes? With diisopropylamine being the equivalent secondary amine?

Or am I way off :)

Wizard X

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Re: Monomethylation of Amphetamines
« Reply #24 on: September 15, 2011, 12:24:18 AM »
Interesting, aminating acetone provides isopropylamine yes? With diisopropylamine being the equivalent secondary amine?

Or am I way off :)

Yes, Isopropylamine, http://en.wikipedia.org/wiki/Isopropylamine

Yes, Diisopropylamine, http://en.wikipedia.org/wiki/Diisopropylamine
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dingbow

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Re: Monomethylation of Amphetamines
« Reply #25 on: September 15, 2011, 10:31:25 AM »
excellent, thanks. I should get on to this once im happy with the hofmann.

dingbow

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Re: Monomethylation of Amphetamines
« Reply #26 on: September 17, 2011, 05:01:23 AM »
Klute of SM showed (with pictures) the succesful monomethylation of phenethylamines byfirst  using benzaldehyde to form a protective imine, then methylation with home-made (also pictorial by Klute is available) methyl tosylate, followed by hydrolysis to give a methylated amine. it is easy and simple. methyl tosylate is far less nasty then the usual methylating agents (DMS, MeI) but still will methylate your dna if given a chance, so use normal precautions.
Im starting to research this again, some of it is coming back to me. Benzaldehyde seems easily obtainable, from cinnamaldehyde, with the latter being available OTC :)

So that leaves the need for a methylating agent. Back when I was researching OTC methylating agents, I came across this:
hxxp://www.sciencemadness.org/talk/viewthread.php?tid=10507#pid126542

Methyl bromide generated on demand for methylation. Does anything think this would not work in replacing methyl tosylate?
« Last Edit: September 24, 2011, 12:46:46 AM by dingbow »

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Re: Monomethylation of Amphetamines
« Reply #27 on: September 22, 2011, 07:18:15 AM »
methyl bromide, like all other methyl halides are nasty. the higher you go in the periodic table, the nastier due to increased volatility. i would not even contemplate using it outside the hood, and i would be very careful when working in the hood. you do not want something going wrong. you will become n-methyldingbow and so will your dna.

dingbow

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Re: Monomethylation of Amphetamines
« Reply #28 on: September 24, 2011, 12:46:27 AM »
lol methyld...

I thought the methyl halides lower on the table were more toxic, with MeI being the worst?

Anyway Klutes method is looking pretty good right now and working with liquids is always easier then gases. Almost all bases are covered, just one thing left to work out.

fries

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Re: Monomethylation of Amphetamines
« Reply #29 on: October 25, 2011, 12:57:21 PM »
I'm thinking of giving this a go soon - imine formation with paraformaldehyde and reduction with zinc or calcium.
« Last Edit: October 25, 2011, 01:33:36 PM by fries »

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Re: Monomethylation of Amphetamines
« Reply #30 on: October 25, 2011, 08:35:03 PM »
Really makes me wounder why people are still messing around with HgCl2 when performing reductive aminations when it can be done with non toxic materials such as this. Yield does not look that bad.
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fries

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Re: Monomethylation of Amphetamines
« Reply #31 on: October 25, 2011, 09:50:00 PM »
I want to try the imine reduction with zinc in basic aqueous conditions. I'm not too sure what the solubility and other chemical properties of the imine is like and how to extract it from the alcohol it was formed in. Do you think flushing it with water will force it to precipitate out?

Another question, should i be worried about diimine formation? Would these side-products be easy to remove?
« Last Edit: October 26, 2011, 04:45:21 PM by fries »

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Re: Monomethylation of Amphetamines
« Reply #32 on: October 27, 2011, 01:49:49 AM »
You should be able to test the reduction method using Acetone and and amine to form the Imine, I would suggest, due to lack of any real steric hindrance to add the Ketone to a saturated alcoholic solution of the amine so that there is large excess at all times of amine.

It should give you enough information to proceed further with more valuable substrates.
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POSEIDON

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Re: Monomethylation of Amphetamines
« Reply #33 on: October 27, 2011, 04:29:10 AM »
look this pdf method II
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fries

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Re: Monomethylation of Amphetamines
« Reply #34 on: October 27, 2011, 12:55:17 PM »
Why is ether used for extraction? Couldn't i use any non polar solvent? The freebase should be soluble in toluene.

fries

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Re: Monomethylation of Amphetamines
« Reply #35 on: October 27, 2011, 03:12:00 PM »
For the zinc/water/NaOH reduction, looking at their table 1, the diamine formation seems to depend on there being a large substituent for r3. There is no entry for the percentage of diamine for the imine on row1h (which has the methyl group on r3). Does this mean they didn't detect any diamine?

"A  small ammount of diamines  3a-e was  formed as a by-product.  In the case of  imines  lf-g  and li-j,  the  formation  of diamine  tended  to be  increased. "

It doesn't mention row 1h so i'm hoping for no diamine... I guess a tlc would be a good idea if i go this route.
« Last Edit: October 27, 2011, 03:38:08 PM by fries »

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Re: Monomethylation of Amphetamines
« Reply #36 on: November 23, 2011, 06:03:02 AM »
who said you can't methylate with dimethyl oxalate?


dingbow

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Re: Monomethylation of Amphetamines
« Reply #37 on: April 18, 2012, 06:27:48 PM »
Alright so heres the deal with the latest runs I did with monomethylation. I ran Klutes method basically, to the tee (well sorta..). All the indicators were spot on and matched Klutes description, but when it came to gassing, it failed, twice.

-I successfully made methyl tosylate. A dense non-polar liquid was formed.
-The imine was formed with the aldehyde, indicated by clear solution becoming opaque with water.
-The water was driven off, indicated by a clear solution (dont have a dean stark unfortunately).
-The methylammonium tolsylate formed, indicated by a dark orange liquid which separated, which was then extracted with h20. This aqueous layer was then basified with KOH, which did indeed release an amine smell, slightly stronger and different to the primary amine smell im used to, very exciting.
-I know at this point, the amine is mixed in with the also liberated aldehyde used originally for the imine formation. Klute from memory says purification of amine can be done via distillation.
-I find this unsuitable due to working at 10 mmole scale, so instead I tried doing a mild A/B hoping it would leave behind the aldehyde and bring over the secondary amine. The indications looked good, upon basifying the acidic aqueous layer, much table salt (presumably) was visually seen and again the smell of an amine was present. A non polar extract yielded a slightly yellow solution.
-This was gassed, which yielded something like 150mg of the HCL salt, which is obviously terrible. Im not even sure if this is just primary amine that went through the whole procedure unreacted.

I ran this twice, with pretty much identical results and yield. Not sure if anyone has any experience or can help out with this one. I cant experiment for a while anyway, but thought the info might be useful to someone. Whilst the primary amine has been great, the elusive secondary amine has been a holy grail for me and it seems its still just out of reach!


dingbow

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Re: Monomethylation of Amphetamines
« Reply #39 on: February 06, 2013, 12:32:47 PM »
...which yielded something like 150mg of the HCL salt, which is obviously terrible. Im not even sure if this is just primary amine that went through the whole procedure unreacted...
All right, its been a long time. But I can confirm that from the bioassay, it seems the producted yielded from this reaction did indeed give me a secondary amine. It was much more euphoric, empathic and way less of a stimulant effect then the primary amine. Great stuff!

Hopefully I can run this procedure again and get some decent yields, but at least it worked.