Electrochemical reductive amination of P2P's

[Rhodium]

This article looks perfect! Dissolve your ketone (MDP2P, P2P or whatever) in alcohol and add to an acidified aqueous solution of an excess of your desired amine, then run 1.75V/50mA through the solution until the resistance of the solution has increased so much as the current drops to 5% of the initial value, then perform an acid/base wash and the crude amine (MDMA/MDE/Meth/whatever) freebase is isolated for vacuum distillation and/or HCl gassing.

The yield is 70-90%! Electricity is almost free, no soluble mercury salts are used, no watched, water-sensitive and/or expensive reducing agents and very little chemical waste.

1-(3-trifluoromethylphenyl)-2-propanone (2.02g, 10 mmol) was dissolved in a mixture of 10ml 70% aqueous ethylamine (150 mmol), 37.5ml 2M HCl and 50ml ethanol, the apparatus flushed with inert gas and electrolyzed at 10°C with a controlled potential of -1.75 Volt in a divided cell with a mercury pool as working electrode and a platinum anode. The current drops from an initial 50 mA to 2-3 mA when the necessary 1960 As has been consumed. Next the electrolyte is acidified to pH 1 by the addition of 2M HCl, the ethanol evaporated under reduced pressure, the aqueous phase washed with 2x50ml ether and 25% NaOH is then added until pH 14. The alkaline solution is extracted with 3x50ml ether, the combined organic extracts dried over MgSO4, filtered and the solvent evaporated in vacuo to give 2.0g (87%) N-ethyl-3-trifluoromethyl-amphetamine (Fenfluramine) freebase.

Synthesis 1005-1007 (1987)

https://www.thevespiary.org/rhodium/Rhodium/pdf/redamin.hg-cathode.pdf

Thanks to Endo1 for bringing the article to my attention.

[hCiLdOdUeDn]

Looks like a good project for HiddenCloud. You will see...

 Swim also got the idea from

https://www.thevespiary.org/rhodium/Rhodium/chemistry/tcboe/chapter7.html

on the section of electrochemical reduction from 3,4-methylenedioxyphenyl-2-nitropropene to mda freebase but that article goes mdp2p to mdma freebase..which is even better for hiddenCloud.

The cell hiddenCloud plans to work on is a divided cell but using graphite rods and a salt bridge instead.

Thanks chief...you will see soon HiddenCloud will have a writeup of electrochemical reduction to make honey  
hcildoduedn

[Osmium]

> The cell hiddenCloud plans to work on is a divided cell
> but using graphite rods

There is a reason why Hg is used. I don't think graphite will work.

> and a salt bridge instead.

The resistance of a salt bridge is too high. You can't use one for electrolysis.

I'm not fat just horizontally disproportionate.

[moo]

-1,75V is the electrode potential, not the cell potential, measured between a reference electrode (eg. saturated calomel electrode) and the working electrode. They should be placed as close as possible without touching each other. The most professional way to run a preparative electroysis is to use a controller that adjusts the current so that the electrode potential stays inside a certain window, allowing to run a very selective reaction, although it is probably possible to run the same reaction without such equipment. Maybe one could do it by hand . A nice find.

[hCiLdOdUeDn]

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Graphite should work. Its conductive and doesnt corrode very much as opposed to many other electrodes.

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Says who?? Swim has used salt bridges many times in the past with great success. Maybe not for electrochemical reduction of mdp2p but with several other inorganic chemicals. Maybe swim will try a porous cermaic substrate so it will allow electrons to flow without having extra resistance.. *just a thought*...

*You will see...in the future...*


hcildoduedn

[Anansi]

Graphite should work. Its conductive and doesnt corrode very much as opposed to many other electrodes.

Conductivity and corrosion are not the only properties that matter!! Hg (and many other elements) have very specific proeprties when used as electrodes in electrolysis which are often unique to the element in question.

...Anansi

[moo]

Hg is probably chosen for its hydrogen overvoltage. Maybe lead could substitute... oh, see

Post 317018

(PolytheneSam: "Condition/preparation of the lead cathode seems ...", Novel Discourse) and the whole thread and don't forget to UTFSE. I bet even ceramic cell divider has its increase in the resistance, no matter what.

[Osmium]

>> The resistance of a salt bridge is too high.

> Says who??

I do.

> Swim has used salt bridges many times in the past with
> great success. Maybe not for electrochemical reduction of
> mdp2p but with several other inorganic chemicals.

So what did you use them for?
There is a big difference between measuring the voltage between some electrodes and pumping a few Faradays of electricity through your cell.
I'm not fat just horizontally disproportionate.

[hCiLdOdUeDn]

Swims had experience with making over 10kilos of potassium chlorate from potassium chloride. Even though this is was an undivided cell...swim believes electrochemistry is the OTC way to go if suitable electrodes can be found.


hcildoduedn

[Flip]

In a month or so if all goes well I should be publishing a writeup for mdma where the primary reagents will be air, light, and electricity. 

Is Flip being sarcastic?  You be the judge.
"Holy shit, would you look at that?"  - Flip (8/4/2002)

[noche]

How about substituting the pool of mercury with amalgamated al aluminium cathod.
The degree of amalgamation could vary from 100mg/dm2 to 1mg/6 dm2.
The electricity should ensure the the mercury stay on the cathod and prevent any Hg to get into the solution.
Because the Al serves as a cathod it wont get oxidized and will therfore be able to use over and over again.
The amalgamated Al cathod should be stored under petrolium or toulene in order to prevent oxidation.
The algamated Al cathod would make it possible to use much less Hg than when using elemental hg.

[sYnThOmAtIc]

I remember a while back that you mentioned that you have never read a detailed setup of one of these or seen such as have many. Here is the most detailed setup I have seen or read that may be of some use to you bees.
 

http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?rxntypeid=108&prep=CV6P0153

Yes, That pic really is me!

[bee186]

This article looks perfect! Dissolve your ketone (MDP2P, P2P or whatever) in alcohol and add to an acidified aqueous solution of an excess of your desired amine, then run 1.75V/50mA through the solution until the resistance of the solution has increased so much as the current drops to 5% of the initial value, then perform an acid/base wash and the crude amine (MDMA/MDE/Meth/whatever) freebase is isolated

That is so kool. The next thing I was going to ask in the newbie forum was 'why is P2P cool?', I was thinking about it a lot earlier today and last night.

So, can any of these "ketones" as you call them be transformed in to any of these "amines", or is there a specific initial ketone to correspond with a final amine?

Sorry if newbies aren't welcome in this forum!

[moo]

True underground chemists take a ketone, do a reductive amination with it while crossing their fingers, after wishing for an end product and throwing a coin in the magical pond (there is only one correct pond so those guys really know their shit).

No. There is a reason why 1-(3,4-methylenedioxyphenyl)-2-propanone (MDP2P) yields 1-(3,4-methylenedioxyphenyl)-2-methylaminopropane (MDMA) after reductive amination with methylamine. If you draw these three molecules on a paper side by side you can understand. Alternatively you can take a look at

https://www.thevespiary.org/rhodium/Rhodium/chemistry/mda.dalcason.html

.

And you are right about the newbee forum thingie. This post belongs there as well.

[bee186]

moo: That's fine, thanks for the direction and explanation. Without looking again I don't think there's much stuff in this forum I could even try to join in. Its all chinese.