microwave amphets

[rickjones]

In reference to post:No 204258

If D phenylalanine is added to PEG 3400 with CsCO3 and heated in a microwave for 45mins one will get D amphetamine??correct?.,what are pitfalls, problems if any,and can this be scaled up to any degree so we are not dealing with 80mg amounts?

[dust4us]

u could burn your amp. real fast it would burn it all up and u would not know until u are done and it smells funny.

[PrimoPyro]

The biggest problem is practicality. Even if the synthesis works blissfully with no errors, in order to scale up one has to add more reagents, meaning more D-phenylalanine.

Pure D-phenylalanine is ungodly expensive. I looked into it less than two weeks ago. It is absolutely ridiculous if you ask me.

                                                    PrimoPyro
Vivent Longtemps la Ruche!

[Rhodium]

If the procedure works (I haven't understood the details of it), then it woulde be more economicaly feasible to start with the racemate and then use as is, or separate the enantiomers. The l-amphetamine can always be racemized to the racemate again.

[jim]

Post 204258 (missing)

(obituary: "alkylation of PA to Amp", Chemistry Discourse)

This post is a reprint of the article I found about 2 years ago.  It deals with the quick facile alkylation of aphla amino acids, I don't know how quickly it would work with a branched chain like phenlyalanine.  If you notice there is not tertiary amino acid produced, which would be the product formed from using phenylalanine.

I gave this synthesis much thought, only experiment will tell.  I feel that this synthesis will take longer than the prescribed 45 minutes in a microwave.

As a secondary issue, I think that NaCO3 can be substituted for the CsCO3.  I don't beleive that the CsCO3 is there for any other reason than to act as a base.

[masterofpuppets]

Couldn't the DL-phenylalanine be used (which fairly expensive but would give half of the right type)?
I wouldn't do that if I were you.....

[jim]

Yes, you can but the product will be less potent.

Has anyone tryed this yet?

[urushibara]

Yeah, does this method work on Phe?

I'm tryin ta figger it out here - firstly have I gathered the essential ingredient list correctly: amino acid, alkali-metal carbonate and PEG. Is disodium carbonate the same as washing soda? where do you get this carbonate stuff from?

Okay, so what's happening in this reaction? I can see that the PEG *might* esterify with the amino, so then how does that pesky =O get removed? Does the carbonate do that? Or is there something else happening in between. Is that alkali metal doing something to the carbonyl? Does the alkali metal maybe somehow make the PEG donate some hydrogens and make it into poly ethene glycol. and our amino into amphetamine.

C'mon peoples, what's going on? this is a very promising thread. There's a chemical mentioned in there which I can't find on chemfinder: 'diphenylmethylene glycinate' That sounds like the ester of phenylmethanol(benzyl alcohol) and glycine (aka aminoacetic acid) What has that got to do with the reaction? It's snuck in next to the PEG in the example reaction described. I can't see what it would do either. other esters aren't mentioned in the rest of it.

What's the mechanism? Methinks it might have something to do with making the alkali metal deionised with electrons donated via the microwaves. If that's the case, the carbonate protects the amine group, and the alkali metal (Na shall I say?) tears up the oxygens and leaves behind a methyl where there was once a carboxylic acid... Deionisation of the alkali metal would explain the warning about mixing the carbonate salt properly through it.

If that's the case, then the PEG is just a nice high-boiling solvent substrate.

Hmmm... could PEG be used in other microwave reactions, for example decarboxylation with an enone?

Shit man, I have nooo idea. someone with more know-how want to give some clues on this one? Please excuse my rambling, I am really interested in microwave chemistry (and for that matter anything new and unusual, and/or OTC) - and I would love to understand this reaction, it might lead somewhere.
I know naaaathing.