Converting pseudoephedrine to ephedrine?

[otb01]

Is this feasible?

[Geneity]

It's unessesary. For whatever you're using it for, psudoephedrine will suffice fine. It's a diastereomer of Ephedrine.

[Acyl]

Is this feasible?You can turn the alcohol into a tosylate by adding tosyl chloride to pseudoephedrine, from there you would have to add water to complete the reaction. This reverses the stereochemistry of the hydroxy group to give you ephedrine as the water you added attacks the tosyl group from "behind" via an Sn2 reaction mechanism.

If you dont know what im talking about dont do it.


You should know what im talking about though, you know chemistry.. dont you?

[fryingsquirrel]

I'm thinking that would just turn it back to pseudo. Not that it matters, pseudo reduces the same anyway.

[Acyl]

How would that turn it back into pseudo...?

That doesnt make sense, once the tosylate leaves it wont react with the newly formed ephedrine in any way shape or form.

[fryingsquirrel]

Replace the alcohol with a tosylate, then replace the tosylate with an alcohol, seems like you journeyed far to get where you started. Why would that reverse the reverse the stereochemistry? I'm missing something I guess.

[Acyl]

Well its no harder than an acid base extraction.. I dont know why he wants to do it, I just gave him a reliable method to doing what he wants to do.

Once the tosylate is formed out of the pseudoephedrine it creates a good leaving group thats easily subjected to an Sn2 reaction. Sn2 reactions are characterized by an inversion of the stereochemistry after the reaction has taken place, the nucleophile, in this case water, attacks the tosylate from "behind" and kicks the tosylate off.

This changes the stereochemistry around the carbon bonded to the hydroxy group to give you ephedrine.

[otb01]

Acyl, I get exactly what you're saying. Wait, but pseudoephedrine has the same effects as ephedrine? So popping sudafed will stimulate you?

I want to convert the pseudoephedrine to ephedrine for use as a stimulant basically.

[Geneity]

As I said before, Psudoephedrine is the diastereomer of Ephedrine, therefore it's effects are the same. Dextroamphetamine's effects are the same as amphetamines. What I'm saying is that even if there is a difference in the effects of the two, you sure won't notice it.

It was used by truckers to stay up on long drives and by students to study before it became like impossible to get.

The conversion is unessesary.

[Acyl]

Thats not true, not all diastereomers have the same effects at all. Thats a very big generalization.

[Geneity]

I wasn't saying that. Though now I look back on that it certainmly looks like I was. I guess I meant to use that as a way to relate the two instead of just saying "Yeah, they're effects are the same"

[Acyl]

Ah

[fryingsquirrel]

Ephedrine and pseudo are something comepletely different from the d and l optical isomers, both of which are possible for each. it's just that the commercially available isomer of each is the one which reduces to d meth, which is 7 times as strong as the l. Not sure the potentency difference for amphetamine, or MDMA. I would guess methylone from a commercial source is racemic.

[framesh1ft]

As I understand it you would have to do the rxn twice, then add the water. Thus making the tosylate then inverting the stereochemistry of the tosylate by repeating the reaction, then replacing with water. Probably one of those things that would make since in the lab under good instruction, but seems crazy on monitor...can't say that I've ever worked with tosyl chloride...so it seems kinda crazy to me now.

[dexisagoodthing]

i dont know anything about chemistry, but isnt ephedrine more potent than pseudoephedrine? i have popped sudafeds(back when it was made from pseudoephedrine) to get a buzz, and it wasnt that great.. mild stimulation/euphoria.. comparable to taking an adderall 20... which isnt much.. never tried snorting pseudo, and never done ephedrine but from what i heard i thought ephedrine is as good as amphetamines.. but swallowing something like 8-12 sudafeds werent even close to snorting crushed up adderalls which can get you pretty tweaked..

[framesh1ft]

They have different effects, its not just a matter of potency. Pseudoephedrine will give no buzz/euphoria, ephedrine does but it is qualitatively different than (meth)amphetamine. Ephedrine has far more cardiovascular effects than either pseudo or the deoxy derivative.

[fryingsquirrel]

from what i heard i thought ephedrine is as good as amphetamines.. Not even close.