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gavinray

The optical resolution of racemic amphetamine/methamphetamine has been known for years.

https://erowid.org/archive/rhodium/chemistry/amphetamine.res...

What has surprised me is how infrequently it seems to be carried out, given the materials required for it.

This is all you need:

- D-Tartaric Acid (You can buy it from import sites in bulk for $30-60/kg)

- Lye/Sodrium Hydroxide

- Ethanol/Everclear (if you're converting meth, you'll also need Methanol)

- Glassware

- Distilled Water

The process is stupid-simple and takes a matter of hours, any idiot could do it, and the difference it makes in effects (racemic vs optically-pure D-Amphetamine vs D-Methamphetamine) is obscene.

It seems like many of the clandestine chemists are behind the curve in the same way that LAMP-stack shops are in terms of the HN crowd in tech.

Source: Originally was an organic chemistry major with an intent to pursue psychopharmacology

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Agreed the process is very simple. The innovation that makes the resolution worth it is (as Derek also mentioned in the blog post) an efficient way to re-racemize the L-meth to DL-meth, which can then be resolved again. With steady state production and pooling this means it can be done using just one batch size (and not ever smaller "brsm" style bathces). If these steps are efficient enough you definitely get much more bang for your buck. Here is one such method[0] which probably inspired these drug manufacturers (as they use thioglycol and AIBN, which has been found in clandestine lab seizures).

[0] https://sci-hub.se/10.1021/jo061033l (published in JOC in 2006 - so only a mere 2 decades behind the curve)

Oh wow, now this is interesting.

To ELI5 this, what the commenter is saying is that you can take the "useless" L-Meth, and convert it to racemic, mixed D/L Meth.

Which you can then perform a second resolution step on, to convert/purify further, to the opposite chirality and get D-Meth.

The very interesting thing about this (if I were a clandestine chemist, or someone who wanted to get high at home), is that:

- AIBN is a readily available reagent, it's not difficult to acquire or would put you on any lists. This is in comparison to much of what you need for other synthesis techniques

- You can buy L-Meth legally over the counter. The extraction process would be a bit of a mess (quite literally) but should be doable, some basic recrystallization and/or conversion to freebase.

To further ELI5, racemic means a mixture of left handed (Dextrorotatory) and right handed (Laevorotatory) versions of the same compound. Some molecules can have two different shapes that are mirror images of each other, and these different shapes can interact differently with our biology.

In this case, the right handed version is available in stores with no prescription, while the left handed version is a very controlled substance.

> The process is stupid-simple and takes a matter of hours, any idiot could do it, and the difference it makes in effects (racemic vs optically-pure D-Amphetamine vs D-Methamphetamine) is obscene

(My organic chemistry is very rusty, and my knowledge of amphetamines is non-existant.)

I'm assuming from what you wrote that the D- enantiomer is one you want. What does the L- enantiomer do, if anything?

The L-enantiomer is actually readily available for purchase over-the-counter.

Vicks Vapor rub/inhalers and other decongestants use L-methamphetamine. The D-enantiomer causes CNS stimulation. The L-enantiomer causes only PNS (Peripheral Nervous System) stimulation, so it produces no euphoria or enjoyable effects.

Only unpleasant side effects, like tachycardia and anxiety, etc.

This is why racemic amphetamine/methamphetamine is so (comparatively) unpleasant, and the pure D-enantiomer is superior and "cleaner" feeling.

Racemic amphetamines have a much higher chance of inducing psychosis.

FWIW I find the Vicks Vapor rub fumes enjoyable and euphoria inducing. Edit: I think it's the eucalyptus oil that I am reacting to.

It's also well known as a miracle cure to various demographics of grandmas.

The active ingredients in Vicks Vapo Rub are just:

Camphor

Eucalyptus oil

Menthol

Perhaps you're thinking of a different Vicks product?

Ah it's just the inhalers then, my mistake

Another interesting one found in inhalers is Propylhexedrine, from Benzedrex inhalers

Is this the difference between Adderall and Dexedrine?

Yeah, Adderall is "Mixed-isomer amphetamine salt", it's a "proprietary" blend of 80/20 dextro/levo.

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