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Working on article for Drink and Drug News - PMK Glycidate and the Rise of 'Super Strength' MDMA Tablets

Fertile

Fertile

Bluelighter
Joined
Mar 31, 2022
Messages
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As the title says, I have been researching the rise of (R) MDMA, high dose (500mg) MDMA tablets and the new(ish) pre-precursor, PMK glycidate.

My logic is that nobody would make a 500mg MDMA tablet that sells for the same price as 100mg MDMA tablets unless you KNOW that what you have is weak. I concluded that 3,4-(Methylenedioxy)cinnamic acid is the source material (PMK was controlled in China in 2015) & that someone had found a direct (or at least chiral) route for the synthesis of MDMA from PMK glycidate. Converting PMK-glycidate to MDP2P is widely known and very simple so their could be 2 explainations:

1)The 'cooks' only know 1 way to make MDMA from PMK-glycidate and so they have no option but to sell a low quality product at a lower price.
2)The direct (chiral) route from PMK-glycidate to MDMA is so efficient that it's more profitable to sell the lower quality product at a lower price.

I am now datamining to see if I can find the second (PMK glycidate to MDMA) because it would imply the first.

I conclude that such a route must have a lot of advantages. I suspect that it does not require methylamine.

I originally thought that the glycidate was being made using the Darzen's reaction. This involves the use of 2-hydroxypropanoic acid. The CHEAPEST way to make this precursor is from lactic acid and as we all know, lactic acid is CHIRAL. That would have answered 50% of the question. But now I'm not so sure.

I would be very grateful for any information people might have. This is not intended to show people how to make MDMA, it's intended to reduce harm and one has to admit that 500mg of MDMA is not an intrinsically safe alternative when compared to 125mg. If you know lactic acid is used somewhere, that would be a clue. If you know that their is a direct route then that would be a clue. It's all going to be clues. I seriously doubt anyone involved in the clandestine synthesis of MDMA is going to pipe up with the answer.

I am also looking into an on-the-spot test for detecting an enantiomeric excess. Currently polarimetry or even more complex methods are used. I'm looking at finding a reagent that only reacts with the (R) isomer and another that only reacts with the (S) isomer. It would be very clever to find 1 reagent that goes a different colour based on the particular isomer.... but I'm betting that 2 simple reagents will be cheaper.

This putative test reagent has no name as of yet. I propose that if we can find these clues, put them together and find a reagent, it be christened 'Bluelight Reagent' on the basis that it will be the work of many people. It also helps drive people to our HR communuty.

Many thanks for your imput.
 
I like the reagent idea, but we have at least 2 recent research articles this supposed mass R-MDMA phenomenon isn’t happening. One finding all samples were racemic and the other showing only one sample with a skewed enatiomeric excess in favor of R but still some S present. These can be found in the “What’s Wrong With MDMA Today?” Thread.

My fairly well educated guess is that we are looking at some impurity that negates the positive effects. The enatiomeric excess theory has been disproven on multiple levels.

But back to the reagent idea (cuz I like that for the simple fact of what if one day you stumble upon a batch with excess, it’d be nice to know) has that ever been done with any other substances isomers before?

-GC
 
I would certainly like some reference on the (R) thing being disproven. Not that I doubt you, but because I want references on everything.

I don't see the logic of selling a pill with 500mg of active material for the same price as one with 100mg of active material. Mistakes happen, but this isn't isolated - it's popping up all over Europe and North America. The pills we paid £20 for in 1987 had 125mg of MDMA in them and that did us for the whole night. A FEW lunatics who wanted to just keep going would take a second one later, but 'double dropping' isn't common. If people want 2, they pay for 2.

It would have to be an impressive route given that the reductive amination of PMK can yield 95% (if you have the right paper). It can only be that a direct route is either the only one the 'cook' knows and/or it's more efficient. I mean, some chemists have telescoped some syntheses really impressively. The reduction of pseudoephedrine is now at once VERY simple but also VERY dangerous.

It strikes me that it would be a route that doesn't practice solvent management, doesn't use any difficult-to-handle reagents (like using nitromethane in place of methylamine in the Al/Hg route) and has a simple workup. There is no obvious candidate BUT it's got to be CHEAP.
 
This one shows only one sample of 12 had a slight enatiomeric excess. (Look up PDF on Google Scholar.)

www.sciencedirect.com

Ecstasy tablets: Rapid identification and determination of enantiomeric excess of MDMA

The consumption of psychoactive substances is a worldwide problem and the sheer number of their seizures is alarming. These substances also include th…
www.sciencedirect.com www.sciencedirect.com

Germany, 90-something samples between 19-20. All samples racemic.


I’ll respond more later when I can.

-GC
 

Same article but not behind a paywall.

Well, 11 of the 12 were racemic which is what one would expect but 1 was 63.6% of the (R) isomer. Not an excess of the (S) as one would expect if someone wanted a stronger product. So it that a route that yield a slight excess of the (R) isomer OR is it MDMA from multiple sources all mixed together for tabletting?

I used to know several MDMA tabletting operations in The Netherlands. The way they worked was to source the MDMA from dozens of kitchen chemists. These guys produced anywhere from 1 to 20Kg per month. That decentralised model meant that when the people doing the tabletting got caught, they did not.

So the paper does show that their is at least one person using a chiral synthesis. It doesn't show if it's a route that produces a slight EE of the (R) isomer OR if one producer is using a route that produces a much higher EE but it's diluted because it's mixed with a lot of racemic product. The last option is that the makers discovered that a 60% (R), 40% (S) mix is more or less identical in effect to a true racemate and (R) MDMA sells for less, BUT if one could choose a route that produces an EE, wouldn't one try to make more (S)?

I don't know of any other chiral MDMA syntheses. Yes, one could employ a chiral auxiliary, resolve the isomers or use a chiral catalyst, but I've never heard of any of these approaches being used.

BTW China has controlled PMK glycidate (specifically the methyl ester) so you will not be surprised to learn that the Chinese are now making and supplying the ethyl ester. Again, this detail seems to be absent in most reports. That and the fact that PMK glycidate is supposed to have been a key factor in brining down the wholesale price of MDMA to £5000/Kg on the dark web (according to a German programme).

I did wonder if the Chinese were forming PMK glycidate from 3,4-methylenedioxy cinnamic acid but can find no evidence. Of course, lack of evidence isn't evidence of absence.

*Edit*

Sorry, didn't see that second link. It doesn't refute the fact that someone IS producing MDMA with an EE of (R) that cannot be explained statistically. None of the routes encountered would explain it and the fact that it is the less active (R) isomer suggests that the makers could not control the stereochemistry.

I just noticed that (R) MDMA is being explored for medical use. Mind Medicine in NYC had a press release in which they mention that they have developed 'an efficient synthetic pathway'. I cannot find a patent or who on their board is a chemist. Again, if anyone knows, that would be a help - I may be able to find his or her paper on (R) MDMA synthesis.
 
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It's hard to see how you would get to MDMA via PMK glycidate without losing chiral information. I bet you could get an article in JACS for something like that!
 
Well, epoxides do react with amines chirally. I haven't found an appropriate example but I don't have another explanation for how an excess of the (R) isomer was found in a sample. One would assume PMK glycidate would simply serve as a source of PMK, but PMK is achiral.

I have noted that 3,4-methylenedioxy cinnamic acid is a possible precursor for PMK glycidate. That would have the benefit of not proceeding via PMK which has been controlled in China since 2015. It is an item of commerce.
 
BTW their is a fairly recent paper on the racemization of phenethylamine stimulants and entactogens:

Escoubet S, Gastaldi S, Vanthuyne N, Gil G, Siri D, Bertrand MP. Thiyl radical mediated racemization of nonactivated aliphatic amines. J Org Chem. 2006;71(19):7288-7292. https://doi.org/10.1021/jo061033lI

I have now confirmed that the PMK glycidate IS being made from 3,4-methylenedioxy cinnamic acid. Now the few papers on the cinnamic acid ---> glycidate ARE chiral. OK, the 3,4-methylenedioxy cinnamic acid is almost all trans, but I do not see how that would impart stereoisomerism.
 
This is about the route to r-mdma, right? R-mdma should be a little bit more psychedelic that the racemate, at least that’s what’s it’s touted. But 500mg should be a clear overdose for most. It should be active at 100mg also. Or am I missing something?
 

Read #109 MDMA | PiHKAL · info

Book II of PiHKAL: A Chemical Love Story. Alexander & Ann Shulgin #109: MDMA
isomerdesign.com

Well, according to Shulgin, 200mg of (R) MDMA produces only a +1 experience so I imagine that 300-400mg would be needed for a +3. The question is, what would constitute an overdose of (R) MDMA?

Since ih has significantly less effect on serotonin release/reuptake compared to the racemate, the usual mechanism of overdose (serotonin syndrome) shouldn't occur, or at least will only occur at significantly larger doses.

If their are more papers on animal/human models of (R) MDMA then they would be of signal interest.
 
I always wanted to separate the isomers of mdma or better methylone to see what difference in effect they produce. I always read that the s enantiomer is more stimulating, as the active principle in meth is the s-enantiomer and the r-enantiomer is more trippy since eg r-dob is the active enantiomer for psychedelic Amphetamines. Mdma and the like seem to lay somewhat in the middle between plain stimulants and the psychedelic Amphetamines.
 
Below is a 'kitchen' resolution of methamphetamine. It would appear that methamphetamine produced via BMK is resolved and the unwanted (R) methamphetamine is racemized to 50:50 (R)/(S)

Main methamphetamine production methods used in Europe | www.emcdda.europa.eu

www.emcdda.europa.eu www.emcdda.europa.eu

Below is an alternative procedure for the optical resolution of methamphetamine.

Below are examples of the class of racemization specified in the above paper. AIBN (azabisisobutyrlonitrile) is a catalyst for the radical reaction.
www.academia.edu

Thiyl Radical Mediated Racemization of Nonactivated Aliphatic Amines

Thiyl Radical Mediated Racemization of Nonactivated Aliphatic Amines
www.academia.edu

If the above doesn't work, their are patents in which tartaric acid and dibenzoyl tartaric acid are used. The latter is more soluble in non-polar solvents such as the ones that freebase MDMA are soluble in. (1R)-(-)-Camphor-10-sulfonic acid has also been used as has (S) naproxen and I think eve (S) lactic acid (lactic acid produced by fermentation, not synthetically) have been used to resolve amphetamine.

The trick is to find the cheapest optically active acid that will bind to one isomer but not the other and which will change solubility sufficiently so that one of the products (be it the unreacted freebase or the reacted amide, sulfonate or whatever) can be washed into another solvent (one that is immiscible with the first solvent) so you end up with one isomer dissolved in the first solvent, the other isomer dissolved in the second solvent.

Then the cool twist the meth makers use - the use of AIBN which will react with the secondary amine (via in imine) so that 50% of the less active/inactive isomer is transformed into the active isomer).

If you really cannot find a route for MDMA and MDA you can be utterly certain that their WILL be a paper by David Nichols or one of his team explaining how to resolve them and indeed, their will be methods to resolve every single chiral compound he ever made.

It's more a matter of finding a methodology that suits your scale, skills and supplies. I'm sure Mexican superlabs can employ methods that us mere mortals wouldn't consider for a moment. I mean, mechanical losses tend to be similar whatever the scale but losing 10 grams for 25Kg is NOT a problem but losing 10 grams from 25 grams is a MAJOR problem.
 
Fertile said:
I don't know of any other chiral MDMA syntheses. Yes, one could employ a chiral auxiliary, resolve the isomers or use a chiral catalyst, but I've never heard of any of these approaches being used.
Click to expand...
Swim in the Chiral Pool: MDMA and MDA Enantiomers from Alanine-Derived Precursors
A divergent two-step process has provided access to optically pure enantiomers of MDMA and MDA, clinically relevant phenylisopropylamine entactogens. Target compounds were synthesized from commercially available alanine-derived aziridines. Critical process parameters were identified, and the reactions were optimized to avoid chromatographic purifications toward gram-scale isolations, providing (R)-(−)-MDMA, (S)-(+)-MDMA, (R)-(−)-MDA, and (S)-(+)-MDA each in greater than 98% purity by UPLC, >99% enantiomeric excess, and net yields between 50 and 60% for the complete process.

https://pubs.acs.org/doi/10.1021/acsomega.3c02358


or


Synthesis of R- and S-MDMA via nucleophilic ring-opening of homochiral N-tosylaziridines
Homochiral (R)- and (S)-3,4-methylenedioxymethamphetamine (MDMA) were prepared in six
steps (each) from the chiral pool precursors D- and L-alanine, respectively. The key step, copper-
catalysed regioselective ring-opening of an N-tosylaziridine with an aryl Grignard reagent,
proceeded in high yield with complete regioselectivity. Elaboration was achieved with preserva-
tion of configurational integrity, affording R- and S-MDMA hydrochlorides with enantiopurities of
>99.5%, as determined by enantioselective HPLC with fluorescence detection. Attempts to apply
the synthetic methodology to the synthesis of the homochiral enantiomers of the α-phenyl
analogue of MDMA (UWA-001) were thwarted by a switch in regioselectivity in the key step.

https://www.publish.csiro.au/ch/fulltext/CH23064

But by in large I believe most MDMA is still made with safrole or glycidate... safrole is a around from a few vendors of commerce in bulk if you look as low as 20 kg....
 
It's an interesting route but is 5-chloro-2H-1,3-benzodioxole really a practical precursor?

Use of a chiral amino-acid is certainly a clever idea and I've seen similar methodologies but they aren't, errr..., , compatible with the level of practical organic chemistry ability I've witnessed in the various amphetamine and MDMA labs I've seen.

I could more readily see a European producer making MDMA, resolving it and then using a free-radical producer to racemize the less active enantiomer. After all, European methamphetamine producers appeared to be the first to do that.

I'm just slightly puzzled that nobody is producing MDAR (example 13 of the original Poos patent on aminorex derivatives) since the immediate precursor, the amino-alcohol isn't legally controlled anywhere (as far as I can tell).

OK, I'm 100% not keen on the idea of 'cooks' playing with BrCN and maybe it IS fear that's stopping them, but historically their has always been someone prepared to take that risk. MDAR is attractive due to both isomers being active. One is more MDA-like, the other more MDMA-like so I leave it to people to imagine what the subjective effects of the raecemate are.

I guess the benzofurans would make aminorex homologues as well although as stated elsewhere, a study of BenzoFury products revealed that the Chinese makers never managed to remove positional isomers.
 
AlsoTapered said:
It's an interesting route but is 5-chloro-2H-1,3-benzodioxole really a practical precursor?

Use of a chiral amino-acid is certainly a clever idea and I've seen similar methodologies but they aren't, errr..., , compatible with the level of practical organic chemistry ability I've witnessed in the various amphetamine and MDMA labs I've seen.

I could more readily see a European producer making MDMA, resolving it and then using a free-radical producer to racemize the less active enantiomer. After all, European methamphetamine producers appeared to be the first to do that.

I'm just slightly puzzled that nobody is producing MDAR (example 13 of the original Poos patent on aminorex derivatives) since the immediate precursor, the amino-alcohol isn't legally controlled anywhere (as far as I can tell).

OK, I'm 100% not keen on the idea of 'cooks' playing with BrCN and maybe it IS fear that's stopping them, but historically their has always been someone prepared to take that risk. MDAR is attractive due to both isomers being active. One is more MDA-like, the other more MDMA-like so I leave it to people to imagine what the subjective effects of the raecemate are.

I guess the benzofurans would make aminorex homologues as well although as stated elsewhere, a study of BenzoFury products revealed that the Chinese makers never managed to remove positional isomers.
Click to expand...
Chinese chemists have been fucking around making grey market chems since forever...
example the methyl ester of lysergic acid. ie LAME thats flooded the market the past year at sub 2 digit pricepoint non bulk... The glycidate of mdp2p etc

Give them a call and see what else they can comeup with or have in stock for.... I wouldnt be shocked IF since the immediate precursor, the amino-alcohol isn't legally controlled anywhere (as far as I can tell). it's alreadly moving alreadly in china not to mention you could probably reachout and get a step or 2 closer then 5-chloro-2H-1,3-benzodioxole, don't you think?

These are just thoughts wasnt 2C-T-7 the first every greymarket chem pool by chemists to just get it done? " I’ll give you an example: Around 1998 there was a group of us that were trying to work on some of Shulgin’s thio-compounds, the 2C-Ts. They were a lot more difficult than the standard phenethylamines and we just couldn’t do it effectively. So eventually a private group of chemists and investors pooled their resources and commissioned a laboratory in Poland to produce a kilogram of 2C-T-7. It was ridiculously expensive, and the entire process felt like a really extreme measure. To the best of my knowledge, that group effort was the first instance of custom syntheses of a gray-market drug by the end users. Less than two years later, the chemical took off and was introduced as Blue Mystic in the Netherlands, and then as a pure chemical in the States. 2C-T-7 was one of the first “research chemicals” in the modern designer-drug sense, and I think some of its initial popularity came from the fact that it had been totally unavailable due to the difficulty of producing it in a clandestine lab. Back then the internet served to disseminate knowledge about drugs. There was less emphasis on disseminating the drugs themselves"

I imagine if you want you can have someone to the heavy lifting, the nitrile of helional is around if you look as a basic example of someone doing the lifting, along with such chemicals like LAME ;)

Discussion on drug synthesis is banned bluelight so I try and be as vague as possible for obvious reasons. But enough to give you without can I haz step by step please... while still answering your question
 
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vash445 said:
Chinese chemists have been fucking around making grey market chems since forever...
example the methyl ester of lysergic acid. ie LAME thats flooded the market the past year at sub 2 digit pricepoint non bulk...

Give them a call and see what else they can comeup with or have in stock for.... I wouldnt be shocked IF since the immediate precursor, the amino-alcohol isn't legally controlled anywhere (as far as I can tell). it's alreadly moving alreadly in china not to mention you could probably reachout and get a step or 2 closer then 5-chloro-2H-1,3-benzodioxole. don't you think?
Click to expand...

Oh, most certainly. What I learnt through bitter experience is that MOST Chinese suppliers WILL try to rip the buyer off given half the chance. But for that route you posted, I don't think many would

Their are ways around this but it requires a lot of time and effort on behalf of the buyer. You really have to micro manage them because they are really creative in ripping buyers off.
 
AlsoTapered said:
Oh, most certainly. What I learnt through bitter experience is that MOST Chinese suppliers WILL try to rip the buyer off given half the chance. But for that route you posted, I don't think many would

Their are ways around this but it requires a lot of time and effort on behalf of the buyer. You really have to micro manage them because they are really creative in ripping buyers off.
Click to expand...
This is a little over my head but I saw this one is interesting

Bioreduction of α-methylcinnamaldehyde derivatives: chemo-enzymatic asymmetric synthesis of Lilial™ and Helional™†​

Abstract​


Nonracemic aryl-substituted α-methyldihydrocinnamaldehyde derivatives employed as olfactory principles in perfumes (Lilial™, Helional™) were obtained via enzymatic reduction of the corresponding cinnamaldehyde precursors using cloned and overexpressed ene-reductases. (R)-Enantiomers were obtained using the old-yellow-enzyme (OYE) homolog YqjM from Bacillus subtilis and 12-oxophytodienoic acid reductase isoenzyme OPR1 from tomato (e.e.max 53%), and (S)-aldehydes were furnished in up to 97% e.e. using isoenzyme OPR3, nicotinamide 2-cyclohexene-1-one reductase NCR from Zymomonas mobilis and yeast OYE isoenzymes 1–3 under optimised reaction conditions in the presence of t-butyl methyl ether as the co-solvent. The stereochemical outcome of the reduction of α-methylcinnamaldehyde using NCR and OYEs 1–3 [previously reported to be (R)] was unambiguously corrected to be (S).
 
It's worth noting that PMK glycidate salts/esters are now the most common pre-precursor to MD(x)A since they can be hydrolized to PMK.

BUT more interestingly, PMK glycidates aren't made from PMK. They are made from 3,4-methylenedioxy cinnamic acid by way of an ester. It's found naturally in a number of plants. None of them controlled.

Plain cinnamic acid could be converted to BMK via the glycidate.

In an effort to control the flow of precursors, chemists have realized that many previously ignored natural sources are viable.
 
AlsoTapered said:
BUT more interestingly, PMK glycidates aren't made from PMK. They are made from 3,4-methylenedioxy cinnamic acid by way of an ester. It's found naturally in a number of plants. None of them controlled.

Plain cinnamic acid could be converted to BMK via the glycidate.
Click to expand...
There's no reasonable way to do so without α-methyl. You need α-methylcinnamic acid to make a ketone. Alternatively, those glycidates can be made from benzaldehyde and piperonal by Darzens condensation.


( https://www.researchgate.net/public...ospective_search_in_German_profiling_database )
 
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AlsoTapered said:
It's worth noting that PMK glycidate salts/esters are now the most common pre-precursor to MD(x)A since they can be hydrolized to PMK.

BUT more interestingly, PMK glycidates aren't made from PMK. They are made from 3,4-methylenedioxy cinnamic acid by way of an ester. It's found naturally in a number of plants. None of them controlled.

Plain cinnamic acid could be converted to BMK via the glycidate.

In an effort to control the flow of precursors, chemists have realized that many previously ignored natural sources are viable.
Click to expand...
If the trick is to find the cheapest optically active acid that will bind to one isomer but not the other and which will change solubility sufficiently so that one of the products (be it the unreacted freebase or the reacted amide, sulfonate or whatever) can be washed into another solvent (one that is immiscible with the first solvent) so you end up with one isomer dissolved in the first solvent, the other isomer dissolved in the second solvent.

Earlier today," I heard that some labs were using Naproxen (like the NSAID) as the enantiopure acid. But I haven't been able to find any info at ALL on this method, so I really can't say with certianty."

so I did a little digging from my understanding and granted I don't understand much... just enough... anyways I did some digging and this what was found .


It could have probably been based on this retort? If the trick is to find the cheapest optically active acid that will bind to one isomer but not the other and which will change solubility sufficiently so that one of the products (be it the unreacted freebase or the reacted amide, sulfonate or whatever) can be washed into another solvent (one that is immiscible with the first solvent) so you end up with one isomer dissolved in the first solvent, the other isomer dissolved in the second solvent. Based on what this says what do you think.



The scheme
https://ibb.co/L5znKLH


The Retort





Resolution of Enantiomers via Diastereomeric Salt Formation: Naproxen



In my biochem slides from
CHE322 the analgesic naproxen is resolved in a manner very similar to that discussed in CHE321. Naproxen is a chiral carboxylic acid, and it is the (d)-(S)- enantiomer that is sold as the active drug.


Racemic naproxen is resolved by a modification of the salt-formation technique we learned in class. There are two twists to the protocol that make the process even more useful for commercial production of enantiomerically pure naproxen. First, in a twist known as the Pope-Peachy method, only half an equivalent of chiral amine is used. Half an equivalent of a cheaper, optically inactive amine base is used in its place. This not only makes the process cheaper, but results in a more dramatic difference in solubilities. The conjugate base of the desired (d)-(+)-enantiomer crystallizes out with the conjugate acid of the chiral amine, with high selectivity. This leaves the more soluble salt product of (l)-(-)-naproxen and the achiral amine behind in solution.

The second twist is that, by simply heating the “mother liquor” (the solution that remains after filtration) , the undesired enantiomer of naproxen can be converted back to a racemate. You will learn in CHE322 that protons next to a carbonyl are modestly acidic; this means that if you have a methine stereocenter next to a carbonyl you always have to be wary that its configuration can get “scrambled” by deprotonation/reprotonation. In this case, however, we want the configuration to equilibrate back to a racemic mixture, and the achiral base that was used, plus heat, is enough to do the job.



This process allows naproxen to be synthesized by a simpler, cheaper route as a racemate instead of a single enantiomer. Not only can the two enantiomers be resolved by this process, but the “undesired” enantiomer is converted to the desired, rather than being discarded--effectively doubling the yield of product.



Reference: Harrington, P.J.; Lodewijk, E. “Twenty Years of Naproxen Technology”. Organic Process Research and Development, 1997, 1, 72-76.


Or this

The scheme

https://dump.li/image/9c18be102836e02a.gif

Non-enzymatic dynamic kinetic resolution of racemic α-arylalkanoic acids: an advanced asymmetric synthesis of chiral nonsteroidal anti-inflammatory drugs (NSAIDs)

An efficient protocol was developed to produce chiral 2-arylalkanoic esters in high yields (up to 99%) from racemic carboxylic acids utilizing the racemization of the mixed-anhydrides generated from acid components with pivalic anhydride in the presence of an acyl-transfer catalyst. The present DKR involves the enantio-discriminating esterification of the racemic 2-arylalkanoic acids and the rapid racemization of the chiral 2-arylalkanoic acids under suitable reaction conditions using pivalic anhydride, diisopropylethylamine, and benzotetramisole (BTM) in a polar solvent, and this method was successfully applied for the preparation of pharmacodynamically active (S)-enantiomers of nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and naproxen.


pubs.rsc.org

Non-enzymatic dynamic kinetic resolution of racemic α-arylalkanoic acids: an advanced asymmetric synthesis of chiral nonsteroidal anti-inflammatory drugs (NSAIDs)

An efficient protocol was developed to produce chiral 2-arylalkanoic esters in high yields (up to 99%) from racemic carboxylic acids utilizing the racemization of the mixed-anhydrides generated from acid components with pivalic anhydride in the presence of an acyl-transfer catalyst. The present...
pubs.rsc.org pubs.rsc.org
https://doi.org/10.1039/C2CY20329D
 
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