Sciencemadness Discussion Board

Aldol Condensation of Piperonal with Acetone

idontlie - 3-1-2010 at 15:35

Essentially this document is why the DEA isn't worried about aldol condensation of piperonal. Maybe they are but are killing off those who discover the secret. What do you think?

The reactive portion on piperonal, the aldehyde, in an Aldol condensation can be thought of as Benzaldehyde. We must be wary of damaging the Methylenedioxy group and being forced to clean up the product. Either by throwing away the incorrect product which would kill the yield. Alternatively you could follow the eugenol/vanillin Demethylation and Methylenation procedures discussed in detail, elsewhere, to hope to fix your little mess. Which would remove the benefit of spending the effort to extract piperine, and following the path through piperic acid then to piperonal via copper oxides [1] which is in and of it self a piece of work, rather than starting with eugenol or pyrocat.

Primary Reaction:

Benzaldehyde + Acetone in NaOH, Water, and EtOH yielding Benzalacetone. [2] Suggests shaking our Benzaldehyde (piperonal) with soda ash (PH Plus at pool stores) then distilling to get fresh, clean and happy product.

Take special note of note 8 of [2]. This is a anisaldehyde (similar to vanillin) + acetone of the same procedure yielding anisalacetone at 83%. So our condensation should give around 80% yields from piperonal.

Side Reaction:

Benzaldehyde + Acetone in NaOH, Water, and EtOH solution yields Dibenzylideneacetone. [3][4] Just look at that sucker. It would be much better to avoid this product all together than to attempt to convert it. We can avoid this by excess acetone. Acetone is 4$/L, How much is your piperonal worth?


At this point we have 3,4-methylenedioxy-Benzalacetone, CAS 3160-37-0. This is not MDP2P our chain is one carbon to long on the MD-Benzene side of the ketone. Additionally we have a double bond between 1 and 2 carbons in our chain. So the route for methyl phenyl butanone to P2P discussed in the hive wont do anything useful for us.

So where can we go from here? Can't it be oxidized with peracetic acid to to MDP2P?

It makes an isosafrole ether


"In this connection it is of interest that Boeseken and Kremefl recently
have observed that benzalacetone, in a closely analogous manner, is transformed
by means of peracetic acid into styryl acetate
C6H5CH=CHCOCH3 -> C6H5CH=CHOCOCH3" [5]

The DEA's fine scientists laugh at these feeble attempts to create mdma from pepper without the fun of nitroethane. Can they be proved wrong?

[B]References[/B]
[1] Pepper no 5 http://www.zshare.net/download/6302381912893464/

[2]http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV1P0077

Dibenzylideneacetone Aldol Condensation:
[3]http://www.scribd.com/Aldol-Reaction/d/493707
[4]http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv2p0167

[5] THE REACTION BETWEEN KETOXIDO COMPOUNDS AND GRIGNARD REAGENTS
Ernst Bergmann, H. A. Wolff
J. Am. Chem. Soc., 1932, 54 (4), pp 1644–1647

[Edited on 3-1-2010 by idontlie]

[Edited on 3-1-2010 by idontlie]

turd - 3-1-2010 at 16:29

Nice post!

But this seems to be quite useless if the goal is one of the essential amphetamines. First of all "iso-safrole acetate" (I think there's a C missing in the picture!) is not and will not hydrolize to iso-safrole. And even if one could remove that OH-group, one is still at least 2-3 steps away from the final amine.
Let's say 6 steps in total with 50% yield per step makes 0.5^6 ~ 1.5% of total yield. For 15g of final product one would have to start with 1kg of piperonal. This is not counting initial optimization experiments. Now imagine what kind of solvent volumes and equipment are needed at that scale!

And contrast that to the simple well known two step condensation + reduction reaction... I think making nitroethane, even if troublesome, would be easier...

Arrhenius - 3-1-2010 at 17:12

The Baeyer-Villiger oxidation of the enone is going to be problematic. This is a nucleophilic reaction, and enones are not particularly reactive towards 1,2-addition. You're adding three carbons in the aldol condensation, and then wanting to remove two. Why not use nitromethane?

Nitromethane is commonly employed in the Henry reaction as a "one carbon building block". Hydrogenation or hydride reducation of the double bond, followed by the Nef reaction would give the phenylacetaldehyde much more effectively.

You'll find your time better spend scheming up ways to make exactly what you want, not scheming up reactions to do with a given substrate.

idontlie - 3-1-2010 at 17:32

Quote: Originally posted by turd  
Nice post!


Thank you!
Quote: Originally posted by turd  
But this seems to be quite useless if the goal is one of the essential amphetamines. First of all "iso-safrole acetate" (I think there's a C missing in the picture!) is not and will not hydrolize to iso-safrole. And even if one could remove that OH-group, one is still at least 2-3 steps away from the final amine.


I wouldn't be surprised that I'm missing a carbon. I just had the computer generate styryl acetate and added the methylenedioxy group. This was a last minute addition from another conversation that peracetic acid was suggested as a direct mdp2p which was found to not be the case. Just had it there for "posterity." This is simply writing on the fly to track thoughts and to share the thoughts.
Quote: Originally posted by turd  

Let's say 6 steps in total with 50% yield per step makes 0.5^6 ~ 1.5% of total yield. For 15g of final product one would have to start with 1kg of piperonal. This is not counting initial optimization experiments. Now imagine what kind of solvent volumes and equipment are needed at that scale!


hehe. Yeah not economical but "novel." Even though this is "novel," I was hoping for the off chance of 80% yields from the reaction chain. With an overall yield of ~25%. The aldol condensation itself should be around 80% (see note 8 of [4]) After the condensation, I haven't seen anything worth following or even know where to look.
Quote: Originally posted by turd  

And contrast that to the simple well known two step condensation + reduction reaction... I think making nitroethane, even if troublesome, would be easier...


You're probably right. I'm in no way saying this is a good idea to try on a production scale but rather to say, "Ok, we all hear about aldol condensation being thrown around as the big beast. Does it actually work to reach a goals and if so how?"
Quote: Originally posted by Arrhenius  
The Baeyer-Villiger oxidation of the enone is going to be problematic. This is a nucleophilic reaction, and enones are not particularly reactive towards 1,2-addition. You're adding three carbons in the aldol condensation, and then wanting to remove two. Why not use nitromethane?

Nitromethane is commonly employed in the Henry reaction as a "one carbon building block". Hydrogenation or hydride reducation of the double bond, followed by the Nef reaction would give the phenylacetaldehyde much more effectively.

You'll find your time better spend scheming up ways to make exactly what you want, not scheming up reactions to do with a given substrate.


Thank you, I have some reading to do.

mr.crow - 3-1-2010 at 17:34

Well it is rather fun thinking of synthetic routes, even dubious ones...

What would be better would be hydrogenate the double bond and make something like Raspberry Ketone. I bet the piperonal derivative would smell really nice!

entropy51 - 3-1-2010 at 17:39

Quote: Originally posted by idontlie  
Essentially this document is why the DEA isn't worried about aldol condensation of piperonal. Maybe they are but are killing off those who discover the secret. What do you think?
I think you needn't lose sleep about the prospect of DEA putting out a contract for a hit on you.

idontlie - 3-1-2010 at 18:07

Quote: Originally posted by mr.crow  
Well it is rather fun thinking of synthetic routes, even dubious ones...

What would be better would be hydrogenate the double bond and make something like Raspberry Ketone. I bet the piperonal derivative would smell really nice!


I looked at the paper for raspberry ketone its missing that double bond found in our condensation product cute little tail. Not sure on the why as its created using crossed aldol. Perhaps I don't understand all of aldol, which is likely the case.

EDIT:
Turns out I do understand aldol condensation. The Benzalacetone like produce will always have that double bond. It is stripped by "Selective atmospheric hydrogenation over Pd/C." [6]
Quote: Originally posted by entropy51  
I think you needn't lose sleep about the prospect of DEA putting out a contract for a hit on you.

I know but its much more fun to think this way. =)

References:
[6] http://www.homechemistry.org/index.php?title=Preparation_of_Zingerone_(Ginger_aroma)_from_vanillin#Second_step:_Selective_atmospheric_hydrogenation_ov er_Pd.2FC

[Edited on 4-1-2010 by idontlie]

mr.crow - 3-1-2010 at 19:09

So its the aldol reaction, then hydrogenation

You should read the PDF in this thread, very well done http://www.sciencemadness.org/talk/viewthread.php?tid=12780

idontlie - 3-1-2010 at 19:13

Quote: Originally posted by mr.crow  
So its the aldol reaction, then hydrogenation

You should read the PDF in this thread, very well done http://www.sciencemadness.org/talk/viewthread.php?tid=12780


Haha, Thank you. I just saw that from another source. =) Check my edit above.

Bolt - 3-1-2010 at 22:06

The condensation with methyl ethyl ketone followed by the Baeyer-Villager oxidation is more along the lines of what you're wanting, I think.

http://www.sciencemadness.org/talk/viewthread.php?tid=6449

idontlie - 3-1-2010 at 22:30

Quote: Originally posted by Arrhenius  
The Baeyer-Villiger oxidation of the enone is going to be problematic. This is a nucleophilic reaction, and enones are not particularly reactive towards 1,2-addition. You're adding three carbons in the aldol condensation, and then wanting to remove two. Why not use nitromethane?

Nitromethane is commonly employed in the Henry reaction as a "one carbon building block". Hydrogenation or hydride reducation of the double bond, followed by the Nef reaction would give the phenylacetaldehyde much more effectively.

You'll find your time better spend scheming up ways to make exactly what you want, not scheming up reactions to do with a given substrate.


Back here... The nitromethane addition is documented at rhodium under "3,4-Methylenedioxyphenyl-2-Nitropropene From Piperonal, Nitroethane & NaOH" see 2,5-Dimethoxynitrostyrene from 2,5-Dimethoxy benzaldehyde. [7]

The nitromethane addition is documented in detail. [8]

Is there anything worth looking at in the "magic" section for our nitroalkane.

edit:

Im not sure about this but the, suggested, nef reaction yields this?





References:
[7] MDP2NP Rhodium
[8] http://www.organic-chemistry.org/namedreactions/henry-reaction.shtm

[Edited on 4-1-2010 by idontlie]

[Edited on 4-1-2010 by idontlie]

Nicodem - 4-1-2010 at 03:31

Quote: Originally posted by idontlie  
Essentially this document is why the DEA isn't worried about aldol condensation of piperonal. Maybe they are but are killing off those who discover the secret. What do you think?

I think that self deluding into believing such things is highly infantile. If you think you need to be kewlish to be interested in chemistry you are quite wrong. Chemistry can be interesting even if you drop the kewlish attitude and take it seriously and maturely. It might look hard and confusing at the beginning and this may put you off, so it may be fine for you to believe that fantasizing about opposing the authorities by pretending criminal intent is helping you to get over the initial learning phase. Yet do us a favour and spare your dirty little fantasies to yourself and stick only to science in your public posts. That's just what I think about it.

idontlie - 4-1-2010 at 05:58

Quote: Originally posted by Nicodem  
...


Thank you.

I don't want to be cool or even attempt these reactions. I have no intention of breaking the law or ever even having piperonal much less using it to make something else illegal. This is meant to be a discourse on the avoidance of nitroethane. I just was curious about these thing called aldol condensation after it was mentioned in passing conversation as the "Dark Secret."

I figured if it was actually useful it would have been documented and as there was a lack of documentation; I wanted to share why aldol is in fact not used, at least in the way mentioned. Furthermore, I figured it would be novel to display an alternate route.

If someone actually wanted to produce an illegal substance they would be more than willing to take the risks and go through the effort to make nitroethane and get exactly what they want. Hell they probably wouldn't even want to experiment with their "product" in fear of ruining their cooking.

But thank you for dismissing my curiosity as infantile. You truly inspire the masses.


__________________

edit:

I am curious about the nef reaction on the nitromethane product of piperonal. The product does not look right to me, especially not the carbon being double bonded to both another carbon and the nitrogen but as I am only an infant and don't know better... Wouldn't this be an unstable product prone to decomposition?

Will the product have to be hydrogenation to strip the double bond, becoming saturated, then used in the nef reaction?

[Edited on 4-1-2010 by idontlie]

Nicodem - 4-1-2010 at 09:54

Quote: Originally posted by idontlie  
This is meant to be a discourse on the avoidance of nitroethane. I just was curious about these thing called aldol condensation after it was mentioned in passing conversation as the "Dark Secret."

Maybe you watch too much television, because I don't think there is any such thing as a "Dark Secret" in chemistry.
There is a thread on the forum about acid catalysed aldol condensation of methyl ethyl ketone with benzaldehyde followed by a Baeyer-Villiger oxidation to yield 1-phenylpropen-2-yl acetate. It is most likely you got your idea from there via somebody who did not fully understood the synthetic route.

Quote:
But thank you for dismissing my curiosity as infantile.

My pleasure. :)
Quote:
I am curious about the nef reaction on the nitromethane product of piperonal. The product does not look right to me, especially not the carbon being double bonded to both another carbon and the nitrogen but as I am only an infant and don't know better... Wouldn't this be an unstable product prone to decomposition?

The product you depicted is from a class of compounds called ketenes (R2C=C=O). These are highly electrophilic and react relatively rapidly with any nucleophiles (including water). In this respect they are analogous to acid chlorides, not just due to the reactivity, but also because in their polar reactions they give the same products as the corresponding acid chlorides (R2CHCOCl). They are also very reactive in many pericyclic reactions, even so much that unless the substituents (R) are bulky enough they slowly react with themselves forming four membered rings. But this is not important because you can not prepare ketenes via the Nef reaction. If you check the mechanism of the Nef reaction you will see that it is actually a hydrolysis of the nitronate salt. To obtain a nitronate you need a nitroalkane (and not a nitroalkene as in your case). The beta-nitrostyrenes can form a nitronate with hydroxides but only after the 1,4-conjugate addition of a hydroxide. Such a nitronate, even if it could be hydrolysed, would give 2-hydroxy-2-phenylacetaldehyde (or its rearrangement/decomposition products, due to the instability in acidic media required for the hydrolysis).

The simplest 1C synthon you can attach on a beta-nitrostyrene is formaldehyde via the Baylis-Hillman reaction. For example, as described in Tetrahedron Letters, 45 (2004) 4745-4748.

turd - 4-1-2010 at 14:55

It's quite strange that, given that you start with a 1C chain and want to end with a 3C chain, you first tried an addition of 3 Cs and then 1 C, when the obvious choice would of course have been to add 2 Cs. :) Maybe a Grignard with EtMgBr? No idea if that would work (I faintly remember cooking a Grignard eons ago where the substituent then ended up on the ring instead of on the side-chain!), but the resulting alcohol sure looks like it would easily dehydrate to iso-safrole.

There's a standard text on organic synthesis: "S. Warren, Organic Synthesis: The Disconnection Approach". Maybe this can help you better organize your synthesis plans. As in concentrate on the product, and do not start with random synthesis steps. For me this will always be black magic, I'm glad when I can make my few favorite target molecules... :)

idontlie - 4-1-2010 at 18:03

Quote: Originally posted by turd  
...

Thank you.

The only source that I've found for a somewhat similar grignard reaction has reported yields of 18%. And by somewhat I mean just about not at all. Are there catalysts that exist to increase this yield?

Especially considering piperonal from piperine is a rather lossy. Not to even mention the 3 to 5% yield of piperine from raw pepper and thats using a microwave extraction, which is supposedly better. Then two ~70% reactions the first being the wonderful little degradation to piperic acid. The second being piperic acids cleavage using hydrated copper sulfate and lye.

Also, these reactions seem to be only documented in ether and ether is scary. I read a document by weylchem that claims that solvents as common as toluene. [1] Toluene is nice, cheap and legal.

Anyways, I'll be sure to check out the book.

[1] http://www.weylchem.com/fileadmin/Downloads/WEYL_GrignardReagents.pdf

turd - 5-1-2010 at 01:56

Organikum states 78% for benzaldehyde + EtMgBr --> 1-phenyl-propan-1-ol and usually these old socialists know what they are doing. ;) How will the methylenedioxy group interfere? Well, don't ask me!

Grignard reactions can be done in a home-chemistry setting, been there, done that, great yields. I think with an endeavor like that the ether is the least of your troubles...

BTW: Check out if there is a chemistry library in your vicinity with SciFinder and/or Beilstein/Crossfire access. There you will find many (but not all) published reactions.

JohnWW - 5-1-2010 at 02:12

That reminds me: it is about time that someone, with appropriate access, downloaded the whole of SciFinder and Beilstein Crossfire, and re-uploaded them to either Madhatter's FTP or to a file-hosting site (such as rapidshare.com) that can accept appropriately large files.

entropy51 - 5-1-2010 at 06:43

Benzaldehyde + MeMgBr -> phenylmethyl carbinol

90% when run in toluene. Grignard was made in ether, of course.
The benzaldehyde was substituted, but NOT methylenedioxy.
Quote:
ether is scary
If ether scares you, please don't try to make methylenedioxy whatever. Prison is much more scary than ether.

[Edited on 5-1-2010 by entropy51]

idontlie - 5-1-2010 at 10:21

@entropy51:
I have a healthy fear of all things other than plain white bread. I have no intention of doing any of these reactions or even having the means to do so; I simply enjoy talking and learning. I was a danger to myself and others in high school chem. lab and decided that was the end of physical experimentation. Talking won't get you thrown in the bing.

@turd:
I believe the library does in fact have SciFinder access but the remote access I've been using is problematic at best. (the library shares its accounts with other libraries and decides you've been inactive immediately). I'll have to try using it when at the library, next.

Thank you for the suggestion, once again.

Klute - 5-1-2010 at 14:26

You seem pretty confused as of what can be obtained from the enol ester.. The oxygene isn't going to chup off like that and leave an alkene..

If one wanted to form a phenylpropylamine, one would better do the acidic aldol with mek followed by a Bayer Villiger oxidation with your favourite peracid, followed by hydrolysis, although the aldol with piperonal is rather low yielding compared to benzaldehydeIIRC (some japanese ref somewhere).

If I had some piperonal, I would do the aldol with acetone just like you suggested, then hydrogenated it as per my write up you referenced! You would obtain the aroma of blackcurrant! It must smell extremly nice!

That would be the best use of piperonal according to me :)

idontlie - 5-1-2010 at 16:49

Quote: Originally posted by Klute  

If one wanted to form a phenylpropylamine, one would better do the acidic aldol with mek followed by a Bayer Villiger oxidation with your favourite peracid, followed by hydrolysis...


First, thank you for that write up. You might want to check step one your vanillin is wrong. You have some ketone rather than the aldehyde you want to be displaying. Not that it really matters.

Second, like I said I am not in any way a chemistry buff. I just enjoy learning new things. But I have a problem with your procedure. You are saying 3,4-methylenedioxy-Benzalacetone obtained after the condensation is going to go through Baeyer-Villiger Oxidation to form my isosafrole Ester and ill be able to do what to get a phenylpropylamine?

From what I understand I'm going to end up with a acetone salt and an alcohol. That alcohol is rather problematic isn't it? Wouldn't I end up with a aldehyde at best?

I was looking at
http://www.organic-chemistry.org/namedreactions/baeyer-villi...

If you could show some sources that would be amazing. Thank you.

Nicodem - 6-1-2010 at 00:37

Quote: Originally posted by idontlie  
If you could show some sources that would be amazing. Thank you.

I already told that this was already discussed here. All you needed to do is UTFSE:

http://www.sciencemadness.org/talk/viewthread.php?tid=6449
http://www.sciencemadness.org/talk/viewthread.php?tid=6880
http://www.sciencemadness.org/talk/viewthread.php?tid=9814

There might be other threads on topic, but I leave you to practice on how to UTFSE yourself.

Klute - 6-1-2010 at 03:22

No, no, I was talking of the aldol product with MEK, catalyzed by HCl gas.. That would get you to the propanone, but with low yields..

ANd you would not obtain a alcohol from your enol ester, as it is a ENOL ester, as soon as it would be hydrolyzed (giving acetic acid), it will tautomerize to the phenylacetaldehyde..

Sedit - 6-1-2010 at 06:05

People have discussed in the past the acid catalysed Aldol condensation of MEK and piperonal but to me this appears completely unreasonable. The methylenedioxy ether is very sensitive to acid cleavage as I understand it so how on earth could it possibly withstand the abuse of hours on end of HCl gas being pumped into the solution without leaving you with nothing more then polymerized goop?

wolff kishner

Ephoton - 10-1-2010 at 05:38

the aldol does work on piperonal and in reasonable
yeild in the documents I have read.

the one thing that piperonal does not do is form an alpha
methyl butenone if formed by the acid condensation with
MEK.

both acid and base condensation give the same product.

having said this if you were to use acetone as stated above
the preform a wolff kishner you would have an alkene that
would oxidize too mdp2b not too bad realy.

Klute - 10-1-2010 at 06:33

The same product from acid or base catalysis? Do you have a ref for that? I'm quite surprised.

What is possible is that the double condensation product is obtained with acid catalysis like veratraldehyde and vanillin, as claimed by this document.

Although it's a waste of piperonal, teh double condensation product will give a ester that hydrolyzes to MDP2P, and MDcinnamic acid.

Sedit - 10-1-2010 at 16:20

"both acid and base condensation give the same product."

This is simply not true.

Ephoton - 10-1-2010 at 19:21

sorry you are right :(
it was a long time ago I read that and played with aldol.

Klute - 18-1-2010 at 12:30

here is a patent were they do the aldol between piperonal and acetone, then hydrogenate the product to Cassione, aka 4-(3,4-methylenedioxyphenyl)butan-2-one, the aroma of Cassis.

See the description here:http://www.thegoodscentscompany.com/data/rw1012851.html

Synthesis of Medroxalol intermediates - US Patent 4697024

This ketone could actually be used to make HMDMA, a derivative of MDMA, see: Indentification of N-Methyl-4-(3,4-Methylenedioxyphenyl)Butan-2-Amine, Distributed as MBDB

I would pretty much just keep it as is though, smells nice :)

[Edited on 18-1-2010 by Klute]

Bolt - 27-1-2010 at 21:04

Quote: Originally posted by Klute  

This ketone could actually be used to make HMDMA, a derivative of MDMA, see: Indentification of N-Methyl-4-(3,4-Methylenedioxyphenyl)Butan-2-Amine, Distributed as MBDB
[Edited on 18-1-2010 by Klute]


I saw a paper that said HMDMA substitutes for MDMA in 5/7 rats at about six times the dose of MDMA. I was surprised [that it substituted for MDMA at any dose].

[Edited on 28-1-2010 by Bolt]

turd - 28-1-2010 at 02:29

:P
By extrapolation that gives an active dose of 600-800mg. Then it's really better to leave it in the olfactorily pleasing ketone state than to transform it into the fishy/bitter amine state. I would have been surprised if it was more active. I always was under the impression that the phenethylamine substructure does not allow for much variation for amphetamine like effects. My guess would have been that it is not active at all - and who knows what it really does.