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turd
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Well, for starters you could check the paper I linked to upthread. It gives a few examples of beta-carboline side products obtained in ketone
catalyzed decarboxylations. 
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antibody
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Yes, Thanks for that Turd. I downloaded it earlier today but haven't had the time yet to delve into it yet. This evening . . . much appreciated!
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madscientist
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That's actually the same paper I was going to post! 
I weep at the sight of flaming acetic anhydride.
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ChemichaelRXN
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I would assume methyl benzoate will work as the solvent for this reaction? (It has a high b.p. at 199.6C and also easy to make.)
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madscientist
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Esters react with amines to form amides - I would use a different solvent.
I weep at the sight of flaming acetic anhydride.
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ctrlphreak
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Glycol/Glycerine is an excellent solvent for the decarboxylation, and according to a paper I have analyzing the various solvents, and ketones, as is
described all over the web, and noted the various Beta-carbolines formed from various procedures.
The interesting thing to note was that in every case, the L-Carverone I believe it was did NOT have the issue of converting the Tryptophan into a
BETA-Carboline.
Glycerine has also been used alone to effect a decarboxylation thermally, but yeah, just saying.
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jon
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the reason carvenone and cylcohexenone don't cause cyclization is due to the steric bulkiness of the ketones.
a useful thing to consider are balwin's rules for cyclization when dealing with tryptamines.
http://en.wikipedia.org/wiki/Baldwin's_rules
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Vogelzang
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Here's two good articles about decarboxylation of amino acids.
Attachment: LaDecarbI.pdf (765kB)
This file has been downloaded 2630 times
Attachment: LaDecarbII.PDF (482kB)
This file has been downloaded 1724 times
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12332123
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I have some success to report...
I refluxed 5g of tryptophan and 22g of naphthalene with 2ml of peppermint oil under a dry condensor with vigorous stirring till the reaction went
clear (~1 hour). On cooling a dark amber glass was formed which was dissolved in around 300ml of DCM. The solution was filtered under gravity and then
cooled in an ice bath. I then gassed it with CO2, giving a fine tan precipitate of Tryptamine carbonate which was filtered off and washed with several
small portions of DCM. This was then warmed in around 200ml of anhydrous isopropanol and fumaric acid was added until no more fizzing was observed.
Tryptamine fumarate was collected and washed with several small portions of isopropanol and DCM, giving a nearly white fine powder. Yield ~70%.
[Edited on 12-4-2011 by 12332123]
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GreenD
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WELL THERE YA GO!
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Nicodem
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Quote: Originally posted by 12332123  | ...
I then gassed it with CO2, giving a fine tan precipitate of Tryptamine carbonate which was filtered off and washed with several small portions of DCM.
This was then warmed in around 200ml of anhydrous isopropanol and fumaric acid was added until no more fizzing was observed. Tryptamine fumarate was
collected and washed with several small portions of isopropanol and DCM, giving a nearly white fine powder. Yield ~70%. |
Very interesting work up and good yields. And an original choice of solvent as well. Have you confirmed the product identity? The mp?
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12332123
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I recently managed to break my thermometer so I unfortunately can't say for sure that its pure, but I'll try and
get a melting point ASAP. I thought I'd probably have problems with sublimation of the napthtalene, but this luckily turned out not to be a problem at
all and the reaction went very cleanly; its a very nice OTC choice.
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jon
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i'd bet it would get even more intersting if you reacted it with isopropyl iodide in the prescence of hunig's base
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GreenD
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Interesting, Jon. I've never heard of the compound you refer too. Looks like it is worth investigating.
[Edited on 13-4-2011 by GreenD]
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12332123
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Is my product more likely to be ditryptamine fumarate or monotryptamine fumarate?
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GreenD
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The french paper that vogal zang gives says that decarboxylation of phenylalanine (100% conversion) happens in acetophenone over 3 hours at 150°C
(below reflux).
and decarboxylation of tryptophan (100%) happens in acetophenone at 130° C over 4 hours...
VERY INTERESTING.
12332123, I would assume you're going to have a mixture of both, depending on the equivalents you used... If you use less than 2 equivalents your
majority is going to definitely be in the mono-region.
Why didn't you mix directly a fumaric solution. Why did you gas first?
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12332123
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Fumaric acid is not very soluble in organic solvents, and a water soln would dissolve some of the product. Plus, I wanted to see if the patent
floating around about tryptamine carbonates actually worked. Anyway, the issue of which salt I had is a little moot now, as I've made some nice white
freebase crystals from it.
[Edited on 14-4-2011 by 12332123]
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GreenD
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Does that have a distinct smell ?
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turd
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Nice one!
I am quite happy with the workup by student (http://www.erowid.org/archive/rhodium/chemistry/tryptophan.h...). 25 % aq. NH4OH seems to be the wonder cure.
150 ml tetralin, 20 g tryptophan and 2 ml carvone, refluxed for 70 min. Cooled, filtered and tetralin removed under vacuum. Dissolved residue in 5%
AcOH, washed with 20 ml CCl4 (bad choice, doesn't dissolve the solids), centrifuged off remaining solids and organic phase. Added NaHCO3 until only
little foaming. Washed with 20 ml CCl4, centrifuged off remaining solids. Basified with small amount of 20% NaOH. Cooled, filtered and got a nasty
sticky semi solid. Wased with 25 % ice cold NH4OH and first surprise - semi-solid crystallized. Second surprise - wonderful white crystals in the
mother liquor! Filtered, dried over sicapent, got in total 9 g, overall purity propably not as good as distilled, but most of it excellent.
[Edited on 26-4-2011 by turd]
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chemrox
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| Quote: Originally posted by Nicodem | | But first you will need to properly decarboxylate tryptophan. Xylene is too low boiling for the decarboxylation to finish in 9 hours.
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I think so too. I'd love it if it worked. I priced some high boiling ethers and the cost of them made conversion from indole look pretty good in
comparison.
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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rannyfash
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well i came up with this idea http://www.sciencemadness.org/talk/viewthread.php?tid=19194#... if you replace the dimethylamine with ammonia in the final step.
but i guess you could extract enzymes produced from the yeast by macerating cells using dichloromethane/methanol and running a column chromatography
on the resulting aqueous layer, testing the different separated enzymes (or a mix) to exclude the enzyme that converts the amine to an alcohol,
[Edited on 28-4-2012 by rannyfash]
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GreenD
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I attempted this decarboxylation and must say without ethyl acetate, the work up gave me <10% yields.
:\
ʃ Ψ*Ψ
Keepin' it real.
Check out my new collaborated site: MNMLimpact.com
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Crowfjord
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Hello all! I have been experimenting with this reaction for some time now, and I thought I would share the results of my latest, and so far most
successful attempt.
Abstract: A facile synthesis of tryptamine may be conducted using everyday, easy to find materials; there is no need for such solvents as tetralin,
diphenyl ether, acetophenone or others. Decarboxylation of tryptophan occurred in regular drugstore mineral oil with a spearmint oil catalyst, the
reaction complete (cessation of effervescence) at about 45 minutes of heating at 225-230 degrees C. After workup, crude tryptamine (MP: 105-107 C)
was isolated at 70% yield.
Experimental: To a 250 mL round bottom flask with egg-shaped stirbar was added 80 mL mineral oil (USP, contained ~0.1% mixed tocopherols according to
MSDS), 7.58g L-tryptophan (USP grade) and 6 mL naphtha (Ronson lighter fluid)(*). the flask contents were swirled to form a cream-colored slurry,
0.75 mL of spearmint oil (Mountain Rose Herbs) was added and the flask swirled again to incorporate.
The flask was set up for reflux on an oil bath (condenser water ~14.5 *C) and heating began with medium-speed stirring. Some bubbling was observed
when the bath temperature reached 209 degrees C - possible boiling of naphtha/catalyst.
Oil bath temperature was held between 225-230 degrees C for about 45 minutes(**), at which point the mixture became transparent and effervescence
ceased. The solution was a golden color at this point. The flask was removed from the the oil bath and as it cooled, the solution quickly became a
turbid/opaque peach color. The flask was held under running water until it reached about 30 degrees C.
The flask contents were poured into a 1000 mL separatory funnel, the flask rinsed with 100 mL 5% acetic acid (AcOH), then 50 mL ethyl acetate (EtAc,
Kleen Strip MEK Substitute), then 2 X 25 mL EtAc to remove the thick red oil from the bottom of the flask. All was added to the separatory funnel and
shaken together vigorously. Three layers formed - the lowermost (aqueous) layer was removed and the remaining upper two layer were extracted with4 X
30 mL 5% AcOH. 1 mL 99% AcOH and 2 mL distilled water (d. H2O) were added, shaken, separated and pooled with the rest of the aqueous extracts.
The acidic (pH = ~4) aqueous extracts were pooled and washed with 3 X 30 mL EtAc, then chilled about 15 minutes in the freezer. The chilled extract
was basified with 25% NaOH (persistent cloudiness was noted at ~pH 10) to ~pH 11 and extracted with 30 mL EtAc. 3 mL 25% NaOH were added to the aq.
extract to precipitate more (suspected) tryptamine, extracted again with 30 mL EtAc. This was repeated with 4 mL 25% NaOH and 30 mL EtAc. EtAc
extracts were pooled and stored in the freezer for 7 days.
The golden EtAc solution was extracted with 4 X 30 mL 5% AcOH. To this aqueous solution was added 25% NaOH until it was about pH 13 (low resolution
on indicator papers). An amber colored oil separated and sank top the bottom of the flask. This was removed for further inspection, and placed in
the freezer. A small amount of oil remained suspended in the clear aqueous solution.
At this point I was vexed; I had expected a solid precipitate as before, but the previous solutions had not been treated with ethyl acetate as this
had. It seemed that maybe some N-actyl trypamine had formed and made a mixture, causing the tryptamine to oil out. And then - a happy accident.
Just to see what would happen, I added 1 mL of 25% NaOH to the remaining aqueous solution, which immediately became turbid. The suspended oil
droplets coalesced and then solidified to waxy yellow globs. The previously separated oil, which had been sitting in the freezer had formed some
light yellow crystals among the amber oil. The entirety of this was added back to the solution with swirling, and the remaining oil NaOH solution
(about 15 mL) was added 1 mL at a time with swirling.
The rest of the oil solidified, and more white, waxy, shimmering solid crystals precipitated. The solids were vacuum filtered on a Buchner funnel
and dried over NaOH. Crude yield: 4.17 g of pale yellow crystals, 70%. MP: 105-108 degrees C. (Lit. 113-116 C)
The product seems to be tryptamine, albeit still slightly contaminated by oxidation products, and possibly N-acetyl tryptamine, from the slightly
depressed melting point. It shall have to be recrystallized. Does anyone have any suggestions? I was thinking of using ethyl acetate/pentane but am
worried about amide formation. I also read that heptane works, but currently do not have any.
Any and all questions and/or comments are welcome. Thanks!
* Naphtha was added in an attempt to provide an inert atmosphere
**It should also be noted that mineral oil boils at a much higher temperature than 250 degrees C (as high as my thermometer reads) so careful
monitoring and adjustment of the temperature is necessary.
[Edited on 7-5-2013 by Crowfjord]
[Edited on 7-5-2013 by Crowfjord]
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turd
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Cool. It's always nice to read about tryptamine chemistry.
If you write AcOH for acetic acid, then ethylacetate is AcOEt. Accordingly, AcEt is MEK.
I doubt that AcOEt is a good solvent for extracting highly basic NaOH solutions. It reacts according to AcOEt + NaOH --> NaOAc + EtOH!
As for recrystallization - I believe(!) both toluene and aliphatic hydrocarbons work. But be very careful and patient.
[Edited on 14-5-2013 by turd]
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Crowfjord
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@Turd: thanks for the tip. You are of course right about the basic cleavage of ethyl acetate (and other esters). I considered using methyl ethyl
ketone or methyl isobutyl ketone for that reason, but the store did not have it. I believe though that the cleavage of ethyl acetate is slow enough at
the temperatures I worked at (20-25 degrees C) to not be of much consequence to the goal. It worked quite well.
As for recrystallization, maybe I will try a small variety of solvents, and see what works best.
Also, for the sake of thoroughness, I should mention, since I forgot to in my previous post, that I washed the filter cake with extra strength
household ammonia prior to drying.
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