Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
 Pages:  1    3    5  ..  7
Author: Subject: L-tryptophan decarboxylation
hive3
Harmless
*




Posts: 27
Registered: 3-7-2013
Member Is Offline

Mood: No Mood

[*] posted on 3-7-2013 at 09:29
Recrystalization


I have used boiling Heptane and it works very well. It requires a lot of patience though, I only seem to get about 50mg per 25ml pull. It will really clean up the product though as it only seems to absorb the tryptamine, not the colored gunk. Be sure to run a reflux condenser while boiling, and no open flame of course.
View user's profile View All Posts By User
hive3
Harmless
*




Posts: 27
Registered: 3-7-2013
Member Is Offline

Mood: No Mood

[*] posted on 17-7-2013 at 11:56
Success with Crowfjord's mineral oil conversion


I was very excited to also see beautiful Tryptamine crystals forming from the oil 24 hours later.

Experimental: To a 250 mL round bottom flask with egg-shaped stirbar was added 80 mL mineral oil 7.58g L-tryptophan (USP grade) . The flask contents were swirled to form a cream-colored slurry, 0.75 mL of Spearmint oil was added and the flask swirled again to incorporate.

Flask was capped with a 1-2 neck converter with a thermometer placed in the neck over the flask so the solution temperature could be monitored. A vacuum take off condenser elbow was added to the second neck and stoppered. The the vacuum adaptor attached to a trap and then the trap attached to a bubbler. The glassware was flushed with nitrogen instead of using naphtha to create an oxygen barrier.

The solution was slowly brought up to 225C in a mineral oil bath. The oil bath smoked mildly during the process. As the temperature came up to 200C no bubbling was noted. Earlier carvone had been distilled off this spearmint oil and it appeared there was less than 10% carvone in the oil. To compensate, 10 drops of pure carvone was added from the earlier distillation and bubbling commenced almost immediately. As the reaction heated up bubbles appeared at approximately a 1 to 2 second interval and the reaction proceeded to completion in approximately 1 hour as indicated by the solution turning a clear amber and bubbling stopped.

A deep amber oil appeared at the buttom of the flask. The solution was left for 24 hours at 30C and upon examination white crystals appeared at the bottom of the flask growing among the very viscous amber oil.

Thanks Crowfjord for this great OTC conversion. It was much cleaner, faster and less odorous than the turpentine process.


[Edited on 17-7-2013 by hive3]

[Edited on 17-7-2013 by hive3]

[Edited on 17-7-2013 by hive3]
View user's profile View All Posts By User
megalodon
Harmless
*




Posts: 16
Registered: 11-6-2013
Location: behind seven (7) proxies
Member Is Offline

Mood: No Mood

[*] posted on 26-7-2013 at 11:16


I would also like to thank Crowfjord for a much more pleasant decarboxylation technique :)

A bit of internet history: What appear to be the original Student's postings to the Hive.

http://y47ylcppnh3afqk4.onion/the-hive.ws/tryptamine/0002716...
http://y47ylcppnh3afqk4.onion/the-hive.ws/tryptamine/0002843...

Note that these are .onion pages and will require Tor or similar to access. (Don't know of any other complete Hive archives, sorry!)
View user's profile View All Posts By User
solo
International Hazard
*****




Posts: 3732
Registered: 9-12-2002
Location: Estados Unidos de La Republica Mexicana
Member Is Offline

Mood: ....getting old and drowning in a sea of knowledge

[*] posted on 26-7-2013 at 13:10


Reference Information





One-pot Sequence for the Decarboxylation of a-Amino Acids
Laval, Bernard T. Golding
Synlett
2003, No. 4, Print: 12 03 2003.



Uploaded with ImageShack.us

Abstract
Treatment of an ?-amino acid with N-bromosuccinimide
in water at pH 5 or in an alcoholic-aqueous ammonium chloride
mixture, followed by addition of nickel(II) chloride and sodium
borohydride, effected an overall decarboxylation via an intermediate
nitrile to afford the corresponding amine in good yield.


[Edited on 26-7-2013 by solo]

Attachment: one pot sequence for the decarboxylation of alpha amino acids.pdf (66kB)
This file has been downloaded 745 times





It's better to die on your feet, than live on your knees....Emiliano Zapata.
View user's profile View All Posts By User
hive3
Harmless
*




Posts: 27
Registered: 3-7-2013
Member Is Offline

Mood: No Mood

[*] posted on 25-8-2013 at 15:54
Purification of Tryptamine from Crowfjord’s process


The mineral oil and participated crystals and orange oil were heated to 80C, washed 3 times with 50ml 5% acidic acid in a separation flask and the washes combined. Ph was brought up using 25% NaOH. As I added the NaOH a white participate appeared and then went back into solution. At PH7.0-7.5 orange gunk crashed out of solution. I have no idea what it was but I vacuum filtered through fast paper and was left with a cloudy solution and a orange gunk in the filter paper. I continued adding NaOH until the PH reached 12 and then put in the freezer for ½ hour. Pure white fine crystals crashed out along with what appeared to be the same crystals in yellow orange oil. The solution was vacuum filtered again through fast paper and washed twice with 10% Ammonia at -10C. The filter paper with the filtrate was placed in a damp rid container filled with Nitrogen and allowed to dry for 1 day.

The dry filtrate was weighed at 3.34g. 1g of the filtrate was placed in 25ml of boiling heptane in a 125 ml flask with a condenser set up for reflux. Orange oil separated and fell to the bottom of the flask. White crystals formed around the boil line. The boiling heptane was transferred to a 50ml round bottom flask and white crystals immediately started to fall out. The orange oil remained in the original flask sticking to the bottom and sides. The 50ml flask containing clear heptane and no oil by products was placed in 60C water bath and roto vaped under vacuum. Final product weighed .353 g as a white sticky powder with a strong Tryptamine smell that clung to the flask. None of the tallow/orange tinting remained.

The product was left in the flask, and stored in a freezer at -10C under vacuum. Previous runs turn orange and then brown in days when stored in an oxygen environment. The conversion rate of 18% is bothersome given documented conversions of over 60% in literature.

[Edited on 26-8-2013 by hive3]
View user's profile View All Posts By User
Crowfjord
National Hazard
****




Posts: 390
Registered: 20-1-2013
Location: Pacific Northwest
Member Is Offline

Mood: Ever so slowly crystallizing...

[*] posted on 25-8-2013 at 16:36


Nice. It's good to see some practical reports on purification. I've been meaning to try some things along those lines as well, but have been too busy or tired from work to do much tinkering lately. I need to get some more melting point capillaries, too.

The visual observations are encouraging, but did you take a melting point or TLC or something to get an idea of the purity?

Also, I bet you can increase yield by doing another recrystalliztion on the orange leftover gunk.
View user's profile View All Posts By User
megalodon
Harmless
*




Posts: 16
Registered: 11-6-2013
Location: behind seven (7) proxies
Member Is Offline

Mood: No Mood

[*] posted on 25-8-2013 at 17:23


I am away from my notebook so you will have to forgive a bit of generalization and vagueness. I'll fill in any missing details later.

I generally have had good success with a modified version of Student's workup. My procedure is as follows:

1) Refrigerate the reaction vessel to solidify the dark oil which forms.
2) Pour off the mineral oil. I have never expected it to contain much product; perhaps I'm wrong?
3) Extract with 2x75 mL boiling 5% acetic acid, while heating and stirring the mixture to soften and mix the dark oil. A cloudy lemonade-yellow liquid results. This is filtered into a sep funnel. I do this in batches due to the size of my sep funnel.
4) The vinegar is extracted with a few mL chloroform. The aqueous layer is poured into a beaker and the organic layer discarded.
5) A few mL chloroform are added. With stirring, sodium bicarbonate is added by the knifetip until only mild fizzing results and the pH is 7-8. Quite a bit of nasty garbage comes out at this point, forming a sticky, hard-to-remove residue which seems to absorb the chloroform.
6) The liquid is filtered into a sep funnel and any remaining chloroform removed. The aqueous layer is poured into an Erlenmeyer flask.
7) 2 grams sodium hydroxide are dissolved in a bit of water and added. This solution is added to the flask. Immediately, the solution turns a milky white. The solution is refrigerated overnight.
8) Some combination of crystals and precipitate result. The mixture is vacuum filtered.

The product is generally some shade of tan. I haven't taken an mp yet (my thermometer doesn't go high enough) but TLC shows it to be pretty clean. I have had good results with recrystallization from boiling hexane if you desire a lily-white product.

View user's profile View All Posts By User
hive3
Harmless
*




Posts: 27
Registered: 3-7-2013
Member Is Offline

Mood: No Mood

[*] posted on 26-8-2013 at 04:19
Megalodon’s purification process


Thanks for the pointers. I will definitely try the boiling acidic acid extraction in the future.

Have you computed your yields from hexane? My frustration with both the turpentine and mineral oil processes is that I have not been able to produce the tryptamine with more than a 20% conversion rate from tryptophan. (Tryptamine mw 160, Tryptophan 204 Theroretical yield = .78 of starting material. I started with 7.5g of Tryptophan so theroretical yield should be 5.85g of Tryptamine. Based on my extractions to this point, I project 3.34*.353 = 1.17g or 1.17/5.85 = 20 % yield) . From my tests:

The initial acidic acid extraction leaves behind a very dark solid oil. It still smells of Tryptamine but if there is Tryptamine left in it, subsequent extractions don’t pull anything out of it. I have saved this material by dissolving it in EtOac, and I will TLC it .
Additional gunk drops out of the extraction when brought to a PH of 7. This is a significant amount of material but I have not weighed it, or saved it.

Using Chloroform extractions to purify at the extract at this point just seems to dissolve the gunk and allow it to be separated without filtering. It has not affected my final yield in the past and since I don’t have a lot of chloroform I prefer to use filter paper.

During the heptane extraction a thick dark oil that clings to the sides of the beaker is left behind, generally 60 to 70 percent of the starting material is left behind during this step. It is similar to the material left behind during the acidic acid extraction and still smells strongly of Tryptamine.

Tryptamine seems to be very reactive with O2. Almost white Tryptamine recrystallized from heptane quickly yellows when the heptane is poured off and left to evaporate in the atmosphere. This is why I am now evaping the heptane under vacuum .I have a .25g sample that I saved from my last run that is about a month old and has turned a dark brown/grey. It was kept in a sealed 10 ml. bottle. This stuff is very unstable.

I will do a MP test tonight and let you know the results.


[Edited on 26-8-2013 by hive3]
View user's profile View All Posts By User
Nicodem
Super Moderator
Threads Merged
26-8-2013 at 04:52
hive3
Harmless
*




Posts: 27
Registered: 3-7-2013
Member Is Offline

Mood: No Mood

[*] posted on 26-8-2013 at 17:23
MP's


Tryptamine Melting Points


I did the MPs tonight.

MP of Filtered Tryptamine after Ammonia wash 101-105C
MP of heptane recrystallized Tryptamine 114-115 (published 113C to 116C)

I will confess that my technique was not the best, the oil bath was increasing at probably 30 seconds per degree, but I pulled it off the burner and it topped out at 115C on the second test and by that time all of the tryptamine melted at that temp.

For the first test please note that there were 2 distinct layers of the tryptamine in that sample. Some was just off white and the other the yellow slightly oily stuff. The white melted at 105C and the yellow at 101C

[Edited on 27-8-2013 by hive3]
View user's profile View All Posts By User
megalodon
Harmless
*




Posts: 16
Registered: 11-6-2013
Location: behind seven (7) proxies
Member Is Offline

Mood: No Mood

[*] posted on 28-8-2013 at 15:48


I typically get yields ~85-90% (eg, 4.5g tryptamine from 6.8 g tryptophan).

I've found that the scum that drops out upon basification seems to dissolve well in isopropyl alcohol.
View user's profile View All Posts By User
Crowfjord
National Hazard
****




Posts: 390
Registered: 20-1-2013
Location: Pacific Northwest
Member Is Offline

Mood: Ever so slowly crystallizing...

[*] posted on 3-9-2013 at 23:49


I finally got around to trying a few things to purify my tryptamine that has been busily oxidizing since I made it nearly four months ago. The pale yellow powder/chunks had since turned an orange-brown color, similar to rust. I tried recrystallizing from n-pentane, but tryptamine is very sparingly to completely not soluble in it.

Boiling in ethyl acetate (EtOAc) and triturating with pentane gave a foggy solution, but no crystals. So, I went about doing an acid/base purification, very similar to the one that I posted up thread.

1.0 g crude tryptamine was dissolved in about 20 mL EtOAc and 10 mL n-pentane, then extracted with 30 mL then 10 mL 5% acetic acid (made with 99% acetic acid and distilled water). The aqueous layer was extracted twice with a mixture of 30 mL EtOAc and 2 mL pentane*. The aqueous layer at this point was a tiny bit turbid and just ever-so-slightly yellow. It was slowly and carefully basified with 25% NaOH solution with stirring, just until cloudiness persisted. The container with the solution/suspension was capped and placed in the freezer for about 15-20 minutes. I was pleasantly surprised when I was greeted with a suspension of shimmering crystals! These were vacuum filtered, washed with ice-cold ammonia and dried over NaOH to give 0.90 g of waxy, nearly colorless crystals.

Unfortunately I am out of melting point capillaries, so no analysis until I get more in a week or two. Here's a picture, though. :D



photo (598x800).jpg - 305kB
View user's profile View All Posts By User
hive3
Harmless
*




Posts: 27
Registered: 3-7-2013
Member Is Offline

Mood: No Mood

[*] posted on 4-9-2013 at 12:24


Very nice result and an excellent yield from recrystallization. Did you record the PH before recrystallation?

I have extracted again the remainder of the 1g of unpurified tryptamine using a second heptane extraction and sure enough I have more pure tryptamine. The problem for me seems to be not using enough heptane and of course not checking the solubility.

[Edited on 4-9-2013 by hive3]
View user's profile View All Posts By User
Crowfjord
National Hazard
****




Posts: 390
Registered: 20-1-2013
Location: Pacific Northwest
Member Is Offline

Mood: Ever so slowly crystallizing...

[*] posted on 4-9-2013 at 15:25


I did not check the pH, but in retrospect I should have. When I get the time I will do another run and take detailed notes. I'm really hopeful that I can make a good reproducible method.
View user's profile View All Posts By User
Mythrilium
Harmless
*




Posts: 5
Registered: 5-8-2013
Member Is Offline

Mood: No Mood

[*] posted on 15-10-2013 at 07:54


I often tried this with tetralin and MEK / acetone and would like to share my experiences:

All in all I never reached a yield (purified tryptamine) higher than 40%

Stripping off tetralin (or other high boiling solvent) under vaccuum always ended up with a sticky oil, which wouldn't crystallize but can be easily recrystallized from acetone in freezer, but will remain still very impure.
Further recrystallisation from hexan/heptan/petroleum is possible but needs huge amount of solvent.

Using aqueous HCl to extract the amine never led to a product, but often formed sticky mess which evolved ammonia-steam when basified.

Best way to purify the crude tryptamin was found to be percipitation of the (di-?)carbonate, simply by bubbling CO2 through a diffusor. Leads to very light yellow/white powder. Works bad from acetone, great from DCM, maybe works also directly from Cyclohexanol/Acetophenone ?!
The vaccuum filtered carbonate is then dissolved in water and brought up to about 50-60°C. Brown impuritys start to float on the surface and will stick to the walls (they can be easily extracted by a mix of EtOAc and hexan). Now aqueous NaOH is added (PH > 11) and cream-white snowflakes of pure tryptamine start to form in the aqueous solution. Let it sit for 2-3 hours in the fridge (about 5-7°C), then it can be filtered off and eventually dried on common ways.
View user's profile View All Posts By User
hive3
Harmless
*




Posts: 27
Registered: 3-7-2013
Member Is Offline

Mood: No Mood

[*] posted on 15-10-2013 at 11:54


Is the 40% yield from the carbonate process? I have used the boiling heptane method and it is a time consuming process as the product of the decarbolization is in a very viscous oil even in the boiling heptane. I usually do repeated extractions and the oil gets more and more viscous. After 3 extractions I still only get about a 35% yield after crystallation and evaporation of the heptane, although very pure. Your process looks significantly faster.

View user's profile View All Posts By User
Mythrilium
Harmless
*




Posts: 5
Registered: 5-8-2013
Member Is Offline

Mood: No Mood

[*] posted on 15-10-2013 at 14:57


Yeah, 40% from the carbonate process
(probably limited by impure tetralin + tryptophan)

The process was my best try to be fast, whole reaction + workup done in <8h.
Heptane pulls are very time consuming, I know that experience...
(might be worth it for alkylated T) :cool:


Has anybody tried pure acetophenone for reflux?

View user's profile View All Posts By User
bahamuth
National Hazard
****




Posts: 382
Registered: 3-11-2009
Location: Norway
Member Is Offline

Mood: Infected

[*] posted on 16-10-2013 at 06:28


I tried synthesis grade acetophenone a few years ago, but had great troubles recovering the tryptamine, due to not knowing an efficient extraction method and a very busy schedule so it was abandoned. Only thing I remembered was the speed and apparent total conversion in a short time.

Was actually planning a trial tomorrow and will take some pics and post my notes.




Any sufficiently advanced technology is indistinguishable from magic.
View user's profile View All Posts By User
I Like Dots
Hazard to Self
**




Posts: 69
Registered: 10-4-2013
Member Is Offline

Mood: frisky

[*] posted on 18-10-2013 at 07:37


Could you extract the tryptamine from the acetophenone with a dilute hcl solution? Maybe not because the acetophenone is slightly soluble in water.. Trying to distill the acetophenone would not be favorable either. it looks like the tryptamine might come over first!The CO2 sounds promising.



View user's profile View All Posts By User
Alyosha Karamazov
Harmless
*




Posts: 4
Registered: 19-10-2013
Member Is Offline

Mood: counterbalancing

[*] posted on 19-10-2013 at 01:18


As said here before, it's safer to use dilute acetic acid solutions instead of HCl with tryptamine for extraction. Acetophenone has a 100% conversion (search the board, the original french ref was posted too), but the literature did not provide details on the isolation of the target amine. Several problems have been encountered during several different workup approaches. Transamination was one, also the intermediate imine is said to be very stable with acetophenone.

The best results I have had is what most people seem to do now, extracting the post-decarboxylation solution multiple times with white vinegar, neutralizing with NaHCO3 until pH 7, filter off small amount of precipitate, wash with ethyl acetate or dichloromethane, and basify with ammonia or dilute NaOH.

The result is however very unreliable, sometimes an acceptable yield is obtained, more often the isolated amount is rather low. The product is also waxy and hard to handle, the initial white precipitate becomes yellow and oily within minutes.

After repeated recrystallisation attempts from hexane (which uses way too much solvent) my product will always turn yellow and resinous very quickly. But a TLC run against a commercial tryptamine sample always shows a single spot where it should be.

Passing CO2 through the post-reaction black acetophenone solution makes it cloudy but nothing seems to precipitate. Or it is so fine it goes right through filter paper. When I try making the carbonate salt of the isolated tryptamine, it also precipitates as a yellow sticky resin that is too frustrating too handle.

I think that the best option would be short-path distillation. But I wonder if my refrigerator compressor vac pump (around 20 mmHg) is enough for that job? Although sublimation is a valid option for purifying small amounts (up to a gram or so).

Flash chromatography was used in the copper chelate decarboxylation procedure:
Quote:
After distillation of the solvent, the resultant residue was purified by flash chromatography on silica gel to give tryptamine

The resultant residue from that route is an unfathomable black tarry mess, so it might hold some value. Flash chromatography could be done using a large 100ml (kitchen-type) plastic syringe packed half-way with silica gel and the solvent (chloroform?) pushed through in a crude mcgyver version.

This page has good information on how to screen the solvent combination using a TLC batch for flash chromatography:
http://www.reachdevices.com/SetUpColumn.html

[Edited on 19-10-2013 by Alyosha Karamazov]

[Edited on 19-10-2013 by Alyosha Karamazov]
View user's profile View All Posts By User
Alyosha Karamazov
Harmless
*




Posts: 4
Registered: 19-10-2013
Member Is Offline

Mood: counterbalancing

[*] posted on 19-10-2013 at 01:26


The oil that precipitates from the mineral oil in this procedure, it is probably largely tryptamine. I hope to hear the TLC result soon. Why not try short-path destillation directly from there and skip the acid/base extraction?
View user's profile View All Posts By User
hive3
Harmless
*




Posts: 27
Registered: 3-7-2013
Member Is Offline

Mood: No Mood

[*] posted on 21-10-2013 at 08:09


I have not tried a distillation. Others who have tried using standard short path distillations seem to have issues with clogging of the head during the process. It seems short path ball to ball distillation would work best, but I don't have the equipment. Anyone try this with a Kugelrohr? I suspect this would be the quickest (but most expensive) workup method.

I have run a TLC on heptane extracted Tryptamine from the mineral oil process. One Dot, but I don't have a reference. After Crystallization, I did pour off the Heptane and then rotovaped under vacuum to get the final product. This prevented oxidation leaving me with an almost pure white crystals. I have it stored in a freezer under nitrogen and it has stayed white.

This product works perfectly in followup reactions.

[Edited on 21-10-2013 by hive3]
View user's profile View All Posts By User
stoichiometric_steve
International Hazard
*****




Posts: 738
Registered: 14-12-2005
Member Is Offline

Mood: satyric

[*] posted on 21-10-2013 at 08:32


i have successfully distilled it, not using short path but with a regular Liebig condenser filled with hot water. it is a laborious process, since the head does indeed get clogged from time to time, but heating it with a heat gun takes good care of this.

and this is what it looked like afterwards:

index.jpeg - 114kB
View user's profile View All Posts By User
hive3
Harmless
*




Posts: 27
Registered: 3-7-2013
Member Is Offline

Mood: No Mood

[*] posted on 21-10-2013 at 08:38


Absolutely beautiful!!!!!
View user's profile View All Posts By User
palico
Harmless
*




Posts: 21
Registered: 1-10-2013
Member Is Offline

Mood: No Mood

[*] posted on 21-10-2013 at 13:23


Ok, you are ready for the next step.
View user's profile View All Posts By User
Mythrilium
Harmless
*




Posts: 5
Registered: 5-8-2013
Member Is Offline

Mood: No Mood

[*] posted on 21-10-2013 at 14:47


What kind of heat-source would you recommend for short path distillation?
And how did you get rid of the solvent? Freezing out or also distillation?
What was the overall yield?

I'm still looking for an easy way, as i haven't tried CO2 through cyclohexanol/acetophenon yet, and want to be sure which solvent to look for.

@ Alyosha Karamazov: How long did you pass CO2 through the reaction mixture, and at which temperature was it? Tryptamincarbonate seems to be soluable in alochols and ketones, but not at low temperatures (liquid CO2 and crystalisation should cool the reaction mixture well beyond 0°C) I used to proceed CO2 bubbling for about 40-50 minutes on 600ml of Solvent (DCM) which yielded (as said before) about 35-40%
View user's profile View All Posts By User
 Pages:  1    3    5  ..  7

  Go To Top