The Vespiary
The Hive => Tryptamine Chemistry => Topic started by: Bandil on March 08, 2004, 01:33:00 AM
-
Hi there!
Tryptamines seem to be my Nemesis... I've never been able to purify any successfully. With my newfond liking of steam distillation this would seem like an obvious choise.
Are tryptamines such as alpha-methyltryptamine volatile enough to be steam distilled?
Thanks!
Regards
Bandil
-
Definitely not :) Maybe dimethyltryptamine, but I doubt it.
-
F...
Any ideas on how to purify the tryptamines without using a gazillion-powerfull vacuum source? I usually just use DCM all the way as a solvent? Perhaps using EtOAc for the extraction will make things more specific?
Why oh why are tryptamines so fucking hard to work with ::)
-
You could try to recrystallize them as a salt (oxalate or fumarate) and/or purify them by column chromatography.
-
It's the crystallization i am completely unable to initiate. I've tried almost every trick in the book. Columns chromatography just seems a bit excessive; surely there are easier ways of getting the substances pure enough to recrystallize them?
-
Have you tried the specific salts suggested above, or just hydrochlorides?
-
I tried the acetate as suggested somewhere on your page... Perhaps the oxalate is easier to crystallize? I'll give it a whirl if you believe so...
thanks mate's!
Regards
Bandil
-
You did already try to make the salts and they didn't crystallize? That sounds very strange. Maybe you can provide us with some more details.
-
Yes! I dissolved the not-so-white freebase in dry IPA, and neutralized with GAA. This was put in the freezer and absolutely nothing happened (it was sitting around for several days). I tried all the usuall tricks with glas-rod scratching, slowly cooling, dancing native dances, praying, but nothing seems to help..
-
I wouldn't expect acetates to easily crystallize ::) Oxalates and fumarates are used for a reason!
-
Good thing i have a bottle of oxalic acid in my left hand then ;) I'll try it out tonight!
-
BTW, Oxalic acid has a good solubility in ether and THF.
-
The acetate salt of ?-MT may be too soluble in IPA. Try evaporating the solution to a syrup, then add perhaps 5 ml EtOAc per 1 g of the substance (if it doesn't dissolve completely, several drops of IPA or EtOH may be helpful) and stimulate crystallization. If nothing happens, add diethyl ether in small portions with stirring until the solution becomes slightly turbid and stimulate crystallization again. Do not cool the solution at this point: this may result in deposition of an oil. It's only after completion of the crystallization, that the mixture can be cooled to precipitate more product.
This methodology worked in the case of ?-ET. However, I don't remember the actual amounts of solvents SWIM used.
-
Make the acetate in IPA and strip off the solvent. To the viscous goo add 4-5 volumes EtOAc and slowly strip off this solvent too. As the salt becomes dry and the residual IPA leaves it crystals will form. You might have to strip off all of the EtOAc and replace it with a second portion though since the acetate can be reluctant to give up the last bit of water.
Oxalic acid dissolved in methanol is useful too and the oxalate is way easier to crystalise than the acetate.
-
I used a 1.1:2 molar ratio of oxalic acid to alphaMT to form the (AMT)2oxalate. I suppose this is the way to go and not double up the amounts of oxalic acid?
Regards
Bandil
-
For the oxalate you have to use exactly 1:1, for the hydrogenoxalate you have to use > 1:2. Both should work, the latter is easier.
-
The concept of salts with multiple bases or acids in them is something i have recently learned about (although i'm sure i was taught about pKa's and multi-pka acids and bases, eg the sodium carbonate/bicarbonate thing).
Once upon a time an elf named spice took about a gram of acacia obtusifolia alkaloids and mixed them up with a roughly equimolar quantity of tartaric acid and it seemed to form a solid amorphous red mass. It was slightly over-acidified, which is because i hadn't grokked the concept of acidic extraction as titration (i just mixed the acid and base together after weighing the acid).
However, on a previous occasion i was not quite so precise and i did get a crystallisation. After reading what Lilienthal is saying in this thread, what about making a tartrate salt at 1:2 base-acid combination. or citrate. Ascorbic acid is very close in molar mass but it is too prone to changing to dehydroascorbic acid which changes it (etc). there's also malic acid. I wasn't aware that dmt crystallised as a fumarate, just that the fda approved it. Of course that may well have been on account of it's superior self-affinity when crystallising making it easier to get to analytical purity.