charles
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tryptophan decarboxylation
hi,
i'm asking which is the best route to get pure tryptamine from tryptophan.
I would try the ketone catalized in tetraline (1,2,3,4 tetrahydronaphtalene), have you some references and tips?
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Decarboxylation of Tryptophan in Tetralin With a Ketone Catalyst4
L- or DL-Tryptophan (102.1 g, 0.5 mol) was suspended in tetralin (250 ml) containing acetone (2.9g, 0.5 moles) and the mixture was heated to reflux
for 8-10 hours with vigorous stirring until no more carbon dioxide was evolved and the reaction mixture became clear. The solvent was removed under
vacuum, and the residue was distilled under reduced pressure to give a yellow crystalline solid, bp 140-155°C at 0.25 mmHg. This was recrystallized
from boiling benzene to afford faint yellow prisms, mp 116-117.5°C (lit 115-117°C).
The yield with acetone as catalyst was 75%, methyl ethyl ketone 84.4%, 3-pentanone 85% and 2-pentanone 86.2%.
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tryptophan should be put to reflux in a high boiling solvent and an equimolar quantity of ketone (acetone) should be added. the yield should be around
60% (procedure says 75%).
now, i will have a tetraline solution of tryptamine (60%) and tryptophan (perhaps ~ 20%) and other products.
in this procedure when no more Co2 evolves in the solution, solvent removed and the tryptamine is vacuum distilled off the rxn mixture. i can't
perform this kind of vacuum distillation since i can't controll my vacuum level to choose the right fraction while distilling the solid...
SO i would separe tryptamine from the unreacted tryptophan by a simple base separation, i'll dissolve the apolar mixture of tetraline in a pH12
aq. solution where only triptophan (that has a carboxyl group) will migrate. tryptamine should be quite in the apolar layer.
Now my questions are:
-which is the tryptamine solubility ina strong alcaline water solution?
-will tryptamine hurt itself in a basic solution?
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sparkgap
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You may also want to check this thread out.
Anyway, tryptamine is a weak base, so it should have limited solubility in basic water. I doubt, however, that tryptophan will be soluble in tetralin
since it's effectively a zwitterion that will abhor nonpolar solvents. Maybe you can do an acid extraction instead from the tetralin.
sparky (^_^)
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charles
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tnx, intresting post!
after evap off the solvent (tetralin) I will solve the tryptamine /tryptophan in a DCM solution, wash it with 3X200 ml pH12 water where tryptophan
will migrates and tryptamine will be in DCM
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trilobite
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Did you already notice this method of tryptamine purification?
http://www.sciencemadness.org/talk/viewthread.php?tid=2099
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charles
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thank you very very much!
your help is very usefull!
I can try to drop some conc. h2so4 in flask of NaCO3 and a tube that end with a glass pipette bubbling CO2 in the tryptamine solution.
the decomposition should be easy.
my only concern is that also tryptophan could be the complex try-C=OO-try like tryptamine does...
i will try and if it's good i will post a report
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