Decarboxylation, as described by Drone #342

Decarboxylation is accomplished by mixing about 80 g tryptophan in 250 mL of 
high-boiling solvent (xylol, DMSO, cyclohexanol, etc.), adding a dash of a 
ketone (I like 5 g of cyclohexanone, but a couple grams of MEK works reasonably 
well), heat it to around 150 deg, and when evolution of CO2 ceases/solution is 
clear, the reaction is complete. This takes anywhere from 1.5 to 4 hours. After 
this is over, the solvent is boiled off (or at least greatly reduced in volume), 
and the residue is dissolved in DCM. This is washed with a 5% baking soda soln,
then a distilled water solution, then the DCM layer is separated off, dried 
with MgSO4, and the DCM is boiled off. You now have reasonably pure tryptamine.

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Since I'm a fan of natural products I thought that I would throw this out in 
case it is of interest. It's from The Alkaloids Vol. II

The condensation of gramine methiodide with sodioacetaminomalonic ester gives 
rise to a 63% yeild of ethyl-alpha-acetamino-alpha-carbethoxy-beta-(3-indolyl)-
propionate (IV), which by saponification and subsequent carboxylation and 
hydrolysis can be converted into dl -tryptophan in 81% yeild (38,39). 
This last systhesis has been improved by the discovery that gramine itself, 
when heated in toluene with acetaminomalonic ester in the presence of a small 
amount of powdered sodium hydroxide, produces a 90% yield of IV (40). 
Tryptophan can also be obtained more directly by heating gramine with ethyl 
nitroacetate in xylene solution. The resulting ethly alpha-nitro-beta-
(3-indolyl)-propionate is reduced catalytically to the corresponding amino 
compound which on saponification yields dl -tryptophan (40). Gramine can 
also be converted to alpha-ethyltryptamine by condensation with nitropropane 
and catalytic hydrogenation of the product (42).

[38] J. Am. Chem. Soc. 66:200
[39] J. Am. Chem. Soc. 66:500
[40] J. Am. Chem. Soc. 67:38
[41] J. Am. Chem. Soc. 69:2118