My recent post Post 276680 (https://www.thevespiary.org/talk/index.php?topic=13064.msg27668000#msg27668000)
(Student: "Re: Decarboxylating Tryptophan", Tryptamine Chemistry) outlines a way to convert tryptophan to tryptamine using spearmint oil and xylene or turpentine. The procedure was optimized for simplicity and ease, and the equipment and ingredients were optimized for availability. Two areas needing further study were the suitability of turpentine as a solvent and a procedure for scaling the reaction up from the original small (500 mg) scale.
The advantage of turpentine is that the reaction takes hours instead of days. The downside is that there is significant non-volatile residue, at least in the can of turpentine studied.
A scaled up reaction using xylene began as follows: 50 mL of xylene (straight from the can), 4.78 g of L-tryptophan and 10 drops (about 0.2 mL) of spearmint oil were placed in a 250 mL Erlenmeyer flask and a cork with a four inch piece of glass tubing in it was placed in the top. No boiling stone was added since the decarboxylation was expected to provide bubbles to smooth the boiling, and magnetic stirring was not provided to simplify the equipment needed. The mixture was boiled at a sufficient rate to bring the refluxing vapor to the 150 mL mark but there was significant bumping because the solid settled and allowed overheating. After about 12 hours the cork had popped out of the flask, 10 mL of solvent had evaporated, and the mixture had begun to darken due to air exposure.
To rescue the $2 worth of tryptophan, the lost solvent and catalyst (assumed evaporated) were replaced and the cork was replaced with a rubber stopper holding a water cooled reflux condenser and the heat was turned up enough so that there was a fast return of solvent from the condenser. Rather than making the bumping worse, the bumping disappeared entirely because the rapid boiling kept the solid suspended. There was no further darkening and the reaction is still in progress.
Yes, the acid/base extraction in this process is removing turpentine and other non-amine impurities. The process was modeled after the tryptamine purification outlined in the Tryptophan and Tryptamine FAQ (https://www.thevespiary.org/rhodium/Rhodium/chemistry/tryptophan.html (https://www.thevespiary.org/rhodium/Rhodium/chemistry/tryptophan.html)
. The main improvement I found for the procedure was to rinse with aqueous ammonia to minimize loss of the product, whereas the FAQ leaves the wash solvent unspecified.
It sounded like the change you were suggesting was to replace chloroform with naphtha. This may be a good alternative, but chloroform is a good solvent for the dark impurities and I doubt that naptha would be. It would certainly get rid of turpentine though. Although chloroform is not easily obtained OTC, there is what sounds like an excellent procedure for its preparation from bleach and acetone at https://www.thevespiary.org/rhodium/Rhodium/chemistry/chloroform.html (https://www.thevespiary.org/rhodium/Rhodium/chemistry/chloroform.html)
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