Tryptamine from DL-tryptophane

[Stanley]

Greetings.

Recently, I gave the ketone-catalyzed decarboxylation of DL-tryptophan a try, and to my disappointment, the yield was somewhere around 2%. I speculate that the reason is the xylene used as solvent: its b.p. is 140 °C. I figure this is not warm enough for a decarboxylation to take place (even if ketone-catalyzed).

I used 5 g of DL-tryptophan, 0,5 ml of MEK in 30 ml of xylene, and refluxed for 13 h (I thought the reaction time would compensate for the low temperature).

I'm thinking about trying the same ratio again, but I'll use naphtalene instead of xylene.

Comments?


Stanley

[foxy2]

You could also try a higher boiling keytone.

Thujone comes to mind as accessable one.

http://chemfinder.com

  for the structure if interested

http://www.execpc.com/~goodscnt/data/es1040992.html

Do Your Part To Win The War

[Rhodium]

How was the tryptamine isolated? If the reaction did not produce more than 2% tryptamine, then you should be able to recover the rest of the tryptophan unchanged.

https://www.rhodium.ws

[Stanley]

I'm thinking cyclohexanone and naphtalene. The tryptamine was isolated as the hydrochloride salt. And yes, of course, the tryptophan is to be recovered!

I think I'll give that cyclohexanone/naptha a try, and see what I come up with.


Stanley

[foxy2]

Definately go for cyclohexanone.
My suggestion was for the less connected bee's.  You know that cyclohexanone is slightly watched right?  Due to its use in PCP.
Later
Foxy
Do Your Part To Win The War

[racemic]

If I don't get side tracked I'll be trying this reaction in d-limonene (bp 176) w/ ketone catalyst some time in the near future. d-Limonene is cheap and unwatched and seems to fit the requirements for this rxn. Any thoughts or comments?