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