20 grams of L-Tryptophan was dissolved in 150 ml cyclohexanol containing 1.5 ml of 2-cyclohexen-1-one, and the temp of the solution was held at 154°C for 1.5 hours. The tryptamine was isolated as the HCl salt, mp 256°C. Yield 92.3%.
Ref: M. Hashimoto, Decarboxylation of Amino Acids with 2-cyclohexanone, Chem. Lett. 893 (1986) (https://www.thevespiary.org/rhodium/Rhodium/chemistry/trp.decarbox.enone.html)
(https://www.thevespiary.org/rhodium/Rhodium/chemistry/trp.decarbox.enone.html)