The first attempt of tryptophan decarboxylation was described at
Post 478376 (missing)
(Erny: "Äåêàðáîêñèëèðîâàíèå òðèïòîôàíà - áåòà âåðñèÿ", Russian HyperLab) (1)Here I'll describe the second:
In a 250 ml erlenmeyer flask there were added 15 g of D,L-tryptophan along with 150 ml of cyclohexanol and 2 ml commercial cyclohexen-2-one. A reflux condenser was attached and the RM was brought to reflux while stirring magnetically. Warm water was used in the reflux condenser as, when using cold water, cyclohexanol crystallized in it. After 2,5 h of reflux only about a half of the tryptophan had dissolved, and the RM was orange. It was cooled to approx 50°C and as the air went into the flask the RM turned brown. 50 ml of petroleum ether
(2) and 200 ml of diluted hydrochloric acid were added, layers were separated and the slightly acidic water layer
(3) was evaporated to give 9 g of brown sparkling crystalline mass. After grinding it with acetone, filtering on buechner and washing with acetone it became pink, was turned into freebase and recrystalized from benzene
(4). 3,7 g of white sparkling sugar-like crystals were obtained. It's mp was correct and DMT was made from it a la Shulgin wia the ethylformiate/LAH route.
Notes:1. In the first attempt 15 g of tryptophan, 1,5 ml of cyclohexen-2-one and 150 ml of cyclohexanol were used. Reaction time was 6,5 h and the final yield of tryptamine - 3,3 g.
2. Petroleum ether was added for the better separation of phases.
3. To evaporate the acidic solution was a great mistake: when almost all of the water was gone, pH was already <2 and it dropped the yield more than twice (as can be seen from the amount of hydrochloric acid used to neutralise the tryptamine during the extraction).
4. Dichloromethane may be used instead of benzene. The best solvent for the extraction of tryptamines is EtOAc.
5. The solvents/reagents were not dried and, as the water is present in the equilibrium amine + ketone <
__> imine + H
2O, drying may also improve the yield.