Decarboxylation of phenylalanines to phenethylamines

by Ritter

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Mix 10g phenylalanine isomer of your choice in 50ml cyclohexanol. Add about 0.1 to 0.3ml cyclohexanone. Amino acid will not dissolve in cyclohexanol until it is pretty hot. Bring mix up to about 140°C. Rapid and somewhat violent decarboxy-lation will start. The soln will bubble like beer (CO2 release) and slowly turn a light yellow. An interesting crackling noise is produced as temp gets up to reflux point (161°C) that sounds like popcorn popping. It is actually pretty startling when done on a larger scale! When CO2 emission comes to a halt after about half an hour cool mix and extract w/ dilute HCl. Basify HCl extract to isolate the pretty pure phenethylamine as a light yellow fishy smelling liquid. Yield unfortunately is variable - anywhere from 4-8g has been isolated from this rxn. I'm sure other high BP solvents will work fine, cyclohexanol happens to be what was at hand.