NONVOLATILE COMPOUNDS FORMED ON THE THERMAL-DEGRADATION OF PHENYLALANINE

L-Phenylalanine was heated in liquid paraffin at 210 degrees C for 15 min. Methanol extracted 76.4% of the resulting colored material, on the basis of absorbance measurements at 420 nm. Nonvolatile, relatively nonpolar compounds of the methanol extract were separated by reversed-phase HPLC, and two phenylalanine degradation products were characterized using UV-visible, IR, NMR, and mass spectrometry. They were identified as N-(2-phenylethyl)-3,4-diphenylpyrrole and N-(2-phenylethyl)-3,4-diphenyl-3-pyrroline-2,5-dione.