2,3,5-Trimethyl-4-oxo-cyclohex-2-en acetic acid 5 treated with PyHCl aromatizes to the corresponding 2,3,5-trimethyl-benzene acetic acid 9 through a mechanism different from that leading to arylacetic acids from 2-oxo-cyclohex-3-en acetic acids 3. 2,3,4,6-Tetrakyl cyclohexenone 11, lacking the 2-carboxymethyl group, also aromatizes to tetralkyl benzene 13.