The Fries rearrangement is an organic reaction used to convert a phenyl ester to an ortho- and para-hydroxy aryl ketone using a Lewis acid catalyst and Brønsted acid work-up. 3-Amino-4-methylpicolinic acid structure The mechanism begins with coordination of the ester to the Lewis acid, followed by a rearrangement which generates an electrophilic acylium cation. The aromatic compound then attacks the alkyl cation (both the ortho and para attack are allowed) via an electrophilic aromatic substitution (S_EAr). 4-Bromoquinolin-7-ol uses Deprotonation to regenerate aromaticity and Brønsted acid work-up to regenerate the Lewis acid catalyst provide the two hydroxy aryl ketone products. ^[1][2]