6-acyl-2 (3H)-benzoxazolone and 6-acyl-2 (3H)-benzothiazolone derivatives have particularly interesting anti-inflammatory, antiepileptic, analgesic and antiviral properties. In this study, we report an original method of acylation on the 6-position of 2 (3H)- benzoxazolone and 2 (3H)-benzothiazolone which consists in a two-step procedure involving migration of the acyl group from the N-position to the 6-position of the ...