“Fries like” rearrangement: A novel and efficient method for the synthesis of 6-acyl-2(3 H)-benzoxazolones and 6-acyl-2(3 H)-benzothiazolones

Abstract

6-acyl-2(3 H)-benzoxazolone and 6-acyl-2(3 H)-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(3 H)-benzoxazolone and 2(3 H)-benzothiazolone which consists in a two-step procedure involving migration of the acyl group from the N-position to the 6-position of the heterocycle, at 165°C and catalyzed by AlCl 3. This new procedure was found to be more efficient with regard to the consumption of AlCl 3 and the yield (76–90%) than other acylation methods previously described.