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

Article abstract of DOI:10.1016/S0040-4020(97)10400-8

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)-banzoxazolone 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 hetexocycle, at 165 °C and catalyzed by AlCl₃. This new procedure was found to be more efficient with regard to the consumption of AICI₃ and the yield (76-90%) than other acylation methods previously described.