FRIES LIKE REARRANGEMENT - A NOVEL AND EFFICIENT METHOD FOR THE SYNTHESIS OF 6-ACYL-2(3H)-BENZOXAZOLONES AND 6-ACYL-2(3H)-BENZOTHIAZOLONES

6-Acyl-2(3H)-benzoxazolone and 6-acyl-2(3H)-benzothiazolone derivative s have particularly interesting anti-inflammatory, antiepileptic, anal gesic and antiviral properties. in this study, we report an original m ethod of acylation on the 6-position of 2(3H)-benzoxazolone and 2(3H)- benzothiazolone which consists in a two-step procedure involving migra tion of the acyl group from the N-position to the 6-position of the he terocycle, at 165 degrees C and catalyzed by AlCl3. 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 descr ibed. (C) 1998 Elsevier Science Ltd. All rights reserved.