'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 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.
Ucar, Huseyin,Van Derpoorten, Kim,Depovere, Paul,Lesieur, Daniel,Isa, Majed,Masereel, Bernard,Delarge, Jacques,Poupaert, Jacques H.
Design and synthesis of 3-acyl-2(3H)-benzoxazolone and 3-acyl-2(3H)- benzothiazolone derivatives
A simpler and efficient "green" method using solid sodium hydroxide in a solvent mixture of acetone/water was found to catalyze N-acylation of 2(3H)-benzoxazolones and 2(3H)-benzothiazolones for facile and rapid synthesis of N-acyl derivatives in excellent yields. This method was applied to the synthesis of a series of 132 compounds employing a variety of acyl chlorides. Graphical abstract: [Figure not available: see fulltext.]
Guenadil, Faouzi,Aichaoui, Hocine,Kapanda, Coco N.,Lambert, Didier M.,McCurdy, Christopher R.,Poupaert, Jacques H.
experimental part
p. 67 - 80
(2011/09/20)
The N-Phosphobiotin Route: a Possible New Pathway for Biotin Coenzyme
The formation of N-acylureas from N-phosphorylated ureas under very mild conditions is presented as a possible route to the formation of carboxybiotin from biotin in biotin-mediated enzymatic carboxylations in which an N-phosphobiotin is the activated form.The detailed mechanistic pathway for the model reaction indicates that an intermediate acylphosphate is formed, the rate-determining step being a nucleophilic attack of the ureido anion or its enol on this acylphosphate.In no case was an O-phosphorylated intermediate (of the phosphobiotin type) involved.