2-amino-, 2-alkoxy- and 2-alkylthio-substituted 4H-3,1-benzoxazine-4-ones are potent inhibitors of serine hydrolases acting through the formation of covalent acyl-enzyme intermediate [1-4]. Contrary to the 2-amino- and 2-alkylthio-(4H)-3,1-benzoxazine-4-ones, few synthetic routes have ever been reported for 2-ethoxy-(4H)-3,1-benzoxazin-4-ones. Herein, we wish to develop a convenient method for the synthesis of 2-ethoxy-(4H)-3,1-benzoxazine-4-ones. The condensation reaction of anthranilic acid derivatives with diethyl dicarbonate and then, cyclization reaction of the obtained carbamates with cyanuric chliride in PEG or CHCl3 under mild conditions, leads high yields of the title compounds.
