Synthesis of new N-Benzoxazole and N-Benzothiazole derivatives of 3-(4-Substituted- phenyl)aminoisoxazol-5(2H)-ones and comparison of their base induced rearrangement

3-Arylaminoisoxazol-5(2H)-ones, substituted on nitrogen with benzoxazole and benzothiazole groups react with triethylamine in ethanol under reflux to afford the corresponding indole and imidazobenzothiazole derivatives, respectively.