Synthesis of 5-aryl-3H-[1,3,4]oxadiazol-2-ones from N′-(chloro-aryl-methylene)-tert-butylcarbazates using basic alumina as an efficient and recyclable surface under solvent-free condition

The synthesis of biologically important 5-aryl-3H-[1,3,4]oxadiazol-2-ones has been carried out by heating the easily synthesized N′-(chloro-aryl-methylene)-tert-butylcarbazates on basic alumina surface under solvent-free condition. The dual characteristic of basic alumina as a solid support as well as a nucleophile is successfully exploited in these reactions. The method provides special attributions such as reduced reaction times, easier work-up procedures, and good to excellent yields as well as increased purity of products and most importantly environmentally friendly protocols. The basic alumina is easily recovered and utilized for further reactions several times without serious loss of activity.