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Chemical data Collections, Vol 28, 2020, 100431.

You can try with Hydrazide, aromatic acids and in presence of POCl3 with organic solvent to get 1,3,4-oxadiazole.

thanks

give me the procedure for get 1,3,4- oxadiazole in the presence of POCl3 and determined the solvent ?

Best way to convert aromatic carboxylic acid derivatives into1,3,4-oxadiazole by reacting aryl hydrazide(Ar-CONHNH2 with phenyl isocyanate(Ph-NCO) to get carbamide ArCONHNHCONHPh which undergoes cyclodehydration in presence of H2SO4 to get 1,3,4-oxadiazole derivative.

POCl3 is often suggested by researchers, but it's pretty hazardous.

Instead, you can use Chloramine-T or Iodine as cyclizing agents.

Check out this article for more info.

Article Chloramine-T (N-chloro-p-toluenesulfonamide sodium salt), a ...