Recently, cis-1,4-bis(triphenylphosphonium)-2-butene peroxodisulfate (BTPBPD), an inexpensive and environmentally safe oxidation reagent, has been used for synthesis of 2,5-disubstituted-1,3,4-oxadiazoles, [ 9 9. Badri , R. ; Gorjizadeh , M. A novel, one-pot synthesis of 2,5-disubstituted-1,3,4-oxadiazoles using 1,4-bis(triphenylphosphonium)-2-butene peroxodisulfate . Phosphorus, Sulfur Silicon Relat. Elem. 2010 , 185 , 544 – 549 . [Taylor & Francis ...