A Preferred Synthesis of 1,2,4‐Oxadiazoles

An efficient and high-yielding one-pot synthesis of 1,2,4-oxadiazoles from carboxylic acids and amidoximes is described. Activation of the carboxylic acid using hydroxybenzotriazole (HOBt) and EDC/HCl followed by reaction with an amidoxime generates an oxime ester. Without isolation, the oxime ester is dehydrated to give the oxadiazole ring.