An Efficient One-Pot Synthesis of 5-(substituted amino)-1,2,4-thia- and -oxa-diazoles

A general protocol for the synthesis of 5-(substituted amino)-1,2,4-thiadiazoles by the cyclocondensation reaction of amidoximes with N-substituted thioureas in the presence of KF/Al 2 O 3 , and of 5-(cyclohexylamino)-1,2,4-oxadiazoles with DCC in the presence of KF/Al 2 O 3 and thiourea, is described. The structures of the new compounds were elucidated by spectroscopic and physical data, and the crystal structure determination by X-ray diffraction of three examples.