Abstract
3-Pyridyl-4-alkyl (or aryl)-1,2,4-oxadiazole-5(4H)-thiones are prepared by the reaction of N-alkyl (or aryl) pyridine carboxamide oximes with thiophosgene. Rearrangement, catalysed by metallic copper, yields the corresponding 3,4-disubstituted-1,2,4-thiadiazole-5(4H)-ones.