n, n΄-3, 4-di(methylamino)-1, 2, 5-oxadiazole (1f) was prepared by dehydration of n, n΄-3, 4-di(methylamino)glyoxime (2f) in aqueous potassium hydroxid at 170-180 ˚c. under similar conditions n, n΄-3, 4-di(benzylamino)-1, 2, 5-oxadiazole (1c) and n, n΄-3, 4-di(isopropylamino)-1, 2, 5-oxadiazole (1e) were not obtained, but, n, n΄-3, 4-di(ethylamino)-1, 2, 5-oxadiazole (1g) was appeared with smal...