No abstract

A series of 14 new 2; 4‐substituted‐δ2‐1, 3, 4‐oxadiazolin‐5‐ones was prepared by a novel ring closure of the corresponding l‐acyl‐2, 2‐dialkylhydrazines with phosgene, whereby one alkyl group is lost as alkyl chloride. This new cyclization was carried out too with thiophosgene and with p‐chlorothiobenzoic acid, 2, 2‐dimethylhydrazide to give the corresponding 2,4‐disubstituted‐δ2‐1, 3, 4‐oxadiazoline‐5‐thione, ‐thiadiazolin‐5‐one and ‐thiadiazoline‐5‐thione, respectively.